Search

A much replicated finding is that only humans above the age of five succeed spontaneously on Premack’s Relational Match to Sample task, which has been widely used in the comparative and developmental literatures to probe relational reasoning capacities. We review four different types of explanations for the failures of young children and non-human animals, two that posit capacity limitations and two that posit differences in learning histories alone. We review training studies that rule out capacity limitations, at least for crows, parrots, four-year-old children, and a variety of primate species. Finally, we review recent studies demonstrating that population differences sometimes reflect differences in inductive biases alone and discuss the crucial importance of inductive biases in relational reasoning.

Deciphering nonhuman communication – particularly nonhuman vocal communication – has been a longstanding human quest. We are, for example, fascinated by the songs of birds and whales, the grunts of apes, the barks of dogs, and the croaks of frogs; we wonder about their potential meaning and their relationship to human language. Do these utterances express little more than emotional states, or do they convey actual bits and bytes of concrete information? Humans’ numerous attempts to decipher nonhuman systems have, however, progressed slowly. We still wonder why only a small number of species are capable of vocal learning, a trait that, because it allows for innovation and adaptation, would seem to be a prerequisite for most language-like abilities. Humans have also attempted to teach nonhumans elements of our system, using both vocal and nonvocal systems. The rationale for such training is that the extent of success in instilling symbolic reference provides some evidence for, at the very least, the cognitive underpinnings of parallels between human and nonhuman communication systems. However, separating acquisition of reference from simple object-label association is not a simple matter, as reference begins with such associations, and the point at which true reference emerges is not always obvious. I begin by discussing these points and questions, predominantly from the viewpoint of someone studying avian abilities. I end by examining the question posed by Premack: do nonhumans that have achieved some level of symbolic reference then process information differently from those that have not? I suggest the answer is likely “yes,” giving examples from my research on Grey parrots (Psittacus erithacus).

Understanding the perspectives of others is a critical skill. Theory of mind (ToM) is an essential ability for social competence and communication, and it is necessary for understanding behaviors that differ from our own (Premack and Woodruff, 1978). Although all individuals possess a ToM to varying degrees, bilinguals are especially adept to perspective-taking. Research has reported that bilinguals outperform monolinguals in ToM tasks (e.g., Goetz, 2003; Rubio-Fernandez & Glucksberg, 2012). However, the mechanisms underlying this effect are unclear. Studying individual differences in ToM performance between bilinguals and monolinguals can help explain these mechanisms. Yet this promising area of research faces an important challenge: the lack of psychometric research on ToM measurement. Recent research suggests that tests that measure the ToM construct might not be as reliable as previously thought (Warnell & Redcay, 2019). This hinders the interpretation of experimental and correlational findings and puts into question the validity of the ToM construct. This dissertation addresses these two questions empirically to improve our understanding of what constitutes ToM. Study 1 examines the structure of ToM, crystallized intelligence (Gc), and fluid intelligence (Gf) to understand (a) whether ToM constitutes a construct separate from other cognitive abilities and (b) to explore whether tasks of ToM present adequate construct validity. For this, three confirmatory factor analyses (CFAs) were conducted. The results demonstrated that a model with three latent factors (ToM, Gf and Gc) did not adequately fit the data and was not significantly different from a model with only two latent factors (ToM-Gf and Gc). In addition, an exploratory factor analysis (EFA) showed that two of the ToM tasks loaded onto a Gf factor whereas one of the tasks loaded onto a third factor by itself. Finally, an exploratory network analysis (NMA) was conducted to observe relationships among the tasks. The results showed that the ToM tasks were no more related to each other than to some tasks of Gf and Gc, and that ToM tasks did not form a consistent cluster. Overall, the results of Study 1 suggest that ToM tasks are likely not measuring a monolithic ToM construct. Study 2 examines individual differences in metalinguistic awareness, executive function, and bilingualism as predictors of ToM. The results showed that all variables significantly predicted ToM, but bilingualism was not a significant moderator of ToM. Overall, the findings suggest that in this sample there was no difference in the processes used to predict ToM based on being bilingual or monolingual. Implications for measurement and individual differences in ToM are discussed.

As robots move from the factory and into the daily lives of men, women, and children around the world, it is becoming increasingly clear that the skills they will require are vastly different from the majority of skills with which they were programmed in the 20th century. In fact, it would appear that many of these skills will center on the challenge of interacting with humans, rather than with machine parts or other robots. To this end, modern-day roboticists are actively studying the problem of human-robot interaction – how best to create robots that can interact with humans, usually in a social setting. Among the many problems of human robot interaction, one of the most interesting is the problem of intent recognition: the problem of predicting the intentions of a person, usually just by observing that person. If we understand intentions to be non-observable goal-directed mental activities, then we may (quite understandably) view the intent recognition problem for robots as one of reading peoples’ minds. As grandiose as this claim may sound, we believe that this understanding of intent recognition is quite reasonable; it is this interpretation that we seek to justify in the following pages. Every day, humans observe one another and on the basis of their observations “read people’s minds,” correctly inferring the intentions of others. Moreover, this ability is regarded not as remarkable, but as entirely ordinary and effortless. If we hope to build robots that are similarly capable of successfully interacting with people in a social setting, we must endow our robots with an ability to understand humans' intentions. In this paper, we review the intent recognition problem, and provide as an example a system we have been developing to recognize human intentions. Our approach is ultimately based on psychological and neuroscientific evidence for a theory of mind (Premack & Woodruff, 1978), which suggests that the ease with which humans recognize the intentions of others is the result of an innate mechanism for representing, interpreting, and predicting other's actions. The mechanism relies on taking the perspective of others (Gopnick & Moore, 1994), which allows humans to correctly infer intentions. Although this process is innate to humans, it does not take place in a vacuum. Intuitively, it would seem that our understanding of others' intentions depend heavily on the contexts in which we find ourselves and those we observe. This intuition is supported by Source: Human-Robot Interaction, Book edited by: Daisuke Chugo, ISBN 978-953-307-051-3, pp. 288, February 2010, INTECH, Croatia, downloaded from SCIYO.COM

Premack’s principle describes how students are more likely to engage in non-preferred tasks when those tasks are followed by more preferred tasks (e.g., extra recess is available after math is completed). This principle can be paired with a visual schedule in which the order of activities is presented for a student using visual representations of tasks or events such as pictures, symbols, or written words. This case study illustrates creating a visual schedule that strategically places preferred activities after non-preferred tasks for a high school student with autism Spectrum Disorder.

Five experiments compared preschool children's performance to that of adults and of non-human animals on match to sample tasks involving 2-item or 16-item arrays that varied according to their composition of same or different items (Array Match-to-Sample, AMTS). They establish that, like non-human animals in most studies, 3- and 4-year-olds fail 2-item AMTS (the classic relational match to sample task introduced into the literature by Premack, 1983), and that robust success is not observed until age 6. They also establish that 3-year-olds, like non-human animal species, succeed only when they are able to encode stimuli in terms of entropy, a property of an array (namely its internal variability), rather than relations among the individuals in the array (same vs. different), whereas adults solve both 2-item and 16-item AMTS on the basis of the relations same and different. As in the case of non-human animals, the acuity of 3- and 4-year-olds' representation of entropy is insufficient to solve the 2-item same-different AMTS task. At age 4, behavior begins to contrast with that of non-human species. On 16-item AMTS, a subgroup of 4-year-olds induce a categorical rule matching all-same arrays to all-same arrays, while matching other arrays (mixed arrays of same and different items) to all-different arrays. These children tend to justify their choices using the words "same" and "different." By age 4 a number of our participants succeed at 2-item AMTS, also justifying their choices by explicit verbal appeals using words for same and different. Taken together these results suggest that the recruitment of the relational representations corresponding to the meaning of these words contributes to the better performance over the preschool years at solving array match-to-sample tasks.

