Search

Novel pop-out refers to the relative ease in locating an unfamiliar target against a background of familiar distractors in visual search tasks. For instance, when one novel item is presented along with three familiar items, it is located faster than when the target is itself familiar, or when all items are novel or familiar. However, the reliability and generality of the novel pop-out effect has been questioned. Three experiments with human participants examined the reliability of within-array novel pop-out effects, and explored the conditions under which these effects can be obtained. The degree to which subjects could identify a novel item when presented against a background of familiar items, or against a background of other novel items, was assessed using two different visual search tasks. Experiments 1 and 3 replicated the theoretically important within-array novel pop-out effect, using the original procedure adopted by Johnston and colleagues. In the current studies, the array items were rendered novel or familiar by virtue of their previous absence or presence, respectively, in a pre-exposure phase, which allowed greater control over their novelty or familiarity. However, the use of this procedure abolished the typically-reported advantage for all-familiar versus all-novel arrays (Experiments 2 and 3). It is suggested that any model of attention should be sensitive to the present goal state of the subject, and that the literature on latent inhibition may provide one such mechanism through which such a set of effects could be explained. [ABSTRACT FROM AUTHOR]

The current study explored similarities and differences in parenting stress (PSI) and behaviours in parent reports of autism spectrum disorder (ASD) and attachment disorder (AD). 155 parents whose children had developmental delays and disorders completed the social communication questionnaire, Randolph attachment questionnaire, strengths and difficulties questionnaire, PSI, and parent–child relationship inventory. Parents of children with AD reported greater levels of PSI than parents of children with ASD. Parents of children reaching criteria for both disorders reported the greatest levels of PSI. Limit setting was poorest in parents of children with both classifications, followed by parents of children with AD, and then ASD. Limit setting mediated the relationship between PSI and child behaviour problems for parents of children with ASD < but not for parents of children with AD. These findings suggest different areas of difficulty for parents of children with these conditions, which may be of help in designing interventions. [ABSTRACT FROM AUTHOR]

In summary, the current results demonstrated that withdrawal effects for those with higher levels of internet addiction can be seen in samples whose prime access of the internet is through mobile devices. For the older participants, there was a significant change from zero for those with higher levels of internet addiction and who used social media, I z i = 2.032, I p i = 0.042, but not for the higher internet addiction group not using social media, I z i = 0.319, I p i > 0.30, or for the lower internet groups whether using, I z i = 0.864, I p i > 0.30, or not using, I z i = 0.319, I p i > 0.30, social media. However, with changes in usage patterns of those accessing digital resources (i.e. for social media rather than traditional internet resources), it is unclear whether withdrawal effects would be observed when higher PIU scores are associated with mobile device use for social media. [Extracted from the article]

Individual differences in behaviors are seen across many species, and investigations have focused on traits linked to aggression, risk taking, emotionality, coping styles, and differences in cognitive systems. The current study investigated whether there were individual differences in proactive interference tasks in rats (Rattus Norvegicus), and tested hypotheses suggesting that these tasks should load onto a single factor and there should be clusters of rats who perform well or poorly on these tasks. The performance of 39 rats was tested across three learning tasks that all involved disengagement from an irrelevant previously learned stimulus to a relevant stimulus: latent inhibition (LI), partial reinforcement extinction effect (PREE), and reversal learning (RL). An exploratory factor analysis revealed the existence of one factor underlying performance. A cluster analysis revealed the existence of sets of rats displaying either weak LI and strong PREE and RL effects, or vice versa. These findings suggest that proactive interference may be based on a single underlying psychological system in rats. [ABSTRACT FROM AUTHOR]

Three experiments examined human rates and patterns of responding during exposure to various schedules of reinforcement with or without a concurrent task. In the presence of the concurrent task, performances were similar to those typically noted for nonhumans. Overall response rates were higher on medium-sized ratio schedules than on smaller or larger ratio schedules (Experiment 1), on interval schedules with shorter than longer values (Experiment 2), and on ratio compared with interval schedules with the same rate of reinforcement (Experiment 3). Moreover, bout-initiation responses were more susceptible to influence by rates of reinforcement than were within-bout responses across all experiments. In contrast, in the absence of a concurrent task, human schedule performance did not always display characteristics of nonhuman performance, but tended to be related to the relationship between rates of responding and reinforcement (feedback function), irrespective of the schedule of reinforcement employed. This was also true of within-bout responding, but not bout-initiations, which were not affected by the presence of a concurrent task. These data suggest the existence of two strategies for human responding on free-operant schedules, relatively mechanistic ones that apply to bout-initiation, and relatively explicit ones, that tend to apply to within-bout responding, and dominate human performance when other demands are not made on resources. [ABSTRACT FROM AUTHOR]

