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Purpose Criminology both as a field of study and as a practice draws on a broad range of disciplines from the social, behavioural, human, natural and medical sciences. However, over recent times, the natural and medical sciences have been dismissed, overlooked and even ridiculed, largely since the rise of critical criminology and related contemporary conflict and social harm approaches from the 1960s onwards. This has led to a chasm emerging between the study of criminology and the practice of criminology such as within a policing context. This paper aims to provide a review of an emerging forensic biological method, that of neuroscience, within a criminological context, to illustrate the importance of criminology embracing and reawakening its natural and medical science roots. Design/methodology/approach The paper draws on a conceptual design to realign criminology with the full range of disciplines used to inform its theory and application. Findings Through illustrating the role of forensic neuroscience, the paper reawakens the scientific method and inquiry of criminology reflecting the importance of the discipline being, and remaining, multi- and trans-disciplinary in nature. The paper, while reflecting on the limitations of scientific method and inquiry, outlines the strengths this approach to criminology engenders, promoting and delivering a scientific-based research agenda that aims to support industry partners in the prevention, disruption and reduction of crime, disorder and threats to public security. Practical implications Firstly, it is important for criminology as a field of study to (re)engage with its scientific method and inquiry. Secondly, criminology, by engaging in robust scientific method and inquiry, has a significant contribution to make to professional practice and the work of industry professionals. Thirdly, while there are limitations to such scientific method and inquiry, it should not lead to this component of criminology being discarded. Fourthly, there is a need for contemporary research in the area of scientific method and inquiry and its application to criminological contexts, including that of police practice. Finally, by engaging in scientific method and inquiry that is evidence based, a chasm between the field of study and the practice associated with criminology can be addressed. Originality/value This paper addresses the gap between criminology as a field of study and as a practice by reengaging with scientific method and inquiry, illustrating the need and value of criminology being and remaining multi- and trans-disciplinary, ensuring professions underpinned by criminology are supported in their practice.

Animals in captivity can develop physiological characteristics such as obesity that could negatively affect their health. In the captive brushtail possum (Trichosurus vulpecula), it is unknown what effect long-term free-feeding has on body weight. In this study, which took place over 12 months, three possums were fed according to a free-feeding regime. Food intake was measured daily, and the possums were weighed every four days. The possums all gained weight but showed bouts of stable body weights across the year. Stability was evaluated using mathematical models. It was concluded that long-term free-feeding is not recommended for animals-in-waiting for use in operant experiments to mitigate weight gain due to overeating.

This study measured the responses of dogs to signals delivered via hand and voice signals. The study sought to determine whether dogs would display differential stimulus control when switching from a compound stimulus (auditory-visual) cue to presentation of only one of its elements. Twelve dogs performed a target behavior in response to a 2-element compound stimulus composed of a hand (visual modality) signal and a voice (auditory modality) signal. The mean percent correct responses to the visual element (M = 56.5, SD = 20.74) and the auditory element (M = 67.5, SD = 21.57) were both significantly lower than the 85% correct for the compound stimulus, P < 0.017. There was also evidence of a preference for one of the elements of the compound stimulus. The mean percent correct for the more favoured element (M = 77.25, SD = 12.53) was significantly higher than for the less favoured element (M = 46.75, SD = 17.2), P < 0.001. The identity of the favoured element was not consistent across the animals with 75% preferring the auditory element and 25% the visual element. This study contributes to an understanding of factors related to the stimulus control of learned behaviors. The differential control of behavior by alternative cues has implications for the training of assistance or service and other working animals with multiple cues. The results would strongly suggest that training with a compound stimulus is not appropriate if only elements of the compound stimulus are to be subsequently used.

This study investigated if meditators living in India (Eastern Meditators: EMs) differed from those living in Western countries (WMs) in self-reported levels of mindfulness, depression, anxiety, st...

This study investigated the effects of a brief mindfulness meditation induction on trait mindfulness, and its components, mind-wandering, and negative affect, in comparison to control conditions. Fifty-five non-meditators (M = 48 years, SD = 16 years; 62% female) completed pre- and post-intervention measures of trait mindfulness, negative affect, and both state and trait mind-wandering. Participants were randomly allocated to one of three 15 min intervention conditions: brief mindfulness meditation (MM) induction, progressive muscle relaxation (PMR; active control), or viewing a Ted Talk video (passive control). There were non-significant increases in trait mindfulness and its components, non-significant decreases in mind-wandering and negative affect, and the groups did not differ significantly from each other. However, medium and large within-group effect sizes were found for attention and non-judging, respectively with other effect sizes being either small or negligible. Time x condition interaction effect sizes were medium for trait mindfulness, acceptance, and non-judging, and small or negligible for all others. The 15-min brief mindfulness meditation induction was insufficient to produce statistically significant changes in trait mindfulness, attention, non-judging, mind-wandering or negative affect. Although the time x condition interaction for acceptance was significant, this relates to increases in the MM group in comparison to decreases in the control conditions, which needs further investigation. The medium within-group effect size for attention suggests that longer mindfulness meditation inductions may result in larger increased levels of attention. Larger samples are recommended for future studies, with longitudinal designs to determine any lasting beneficial impacts.