Sarah the chimpanzee was the primary participant in David Premack's language studies initiated at University of California at Santa Barbara in 1967. The first author was an undergraduate assistant training Sarah from 1967 to 1969. This article describes some of the early work with Sarah and our recent search for her. Sarah's whereabouts during the intervening years, and subsequent reunion with her in 2016 at Chimp Haven, a chimpanzee sanctuary in Louisiana, are described. It was found that despite her illness, Sarah engaged with the first author and demonstrated that she remembered him and the mechanics of the communication procedure that served as the foundation for testing Sarah's cognitive reasoning abilities as they pertained to language. There was no evidence she remembered any of the 5 symbolic nouns that were presented during a matching-to-sample procedure. The authors expressed their gratitude to the staff at Chimp Haven for the excellent care of Sarah.

This chapter examines young children’s growing awareness and understanding of their own, and other people’s, minds. As J. W. Astington suggests: The understanding of minds that children acquire in the preschool years underlies their social interactions with family and friends and provides the foundation for their cognitive activities in school. H. M. Wellman suggests that, along with language, theory of mind is ‘a distinctively human core capacity’ that shapes human thought and learning. D. Premack and G. Woodruff’s paper instigated considerable discussion, including how having a theory of mind might be demonstrated. The chapter focuses on self-regulation, particularly cognitive self-regulation, and metacognition. J. H. Flavell suggests that the development of metacognition, for example, is ‘one of the really central and significant cognitive-developmental hallmarks of the early childhood period’. C. M. Roebers suggests that executive function (EF) and metacognition both play a central role in models of self-regulation. The deaf children performed significantly less well on EF tasks.

Since the publication of Premack and Woodruff’s classic paper introducing the notion of a ‘theory of mind’ (Premack and Woodruff in Behav Brain Sci 1(4):515–526, 1978), interdisciplinary research in social cognition has witnessed the development of theory–theory, simulation theory, hybrid approaches, and most recently interactionist and perceptual accounts of other minds. The challenges that these various approaches present for each other and for research in social cognition range from adequately defining central concepts to designing experimental paradigms for testing empirical hypotheses. But is there any approach that promises to dominate future interdisciplinary research in social cognition? Is social cognition witnessing a gradual paradigm shift where hitherto grounding notions such as theory of mind are no longer viewed as explanatorily necessary? Or have we simply lost our way in attempting to devise adequate experimental setups that could sway the debate in favour of one of the contending accounts? This special issue addresses these questions in an attempt to discover what the future holds for interdisciplinary research in social cognition.

Chimpanzees (Pan troglodytes) with the aid of token training can achieve analogical reasoning, or the ability to understand relations-between-relations (e.g., Premack, 1976; Thompson, Oden, & Boysen, 1997). However, extraordinarily few numbers of old- and new-world monkeys have demonstrated this ability in variants of relational matching to sample tasks. Moreover, the rarity of replications leaves open the question of whether the results are normative for other captive colonies of the same species. In experiment one we attempted to replicate whether old world rhesus monkeys (Macaca mulatta) might demonstrate the same level of proficiency on a spatial above/below relational matching task as reported for old world baboons (Papio papio). None of the rhesus monkeys attained above chance performances over 10,000 training trials. In experiment two we attempted to replicate results demonstrating that new-world capuchin monkeys (Cebus apella) match above/below relations. The capuchin monkeys performed above chance only in the absence of 'Clever Hans' controls for cuing of the correct choice by the experimenters. These failures to replicate previously reported results demonstrate that some, but definitely not all monkeys can judge the equivalence of abstract 'relations between relations' and warrant further investigations into the behavioral and cognitive characteristics that underlie these similarities and differences within population and between individuals of different primate species.

The Response Deprivation Model states that any behavior in an organism’s repertoire can serve as a reinforcer if access to that behavior is restricted. A deprivation contingency requires the organism to engage more in the target behavior in order to obtain access to the restricted behavior. This model replaces the limited and sometimes incorrect Premack Principle. By applying this model to Organizational Behavior Management, businesses can increase workers’ productivity by restricting their access to certain tasks. The reviewed studies include applications to sales and quality management. The relative paucity of current applications in Organizational Behavior Management, possible reasons for this, and solutions are discussed.

When training and working a substance detection canine, a trained final response should be performed immediately upon recognition of odor (Generally, a 1-3 s window is preferred within our detection practices). Typical canine training places much emphasis on planning and setting up training scenarios to achieve specific objectives but not much consideration is given to how to end a training session. When the canine fails to maintain criteria, trainers are left trying to determine the cause of poor performance. One consideration often overlooked is a phenomenon called End of Session Cueing that may exist in detection training whereby a previously trained canine no longer responds to odor because it has taken on aversive association. This may be due to several factors associated with motivation. The sequence of events at the end of a session can be as equally important to maintain motivation for the task of scent detection in future sessions. This paper will identify and examine multiple factors associated with "End of Session Cues" in working dogs, how they may be responsible for poor final response performance and discuss potential strategies to address them.

The term theory of mind (ToM) was introduced by Premack and Woodruff as the ability to infer mental states of others. Many researchers believe that social deficits seen in children with autism spectrum disorders (ASD) are directly linked to deficits in ToM or the inability to realize that others’ perspectives are different from their own, decreasing social understanding. The present review examines the empirical research of effectiveness of interventions targeting social perspective-taking skills for high-functioning individuals with ASD. Twelve studies have been published since the year 2000. Results indicate that perspective-taking skills can be taught using systematic instruction, group interventions, and technology. Generalization of skills into naturalistic settings was inconsistent. Practice implications and future research directions are discussed.

This paper includes a detailed description of a familiarization protocol, which is used as an integral component of a larger research protocol to collect electroencephalography (EEG) data and Event-Related Potentials (ERPs). At present, the systems available for the collection of high-quality EEG/ERP data make significant demands on children with developmental disabilities, such as those with an Autism Spectrum Disorder (ASD). Children with ASD may have difficulty adapting to novel situations, tolerating uncomfortable sensory stimuli, and sitting quietly. This familiarization protocol uses Evidence-Based Practices (EBPs) to increase research participants' knowledge and understanding of the specific activities and steps of the research protocol. The tools in this familiarization protocol are a social narrative, a visual schedule, the Premack principle, role-playing, and modeling. The goal of this familiarization protocol is to increase understanding and agency and to potentially reduce anxiety for child participants, resulting in a greater likelihood of the successful completion of the research protocol for the collection of EEG/ERP data.

The disequilibrium approach to reinforcement and punishment, derived from the probability-differential hypothesis and response deprivation hypothesis, provides a number of potentially useful mathematical models for practitioners. The disequilibrium approach and its accompanying models have proven effective in the prediction and control of behavior, yet they have not been fully espoused and integrated into clinical practice. The purpose of this tutorial is to detail the disequilibrium approach and adapt its mathematical models for use as a tool in applied settings. The disequilibrium models specify how to arrange contingencies and predict the effects of those contingencies. We aggregate these models, and provide them as a single tool, in the form of a Microsoft Excel® spreadsheet that calculates the direction and magnitude of behavior change based on baseline measures and a practitioner's choice of intervention parameters. How practitioners take baseline measures and select intervention parameters in accordance with disequilibrium models is explicated. The proposed tool can be accessed and downloaded for use at https://osf.io/knf7x/.