This study adopted a novel approach to relating nonhuman and human studies of anxiety and latent inhibition, by exploring the degree to which rats' "temperaments" in relation to anxiety predicted the development of latent inhibition. It investigated whether anxiety levels in one situation (i.e., an elevated-plus maze) involving 38 intact, mature rats, could predict performance on a latent inhibition task (i.e., an animal model of attention), and, thus, reproduce findings from human studies. Rats were subjected to two tasks: a novel within-subject, appetitive stimulus pre-exposure procedure, and an elevated-plus maze task. In the stimulus pre-exposure task, non-reinforced exposure to a light led to facilitation of conditioning (perceptual learning) during the first 3 days, and to retardation of conditioning (latent inhibition) during the last 5 days. In the elevated-plus maze task, moderate levels of anxiety were observed. Regression analyses revealed that anxiety levels (plus maze) were a significant predictor of latent inhibition (stimulus pre-exposure). Measures of locomotor activity did not predict performance on the latent inhibition task. Rats with moderate levels of anxiety had better performance in the late inhibition task than animals with low levels of anxiety. These data and the methodology have implications for understanding nonhuman models of schizophrenia, and for the design of studies investigating these issues with nonhumans. [ABSTRACT FROM AUTHOR]

The effects of brief mindfulness induction on a central trait of autism spectrum disorder (over-selective attention) were examined in order to assess whether different mechanisms act in those with lower and higher levels of autism traits, and determine which intervention may be most appropriate for individuals with different sets of symptoms. Two hundred and 24 volunteer participants (110 male; 114 female) were assessed for levels of autism traits (autism quotient; AQ), anxiety and depression (Hospital Anxiety and Depression Scales), and mindful awareness (Toronto Mindfulness Scale). They were randomly assigned to mindfulness, relaxation, or no-intervention groups. After three 10-min sessions, held on alternate days, participants underwent simultaneous discrimination training between two two-element compound stimuli (AB+ CD−), followed by an extinction test (AvC, AvD, BvC, BvD) to determine the amount of over-selectivity present. Levels of depression, anxiety, and mindfulness were re-assessed. Participants with greater autism traits demonstrated greater over-selectivity, than those with lower autism traits. Mindfulness reduced over-selectivity, and did so independently of the level of AQ displayed by the participants. For lower scoring AQ participants, mindfulness worked more effectively than relaxation. In contrast, for participants with higher AQ scores, there was little difference between the impact of mindfulness and relaxation. The latter group displayed no improvement in mindful awareness. Mindfulness induction can be effective, but may work through different mechanisms for those with higher and lower autism traits, and consideration should be given as to whether this intervention may be the most suitable in all cases where autism traits are present. [ABSTRACT FROM AUTHOR]

Hungry rats were trained in a two-lever conditioning chamber to earn food reinforcement according to either a win-shift/lose-stay or a win-stay/lose-shift contingency. Performance on the two contingencies was similar when there was little delay between the initial, information part of the trial (i.e., win or lose) and the choice portion of the trial (i.e., stay or shift with respect to the lever presented in the information stage). However, when a delay between the information and choice portions of the trial was introduced, subjects experiencing the win-shift/lose-stay contingency performed worse than subjects experiencing the alternative contingency. In particular, the lose-stay rule was differentially negatively impacted relative to the other rules. This result is difficult for ecological or response interference accounts to explain. [ABSTRACT FROM AUTHOR]

The relationships of autism quotient (AQ), systematizing (SQ), and empathizing (EQ), with over-selectivity were explored to assess whether over-selectivity is implicated in complex social skills, which has been assumed, but not experimentally examined. Eighty participants (aged 18-60) were trained on a simultaneous discrimination task (AB+CD−), and tested in extinction on the degree to which they had learned about both elements of the reinforced (AB) compound. Higher AQ and lower EQ scorers demonstrated greater over-selectivity, but there was no relationship between SQ and over-selectivity. These results imply that high AQ scorers perform similarly to individuals with ASD on this cognitive task, and that over-selectivity may be related to some complex social skills, like empathy. [ABSTRACT FROM AUTHOR]

Two experiments examined acquisition of win-stay, win-shift, lose-stay, and lose-shift rules by which hungry rats could earn food reinforcement. In Experiment 1, two groups of rats were trained in a two-lever operant task that required them to follow either a win-stay/lose-shift or a win-shift/lose-stay contingency. The rates of acquisition of the individual rules within each contingency differed: lose-shift and lose-stay rules were acquired faster than win-stay and win-shift rules. Contrary to a number of previous reports, the win-shift rule was acquired less rapidly than any of the other rules. In Experiment 2, the four rules were taught separately, but subjects still acquired the win-shift rule more slowly than any of the other rules. [ABSTRACT FROM AUTHOR]

The article presents a study related to the investigation of traits associated with autism, along with depression, anxiety, loneliness, quality of life, and social anxiety. It mentions that very less number of students had scores above cut-off on the Autism Spectrum Quotient (AQ) self-report questionnaire. It states that quality of life (QoL) was best predicted for by scores of depression, loneliness, and social anxiety.