Objectives: The study investigated (1) if meditators and non-meditators differ in their levels of mindfulness, attention, acceptance, loving-kindness, compassion, joy, equanimity, and empathy; and (2) whether and how mindfulness practice affected the above qualities. Methods: The 241 participants (18–81 years, M = 40.3, SD = 14.8; 64% female) completed an online questionnaire consisting of scales measuring mindfulness components (mindful attention, acceptance, non-judging), and mindfulness related qualities, including loving-kindness, compassion, joy, equanimity, and empathy. The participants who reported being meditators (N = 122; 50.4%) were also asked questions about their meditation practice. Results: Meditators differed significantly from non-meditators in relation to their levels of mindful attention (t(239) = 4.80, p

This study assessed brushtail possums' performance on the Mechner counting procedure. Six brushtail possums were required to produce different Fixed-Ratio (FR) response targets by lever pressing. Their responses provided access to food reinforcement delivered either upon completing the target FR response requirement on a single lever or, in different conditions, on completing the target FR before producing an additional response on a second lever. The mean number of responses on the first lever before switching to the second lever typically occurred just above the target FR response requirement (FR: 4, 8, 16, 32 and 64). The variability in the number of switches between the levers around the target FR decreased from the first 10 days to the last 10 days, indicating an improvement in counting accuracy over sessions. The time to switch between the first and second lever was consistently variable across response requirements suggesting that it is unlikely the possums were using time to predict when to switch levers. This research further supports the use of the Mechner procedure as a method for measuring counting ability in animals and confirms the possibility of numerical competence in a marsupial species.

Weber’s law predicts that stimulus sensitivity will increase proportionally with increases in stimulus intensity. Does this hold for the stimulus of time – specifically, duration in the milliseconds to seconds range? There is conflicting evidence on the relationship between temporal sensitivity and duration. Weber’s law predicts a linear relationship between sensitivity and duration on interval timing tasks, while two alternative models predict a reverse J-shaped and a U-shaped relationship. Based on previous research, we hypothesised that temporal sensitivity in humans would follow a U-shaped function, increasing and then decreasing with increases in duration, and that this model would provide a better statistical fit to the data than the reverse-J or the simple Weber’s Law model. In a two-alternative forced-choice interval comparison task, 24 participants made duration judgements about six groups of auditory intervals between 100 and 3,200 ms. Weber fractions were generated for each group of intervals and plotted against time to generate a function describing sensitivity to the stimulus of duration. Although the sensitivity function was slightly concave, and the model describing a U-shaped function gave the best fit to the data, the increase in the model fit was not sufficient to warrant the extra free parameter in the chosen model. Further analysis demonstrated that Weber’s law itself provided a better description of sensitivity to changes in duration than either of the two models tested.

Detector dogs could be trained to find invasive insect pests at borders before they establish in new areas. However, without access to the live insects themselves, odor training aids are needed to condition dogs to their scent. This proof-of-concept study assessed 2 potential training aids for insect detection: a scent extract and dead specimens of the target species. Using Musgraveia sulciventris (Hemiptera: Tessaratomidae) as an experimental model, gas chromatography–mass spectrometry (GC-MS) analyses were carried out to compare the chemical headspaces that make up the odors of live specimens and these 2 training aids. This was then followed by canine scent-detection testing to investigate biosecurity detector dogs’ (n = 4) responses to training in an ecologically valid context. Both the scent extract and the dead specimens shared the majority of their volatile organic compounds (VOCs) with live insects. Of the dogs trained with scent extract (n = 2), both were able to detect the live insects accurately, and of those trained with dead specimens (n = 2), one detected the live insects accurately. These findings lend support for these training aids as odor-proxies for live insects—particularly scent extract, which is a relatively novel product with the potential for broad application to facilitate and improve insect-detection training.

This study investigated if trait mindfulness and its components, mindful attention, acceptance, and non-judging correlate negatively with self-reported and indirect markers of mind-wandering. The 552 participants of the study completed an anonymous online questionnaire consisting of trait mindfulness and mind-wandering scales. They also completed the computer-based Sustained Attention to Response Task (SART), an objective measure of mind-wandering. The total mindfulness score and acceptance and non-judging subscale scores were strongly negatively correlated with both self-reported trait mind-wandering (TMW) and SART indices of mind-wandering. In contrast, attention was significantly positively correlated with both. These findings suggest that trait mindfulness conceptualised as a multi-component construct, but not a uni-component one, is probably an opposing construct to trait mind-wandering. Furthermore, mindfulness and its components, acceptance and non-judging, are associated with a reduction in the more common form of SART errors. However, only the acceptance component made a unique contribution to the variance in TMW and SART performance. Therefore, it is advisable for researchers to specify whether they investigated mindfulness as a uni-component or multi-component construct. Furthermore, it would be beneficial if future research investigates the relationship of mindfulness and its components with mind-wandering further by also incorporating a measure of state mindfulness.