Play develops skill across all developmental domains in early childhood: cognitive/academic, communication/language, social-emotional, physical, and adaptive. Children with ASD often refrain from engaging in any type of play, or they may prefer play that is highly repetitious, sensory-based and of a ?cause/effect? type. Encouraging a child with ASD to engage in novel types of play can be challenging, especially if the child has limited play skills in his repertoire. However, it is critically important that we discover ways to increase play skills of children with ASD. This article will discuss strategies for teaching and encouraging novel play for children with ASD. Strategies to consider are visual supports, such as video modeling, or social narratives, and reinforcement-based strategies: the Premack Principle or utilizing an existing area of interest.

Parcela da literatura operante sustenta expressiva produção de conhecimentos sobre resolução de problemas, resposta de observação e relações de contingência entre respostas com diferentes probabilidades de ocorrência (Princípio de Premack). O presente trabalho investigou possíveis convergências entre uma análise descritiva do comportamento ordinal e tal parcela da literatura operante. Análises conceituais e metodológicas de material bibliográfico salientaram a relevância da sequência de eventos funcionalmente relacionados na caracterização da produção de conhecimentos sobre resolução de problema, sobre resposta de observação e sobre o Princípio de Premack viabilizando aproximações entre programas de pesquisas sobre repertórios comportamentais complexos, bem como expansões em estratégias de investigação sobre responder ordinal.

Two of Timberlake's major contributions, amongst numerous other good notes, are Behavior Regulation Theory (BRT), and Behavior Systems Theory (BST). BRT was a refinement of the Premack Principle. What both got right was that reinforcers are responses, not stimuli. For BRT, they were responses that were occurring below the rate at which they otherwise would given free access to them. BST was a larger ethological framework for our science of behavior. We have always needed it, as it opens an important window on our field. With that window closed, it is easy to stumble over a half-dozen anomalies in the dark, ones that we say humph to, scratch our heads, and then move on. When illuminated by BST, however, such anomalies become keys to a deeper understanding of our subject. This paper reviews numerous anomalies that make sense within the joint framework of BST and BRT, and Dickinson's Dual-Process theory of learned behavior. No longer anomalous in that context, all that is now left to do is test the validity and productivity of this general framework for those many strange cases.

It is 35 years since Premack & Woodruff famously asked, ‘Does the chimpanzee have a theory of mind?’ (1978, Behavioral and Brain Sciences , 1 , 515–526). The first wave of experiments designed to tackle this provocative question in the context of cooperative transactions with humans offered largely negative answers. It was not until a landmark Animal Behaviour paper by Hare et al. (2000 , Animal Behaviour , 59 , 771–786) that a different approach based around foraging competition between conspecifics delivered an affirmative (if limited) verdict that, at least, ‘Chimpanzees know what conspecifics do and do not see’. This influential paper laid the foundations for a much more productive decade of studies that provided evidence for apes' recognition in others of states corresponding to knowing, intending and inferring. It further stimulated related studies in other mammalian and avian species too. Here I set the Hare et al. paper in its historical, scientific context, provide an overview of the variety of studies that have followed in its wake and address some core questions about the scientific tractability of identifying phenomena in nonverbal creatures that may be akin to human ‘theory of mind’.

— The ability to flexibly predict others’ behaviorshas been ascribed to a theory of mind (ToM) system. Mostresearch has focused on formal conceptual definitions ofsuch a system, and the question of whom to credit with aToM. In this article, I suggest shifting perspective fromformal definitions to a usage-based approach. Thisapproach views action within human interaction as cen-tral to the emergence and continuous development of theability to flexibly predict others’ behaviors. Addressing thecurrent debate about whether infants have a ToM, I illus-trate how infants use flexible action expectations tointeract with others appropriately. I also discuss the con-tinuous development of ToM and its natural structure froma usage-based perspective. KEYWORDS— action prediction; usage-based theory; falsebelief; prelinguistic communication THEORY OF MIND: WHAT FOR? Theory of mind (ToM) is a cognitive system that “can be used tomake predictions about the behavior of others” (Premack WRakoczy, 2012). Other mental-state concepts, like intentions,desire, and knowledge, are considered precursors to a full, rep-resentational ToM (e.g., Wellman & Liu, 2004), but these stillfollow the logic of formal conceptual definitions of ToM.One problem with formal conceptual approaches is that thepostulated definitions of ToM and their empirical operationaliza-tions influence each other. The validity of the widely used stan-dard false belief tests has been questioned because additionaltask demands like language and executive skills conceal con-ceptual understanding (Bloom & German, 2000). When remov-ing these demands, apparently even 1-year-olds understandfalse belief (Baillargeon, Scott, & He, 2010). For other research-ers, however, the very conceptual definitions require some of theremoved demands, such as language to entail hypothetical —notonly practical—belief scenarios (Perner, 2010), executive skillsto enable flexibility in perspective shifting (e.g., Moses, Carlson,& Sabbagh, 2005), or other general reasoning skills to get frompremises to conclusions. This results in the ambiguous use ofthe term ToM (Rakoczy, 2012) and leads to auxiliary termslike infant ToM and the postulation of separate ToM systems(Apperly & Butterfill, 2009).A second problem is that formal approaches bewitch us to con-ceptualize ToM as a stage-like all-or-nothing affair, obscuring

International audience; Reasoning by analogy is one of the most complex and highly adaptive cognitive processes in abstract thinking. For humans, analogical reasoning entails the judgment and conceptual mapping of relations-between-relations and is facilitated by language (Gentner in Cogn Sci 7:155-170, 1983; Premack in Thought without language, Oxford University Press, New York, 1986). Recent evidence, however, shows that monkeys like ``language-trained'' apes exhibit similar capacity to match relations-between-relations (Fagot and Thompson in Psychol Sci 22:1304-1309, 2011; Flemming et al. in J Exp Psychol: Anim Behav Process 37:353-360, 2011; Truppa et al. in Plos One 6(8):e23809, 2011). Whether this behavior is driven by the abstraction of categorical relations or alternatively by direct perception of variability (entropy) is crucial to the debate as to whether nonhuman animals are capable of analogical reasoning. In the current study, we presented baboons (Papio papio) and humans (Homo sapiens) with a computerized same/different relational-matching task that in principle could be solved by either strategy. Both baboons and humans produced markedly similar patterns of responding. Both species responded different when the perceptual variability of a stimulus array fell exactly between or even closer to that of a same display. Overall, these results demonstrate that categorical abstraction trumped perceptual properties and, like humans, Old World monkeys can solve the analogical matching task by judging the categorical abstract equivalence of same/different relations-between-relations.