Stimulus over-selectivity describes a phenomenon where only a subset of the relevant stimuli present in the environment, control an individual's behavior. The current experiment explored the degree to which over-selectivity increases in old age. The level of over-selectivity in a visual discrimination task in 60 individuals aged 60–89 years was assessed, as well as the degree to which this reflected attentional control. In addition, the intellectual functioning and cognitive flexibility of the participants were assessed. Results showed that, as age increased, three effects were revealed: levels of stimulus over-selectivity increased, IQ scores decreased, and cognitive flexibility decreased. However, over-selectivity was not related to IQ or cognitive flexibility, and appeared related most to attentional impairments. Thus, ageing is related to significant declines in effective stimulus control. These effects can have a serious impact on the physical and psychological health of old adults, as well as their quality of life, and, therefore, this area of research warrants further exploration. The results are discussed in relation to the attention-deficit and comparator theory of over-selectivity. [ABSTRACT FROM AUTHOR]

The current study explore the relationship between various forms of experienced stress (general stress and parenting stress) and both health-related quality of life (QoL) and reported physical health symptoms. One hundred and twenty-two mothers of children with autism spectrum disorder responded to an online survey included questionnaires on general stress, parenting stress, health-related QoL, and physical symptoms. The results suggested that perceived general stress as associated with both a reduced health-related QoL and more physical symptoms. However, parenting stress was only associated with a reduced health-related QoL, and not with physical health. These results are discussed in relation to the complex impact of prolonged and predictable parenting stress on the cortisol response and immune system. [ABSTRACT FROM AUTHOR]

An experiment examined the impact of a procedure designed to prevent response or extinction strain occurring on random interval schedules with a linear feedback loop (i.e., an RI+ schedule). Rats lever-pressed for food reinforcement on either a RI+ or a random interval (RI) schedule that was matched to the RI+ schedule in terms of reinforcement rate. Two groups of rats responded on an RI+ and two on an RI schedule matched for rate of reinforcement. One group on each schedule also received response-independent food if there had been no response for 60 s, and response-independent food continued to be delivered on an RT-60 schedule until a response was made. Rats on the RI and RI+ obtained similar rates of reinforcement and had similar reinforced inter-response times to one another. On the schedules without response-independent food, rats had similar rates of response to one another. However, while the delivery of response-independent food reduced rates of response on an RI schedule, they enhanced response rates on an RI+ schedule. These results suggest that rats can display sensitivity to the molar aspects of the free-operant contingency, when procedures are implemented to reduce the impact of factors such as extinction-strain. [ABSTRACT FROM AUTHOR]

Two experiments examined the conditioning of a discriminated eyeblink response to the abstract property of 'truthfulness' in visually presented verbal statements. Learning was assessed with a measure of change in eyelid activity following conditioned stimulus (CS) presentations. In the first experiment, a list of randomized statements was presented, half of which were true and half of which were false. Each false statement in this experiment was paired with a corneal air puff (the US). The second experiment used the same procedure to compare true and false statements as conditioned stimuli, except it varied the range of CS-US intervals employed. The results support previous findings by showing that the truth value of presented statements can serve as a conditioned stimulus in an eyeblink conditioning procedure, and that both true and false statements can serve as conditioned stimuli. The results also show that the interstimulus interval is an important factor in such conditioning. Implications for future research, and the interpretation of previous studies exploring similar conditioning, are discussed. [ABSTRACT FROM AUTHOR]

This study explored the relationship between problematic levels of Internet use and motivation to study in a university sample. One hundred and sixty-two participants were recruited online and completed four questionnaires: Internet Addiction Test, Hospital Anxiety and Depression Scale, Emotional-Social Loneliness Scale, and the Motivated Strategies for Learning Questionnaire. Participants' scores were analysed to determine the presence of problematic levels of Internet use and any relationship between this factor and motivation to study. The results demonstrated that levels of problematic Internet use were negatively associated with several aspects of motivation to study (intrinsic goal orientation, control over learning, and learning self-efficacy). These relationships were over and above any impact that depression, anxiety, and social isolation had on motivation to study. The results suggest that increasing employment of digital learning technologies in higher education may be generating problems for some students, which may negatively impact their academic experience and outcomes in higher education. [ABSTRACT FROM AUTHOR]