“Peak Shift” usually occurs following intradimensional-discrimination training and involves a shift of the peak of the generalization gradient away from the original discriminative stimulus (S+) in a direction away from an S-. Two theoretical accounts of peak shift, the gradient interaction theory (GIT) and adaptation level theory (ALT), were compared. The effects of asymmetric test stimuli and the impact of instructions to participants for them to treat stimuli as members of categories on generalization gradients were investigated. In Experiment 1, the relation between peak shifts obtained when an extended asymmetric set of test stimuli was employed and the occurrence of categorization of the stimuli involved was investigated in four separate conditions. Two involved temporal discrimination, one involved line-angle discrimination, and one involved a compound line-angle and temporal cue discrimination. If participants treated the stimuli as belonging to discrete categories, such as hands-on a clock, rather than as being on continuous dimensions then responding to the compound cue was expected to result in attenuation of blocking of a peak shift. However, the peak shift obtained to the three cue types were the same. In Experiment 2, an independent group of participants was given explicit instructions to treat the line angles as if they were the hands of a clock face and this eliminated peak shift. The results from the present experiments support an ALT interpretation, although the peak shifts were significantly smaller in magnitude than predicted by this account.

This study evaluated the ability of Killeen's (1994) Mathematical Principles of Reinforcement to account for the effects of changes in reinforcer quality on hens' rates of responding on fixed-ratio schedules. Hens were trained to peck a key on a fixed-ratio schedule of reinforcement and then experienced an ascending series of ratio values in two separate conditions. In different conditions, the food reinforcer was either wheat or puffed wheat. Response rates initially increased with increases in ratio requirement before eventually decreasing at larger ratios. Quantitative fits of the model accounted for the data well. The fits revealed that different foods were systematically associated with changes in the specific activation parameter, a, and these were consistent with previous reports of preference for those food items.

Debates about the utility of p values and correct ways to analyze data have inspired new guidelines on statistical inference by the American Psychological Association (APA) and changes in the way results are reported in other scientific journals, but their impact on the Journal of the Experimental Analysis of Behavior (JEAB) has not previously been evaluated. A content analysis of empirical articles published in JEAB between 1992 and 2017 investigated whether statistical and graphing practices changed during that time period. The likelihood that a JEAB article reported a null hypothesis significance test, included a confidence interval, or depicted at least one figure with error bars has increased over time. Features of graphs in JEAB, including the proportion depicting single-subject data, have not changed systematically during the same period. Statistics and graphing trends in JEAB largely paralleled those in mainstream psychology journals, but there was no evidence that changes to APA style had any direct impact on JEAB. In the future, the onus will continue to be on authors, reviewers and editors to ensure that statistical and graphing practices in JEAB continue to evolve without interfering with characteristics that set the journal apart from other scientific journals.

Weber's law predicts that stimulus sensitivity will increase proportionally with increases in stimulus intensity. Does this hold for the stimulus of time - specifically, duration in the milliseconds to seconds range? There is conflicting evidence on the relationship between temporal sensitivity and duration. Weber's law predicts a linear relationship between sensitivity and duration on interval timing tasks, while two alternative models predict a reverse J-shaped and a U-shaped relationship. Based on previous research, we hypothesised that temporal sensitivity in humans would follow a U-shaped function, increasing and then decreasing with increases in duration, and that this model would provide a better statistical fit to the data than the reverse-J or the simple Weber's Law model. In a two-alternative forced-choice interval comparison task, 24 participants made duration judgements about six groups of auditory intervals between 100 and 3,200 ms. Weber fractions were generated for each group of intervals and plotted against time to generate a function describing sensitivity to the stimulus of duration. Although the sensitivity function was slightly concave, and the model describing a U-shaped function gave the best fit to the data, the increase in the model fit was not sufficient to warrant the extra free parameter in the chosen model. Further analysis demonstrated that Weber's law itself provided a better description of sensitivity to changes in duration than either of the two models tested.

Hens responded under multiple fixed-ratio schedules with equal response requirements and either a 1-s or a 6-s reinforcer. Upcoming reinforcer size was indicated by key color. Components were presented in a quasirandom series so that all four component transitions occurred. Postreinforcement pauses were affected by the upcoming and preceding reinforcer size, with longer pauses after large reinforcers followed by small reinforcers than when followed by large ones, and longer pauses after small reinforcers that were followed by small reinforcers rather than large ones. Pauses increased with fixed-ratio size and the effects of reinforcer size were larger the larger the ratio. When reinforcer size was not signaled-mixed fixed-ratio schedules-pauses were shorter after small than after large reinforcers. Signalling the upcoming reinforcer attenuated the effect of the previous reinforcer size on pause duration when small was followed by small and when either small or large by large, but enhanced the effect when large was followed by small. There was no effect of reinforcer size on pause duration when single fixed-ratio schedules were arranged. The effects of reinforcer size on pauses depends on the size and range of the fixed ratios as well as the exact procedures used in the study.