We recently discovered that young infants learn a new association better in the presence of a prior association than when they learn it alone - a phenomenon we call associative potentiation. When 6-month-olds observed actions modeled on a puppet (remembered for 1 day) in the presence of a toy train they had learned to activate (remembered for 2 weeks), they remembered the demonstration for 2 weeks too. Currently, we examined the generality of associative potentiation. We found that when 6-month-olds learned the train task (remembered for 5 days) in the presence of two previously associated puppets (remembered for 4 weeks); they remembered the train task for 4 weeks too - more than five times longer. We conclude that associative potentiation is a general phenomenon: Cues for any stronger prior association will correspondingly increase the memory strength of any weaker new association that young infants learn in their presence, eliminating the need for repeated practice. We view associative potentiation as an adaptive mechanism that counteracts the rapid forgetting of younger infants by instantly increasing the strength of their new learning to a level characteristic of older infants. Neuromaturational models of infant memory cannot account for associative potentiation, but an ecological model does.

Grey parrot (Psittacus erithacus) abilities for visual inferential reasoning by exclusion were tested in two experiments. The first replicated the Grey parrot study of Mikolasch, Kotrschal, and Schloegl (2011, African Grey Parrots (Psittacus erithacus) use inference by exclusion to find hidden food. Biology Letters, 7, 875-877), which in turn replicated that of Premack and Premck (1994, Levels of causal understanding in chimpanzees and children. Cognition, 50, 347-362) with apes, to learn if our subjects could succeed on this task. Here parrots watched an experimenter hide two equally desirable foods under two separate opaque cups, surreptitiously remove and then, in view of the birds, pocket/eat one of the foods, leaving birds to find the still baited cup. The experiment contained controls for various alternative explanations for the birds' behavior, but birds might still have avoided a cup from which something had been removed rather than specifically tracking the eaten food. Thus, in the second experiment, some trials were run with one food slightly more preferred than the other, during which two items of each type were hidden and only one of the items were removed from one cup. Sessions also included Experiment 1-type trials to see if birds tracked when and when not to use exclusion. Thus, birds would be rewarded for attending closely to all the experimental aspects needed to infer how to receive their preferred treat. Three of four birds succeeded fully.

Since Premack and Woodruf (1978), the study of mindreading abilities in nonhumans, especially primates, has been thoroughly investigated. But attempts to understand the evolution of this aspect of human intelligence have mainly focused on comparisons between apes and human infants, while relatively little is known about the abilities of monkeys. This lack of data on monkeys seems mainly due to the hypothesis of a cognitive "gap" between apes and monkeys. However, in recent years monkeys have been featuring more prominently in the landscape of social cognition research, and some of these systematic studies appear promising. This paper reviews i) current knowledge about monkeys' socio-cognitive abilities, especially regarding gaze processing, attention and intention reading, and perspective-taking, ii) alternative hypotheses regarding the underlying mechanisms of such complex behaviors, and iii) potential new perspectives and future directions for studying ToM in monkeys.

Chimpanzees (Pan troglodytes) have been known to exhibit rudimentary abilities in analogical reasoning (Flemming, Beran, Thompson, Kleider, & Washburn, 2008; Gillian, Premack, & Woodruff, 1981; Haun & Call, 2009; Thompson & Oden, 2000; Thompson, Oden, & Boysen, 1997). With a wide array of individual differences, little can be concluded about the species' capacity for analogies, much less their strategies employed for solving such problems. In this study, we examined analogical strategies in 3 chimpanzees using a 3-dimensional search task (e.g., Kennedy & Fragaszy, 2008). Food items were hidden under 1 of 2 or 3 plastic cups of varying sizes. Subsequently, chimpanzees searched for food under the cup of the same relative size in their own set of cups--reasoning by analogy. Two chimpanzees initially appeared to fail the first relational phase of the task. Meta-analyses revealed, however, that they were instead using a secondary strategy not rewarded by the contingencies of the task--choosing on the basis of the same relative position in the sample. Although this was not the intended strategy of the task, it was nonetheless analogical. In subsequent phases of the task, chimpanzees eventually learned to shift their analogical reasoning strategy to match the reward contingencies of the task and successfully choose on the basis of relative size. This evidence not only provides support for the analogical ape hypothesis (Thompson & Oden, 2000), but also exemplifies how foundational conceptually mediated analogical behavior may be for the chimpanzee.

Research concerning animal cognition explores the abilities and capacity of animals to perceive, think and conceive. As an extension of this, researchers have tried to ascertain the concept of animal minds. The field has been a matter of great debate as it has brought into question the uniqueness of the human mind. This dissertation will review the various areas of research that have contributed to our understanding of animal minds, with a specific focus on non-human primates. The term ‘theory of mind’ was originally proposed by Premack and Woodruff in 1978. The ability entails a recognition and understanding of another’s mental states. Recently, this term has included the cognition of seeing. Throughout this article, the important distinction between theory of mind capabilities and complex behavioural analysis is emphasized. It is important to consider how various primates represent entities in their environment, including their own image. In particular reference to this latter point, self-recognition could act as a first step towards understanding others. With this ability, other individuals may then be understood and manipulated through deception, imitation and teaching. In addition to deception, pretend play and external representation are proposed as another dimension of understanding false representations. Decisions about the evolutionary point at which theory of mind may have developed will depend on interpretations of the evidence for these abilities in non-human primates and whether indeed theory of mind is underlying them. Since the conception of the term ‘theory of mind’, the issue may have evolved beyond whether or not there is theory of mind in non-human primates to a more sophisticated appreciation that the concept of mind has many facets and some of these may exist in non-human primates while others may not.

Identity matching-to-sample consists of matching a sample stimulus to the corresponding identical comparison stimulus from an array of comparison stimuli (Brown, Brown, & Poulson, 1995). For example, if a learner were presented with an array of stimuli such as a block, car, and spoon (the comparison stimuli), then handed a spoon (the sample stimulus), and told to match, the learner should then place that spoon next to the comparison spoon. After the learner has acquired the ability to match all of the three objects, the experimenter could assess whether he or she had also acquired generalized matching-to-sample by using three different objects, such as a plate, sock, and cup to determine if the learner could match the given sample stimulus with the correct comparison stimulus. If the learner is able to correctly match the novel stimuli, then he or she has acquired a generalized identity matching-to-sample repertoire (Brown, et al., 1995). Identity matching-to-sample has been demonstrated with various animal species such as pigeons (Cummings & Berryman, 1961; Cummings, Berryman, & Cohen, 1965; Wright, Cook, Rivera, Sands, & Delius, 1988), California sea lions (Pack, Herman, & Roitblat, 1991), bottle nosed dolphins (Herman & Gordon, 1974; Herman, Honvancik, Gory, Bradshaw, 1989), infant chimpanzees (Oden, Thompson, & Premack, 1988), and macaque monkeys (Washburn, Hopkins, & Rumbaugh, 1989; as cited by Brown et al., 1995). Not only did all of the aforementioned experimenters intend to determine whether or not the various species of animals could acquire an identical matching-to-sample repertoire, but also, would a generalized repertoire develop as well. Cumming and Berryman (1961) were unable to get generalized matching with pigeons; however, Cumming, Berryman, and Cohen (1965) got low levels of generalized matching with their pigeons, and Wright, Cook, Rivera, Sands, and Delius (1988) got high levels of generalized matching with their pigeons (as cited by Brown et al., 1995). Dolphins demonstrated generalized matching (Herman & Gordon, 1974; Herman et al., 1989), as did infant chimpanzees (Oden et al., 1988; as cited by Brown et al., 1995). Following identity matching-to-sample training, California sea lions demonstrated some generalization (Pack et al. 1991) and it is unclear if macaque monkeys acquired a generalized matching repertoire (Washburn et al., 1989; as cited by Brown et al., 1995). Children under five years of age can acquire identity matching-to-sample, but no attempt seems to have been made to assess generalization (Dixon & Dixon, 1978; Lutzer, 1987; Daehler, Lonardo, & Bukatko, 1979; as cited by Brown, et al., 1995). If a skill is going to be targeted for acquisition, it should be taught not only to mastery, but the generalization of that skill needs to be targeted as well. However, Brown, Brown, and Poulson (1995) demonstrated that three typically developing children were able to acquire generalized identity matching-to-sample. While many manuals recommend training matching-to-sample to young children with developmental disabilities (Lovaas, 1981; Taylor, & McDonough, 1996), we have not found any literature actually showing that traditional matching-to-sample can be achieved by young children with developmental disabilities. And although, Saunders and Sherman (1986) taught matching-to-sample to three developmentally delayed teenagers; and all three children demonstrated generalized matching repertoire (as cited by Brown et al., 1995) there is still a need to demonstrate not only matching-to-sample, but also generalized matching in young children with developmental delays. And while generalized matching is an interesting theoretical issue, presumably it is also of considerable practical importance, as the children will have little opportunity to use their matching skills with the specific stimulus used in training. The acquisition of an identity matching repertoire will be of little value to the child if that child has not acquired a generalized matching repertoire, so that he or she can use that skill in a variety of educational and practical contexts where the matching task involves novel, untrained stimuli. …