The current experiment investigated the extent to which three variables (autism severity, nonverbal intellectual functioning, and verbal intellectual functioning) are associated with over-selective responding in a group of children with Autism Spectrum Disorder. This paper also analyzed the association of these three variables with the recovery of responding to a previously under-selected stimulus following extinction of the previously over-selected stimulus. The results demonstrated that participants showed over-selectivity, and demonstrated that extinction of the over-selected stimulus led to recovery of responding to the previously under-selected stimulus. For both over-selectivity, and recovery from over-selectivity, verbal functioning appeared to predict the effects most strongly, with greater over-selectivity in the lower functioning individuals, and greater recovery in the higher functioning individuals. [ABSTRACT FROM AUTHOR]

Two experiments examined the impact of response-independent outcome delivery on human rates of response and judgments of control in an instrumental conditioning task. In Experiment 1, when participants responded on a schedule with a relatively high probability of a response producing an outcome, a random ratio (RR-5), judgments of control declined as rates of response-independent outcomes increased. However, when response-dependent outcomes were delivered with a relatively low probability (RR-15), increasing the rate of response-independent outcomes increased rates of response and judgments of control. Experiment 2 replicated this effect, but also noted a differential effect of response-independent outcome and response-independent sensory presentations on response rate and judgments of causal effectiveness. Ratings of the context in which the conditioning occurred suggested these were correlated with total outcome presentation, and that the role of context on response rate and judgments of control may be important to consider. [ABSTRACT FROM AUTHOR]

Humans responded on multiple random-ratio (RR) random-interval (RI) schedules, and their verbalized performance awareness (PA; i.e., their ability to accurately describe what they did) was measured in three experiments. In Experiment 1, instructions informed participants that to earn points, either sometimes rapid responding and sometimes slow responding would work best (accurate instructions); rapid responding would work best ( go fast instructions); spaced responding would work best ( go slow instructions); or no advice was provided (minimal instructions). In Experiments 2 and 3, participants received either accurate or minimal instructions and were subject to extinction after a multiple RR-RI schedule. In all experiments, both performance awareness, and receiving accurate instructions, were related to schedule-sensitive responding, but were unrelated to one another - participants receiving accurate-rate instructions were not more likely to show performance awareness than those exposed to minimal instructions. Both higher performance awareness and exposure to accurate instructions predicted faster extinction in Experiment 2 but not in Experiment 3. The current results suggest that performance awareness rather than contingency awareness is more strongly related to humans displaying schedule-typical behavior and that this is not strongly related to any explicit verbal instructions that are given. [ABSTRACT FROM AUTHOR]

The areas that were suggested as most important with regard to Quality of Life (QoL) were examined in groups of individuals who were healthy, and those with a chronic condition. An electronic survey was completed by 892 participants (261 healthy and 631 with a chronic condition). They answered three questions relating to QoL: what is most important to you; what areas most impact your QoL; and an open question what does QoL mean to you. Across the three questions both groups highlighted physical functioning, independence and mobility as key areas for QoL. However, the group with a chronic condition tended to find issues of functioning such as pain, fatigue, and sleep as more important to their QoL than the healthy participants. In contrast, the healthy participants tended to note the importance of relationships and family as more important than the group with a chronic condition. That there were such differences between the groups might suggest that different aspects of QoL could be rated as more important when examining this issue with samples with a chronic condition and those without such a condition. [ABSTRACT FROM AUTHOR]

The study assessed whether teacher and parent ratings of child behavior problems were similar for children with autism spectrum disorders. Two informants rated child behaviors in the same home environment, and the degree to which parenting stress impacted the similarity of the ratings was assessed. Overall behavior problem ratings did not differ between groups, but there was poor correspondence between the ratings for individual children, stress did not impact markedly on the discrepancies. Parent-teacher discrepancies in behavior ratings cannot be attributed entirely to differences in the assessment-environment, and there was little evidence of widespread impacts of parenting stress on these discrepant ratings. It was suggested that attention is needed in terms of the teacher characteristics when explaining such results. [ABSTRACT FROM AUTHOR]