Domestic dogs completed a temporal bisection procedure that required a response to one lever following a light stimulus of short duration and to another lever following a light stimulus of a longer duration. The short and long durations across the four conditions were (0.5&ndash, 2.0 s, 1.0&ndash, 4.0 s, 2.0&ndash, 8.0 s, and 4.0&ndash, 16.0 s). Durations that were intermediate, the training durations, and the training durations, were presented during generalization tests. The dogs bisected the intervals near the geometric mean of the short and long-stimulus pair. Weber fractions were not constant when plotted as a function of time: A U-shaped function described them. These results replicate the findings of previous research reporting points of subjective equality falling close to the geometric mean and also confirm recent reports of systematic departures from Weber&rsquo, s law.

Simple Summary Dogs are valued for their odor detection capabilities in a vast range of fields. They help to find hidden and elusive targets, such as explosives, narcotics, missing persons, and invasive or endangered species, amongst an extensive list. In all these roles, dogs are required to find real target odors that vary somewhat from those with which they were trained. For example, dogs might be trained with an explosive mixture or certain explosive compounds, and then must be able to find homemade explosives of differing compositions or manufacturing processes. This ability, to respond to similar odors in the same way as they would respond to the originally trained odor, is known as generalization. A failure to generalize can result in dogs missing targets in working scenarios. Although generalization is usually desired to some extent, dogs must also discriminate against related odors that are not targets. Therefore, research that investigates factors that can influence dogs’ tendency to generalize, and conversely to discriminate, can inform training strategies to improve detection outcomes. However, this field requires further research with greater application to practical training. Abstract Generalizing to target odor variations while retaining specificity against non-targets is crucial to the success of detector dogs under working conditions. As such, the importance of generalization should be considered in the formulation of effective training strategies. Research investigating olfactory generalization from pure singular compounds to more complex odor mixtures helps to elucidate animals’ olfactory generalization tendencies and inform ways to alter the generalization gradient by broadening or narrowing the range of stimuli to which dogs will respond. Olfactory generalization depends upon both intrinsic factors of the odors, such as concentration, as well as behavioral and cognitive factors related to training and previous experience. Based on the current research, some training factors may influence generalization. For example, using multiple target exemplars appears to be the most effective way to promote elemental processing and broaden the generalization gradient, whereas increasing the number of training instances with fewer exemplars can narrow the gradient, thereby increasing discrimination. Overall, this research area requires further attention and study to increase our understanding of olfactory generalization in dogs, particularly detector dogs, to improve training and detection outcomes.

The effective and quick assessment of food preference is important when attempting to identify foods that might function as effective reinforcers in dogs. In the current experiment a food preference assessment was conducted where more highly preferred foods were expected to be associated with faster approaches in a subsequent runway task. Eight dogs were tested in a paired preference assessment offering combinations of two of six types of raw food, including the dog’s staple diet, to identify a rank order of preference for the foods. A different raw food was offered as the staple in two preference tests. The results showed that the staple foods were not preferred as highly as the other foods and that each dog displayed unique and stable preferences for the different foods. In the runway task the dogs were required to walk five metres to obtain a small amount of their most preferred, least preferred or staple foods and latency of approach to the foods was recorded. The approach latencies were faster for their most preferred food compared to their least preferred and the staple foods. The use of a runway to assess reinforcer effectiveness combined an effortful behaviour to obtain food while also requiring the dogs to make a choice, thus precluding the need for more complicated and time-consuming methods of preference assessment. The application of this method for fast and effective identification of preferred reinforcers is currently being investigating further to inform pet owners of simple methods to increase their training successes. Owners of raw food fed dogs are advised to conduct a preference assessment to identify their dogs most preferred food for use as a reinforcer during training.

Many diverse species have demonstrated interval timing, the ability to respond appropriately to time in the range of seconds to minutes, suggesting that an ability to time is adaptive. The peak procedure is a common method of studying interval time perception. In the peak procedure, animals experience a mix of fixed-interval (FI) and extinction (EXT) trials. On EXT trials, responding typically increases to a peak at the time the FI schedule would normally deliver reinforcers before decreasing. Responding on different FI schedules within the peak procedure has been found to conform to Weber's law, whereby response variability is proportional to the length of the fixed interval. We conducted possibly the first investigation of the timing abilities of a marsupial common to Australia and New Zealand, the brushtail possum (Trichosurus vulpecula), using FI 15-, 30-, and 60-s schedules of reinforcement in the peak procedure. Response rates on EXT trials peaked at the time of usual reinforcer delivery, decreasing at longer time intervals, and were well fit by 3-parameter Gaussian curves, demonstrating the ability of possums to respond to time-based stimuli. Coefficients of variation suggested that the ability of possums to time was less accurate than that of mammals, but similar to that of birds, invertebrates, and reptiles. Coefficients of variation did not differ consistently over increasing FI intervals, showing that timing responses of possums likely conforms to the scalar property of timing also shown by other species. (PsycINFO Database Record