Introduction: Behavior Analysis, Language and Stimulus Equivalence According to behaviour analysis, human language is verbal behaviour, emerging from the social contingencies operating in the verbal community. This perspective on cognitive functioning constitutes a very different approach to human language than that found in mainstream cognitive psychology and in many conceptualisations of language pathology. The conventional approach to the study of language has tended to focus on the symbolic nature of words. Language-able humans are said to be able to "manipulate symbols" (Clark, 1994), or to use words to "refer" to objects, events, or relations (Premack, 1976). For the behaviour analyst, however, concepts such as "refer" and "symbol manipulation" remain undefined and therefore are not deemed useful in explaining human language. For behaviour analysis the "meaning" of a word is established through the contingencies that control the emission of the word as an instance of verbal behaviour (Skinner, 1957). For example, the arbitrary vocal stimulus "dinner" has meaning only to the extent that it occasions appropriate behaviour (appropriate being defined by the social contingencies). Originally, behavioural researchers assumed that the meaning of a word was established in much the same way, as are stimulus control processes in nonhuman species. In essence, this conceptualisation of symbolic meaning defined symbols as discriminative stimuli. However, both non-behavioural and behavioural psychologists have questioned whether it is possible to accommodate the sheer flexibility of symbolic relations using the principle of discriminative control (cf. Hayes & Hayes, 1989). For instance, it has often been asked how an explanatory framework, which focuses on a history of previous reinforcement, can account for the fact that language-able humans respond appropriately to sentences that they have never previously heard (Chomsky, 1959). This is precisely the crucial question that a growing number of behavioural researchers have focused on in recent years. Specifically, the investigation of the phenomenon termed "stimulus equivalence" has allowed behaviour analysts to explore the behavioural processes whereby stimuli come to control behaviour in new ways in the absence of explicit reinforcement (see Sidman, 1994, for an extensive review). Stimulus equivalence has normally been studied using the matching-to-sample (MTS) procedure. When a subject is taught a series of related conditional discriminations, using the MTS format, the stimuli that enter into these discriminations become related to each other in new ways, without explicit teaching and/or reinforcement. For example, a subject might be taught, given a novel visual sample A1, to select the form B1, from an array containing B1, B2 and B3 (these visual forms are often abstract shapes or nonsense syllables that bear no formal relationship to each other). At the same time, the subject may also be trained, given the sample A1, to select another visual form C1, from an array containing C1, C2 and C3. Without additional training or explicit reinforcement, the subject may derive other relations among the stimuli; therefore the stimuli are said to be members of an equivalence class, and they show the properties of reflexivity, symmetry and transitivity. Reflexivity is inferred from generalised identity matching (e.g. without any training, given A1 as a sample, the subject picks A1 and not A2 or A3 from an array). Symmetry: If the subject is trained, given A1 to pick B1, then the functional reversibility of this trained relation emerges without any direct reinforcement (given B1, pick A1). Transitivity: If a subject is trained 'given A1 pick B1' and 'given B1 pick C1', the relation 'given A1, pick C1' emerges without any training or reinforcement. The phenomenon of stimulus equivalence appears to be readily observed in the human species, whereas great difficulty has been encountered in attempting to demonstrate the effect in non-humans (e. …

Among long-standing issues in animal cognition is which (nonhuman) animal species have the cognitive ability to learn abstract concepts (e.g., Premack, 1978). The hallmark of abstract concepts is that they transcend specific features of the training stimuli because they are based upon relationships (i.e., relational learning). In a seminal paper that was instrumental in the modern resurgence of animal cognition, David Premack said “…unlike the primate, the behavior of the pigeon is predominantly controlled by absolute rather than relational factors…” (1978, p. 432). Premack’s claim that item-specific learning (i.e., absolute factors) by pigeons has been the accepted explanation for why pigeons, at that time, had failed to learn abstract concepts (e.g., Cumming, Berryman, & Cohen, 1965; Farthing & Opuda, 1974; Santi 1978). Nevertheless, evidence began to emerge that if a large number of training stimuli (e.g., 152 color cartoons) were used, pigeons actually could learn a matching-to-sample (MTS) abstract concept (Wright, Cook, Rivera, Sands, & Delius, 1988). A somewhat more advantageous procedure than MTS for testing abstract-concept learning is the same/different procedure because the matching and non-matching stimuli are presented on separate trials. Details of currently used S/D procedures used to test pigeon abstract-concept learning vary widely including the numbers of stimuli used in training and testing (e.g., Blaisdell & Cook, 2005; Cook, Kelly, & Katz, 2003; Santiago & Wright, 1984; Wasserman, Hugart, & Kirkpatrick-Steger, 1995; Young & Wasserman, 1997). In consideration of the evidence that some species only accurately transfer their performance to novel stimuli following training with a substantial number of training stimuli, we have regularly made the number of training stimuli a parameter in our experiments. In a series of experiments with rhesus monkeys, capuchin monkeys, and pigeons, we began training with a small set of 8 stimuli and then progressively expanded (doubled) the training set followed by transfer tests with novel stimuli (Katz & Wright, 2006; Katz, Wright, & Bachevalier, 2002; Wright, Rivera, Katz, & Bachevalier, 2003). This regime allowed us to assess whether or not the degree of concept learning would depend on the number of training exemplars and whether or not transfer would eventually reach the level of baseline performance with the training stimuli. We anticipated that large numbers of training stimuli might be necessary to achieve a level of transfer equivalent to baseline performance, and therefore used picture stimuli. We selected pictures so that the training and testing pictures would be distinctive from one another and the transfer stimuli were only tested once, by definition of their being novel. In these experiments when the training set was expanded sufficiently (256 items for pigeons, 128 for monkeys), transfer became equivalent to baseline performance which remained above 80% correct. We termed this full abstract-concept learning because the baseline performance sets an upper limit. This result was the first time that pigeons had shown full concept learning in an S/D task, but pigeons required more training exemplars (i.e., stimulus pairs of same or different) than rhesus or capuchin monkeys. We characterized this species difference as a quantitative difference in contrast to the ability to fully learn the S/D abstract concept which we characterized as a qualitative similarity. The purpose of the experiments of this article was to explore whether or not training pigeons with somewhat larger initial sets of stimuli might produce better transfer than those trained initially with an 8-item set in the prior study. Training with the smaller 8-item set might produce carryover effects that would interfere with generalized relational learning which would in turn be necessary for good performance with the large training sets. To this end, we trained different groups of pigeons with larger initial training sets and compared their transfer to groups trained initially with smaller training sets. Such comparisons, of course, would depend upon pigeons being able to learn the S/D task with large training sets. With these considerations, the first group of pigeons was trained on an intermediate set size of 32 pictures.