Three experiments examined the effect of response-outcome contingencies on human ratings of causal efficacy and demonstrated that such ratings transfer to novel situations through derived stimulus relations. Efficacy ratings generally followed the delta probability rule when positive response-outcome contingencies were employed (Experiment 1) and when some outcomes were not contingent on participants' responses (Experiment 2). Experiment 3 employed a negative response-outcome contingency and manipulated performance expectancies in the task. All three groups overestimated their causal efficacy ratings. A learned helplessness effect was observed when the response-outcomes were uncontrollable and in the high-expectancy group when participants' performance in the task was worse than they had expected. In all experiments, ratings transferred to a stimulus presented during the task and often generalized to novel stimuli through derived relations. These results corroborate the view that outcome probability is a determinant of causal efficacy ratings and that schedules can be employed as UCS in procedures that share characteristics of evaluative conditioning procedures. [ABSTRACT FROM AUTHOR]

In the present experiments, we investigated the effects of mindfulness on behavioral extinction and resurgence. Participants received instrumental training; either they received FI training (Experiment 1), or they were trained to emit high rates and low rates of response via exposure to a multiple VR yoked-VI schedule prior to exposure to a multiple FI FI schedule in order to alter their rates of responding learned during Experiment 2. Participants were then exposed to either a focused- (mindfulness) or an unfocused-attention induction task. All participants were finally exposed to an extinction schedule in order to determine whether a mindfulness induction task presented immediately prior to extinction training affected extinction (Experiment 1) and behavioral resurgence (Experiment 2). During the extinction phase, the rates of responding were higher in the control group than in the mindfulness group, indicating that the mindfulness group was more sensitive to the contingencies and, thus, their prior performance extinguished more readily (Experiment 1). Moreover, rates of response in the extinction components less precisely reflected previous training in the mindfulness group, suggesting less resurgence of past behaviors after the mindfulness induction (Experiment 2). [ABSTRACT FROM AUTHOR]

The matching law suggests that behavior is emitted in proportion to the level of reinforcement available. The current study investigated this effect in individuals with autism spectrum disorders (ASD), and focused on the effects of magnitude of reinforcement (Study 1), and rate of reinforcement (Studies 2 and 3), on matching performance. Studies 1 and 2 employed lower functioning children with ASD, and demonstrated matching in both groups, but that the group with ASD displayed greater levels of stimulus bias. Study 3 employed higher functioning children with ASD, and found little evidence of matching, but higher stimulus bias in the group with ASD. These effects suggest a disruption of stimulus control, but not reward sensitivity, in individuals with ASD. [ABSTRACT FROM AUTHOR]

Stimulus over-selectivity occurs when one aspect of the environment controls behavior at the expense of other equally salient aspects. Participants were trained on a match-to-sample (MTS) discrimination task. Levels of over-selectivity in a group of children (4-18 years) with Autism Spectrum Disorders (ASD) were compared with a mental-aged matched typically-developing group. There was more over-selectivity in the ASD group. When retention intervals were added between the sample and comparisons in the MTS task, both groups showed an increased level of over-selectivity, with the ASD group showing a more pronounced effect. [ABSTRACT FROM AUTHOR]

This investigation aimed to determine if children with ASD are impaired in their ability to switch attention between different tasks, and whether performance is further impaired when required to switch across two separate modalities (visual and auditory). Eighteen children with ASD (9-13 years old) were compared with 18 typically-developing children matched with the ASD group for mental age, and also with 18 subjects with learning difficulties matched with the ASD group for mental and chronological age. Individuals alternated between two different visual tasks, and between a different visual task and an auditory task. Children with ASD performed worse than both comparison groups at both switching tasks. Moreover, children with ASD had greater difficulty when different modalities were required than where only one modality was required in the switching task in comparison with participants matched in terms of mental and chronological age. [ABSTRACT FROM AUTHOR]

The effects of fixed-time (FT) reinforcement schedules on the disruptive behavior of 4 students in special education classrooms were studied. Attention provided on FT schedules in the context of a multiple-baseline design across participants substantially decreased all students' challenging behavior. Disruptive behavior was maintained at levels lower than baseline throughout reinforcement thinning and follow-up phases. The results extend existing literature on the use of FT schedules of reinforcement and provide evidence that FT schedules of reinforcement can be practical to implement in special educational classroom settings. [ABSTRACT FROM AUTHOR]

Many individuals with autism spectrum disorders (ASD) have difficulty recognizing emotions in themselves and others. Three children (all males) participated in the study. In a multi-element design children with ASD were trained to tact situation-based emotions (i.e., 'happy', 'sad', 'angry', and 'afraid') using novel video based scenarios. To increase the likelihood that each child would learn a generalized repertoire of emotion understanding, multiple exemplars of emotion identification were trained using a multi-component procedure. The results indicated significant increases in tacting situation-based emotions. To evaluate the generalization of training, novel video stories were employed that depicted the trained emotions. The findings indicated generalization of situation-based emotional tacting to the novel video stories. [ABSTRACT FROM AUTHOR]

