Six hen's preferences between 5-min access to each of two litter substrates, sand and sawdust, were measured using dependent concurrent VI 60 s VI 60 s schedules of reinforcement. The obtained preferences were small and idiosyncratic. Demand functions were generated separately for each of the two substrates by requiring the hens to perform under increasing FR schedules. The demand functions were disorderly, some were linear, some were of mixed elasticity, and others curved upwards. No clear relation between the individual hens' preference and demand measures was found. The overall response rates, running response rates and average post-reinforcement pause durations were atypical compared to previous demand research, possibly due to low levels of reinforcer collection, but were similar for individual subjects in both demand conditions. During the demand assessment, dustbathing took place in a similar proportion of reinforcers for each substrate. During the preference assessment, a greater proportion of dustbathing took place during sand reinforcers. Individual hens did not consistently dustbathe more in their preferred substrate. It was argued that the inconclusive results were a product of the substrates used. The atypical demand functions, response rates and average PRP durations may have been due to behaviour that was not schedule related occurring during key time (i.e., the subjects may have been continuing a dustbathing bout). It is possible, that the two substrates were too similar, and thus the subjects did not have a clear preference for one over the other. In future research preference should be assessed prior to demand, to ensure a clear preference can be obtained, with reinforcers that are qualitatively more different than those used in the present experiment.

BACKGROUND AND OBJECTIVES: Obesity is emerging as the most significant health concern of the twenty-first century. A wealth of neuroimaging data suggest that weight gain might be related to aberrant brain function, particularly in prefrontal cortical regions modulating mesolimbic addictive responses to food. Nevertheless, food addiction is currently a model hotly debated. Here, we conduct a meta-analysis of neuroimaging data, examining the most common functional differences between normal-weight and obese participants in response to food stimuli. DATA SOURCE: We conducted a search using several journal databases and adhered to the 'Preferred Reporting Items for Systematic Reviews and Meta-analyses' (PRISMA) method. To this aim, 10 studies were found with a total of 126 obese participants, 129 healthy controls, equaling 184 foci (146 increased, 38 decreased activation) using the Activation Likelihood Estimation (ALE) technique. Out of the 10 studies, 7 investigated neural responses to food versus non-food images. RESULTS: In response to food images, obese in comparison to healthy weight subjects had increased activation in the left dorsomedial prefrontal cortex, right parahippocampal gyrus, right precentral gyrus and right anterior cingulate cortex, and reduced activation in the left dorsolateral prefrontal cortex and left insular cortex. CONCLUSIONS: Prefrontal cortex areas linked to cognitive evaluation processes, such as evaluation of rewarding stimuli, as well as explicit memory regions, appear most consistently activated in response to images of food in those who are obese. Conversely, a reduced activation in brain regions associated with cognitive control and interoceptive awareness of sensations in the body might indicate a weakened control system, combined with hypo-sensitivity to satiety and discomfort signals after eating in those who are prone to overeat.

Automated systems for large-span roof truss optimization provide engineers with the flexibility to consider multiple alternatives during conceptual design. This investigation extends previous work on multi-objective roof truss optimization to include the design preferences of a human user. The incorporation of user preferences into the optimization process required creation of a mechanism to identify and model preferences as well as discovery of an appropriate location within the algorithm for preference application. The first stage of this investigation developed a characteristic feature vector to describe the physical appearance of an individual truss. The feature vector translates visual elements of a truss into quantifiable properties transparent to the computer algorithm. The nine elements in the feature vector were selected from an assortment of geometrical and behavioral factors and describe truss simplicity, general shape, and chord shape. Using individual feature vectors, a truss population may be divided into groups of similar design. Partitioning the population simplifies the feedback process by allowing users to identify groups that best suit their design preferences. Several unsupervised clustering mechanisms were evaluated for their ability to generate truss classifications that matched human judgment and minimized intra-group deviation. A one-dimensional Kohonen self-organizing map was selected. The characteristic feature vectors of truss designs within user-selected groups provided a basis for determining whether or not a user would like a new design. After analyzing user inputs, prediction algorithm trials sought to reproduce these inputs and apply them to the prediction of acceptable designs. This investigation developed a hybrid method combining rough set reduct techniques and a back-propagation neural network. This hybrid prediction mechanism was embedded into the operations of an Implicit Redundant Representation Genetic Algorithm. Locations within the ranking and selection processes of this algorithm formed the basis of a study to investigate the effect of user preference on truss optimization. Final results for this investigation prove that incorporating a user's aesthetic design preferences into the optimization project generates more design alternatives for the user to examine; that these alternatives are more in line with a user's conceptual perception of the project; and that these alternatives remain structurally optimal.