Thus far, language- and token-trained apes (e.g., D. Premack, 1976; R. K. R. Thompson, D. L. Oden, & S. T. Boysen, 1997) have provided the best evidence that nonhuman animals can solve, complete, and construct analogies, thus implicating symbolic representation as the mechanism enabling the phenomenon. In this study, the authors examined the role of stimulus meaning in the analogical reasoning abilities of three different primate species. Humans (Homo sapiens), chimpanzees (Pan troglodytes), and rhesus monkeys (Macaca mulatta) completed the same relational matching-to-sample (RMTS) tasks with both meaningful and nonmeaningful stimuli. This discrimination of relations-between-relations serves as the basis for analogical reasoning. Meaningfulness facilitated the acquisition of analogical matching for human participants, whereas individual differences among the chimpanzees suggest that meaning can either enable or hinder their ability to complete analogies. Rhesus monkeys did not succeed in the RMTS task regardless of stimulus meaning, suggesting that their ability to reason analogically, if present at all, may be dependent on a dimension other than the representational value of stimuli.

Contingent reward procedures have been found beneficial in improving classroom conduct of ADHD children. Based on the conceptualization of the Premack Principle, a previous single-subject study of an ADHD Autistic child suggested the novel use of physical activity availability as a reinforcer for attentive calmness of the Attention Deficit Hyperactivity Disorder (ADHD) child in a laboratory situation. The present study extended this finding to two older ADHD children in a typical special education classroom. The result is an increase of attentive calmness for the duration of the class for both children. These results suggest the possible use of this special type of reinforcer for general classroom usage in behavioral contingency management programs for ADHD children.

For the benefit of linguists new to the field of language evolution, the author sets out the issues that need to be distinguished in any research on it. He offers a guided tour of contemporary approaches, including the work of linguists (Bickerton, Carstairs-McCarthy, Chomsky, Hurford, Jackendoff, Pinker, Wray), animal behaviour experts (Dunbar, Hauser, Premack, Savage-Rumbaugh), neurophysiologists (Arbib, Calvin), psychologists (Corballis, Donald), archaeologists (Davidson), and computer modellers (Batali, Kirby, Steels). He criticises the expectation that recent discoveries such as ‘mirror neurons’ and the FOXP2 gene will provide easy answers. He emphasises the extremely interdisciplinary nature of this field, and also the importance of involvement in it by linguists, after more than a century of neglect.

College students (N = 151) completed three in-class mathematics assignments that varied with respect to the order of short, medium, and long multiplication problems, including a short-to-long order, a long-to-short order, and a random order. Problem order within assignments did not significantly affect work accuracy, completion time, or assignment preference. However, participants rated (1) the assignment with random order as less difficult than the other two assignments and (2) the assignment with long-to-short order as requiring less time than the other two assignments. Participants were likely to choose a related homework assignment viewed as less effortful, less difficult, or less time consuming. Several concepts (e.g., matching law, behavioral momentum, and Premack reinforcement principle) were used in interpreting the results. Keywords: problem order, mathematics, homework, matching law, behavioral momentum, Premack reinforcement principle. ********** Academic assignments and tests often involve a series of tasks or problems that can be ordered in a variety of ways. A typical pattern is to begin the assignment with the less demanding tasks (briefer, easier) and proceed to the more demanding. A less common order is to begin with the more demanding tasks and proceed to the less demanding. A third order is to randomize task order with respect to difficulty. Because order of tasks within an assignment could affect performance on the assignment, time to complete the assignment, and favorability rating of the assignment, one would expect a plethora of research dealing with the effect of task order on student performance and preference of task order. However, an examination of research on assignment performance and assignment preference reveals few studies that deal specifically with the effects of task order within assignments. Research in this area has focused mainly on exams rather than assignments. Studies of multiple-choice exams have demonstrated mixed effects of item order on performance accuracy. Balch (1989) found that sequential exams (in which the test material was presented in the same order that material was presented in texts or lectures) produced higher scores than randomized or chapter-sequenced exams. In contrast, Neely, Springston, and McCann (1994) reported no differences in accuracy between sequential and randomized questions on undergraduate psychology exams. Similarly, Perlini, Lind, and Zumbo (1998) found no influence of easy-to-hard, hard-to-easy, or random item order on psychology exam performance. Studies of difficulty ratings of exams with different task orders have also produced mixed results. Laffitte (1984) found no differences in perceived difficulty of exams organized as easy-to-hard by chapter, easy-to-hard across chapters, randomly within chapters, and randomly across chapters. In contrast, Olson and Barickowski (1976) reported that hard-to-easy tests were viewed as easier than easy-to-hard, with no differences in accuracy of answers. Whether these research findings on item order with psychology exams can be generalized to assignments that involve skill building in a variety of academic domains remains an issue for further investigation. Research regarding the effects of choosing assignment sequence has been done mainly with children and adults with special needs (e.g., autism, mental retardation) and has typically dealt with the scheduling of assignments rather that the order of tasks within assignments. For example, Kern, Mantegna, Vorndran, Bailin, and Hilt (2001) found that students having intellectual and behavioral problems improved both in task engagement and appropriate conduct when allowed to schedule the sequence of required tasks. Similarly, Seybert, Dunlap, and Ferro (1996) reported that giving high school students with severe mental retardation the opportunity to schedule their tasks increased task engagement and task productivity. …

We are born to be social (Aristotle, 1968), to be grounded with others that nurture diverse and endless forms of pedagogy (Dewey, 1919, 1925; Premack, 1990). What distinguishes the long period of childhood is the chance it provides to get a foothold into the world around us. Foraging for coherence begins here, in a social context of norms and practices that bind us and that trigger ways in which to respond to others.

In the nearly 30 y ears since Premack and Woodruff famously asked, “Does the chimpanzee have a theory of mind?”, the question of exactly how much non-human primates understand about the mental lives of others has had an unusually dramatic history. As little as ten years ago it appeared that the answer would be a simple one, with early investigations of non-human primates’ mentalistic abilities yielding a steady stream of negative findings. Indeed, by the mid-1990s even very cautious researchers were ready to flatly assert that Theory of Mind was a uniquely human capacity. Recently, however, an exciting new theor etical perspective on primate social cognition has arisen, and with it the distinct possibility that our evolutionary relatives may understand far more of the social world than we previously believed. In this paper we r eview ne w theor y and evidence suggesting that non-human primates may indeed represent the mental states of others, at least within the domains for which their distinctive social ecology has prepared them. Having asserted that Premack and Woodruff ’s original question can be answered with a qualified yes, we then consider the new questions that arise in its place, particularly how and why our own Theory of Mind became more domain-general than that of other primates.