In the present study, we investigated the degree to which responding would resurge in children diagnosed with Autism Spectrum Disorders (ASD) following an intervening training period comprising different schedules of reinforcement. Twenty-four children of the ages 7-15, with a diagnosis of an ASD, were taught a play a sequence on a variable ratio- (VR) 3 schedule of reinforcement, during a 30-min session. The play sequence was then extinguished before the participants were taught a second play sequence, using a VR-4 schedule for 30 min, a VR-4 schedule for 60 min, or a VR-2 schedule for 30 min. A 5-min extinction session was then conducted to determine the impact that the intervening schedules had on the resurgence of the original behavior. The original sequence resurged to a greater extent for Group VR-4 30 min than it did for the other two groups. The results provide evidence that the length of time between initial training and testing is not a prime determinant of the level of resurgence, but that the amount of conditioning may play a stronger role: The greater the number of reinforcers received, the smaller the resurgence effect. [ABSTRACT FROM AUTHOR]

Binge eating is often associated with stress- induced disruption of typical eating patterns. Three experiments were performed with the aim of developing a potential model for this effect by investigating the effect of presenting response-independent stimuli on rats' lever-pressing for food reinforcement during both fixed-interval (FI) and fixed-ratio (FR) schedules of reinforcement. In Experiment 1, a response-independent brief tone (500-ms, I05-dB, broadband, noisy signal, ranging up to 16 kHz, with spectral peaks at 3 and 500 Hz) disrupted the performance on an FI 60-s schedule. Responding with the response-independent tone was more vigorous than in the absence of the tone. This effect was replicated in Experiment 2 using a within-subject design, but no such effect was noted when a light was employed as a disrupter. In Experiment 3, a 500-ms tone, but not a light, had a similar effect on rats' performance on FR schedules. This tone-induced effect may represent a release from response-inhibition produced by an aversive event. The implications of these results for modeling binge eating are discussed. [ABSTRACT FROM AUTHOR]

The aim of the four present experiments was to explore how different schedules of reinforcement influence schedule-induced behavior, their impact on evaluative ratings given to conditioned stimuli associated with each schedule through evaluative conditioning, and the transfer of these evaluations through derived stimulus networks. Experiment 1 compared two contrasting response reinforcement rules (variable ratio [VR], variable interval [VI]). Experiment 2 varied the response to reinforcement rule between two schedules but equated the outcome to response rate (differential reinforcement of high rate [DRH] vs. VR). Experiment 3 compared molar and molecular aspects of contingencies of reinforcement (tandem VIVR vs. tandem VRVI). Finally, Experiment 4 employed schedules that induced low rates of responding to determine whether, under these cir- cumstances, responses were more sensitive to the molecular aspects of a schedule (differential reinforcement of low rate [DRL] vs. VI). The findings suggest that the transfer of evaluative functions is determined mainly by differences in response rate between the schedules and the molar aspects of the schedules. However, when neither schedule was based on a strong response reinforcement rule, the transfer of evaluative judgments came under the control of the molecular aspects of the schedule. [ABSTRACT FROM AUTHOR]

In three experiments, we examined the effect of response-outcome relations on human ratings of causal efficacy and demonstrated that such efficacy ratings transfer to novel situations through derived stimulus relations. Causal efficacy ratings were higher, and probability of an outcome given a response was lower, for a differential reinforcement of high rate schedule than for either a differential reinforcement of low rate schedule (Experiment 1) or a variable interval schedule (Experiment 2). In Experiment 3, we employed schedules that were equated for outcome probability and noted that ratings of causal efficacy and the rate of response were higher on a variable ratio than on a variable interval schedule. For participants in all three experiments, causal efficacy ratings transferred to the stimulus present during each schedule and generalized to novel stimuli through derived relations. The results corroborate the view that schedules are a determinant of both response rates and causal efficacy ratings. In addition, the novel demonstration of a mechanism of generalization of these ratings via derived relations has clinical implications. [ABSTRACT FROM AUTHOR]

Two experiments examined whether over-selectivity is the product of a post-acquisition performance deficit, rather than an attention problem. In both experiments, children with Autistic Spectrum Disorder were presented with a trial-and-error discrimination task using two, two-element stimuli and over-selected in both studies. After behavioral control by the previously over-selected stimulus was extinguished, behavioral control by the previously under-selected cue emerged without direct training. However, this effect was only found in higher-functioning children, and not with more severely impaired children. These findings suggest that over-selectivity is not simply due to a failure to attend to all of the stimuli presented. They also suggest that extinction of over-selected stimuli may be a fruitful line of intervention for clinical intervention for some individuals. [ABSTRACT FROM AUTHOR]