Abstract In many extant analyses of the impact of non-reciprocal system of trade preferences it is typical to focus on the details of market access value of tariff concessions as explanation for why export of beneficiaries’ products may or may not respond to incentives. Very often the role that supply-related factors can and do play in the process is relegated to the background. This paper argues that the social absorption capability of a beneficiary’s economy as expressed in her incumbent National System of Innovation is a crucial determinant of export performance response. The experience of sub-Sahara African countries under the US African Growth and Opportunity Act apparel trade incentive is used as a classical illustration of this proposition. It is shown that the comparative efficiency of Lesotho, despite emerging from a relatively weak performance potential background, in recording the highest level of export success among beneficiaries of the scheme is a function of the relative efficiency of her system of innovation in garment.

Preference assessments are an evidence-based procedures used to identify potential reinforcers for persons with developmental disabilities. There is a need to develop effective and efficient procedures to teach students and staff to conduct preference assessments, but only a small number of studies have been conducted and only two have used self-instructional materials. A recent study by Ramon et al. (2012) found that a self-instructional manual was more effective than a method description extracted from published articles for teaching university students to conduct multiple-stimulus without replacement preference assessments for persons with developmental disabilities. The present study extended this research by (a) adapting the self-instructional manual from Ramon et al. for online delivery, (b) adding video modeling as a teaching component, and (c) delivering the training package using a modified computer-aided personalized system of instruction (CAPSI, Pear and Kinsner, 1988). The training package was evaluated using a multiple-baseline design across three university students, replicated across three more students; and a multiple-baseline design across a pair of staff members, replicated a across a second pair. During the baseline phase, participants studied a two-page written description of the assessment procedure adapted from published studies. During the self-instructional manual phase, participants completed all of the following online: studied the self-instructional manual presented in eight units, viewed video demonstrations of the procedure, and completed review exercises scored by the computer program to demonstrate mastery of each study unit. Performance accuracy of each participant was scored using a standard behaviour checklist during a simulated preference assessment conducted following each phase. Clear and immediate improvement in performance accuracy was observed in all participants immediately following the self-instructional training package. Overall, students improved from a mean of 35% correct in baseline to a mean of 94% correct following CAPSI and staff improved from a mean of 23% correct in baseline to a mean of 87% correct following CAPSI. During retention and generalization assessments conducted from 7 to 17 days following self-instructional training, five of the six students and one of the four staff members performed at or above 85% correct (the mastery criterion). The findings showed that online delivery of the self-instructional manual plus video modeling has tremendous potential for providing an effective method for teaching a preference assessment procedure without face-to-face instruction.

Preference assessments are an evidence-based procedures used to identify potential reinforcers for persons with developmental disabilities. There is a need to develop effective and efficient procedures to teach students and staff to conduct preference assessments, but only a small number of studies have been conducted and only two have used self-instructional materials. A recent study by Ramon et al. (2012) found that a self-instructional manual was more effective than a method description extracted from published articles for teaching university students to conduct multiple-stimulus without replacement preference assessments for persons with developmental disabilities. The present study extended this research by (a) adapting the self-instructional manual from Ramon et al. for online delivery, (b) adding video modeling as a teaching component, and (c) delivering the training package using a modified computer-aided personalized system of instruction (CAPSI, Pear and Kinsner, 1988). The training package was evaluated using a multiple-baseline design across three university students, replicated across three more students; and a multiple-baseline design across a pair of staff members, replicated a across a second pair. During the baseline phase, participants studied a two-page written description of the assessment procedure adapted from published studies. During the self-instructional manual phase, participants completed all of the following online: studied the self-instructional manual presented in eight units, viewed video demonstrations of the procedure, and completed review exercises scored by the computer program to demonstrate mastery of each study unit. Performance accuracy of each participant was scored using a standard behaviour checklist during a simulated preference assessment conducted following each phase. Clear and immediate improvement in performance accuracy was observed in all participants immediately following the self-instructional training package. Overall, students improved from a mean of 35% correct in baseline to a mean of 94% correct following CAPSI and staff improved from a mean of 23% correct in baseline to a mean of 87% correct following CAPSI. During retention and generalization assessments conducted from 7 to 17 days following self-instructional training, five of the six students and one of the four staff members performed at or above 85% correct (the mastery criterion). The findings showed that online delivery of the self-instructional manual plus video modeling has tremendous potential for providing an effective method for teaching a preference assessment procedure without face-to-face instruction.