This study investigated the ability of chimpanzees, gorillas, orangutans, and bonobos to make inferences by exclusion using the procedure pioneered by Premack and Premack (Cognition 50:347-362, 1994) with chimpanzees. Thirty apes were presented with two different food items (banana vs. grape) on a platform and covered with identical containers. One of the items was removed from the container and placed between the two containers so that subjects could see it. After discarding this item, subjects could select between the two containers. In Experiment 1, apes preferentially selected the container that held the item that the experimenter had not discarded, especially if subjects saw the experimenter remove the item from the container (but without seeing the container empty). Experiment 3 in which the food was removed from one of the containers behind a barrier confirmed these results. In contrast, subjects performed at chance levels when a stimulus (colored plastic chip: Exp. 1; food item: Exp. 2 and Exp. 3) designated the item that had been removed. These results indicated that apes made inferences, not just learned to use a discriminative cue to avoid the empty container. Apes perceived and treated the item discarded by the experimenter as if it were the very one that had been hidden under the container. Results suggested a positive relationship between age and inferential ability independent of memory ability but no species differences.

Some evolutionary cognitive and developmental psychologists propose that the human mind consists of domain-specific modules. These are characterized as self-contained “mini-computers” that process information of a certain kind. Although, according to my reading, much of the extant human brain research does not necessarily support the module view (Greenwald, 1997), still module theories continue to occupy center stage in cognitive developmental and comparative psychology. One would think that neuroscience, as a study of the behavior beneath the skin, would simply replace cognitive psychology. But, perhaps I missed the value of the psychological construct. In their book, the Premacks set out to provide a synthesis of evidence from various fields in order to identify what they characterize as “original intelligence.” Their synthesis is derived from their reading of findings in comparative psychology, developmental psychology, neuroscience, anthropology and other “life sciences.” All of the evidence and theory from psychology from which they draw their evidence comes from the cognitive perspective including their own contributions to that research. For them, original intelligence includes certain phylogenetic and ontogenetic contributions that they identify as expectancies, capabilities that are present or not present in certain species including humans. These capabilities include inherited expectancies, derived from natural selection; and expectancies derived from experience and its interaction with inherited expectancies. Infants have inherited expectancies not only about how physical bodies “act,” but also about psychological and biological objects, about language, number, spatial navigation, and music. Indeed, infants have inherited expectancies in all the domains into which human problem solving can be divided. These expectancies are an integral part of the infant's modules. (p. 17)

Introduction Complex language is one of the unique repertoires of the human species. Others include teaching and certain "types of imitation" (Premack, 2004), although these too may be pre-or co-requisites for certain functional uses of language. Over the last 40 years linguists have proposed theories and provided evidence related to their interpretation of the structure of language (Chomsky, 1959; Chomsky & Place, 2000, MacCorquodale, 1970; Pinker, 1999). Neuroscientists have identified neurological correlates associated with some aspects of language (Deacon, 1979, Holden, 2004). Behavior analysts have focused on the source of and controlling variables for the function of language as behavior per se (Catania, Mathews, & Shimoff, 1990; Greer & Ross, 2005; Michael, 1984; Skinner, 1957). More recently, scholars have come to view human language as a product of evolution; "Linguists and neuroscientists armed with new types of data are moving beyond the non-evolutionary paradigm once suggested by Noam Chomsky and tackling the origins of speech head-on." (Culotta & Brooks-Hanson, 2004, p. 1315). The current work focuses on the evolution of both the non-oral motor and oral components of speech (Deacon, 1997; Holden, 2004), although some arguments are characterized necessarily more by theory than data. Despite the evidence that primates and pigeons can be taught certa in features of verbal behavior (D. Premack & A. Premack; 2003; Savage-Rumbaugh, Rumbaugh, & Boysen, 1978; Epstein, Lanza, & Skinner, 1980), the speaker-as-own listener capability makes complex verbal behavior possible and may represent what is most unique about human verbal functions (Barnes-Holmes, Barnes-Holmes, & Cullinan, 2001; Lodhi & Greer, 1989; Horne & Lowe, 1996). Some suggest that oral communication evolved from clicking sounds to sounds of phonemes, and cite the extant clicking languages as evidence (Pennisi, 2004). It is likely that sign language and gesture predated both vocal forms; but it is the evolution of the spoken and auditory components of language that are seen as critical to the evolution of language. Some of these include changes in the anatomy of the jaw--Homo sapiens have more flexible jaw than did Neanderthals. Also, the location of the larynx relative to the trachea is different for Homo sapiens, and this anatomical feature made it possible for the humans to emit a wider range of speech sounds (Deacon, 1997). The combination of these anatomical changes, together with the identification of separate, but proximate, sites in the brain for speaking, listening, and imitation seem to be critical parts of what made spoken language possible (Deacon, 1997). The presence of these anatomical and physiological properties made it possible for the evolution of verbal functions through the process of cultural selection (Catania, 2001). The functional effects of speech sounds were acquired by the consequences provided within verbal communities. This latter focus is what constitutes the subject matter of verbal behavior. The new foci on language, as an evolved anatomical and physiological capacity, do not necessarily suggest the existence of a universal grammar; nor, in fact, does it eliminate the possibility of an evolved universal grammar, as some argue (Pinker, 1999). Some of the linguistic neuropsychological searches for an evolved universal grammar now follow the PET and MRI trails and focus on identifying blood flow associated with the speech and hearing centers in the brain (Holden, 2004). Interesting and as important as this work may be, little, if any, is devoted to the function of language as behavior per se. Nor is it concerned with the biological or cultural evolution of verbal function in our species or in the lifespan of the individual, although anthropological linguists point to functions as the initial source. Only the research associated with Skinner's (1957) theory of verbal behavior as behavior per se, and expansions of the theory by contemporary behavior analysts, provide the means for analyzing how cultural selection gave rise to the function of language (Greer, 2002; Greer & Ross, in press; Hayes, Barnes-Holmes, & Roche, 2000; Lowe, Horne, Harris, & Randle, 2002). …

Face recognition has always been an area of interest for the researchers because it seems so fascinating in itself. As the time has passed, the evolution of human brain and social intelligence has enhanced the analysing power of a human brain for the displaying of face to infer the emotion accordingly. Face of a human being is considered to be the most common channel to read and infer the emotion in the case of mind reading. Theory of mind (ToM) is the inbuilt technique provided to every human being “as reported by Premack and Woodruff (Behav Brain Sci 1:515–523, 1991)”. According to ToM, a person has the ability to read someone else’ mind. Mind reading has a great amount of future advancement if worked upon with the different equipment and devices in the high-tech laboratories. The researchers have worked in this direction and have developed softwares. The aim of such software is to apply concept of security in face recognition but still there is a scope for improvement. This paper presents a comparative study between algorithms used for detecting the face as the key component in mind reading. Further, a model is proposed to enhance the security in face recognition. The proposed model also suggests interface that would help users to identify the people watching their pictures posted online.

Educational and behavioural psychologists have made major contributions to the field of communication intervention for individuals with developmental and physical disabilities. A brief personal perspective is provided on some of the major works and contributors that have shaped the field over the past 25 years. Major contributions and personal influences include: (a) David Premack and other ape‐language researchers; (b) Reichle’s work on graphic‐mode communication; (c) Bondy and Frost’s Picture‐Exchange Communication System; and (d) a chance encounter with some unused communication devices. The advances made over the past 25 years in this area have been dramatic and have enabled many non‐speaking individuals with developmental and physical disabilities to communicate more effectively.