The influence of stimulus salience on over-selective responding was investigated in the context of a comparator theory of over-selectivity. In Experiments 1 and 2, participants were presented with two cards, each displaying two colors. In comparison to matched control participants, participants with Autistic Spectrum Disorder (ASD) demonstrated more over-selectivity, which increased when the stimuli differed in salience. In Experiment 3, the over-selected color was extinguished, and the previously under-selected color emerged to control behavior. The results suggest that stimuli of different salience may trigger over-selectivity in individuals with ASD, and provide preliminary support that this may be due to the action of an over-sensitive comparator mechanism functioning at the retrieval level of processing. [ABSTRACT FROM AUTHOR]

This community-based study examined the influence of early teaching interventions on children diagnosed with Autistic Spectrum Disorders, and the dynamics between the time intensity of the interventions and parenting stress, on child outcomes. Intellectual, educational, and adaptive behavior and social functioning were all measured. Sixty-five children were divided into four groups, based on the levels of time intensity of their intervention, and on their parents’ stress levels. There were gains in intellectual, educational, and adaptive behavioral and social skills, and there was a positive relationship between the time intensity of the early teaching interventions and child outcome gains. More importantly, however, high levels of parenting stress counteracted the effectiveness of the early teaching interventions. [ABSTRACT FROM AUTHOR]

In three experiments, we examined the effect on the patterns of responding noted on fixed interval (FI) schedules of prior exposure to a range of interval and ratio schedules. Rats leverpressed for food reinforcement on random ratio (RR), random interval (RI), or variable interval (VI) schedules prior to transfer to F! schedules. In Experiment 1, prior exposure to an RR schedule retarded the development of typical FI patterns of responding. Exposure to a yoked RI schedule produced even greater retardation of typical FI performance. This effect was replicated in Experiment 2, using a within-subjects design. Rats responded on a multiple RR-RI schedule prior to a multiple FI-FI schedule. Typical FI performance emerged more slowly in the component previously associated with the RI than with that associated with the RR. In Experiment 3, exposure to an RR schedule retarded the development of F! performance to a greater extent than did exposure to a VR schedule. The latter schedule was programmed to allow the possibility that inhibitory control would develop after reinforcement. These results confirm that ratio schedules independently result in the disruption of FI responding. This effect was not long lasting and cannot be used plausibly to explain species differences in responding to FI schedules. However, it does suggest that temporal control-as manifested by the transfer of inhibitory control from one schedule to another-could facilitate movement between interval schedules. [ABSTRACT FROM AUTHOR]

The effectiveness of home-based early behavioral interventions for children (2:6–4:0 years old) with autistic spectrum disorders was studied over 9–10 months. Measures of autistic severity, intellectual, educational, and adaptive behavioral functioning were taken. There was no evidence of recovery from autism. High-intensity behavioral approaches (mean 30 h/week) produced greater gains than low-intensity programs (mean 12 h/week). Lovaas- and complete application of behavior analysis to schools approach-type interventions produced largest gains [similar to gains produced by longer-term clinic-based applied behavior analysis (ABA) programs]. Within the high-intensity groups, increased temporal input on the program was not associated with increased gains in the children. The results from clinic-based ABA trials were partially replicated on a home-based sample, using children with greater autistic and intellectual impairments. [ABSTRACT FROM AUTHOR]

In two experiments, food-deprived rat subjects leverpressed for food in three successive training phases. In the first phase of both experiments, rats were exposed to a multiple schedule, one component of which produced a high rate of response, and the other of which produced a lower rate of response (multiple random ratio ERR], random interval [RI] in Experiment 1, and multiple differential reinforcement of high rate, differential reinforcement of low rate in Experiment 2). Rats were then transferred to a multiple fixed interval (FI; 60-sec, 60-sec) schedule, until the effects of the first phase on response rate were no longer apparent and their response rates did not differ from those of rats responding on a multiple FI 60-see, FI 60-sec schedule without previously experiencing a multiple RR, RI schedule. During the third stage of training, all rats were placed into extinction. During extinction, rates of responding were higher in the component previously associated with the high rate of responding in Phase I, and they were lower in the component previously associated with low rates of responding in Phase 1. These results suggest that resurgence effects, like other history effects, are controlled by previous rates of responding. [ABSTRACT FROM AUTHOR]