The aim of this study was to compare the demand for food under concurrent progressive- and fixed-ratio schedules. Twelve brushtail possums participated in 16 conditions where schedule, progression and food type were varied. An incrementing schedule increased the fixed-ratio requirement within and across sessions and was arranged as either a geometric sequence (base 2), or an arithmetic sequence (step 5). Two foods were tested: a flaked barley and coco-pop(®) mix versus rolled oats. Overall, performance was similar for most possums in the within- and across-session incrementing schedules. An analysis of the estimates of essential value and break point produced the same account of demand for foods under the geometric or arithmetic progressions and within- and across-session procedures for 8 of 12 possums. Six possums showed higher demand for rolled oats compared to flaked barley, and two possums showed higher demand for flaked barley compared to rolled oats. Incrementing ratios within, rather than between sessions using an arithmetic progression was demonstrated to be a time efficient procedure for investigating demand for different food types without affecting conclusions about the relative demand for those foods.

In procedures used to study timing behavior, the availability of reinforcement changes according to time since an event. Manipulation of this reinforcer differential often produces violations of scalar timing, but it is unclear whether such effects arise because of a response bias or a change in temporal discrimination. The present experiment investigated the effects of the overall and relative probability of obtaining a reinforcer on performance in the free-operant psychophysical procedure. We arranged short and long trials with unequal reinforcer ratios, at high or low overall reinforcer rates. Changes in the overall reinforcer rate produced only small changes in timing behavior. Changes in relative reinforcer probability, which caused differences in the likely availability of reinforcers across time within a trial, produced a change in both bias and discrimination. We suggest reinforcers affect timing, and that discrimination in timing tasks depends on the distribution of reinforcers in time, as well as on the interval to be timed.

Action video game play as a form of cognitive training shows promise, but has not been widely tested with participants exclusively over age 80 years. Age-related decline in executive function produces widely varying levels of ability to function independently. This study aimed to examine the change in executive functioning after a 3-week action video game intervention in healthy adults aged 80–97 years living in residential care. Participants were randomly assigned to either an experimental or care-as-usual control group: experimental participants played Star Wars Battlefront©, a commercially available video game, for six supervised sessions of 30 min each. Participants completed neuropsychological and quality of life assessments pre-training, post-training, and one month later. The experimental group showed significant improvement in the visual attention and task switching domains, in both post-test and follow-up sessions. Working memory also improved in the experimental group; however, after one month of no game play, memory performance regressed toward baseline levels. Results support the incorporation of video game play as a leisure option for older adults, which may also play a role in enhancing cognitive health. The findings extend previous research conducted below age 80 years to the oldest-old, an age group in which longitudinal follow up data is limited.

Debates about the utility of p values and correct ways to analyze data have inspired new guidelines on statistical inference by the American Psychological Association (APA) and changes in the way results are reported in other scientific journals, but their impact on the Journal of the Experimental Analysis of Behavior (JEAB) has not previously been evaluated. A content analysis of empirical articles published in JEAB between 1992 and 2017 investigated whether statistical and graphing practices changed during that time period. The likelihood that a JEAB article reported a null hypothesis significance test, included a confidence interval, or depicted at least one figure with error bars has increased over time. Features of graphs in JEAB, including the proportion depicting single-subject data, have not changed systematically during the same period. Statistics and graphing trends in JEAB largely paralleled those in mainstream psychology journals, but there was no evidence that changes to APA style had any direct impact on JEAB. In the future, the onus will continue to be on authors, reviewers and editors to ensure that statistical and graphing practices in JEAB continue to evolve without interfering with characteristics that set the journal apart from other scientific journals.

This study examined whether trained variability would generalize across dimensions of the target response. Two experiments used a computerized rectangle drawing task that required participants to click and drag a mouse cursor to create rectangles on a computer screen. In Experiment 1, one group received points when successive rectangles varied in their size, shape and location (VAR), another group were yoked to the VAR group and received points that were allocated to them using a yoking procedure (YOKE), regardless of the variability in the size, shape or location of the rectangle drawn. Variability was higher for a dimension when variability on that dimension was directly reinforced. In Experiment 2, three groups of participants received points when rectangles varied on two dimensions; each group differed in the two dimensions that required variation. Variability was again higher for the reinforced dimensions for two of the three groups. Comparison with the YOKE group showed that the variability on those dimensions where variability was not directly reinforced was affected by reinforcement for variability on the other dimensions. Specifically, the variability in Shape and Location was significantly higher when these two dimensions occurred with other dimensions where variability was reinforced (as in Experiment 2) compared to when they were not required to vary (as in the YOKE group). This suggests that, for these two groups, the reinforced variability on the other two dimensions generalized to the third dimension. Implications of this finding to our understanding of factors that promote behavioral variability are discussed.

