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Although choice between two alternatives has been widely researched, fewer studies have examined choice across multiple (more than two) alternatives. Past models of choice behavior predict that the number of alternatives should not affect relative response allocation, but more recent research has found violations of this principle. Five pigeons were presented with three concurrently scheduled alternatives. Relative reinforcement rates across these alternatives were assigned 9:3:1. In some conditions three keys were available; in others, only two keys were available. The number of available alternatives did not affect relative response rates for pairs of alternatives; there were no significant differences in behavior between the two and three key conditions. For two birds in the three‐alternative conditions and three birds in the two‐alternative conditions, preference was more extreme for the pair of alternatives with the lower overall pairwise reinforcer rate (3:1) than the pair with higher overall reinforcer rate (9:3). However, when responding during the changeover was removed three birds showed the opposite pattern in the three‐alternative conditions; preference was more extreme for the pair of alternatives with the higher overall reinforcer rate. These findings differ from past research and do not support established theories of choice behavior.  相似文献   
154.
    
Choice behavior among two alternatives has been widely researched, but fewer studies have examined the effect of multiple (more than two) alternatives on choice. Two experiments investigated whether changing the overall reinforcer rate affected preference among three and four concurrently scheduled alternatives. Experiment 1 trained six pigeons on concurrent schedules with three alternatives available simultaneously. These alternatives arranged reinforcers in a ratio of 9:3:1 with the configuration counterbalanced across pigeons. The overall rate of reinforcement was varied across conditions. Preference between the pair of keys arranging the 9:3 reinforcer ratio was less extreme than the pair arranging the 3:1 reinforcer ratio regardless of overall reinforcer rate. This difference was attributable to the richer alternative receiving fewer responses per reinforcer than the other alternatives. Experiment 2 trained pigeons on concurrent schedules with four alternatives available simultaneously. These alternatives arranged reinforcers in a ratio of 8:4:2:1, and the overall reinforcer rate was varied. Next, two of the alternatives were put into extinction and the random interval duration was changed from 60 s to 5 s. The ratio of absolute response rates was independent of interval length across all conditions. In both experiments, an analysis of sequences of visits following each reinforcer showed that the pigeons typically made their first response to the richer alternative irrespective of which alternative was just reinforced. Performance on these three‐ and four‐alternative concurrent schedules is not easily extrapolated from corresponding research using two‐alternative concurrent schedules.  相似文献   
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Children with single-suture craniosynostosis (SSC) have higher rates of learning disabilities and related neurocognitive problems than unaffected peers. Executive function (EF) and attention are thought to be areas of particular vulnerability, though studies to date have been limited by small sample sizes and a lack of control groups. We evaluated 179 school-aged children with SSC (cases) and 183 unaffected controls at an average age of 7 years using clinician-administered and parent and teacher report measures of EF and attention. Among children with SSC, we examined differences as a function of suture location (sagittal, metopic, unicoronal, or lambdoid) and age of corrective surgery. We used linear regression analyses, adjusted for potential confounders, to compare the two groups on all outcome measures. Cases scored lower than controls on most measures, though the magnitude of these differences was small and most were statistically insignificant. The largest relative deficit was on a measure of inhibitory control. Results changed little in sensitivity analyses adjusting for potential attrition bias and for the effects of developmental and academic interventions. Among cases, there were few differences in relation to the location of suture fusion or timing of surgery. Overall, we found limited evidence of broad deficits in EF or attention in children with SSC relative to unaffected controls. Neurocognitive development for children with SSC appears to be variable, across affected children and outcomes assessed. Further research is needed to understand the potential sources of this variability.  相似文献   
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While any number of topics would serve to compare and contrast Deleuze and Badiou, this article will focus on the event. Focusing on the event serves several purposes. First, it provides a vantage point from which to elucidate a number of key topics in both philosophers. Second, while Badiou’s most recent work is already organized around his conception of the event, Deleuze’s discussion of the event is more diffuse. Thus, a discussion of the event in Deleuze will serve as heuristic to relate several of Deleuze’s (Deleuze and Guattari’s) texts. Finally, focusing on a single issue will clarify what is at stake in each conception of the event.  相似文献   
157.
This paper investigates how people's food choices can be shaped by the body type of others around them. Using a professionally constructed obesity prosthesis, we show that the body type of a (confederate) server in a taste test study was sufficient to alter both the quantity (Experiment 1) and specific choices (Experiment 2) participants made but that chronic dieters and non-dieters exhibited opposite effects. While non-dieters ate more snacks when the server was thin, dieters ate more when the server was heavy. Dieters were also more persuaded by a heavy (vs. a thin) server, choosing both a healthy and unhealthy snack more often when she recommended it to them. We suggest these results may be attributable to identification with the server.  相似文献   
158.
    
The accuracy with which human judges, before and after 'training', could predict the likely home location of serial offenders was compared with predictions produced by a geographic profiling system known as Dragnet. All predictions were derived from ten spatial displays, one for each of ten different U.S. serial murderers, indicating five crime locations. In all conditions participants were asked to place an 'X' on each spatial display corresponding to where they thought the offender lived. In the control condition, a comparison was made between the accuracy of these predictions for 21 participants on two separate occasions a few minutes apart. In the experimental condition, between their first and second predictions the 21 participants were given two heuristics to follow--distance-decay and circle hypothesis. Results showed that participants with no previous knowledge of geographic profiling were able to use the two heuristics to improve the accuracy of their predictions. The overall accuracy of the second set of predictions for the experimental group was also not significantly different from the accuracy of predictions generated by Dragnet.  相似文献   
159.
    
This study of 315 male and 310 female homeless military veterans in a V.A. inpatient program designed to treat substance abusers, many of whom also suffer psychiatric disorders, was designed to examine gender differences in factors associated with the odds of having suicidal thoughts, and of attempting suicide, in comparison to being nonsuicidal. A maximum likelihood estimation multinomial logistic regression showed childhood and current sexual and physical abuses, depression, fearfulness, relationship problems, limited social support, and low self-esteem was more strongly associated with suicidal thoughts and attempts for women than for men veterans. Extent of alcohol and other drug abuse, aggression, resilience, self-efficacy, combat exposure, combat-related PTSD, and work problems were more strongly associated with suicidal thoughts and attempts for men than for women. Implications of these findings for V.A. programs are discussed.  相似文献   
160.
This paper describes the rationale, design, and methods of the Treatment for Anxiety in Autism Spectrum Disorders study, a three-site randomized controlled trial investigating the relative efficacy of a modular CBT protocol for anxiety in ASD (Behavioral Interventions for Anxiety in Children with Autism) versus standard CBT for pediatric anxiety (the Coping Cat program) and a treatment-as-usual control. The trial is distinct in its scope, its direct comparison of active treatments for anxiety in ASD, and its comprehensive approach to assessing anxiety difficulties in youth with ASD. The trial will evaluate the relative benefits of CBT for children with ASD and investigate potential moderators (ASD severity, anxiety presentation, comorbidity) and mediators of treatment response, essential steps for future dissemination and implementation.  相似文献   
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