The conditions under which stimulus over-selectivity occurred were studied using a matching-to-sample procedure with non-autistic adults. A matching-to-sample discrimination learning task with a number of sample-comparison retention intervals was used. The results demonstrated that an increase in retention interval increased the degree of stimulus overselectivity displayed. In addition, it was shown that the matching-to-sample procedure is suitable for eliciting overselectivity in a non-autistic adult sample. [ABSTRACT FROM AUTHOR]

Three experiments were performed to examine the effect of response force on rats' performance on various schedules of reinforcement. Response force was manipulated by changing the weight of the lever in the operant chamber—a heavy lever for high response force and a light lever for low response force. Using a within-subjects design, Experiment 1 replicated previous findings that rats respond more quickly on variable ratio (VR) than on equivalent variable-interval-plus-linear-feedback (VI+) schedules. Experiment 2 replicated this finding but also showed that the use of a smaller response force abolished the response rate difference between the VR and VI+ schedules. Experiment 3 used a between-subjects design and showed a response rate difference between the YR and VI+ schedules with a high response force but no response rate difference with a low response force. This suggests that under conditions of low force, when the rats' responding can continue at prolonged high rates, these subjects show little difference in their response rates between VR and VI+ schedules. These data are similar to those found for human subjects. [ABSTRACT FROM AUTHOR]

The present study explored whether a similar phenomenon to stimulus over-selectivity occurred in rats, in the hope of establishing a non-human model for the autism. Rats were serially presented with two-15 seconds, two-element compound stimuli prior to the delivery of food, in an appetitive classical conditioning procedure. Each compound stimulus consisted of two lights. Once the rats had acquired a conditioned response (CR) to the stimuli, they were presented with each of the component elements separately in extinction. The rats demonstrated greater conditioning to components of the compound presented just prior to reinforcement than to the components of the temporally distant compound. However, there was a smaller difference between CRs to the components of the compound presented just prior to reinforcement (i.e. less overshadowing) than between the components of the temporally distant compound. It is suggested that rats demonstrated a form of stimulus over-selectivity, resulting in greater overshadowing of one cue by another. Such results may form the basis of a viable non-human model of this symptom of autistic spectrum disorder. [ABSTRACT FROM AUTHOR]

A graduate level research methods and statistics course offered on the World-Wide Web was evaluated relative to the traditional lWith their consent, course members were randomly assigned to the two versions of the course for the first block of sessions. For the second block of sessions the groups crossed over to access the alternative version of the course. Quantitative and qualitative outcome data were collected to sample cognitive and affective domains. Improvements in knowledge and reductions in anxiety were apparent following both versions, with no significant differences between versions being detected. Analysis of course member comments indicated less satisfaction with the teaching input on the web-based version but more satisfaction with the peer collaboration that was stimulated. An activity theory framework is applied in conceptualising the findings and generating recommendations for further course development and evaluation. [ABSTRACT FROM AUTHOR]

Stimulus over-selectivity is a phenomenon displayed by individuals with autism, and has been implicated as a basis for many autistic-spectrum symptoms. In four experiments, non-autistic adult participants were required to learn a simple discrimination using picture cards, and then were tested for the emergence of stimulus over-selectivity, both with and without a concurrent task. Greater stimulus over-selectivity was noted when participants completed the concurrent task. The results are discussed in relation to the implications for the development of a model of memory deficits in autism. [ABSTRACT FROM AUTHOR]

The effect of various relationships between a response (an investment made in the context of a game) and an outcome (a return on the investment) on judgments of the causal effectiveness of the response was examined. In Experiment 1, response rates and causal judgments were higher for a differential-reinforcement-of-high-rate (DRH) schedule relative to a variable-ratio (VR) schedule with the same probability of outcome following a response. Response rates were also higher for a DRH than for a variable-interval schedule matched for reinforcement rate. In Experiment 2, response rates and causal judgments were lower for a differential-reinforcement-of-low-rate schedule relative to a VR schedule with the same probability of outcome following a response. These results corroborate the view that schedules are a determinant of both response rates and causal judgments, and that few current theories of causal judgment explicitly predict this pattern of results. [ABSTRACT FROM AUTHOR]

Examines the influence of a distractor during compound preexposure on latent inhibition. Effects of a nonreinforced presentation of a stimulus on the subsequent acquisition of a conditioned response; Information on the phenomenon of enhanced latent inhibition; Discussions regarding the modified associative interference account of latent inhibition.

Tests the effect of sequential exposure to a series of novel flavors on the subsequent neophobic response of water-deprived rats. Role played by generalization decrement in the generation of primary effects; Mechanisms controlling rats' memory; Investigation of any anomalies the test procedure may have introduced.