The current research examined the ability of dogs to discriminate between different amounts of food. Using a two-alternative-forced-choice procedure, dogs were required to discriminate between a constant amount of 4 pieces of food and another amount that varied across a range from 1 to 7 pieces. The dogs reliably selected the larger of the two alternatives. Discrimination was better when there were fewer than rather than more than 4 pieces of food available on the varying alternative. Specifically, 1 piece was discriminated from 4 pieces more easily than 4 pieces were discriminated from 7 pieces of food. These results confirmed the ability of dogs to discriminate food amount on a psychophysical choice procedure. This research addresses a question fundamental to theories of reinforcement of why reinforcer magnitude does not always control behavior in an intuitive way. We argue that the relative difficulty of discriminating smaller from larger amounts of food is an important factor in understanding the impact of reinforcer magnitude in the development of reinforcer control over behavior

When conducting controlled laboratory studies with non-traditional laboratory animals it is important that methods for determining body weight stability are reliable. This helps ensure the health and welfare of animals when they are maintained during periods of free feeding or food restriction. This study compared different methods for determining body weight stability in six common brushtail possums ( Trichosurus vulpecula) maintained on a free-feeding diet under laboratory conditions. A criterion of five consecutive weighings with less than ±2.5% change across days and no more than two consecutive days of weight loss or weight gain was judged to be the most suitable criteria for determining stability. It is important to study non-traditional animals, especially endangered or pest species, under controlled laboratory conditions and to have robust methods for establishing body weight stability.

This study aimed to assess the role of reinforced behavioral variability in the learning of a 6- digit target sequence (211212) with 3 groups of human participants (n = 39). For the first group (Control), only the target sequence was reinforced. For the second group (Any), the target sequence was reinforced, and any sequence other than the target sequence could be reinforced on a variable interval 60-s schedule. For the third group (Variable), the target sequence was reinforced, and any sequence other than the target sequence could be reinforced on a variable interval 60-s schedule, if it met a variability criterion. The Control group produced the target sequence significantly more often than the Variable group by the end of the experimental sessions. These findings contradict previous studies with rats that have shown that reinforcement of behavioral variability facilitates the learning of difficult response sequences but are consistent with results from previous studies with humans. Potential reasons for this disparity are discussed.

Hens responded under multiple fixed-ratio schedules with equal response requirements and either a 1-s or a 6-s reinforcer. Upcoming reinforcer size was indicated by key color. Components were presented in a quasirandom series so that all four component transitions occurred. Postreinforcement pauses were affected by the upcoming and preceding reinforcer size, with longer pauses after large reinforcers followed by small reinforcers than when followed by large ones, and longer pauses after small reinforcers that were followed by small reinforcers rather than large ones. Pauses increased with fixed-ratio size and the effects of reinforcer size were larger the larger the ratio. When reinforcer size was not signaled-mixed fixed-ratio schedules-pauses were shorter after small than after large reinforcers. Signalling the upcoming reinforcer attenuated the effect of the previous reinforcer size on pause duration when small was followed by small and when either small or large by large, but enhanced the effect when large was followed by small. There was no effect of reinforcer size on pause duration when single fixed-ratio schedules were arranged. The effects of reinforcer size on pauses depends on the size and range of the fixed ratios as well as the exact procedures used in the study.

This study evaluated the impact of a team-skills training intervention on students’ subjective experience of workload when working in collaborative groups. Three cohorts of students (N = 295) taking an undergraduate degree unit were compared across three successive years, in which presence or absence of training was varied. Students in trained groups reported lower levels of subjective workload than those in untrained groups and also performed better across a range of academic exercises. This effect was moderated by whether students were regrouped half-way through the academic year. Results are discussed in terms of theories of team-skill acquisition and issues in skill transferability caused by regrouping.

We propose a novel method to dissociate incentive motivation from memory and motor processes in instrumental performance. Components of a multiple fixed-ratio schedule of food reinforcement were adjusted to envelop the range of response requirements that maintained lever pressing by rats. We sought to manipulate motivation for food rewards with acute administrations of various doses (0-10 mg/kg) of fluoxetine, a 5-HT reuptake inhibitor that reduces food intake. A quantitative model of fixed-ratio performance derived from Killeen's (1994) Mathematical Principles of Reinforcement (MPR) provided an adequate account of data from individual rats. Decreases in response rate resulting from fluoxetine were reflected in changes in estimates of activation, indexed by MPR parameter a; estimates of working memory capacity and lever pressing duration were not systematically affected. These results support the use of MPR parameter a to index incentive motivation using multiple fixed-ratio schedules that are adjusted to individual performance.