This study replicated the response-restriction free-operant procedures of Hanley et al. (2003) and expanded their study by comparing the results to that of a paired choice and multiple stimulus without replacement preference assessments. I also compared the results to a modified version of the Hanley et al. procedures. A statistical analysis was conducted with the hierarchies identified from each assessment using the Spearman Rank order to measure the correlation within and across participants. Finally, I analyzed the results of 32 free operant preference assessments to identify at what point preference was identifiable.

This study examined how differences in magnitude of stimuli across two categories stimuli affected preference when two different response requirements were incorporated into the preference assessments. Four adults with intellectual disabilities participated in the study. In Phase 1, one preferred leisure activity and one preferred edible stimuli were identified for each participant. In Phase 2, preference for the preferred leisure activity and preferred edible items were evaluated across two different magnitudes (high and low). In Phase 3, a reinforcer assessment was attempted to determine if there was a difference in the reinforcing properties of the preferred items as a function of magnitude. However, all participants responded at ceiling levels in a no reinforcement baseline. Thus, in Phase 4, the same from Phase 2 were presented with a work requirement component between the selection response and delivery of the selected stimulus during the preference assessment. The results of this study suggested that stimuli identified as high preferred when there was no response requirement also were identified as high preferred when there was a response requirement. However, fewer stimuli were selected when the response requirement was included, suggesting that adding a response requirement to the preference assessment may enhance the predictive validity of those assessments in identifying reinforcers. Key words: preference rank, type of preference, stimulus magnitude, reinforcing effects, leisure and edible stimuli

Embedded teaching procedures have become a recommended practice and a commonly implemented teaching strategy in early childhood classrooms. Embedded teaching is characterized by instructions and feedback regarding target skills being delivered within child-initiated activities during varied and typical routines. Although embedded teaching strategies have been widely adopted, little research has been conducted on the critical elements of embedded teaching. The purpose of this project is to determine the relative efficacy of and child preference for different embedded teaching conditions that vary in the rate of embedded teacher prompts. Three preschool aged children experienced three teaching conditions 1) Dense Condition (four embedded prompts per min were programmed), 2) Lean Condition (one embedded prompt per min was programmed) and 3) Control Condition (no embedded prompts). The relative efficacy of the teaching conditions were evaluated within a multielement design while a concurrent chains procedure was implemented to directly assess each child's preference for the teaching conditions. The dense and lean embedded teaching strategies were equally efficacious for teaching preschool children food name relations and the participant's preference assessment results were variable across the three participants. One participant showed a preference for the control condition, and the other two participant's preference was variable between the three conditions. The importance of choice making and using evidence based teaching strategies in preschool environments is discussed.

Choice overload is characterized by individuals experiencing a decrease in preference strength and satisfaction (Chemey, 2003) in conjunction with increases in disappointment and regret regarding a chosen option (Schwartz, 2000). Choice overload has been examined in a variety of situations, however choice overload has not been examined with individuals with developmental disabilities or during stimulus preference assessments. While extensive research has been conducted regarding stimulus preference assessments, no research has been conducted evaluating the most effective number of items to use during preference assessments. The purpose of the present study was to compare using six and 18 item arrays during a multiple stimulus without replacement preference assessment, to evaluate the accuracy of both procedures with a reinforcer assessment, and to evaluate the behavior of participants for characteristics of choice overload during the preference and reinforcer assessments. The results of the present study suggest that the results between the six and 18 item preference assessments are strongly consistent; however the six item assessments overestimated the reinforcer efficacy of numerous items in comparison to the 18 item preference assessment. The results also suggest that two participants displayed characteristics associated with choice overload and that a certain level of cognitive functioning may be required for choice overload to occur.