A theory of education requires a theory of the mind that is to be educated. Modules are the central feature of the mind of the infant. Innate learning devices, modules, prepare the infant with the following competences: language, number, theory of mind, spatial navigation, music, etc. We propose that the child be taught what evolution has prepared the child to learn. This program requires adding both modular—e.g., Theory of Mind, morality, art—as well as domain-general competences—e.g., analogies, causal analysis—to the curriculum. The program further requires revamping the presently inappropriate teaching of certain modular competences. Finally it requires correcting “evolutionary errors”—modular competences that were not ideal (see Galileo); or that, though once beneficial, have become harmful in the modern world (see imitation). This proposal is taken from [ Premack, D. & Premack, A. (2003) . Original intelligence . New York: Macgraw-Hill].

We suspect that people have an everyday theory of mind because they explain and frequently talk about the behaviour of others and themselves in terms of beliefs and desires. Having a theory of mind means that we believe that other people have minds like ours and that we understand the behaviour of these others in terms of the contents of their minds: their knowledge, beliefs and desires. But how can we demonstrate experimentally that people are using their theory of mind to predict the behaviour of others. This problem is particularly acute in the case of animals or young human children when they do not have language. Dennett (1978) discussing Premack & Woodruff's (1978) seminal paper ‘Does the chimpanzee have a theory of mind?’, suggested that the use of false beliefs to explain behaviour would provide convincing evidence. When their belief is true (i.e. corresponds to the actual state of the world) we can explain peoples' behaviour on the basis of the state of the world without needing to know about their beliefs. This ambiguity does not arise when the belief is false. The first experiment to use this approach was published by Wimmer & Perner (1983). They showed that at around 4 years of age a child knows that Maxi will look for his chocolates where Maxi believes them to be, even though the child knows that this belief is false because he has seen Maxi's mother moving the chocolates. In the English-speaking world the task involving Maxi and the chocolates has become the Sally-Anne task (see this issue, Lee et al. 2004).

We used response-restriction (RR) assessments to identify the preferences of 7 individuals with mental retardation for a variety of vocational and leisure activities. We subsequently increased their engagement in nonpreferred activities using several procedures: response restriction per se versus a Premack-type contingency (Study 1), supplemental reinforcement for engagement in target activities (Study 2), and noncontingent pairing of reinforcers with nonpreferred activities (Study 3). Results indicated that preferences are not immutable and can be altered through a variety of relatively benign interventions and that the results of RR assessments may be helpful in determining which types of procedures may be most effective on an individual basis.

Summary The present paper describes the successful implementation of a training programme for the parents of a child with moderate learning difficulties presenting with chronic food refusal and provides an example of how professionals can work with families to manage clinical problems in the home. The parents were taught to use the Premack principle to motivate their child in the consumption of previously refused foods. A multiple baseline design across three foods demonstrated the efficacy of the programme and the dietary changes were maintained at the 3-month follow-up.

Correspondence: T. S. S. Schilhab, Centre for the Philosophy of Nature and Science Studies, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen, Denmark (email: Schilhab@nbi.dk). Attempts to show the presence of mental states in nonhumans in areas such as cognitive ethology and comparative psychology are often accused of anthropomorphism, both in conducting empirical work and in interpreting the results (Kennedy 1992). Anthropomorphism is the ‘attribution of human characteristics to nonhuman things and events’ (e.g. Guthrie 1997). It is generally conceived of as a categorical mistake, as it denotes attribution of characteristics considered uniquely human (Fisher 1991, 1996). ‘Category mistakes are made when one treats an entity of one type as if it were an entity of a different type’ (Fisher 1991, page 4). Following this reasoning, studies on precursors of typical human cognitive abilities, imputing mental states such as selfawareness, deception and intentionality (e.g. Gallup 1970; Premack & Woodruff 1978; Whiten & Byrne 1988; Parker et al. 1994; de Veer & van den Bos 1999) to nonhumans, are by some deemed fallacious (Kennedy 1992; Heyes 1993, 1994, 1995, 1998; Bekoff & Allen 1997; Davis 1997). Opinions on the origin of anthropomorphism are diverse (see Mitchell et al. 1997). Some hold that anthropomorphism emerged as a cognitive default resulting from human social cognition (e.g. Kennedy 1992) or is an instantiation of an introspective modelling capacity (Eddy et al. 1993; Gallup et al. 1997). In contrast, others emphasize that anthropomorphism is a product of cultural norms; for example, it is responsible for keeping Western and Japanese primatology apart. ‘To the Japanese researchers, questions about the rational uniqueness of humans did not arise and their reports were filled with mentalistic language’ (Asquith 1997, page 29). Still others believe anthropomorphism to be rooted in a classical logical error called ‘affirming the consequent’ (Davis 1997, page 336). This error, which might result from design faults or tendentious thinking, is what leads us from the fact that ‘I scratch my head’ and the premise ‘I think therefore I scratch my head’ to the logically invalid conclusion that ‘I think’. When ‘affirming the consequent’, other reasons such as mosquito bites or fleas leading to scratching, are ignored. The reasons for shunning anthropomorphism are just

Since my first immersion in the medical environment in 1975, I have had the opportunity to participate in and develop a number of different environments of care and types of services for children, adolescents, and their families. I am reminded that the famous philosopher Yogi Berra once said “You can observe a lot just by watching.” I continue to be impressed by the unique and ever-changing benefits to children’s health brought about by pediatric psychologists. I want to thank my colleagues for bestowing on me the opportunity to reflect on my personal experiences and the growth of our field. When I arrived at the University of California, Santa Barbara (UCSB) to begin my undergraduate education, it was my career goal to become a physicist. However, my path changed very quickly. I was lucky to have had the opportunity to study with a number of outstanding psychologists. I can remember my first course in learning theory taught by David Premack, PHD, of Premack Principle fame. Simply put, the Premack Principle states that a more-preferred activity can be used to reinforce a less-preferred activity (Premack, 1959). Even though his original work was done with monkeys, its application to humans was apparent. In another of my classes, we watched the film “Behavior Modification: Teaching Language to Psychotic Children” (Lovaas, 1969). In essence, Dr Ivar Lovaas had applied his own learning research, the Premack Principle, and other findings from the basic research literature to develop a method to teach mute or echolalic autistic children how to speak and use language!

Contents: C. Moore, D. Frye, The Acquisition and Utility of Theories of Mind. D. Frye, The Origins of Intention in Infancy. D. Premack, The Infant's Theory of Self-Propelled Objects. I. Bretherton, Intentional Communication and the Development of an Understanding of Mind. R.T. Beckwith, The Language of Emotion, The Emotions, and Nominalist Bootstrapping. J. Dunn, Young Children's Understanding of Other People: Evidence from Observations Within the Family. D.F. Hay, C.A. Stimson, J. Castle, A Meeting of Minds in Infancy: Imitation and Desire. J. Perner, On Representing That: The Asymmetry Between Belief and Desire in Children's Theory of Mind. J.W. Astington, Intention in the Child's Theory of Mind. C. Moore, D. Furrow, The Development of the Language of Belief: The Expression of Relative Certainty. T.R. Shultz, Modelling Embedded Intention.