Three experiments investigated temporal generalization in humans. In Experiment 1, a peak shift effect was produced when participants were given intradimensional discrimination training. In Experiment 2, after training with a standard S1 and generalization testing with an asymmetrical series of durations, generalization gradients moved toward the prevailing adaptation level. In Experiment 3, generalization gradients showed a central tendency shift and moved away from the S1 and toward the mean of the test series (of 11 stimulus durations) after participants received training with S1 and S2 durations that in one condition were the 2nd and 4th and in another condition were the 4th and 2nd stimuli in the series, respectively. The results were inconsistent with an absolute account of peak shift but were consistent with an adaptation level account of peak shift.

Author(s): Cameron, Kristie E.; Bizo, Lewis A.; Starkey, Nicola J. | Abstract: The aim of this study was to compare the demand by possums for foods under different arrangements of concurrent progressive-ratio and fixed-ratio schedules of reinforcement. In Experiment 1, every possible food pair made up of berries, chicken, egg, foliage, insects and mushroom was presented (30 pairs in total). The requirement on the progressive-ratio schedule increased within a session and the fixed-ratio was kept constant at 30. In Experiment 2, a subset of the foods from Experiment 1 were used (chicken, mushroom, egg and berries) and in separate conditions the fixed-ratio was either 30 or 10 responses. In Experiment 3, the foods were the same as used in Experiment 2 and the progressive-ratio schedule increased every five sessions and the fixed-ratio schedule was 30 responses. Exponential models of demand were applied to consumption rates to compare the parameters of initial demand, essential value and P max, and break point and cross point across foods. The models described the data well and consumption rates were similar when the incrementing schedules increased within- and across sessions. Demand was highest for berries, egg and locust in Experiment 1 and egg and chicken in Experiments 2 and 3. This finding has practical implications for understanding possum food preferences in the wild as a function of other available food sources.

This study investigated the effects of team-skills training on collaborative learning in a university setting. Groups worked under one of three conditions: (1) groups received team-skill training as a group and remained in that group (Trained-Together), (2) groups received team-skills training, but were then reassigned into new groups (Trained-Reassigned), and (3) groups received no training (Untrained). Each group completed a collaborative task and then group members were tested on the material learned. Scores were highest in the Trained-Together and lowest in the Untrained condition. Results are explained in terms of levels of planning, time management, distribution of effort and strategies adopted.

Despite a vast literature on collaborative learning (CL), there is little research on preparing students to work collaboratively.This two-phase evaluation investigated whether team-skills training could enhance the performance of collaborative groups through the introduction of a team development programme to a group-based undergraduate key-skills unit.Phase 1 compared two consecutive cohorts of second-year students, Cohort 1 (N = 94) who received no preparation, and Cohort 2 (N = 113) who received team-skills training. Phase 2 added Cohort 3 (N = 88), who also received team-skills training, to extend the analysis.In Phase 1, students in both Cohorts 1 and 2 worked on a series of curriculum based key-skill tasks across two semesters. Students worked in one group in Semester 1 and were then formed into new groups for Semester 2. Effects of the training were measured by student group marks and key-skill ratings.Marks and key-skill ratings were significantly higher for the trained cohort in Semester 1 (p.01). However, in Semester 2 performance reduced for the trained cohort in comparison to Semester 1. To explore this further, Phase 2 of the study evaluated Cohort 3, where after training, collaborative groups remained intact throughout the academic year. Results for Cohort 3 showed no attenuation of performance effects in Semester 2.Phase 1 results support the use of team-skills training to enhance CL group performance. The findings for Phase 2 suggest that these benefits may be lost if training groups are disrupted.

The current study examined the effects of the D2 agonist (quinpirole) and D2 antagonist (eticlopride) on temporal discrimination performance in a conditional discrimination task (Experiment I) and a delayed conditional discrimination task (Experiment II). In both experiments rats discriminated between a scheduled stimulus duration of 3 s versus 9 s. Consistent with previous reports, overall discrimination performance decreased in a dose-dependent manner with both drugs. Changes in response bias (the tendency to choose-short or choose-long irrespective of actual stimulus duration), however, were best characterized in terms of both drugs tending to attenuate the bias effects normally observed during baseline drug-free performance. Specifically, the 'choose-short' bias observed in Experiment I and at a relatively short, 0.1 s, delay in Experiment II became less extreme with increasing doses. In addition, the 'choose-long' bias observed at a relatively long, 6 s, delay in Experiment II also became less extreme with increasing doses. Thus, whether there was an apparent shift from a short response bias to long, or vice versa, was the product of the delay interval between stimulus presentation and choice rather than whether the drug in question was a D2 agonist or antagonist. Such an attenuation of bias may have arisen because of subjects confounding the delay interval with the actual discriminative stimulus duration.

Participants were exposed to 3 conditions in a between­ groups design. Participants were told the experiment was about extrasensory perception and were asked to select the word from a pair of words that they thought the experimenter was thinking about. In 1 condition selections of the word with a double letter were reinforced with positive verbal feedback, and in another condition selections of nondouble letters were reinforced. The word selections of a control group were reinforced according to a random and predetermined order. By the end of the experimental session, participants who were reinforced for selecting a particular type of word, double letter or nondouble letter, selected that word significantly more than the alternative that was not associated with reinforcement and those participants in the control group selected the double-letter and nondouble-Ietter words equally often. In a postexperimental questionnaire none of the participants reported an awareness of the contingency. The present experiment replicates and extends previous work and confirms that participants' behavior can be modified by reinforcement without the participants' conscious awareness of the contingency.

The effects of praise on student on‐task behaviour, academic self‐concept and numeracy enjoyment were investigated. Four year four classes and their teachers participated. Two teachers were instructed to use specific praise and two to use positive praise. Classes were independently observed on four occasions, twice before and twice after the praise intervention. Student on‐task behaviour, numeracy enjoyment and academic self‐concept were measured and teachers’ use of praise was observed. Specific praise promoted more on‐task behaviour than positive praise and significantly increased academic self‐concept. Ratings of numeracy enjoyment were not significantly affected. Implications of this research for teaching practice are discussed. Summary of praise types from Harrop and Swinson (2000) Praise typeDefinitionIndividualAny response given to a single pupil following the pupil's behaviourGroupResponse given to more than one pupil following their behaviour (e.g., “That's good Chris and Alex, you are sitting st...

Rats’ leverpressing was reinforced on variable-ratio (VR) schedules. As ratio values increased, response rates initially increased with them, then eventually decreased. In Experiment 1, rates were uniformly higher with one-pellet reinforcers than with two-pellet reinforcers—theparadoxical incentive effect. Killeen’s (1994) mathematical principles of reinforcement (MPR) described the data quantitatively but failed to predict the advantage for the one-pellet condition. In Experiment 2, rats received one-, two-, and three-pellet reinforcers with counterbalanced preloads of pellets; the continued superiority of the smaller reinforcers ruled out a satiation explanation. Experiment 3 introduced a 20-sec intertrial interval (ITI), and Experiment 4 filled the ITI with an alternate response to test a memorial/overshadowing explanation. In Experiment 5, the rats received one or two standard grain pellets or one sucrose pellet as reinforcers over an extended range of ratios. Once again, rates were higher for one than for two pellets at short to moderate VR values; thereafter, two pellets supported higher response rates. The diminution of the effect in Experiment 3 and its reversal in Experiment 4 and in Experiment 5 at large ratios provided evidence for overshadowing and reconciled the phenomenon with MPR.

We attempted to demonstrate that timing performance on a temporal discrimination would be enhanced if rats were required to fill a duration with behavior than when they were not required to respond. Six rats were trained to discriminate between a 3- and 9-s stimulus in a symbolic-matching-to-sample task. In two conditions, a tone was used to signal the sample, and in the other two conditions, a light was used to signal the sample. In two conditions, the rats were required to respond on a lever mounted on the rear wall of the experimental chamber before making their discriminative response to one of the two levers mounted on the front wall of the experimental chamber. In the other two conditions, the rear lever was not presented during sample presentation, and no response was required. Consistent with our predictions, timing performance was significantly better when a lever-response was required during sample presentation than when no response was required.

The behavioral theory of timing assumes that timing is governed by a pacemaker whose pulses move organisms from one state to the next, and that the speed of the pacemaker covaries with the rate of reinforcement in the experimental context. The goal of the present experiments was to clarify just what constitutes that context. In Experiment 1, pigeons responded on signaled fixed-interval 20-sec and 40-sec schedules of food reinforcement that were presented randomly within sessions (alternating condition) or between sessions (isolated condition). In Experiment 2, pigeons categorized the duration of a short or a long set of intervals in the alternating or the isolated condition. Performance in both experiments was under strong control by the signals, with scalar timing between long and short sets, but no significant differences between the alternating and isolated conditions. The context of reinforcement that determines pacemaker period can thus be specific to a particular timing task and signal.

Mathematical principles of reinforcement were developed in order to (1) account for the interaction of target responding and other behavior; (2) provide a simple graphical representation; (3) deal with measurement artifacts; and (4) permit a coherent transition from a statics to a dynamics of behavior. Rats and pigeons were trained to make a target response while general activity was measured with a stabilimeter. The course of behavioral change was represented as a trajectory through a two-dimensional behavior space. The trajectories rotated toward or away from the target dimension as the coupling between the target response and the incentive was varied. Higher rates of reinforcement expanded the trajectories; satiation and extinction contracted them. Concavity in some trajectories provided data for a dynamic generalization of the model.