Visual discrimination of species in dogs (Canis familiaris)

In most social interactions, an animal has to determine whether the other animal belongs to its own species. This perception may be visual and may involve several cognitive processes such as discrimination and categorization. Perceptual categorization is likely to be involved in species characterized by a great phenotypic diversity. As a consequence of intensive artificial selection, domestic dogs, Canis familiaris, present the largest phenotypic diversity among domestic mammals. The goal of our study was to determine whether dogs can discriminate any type of dog from other species and can group all dogs whatever their phenotypes within the same category. Nine pet dogs were successfully trained through instrumental conditioning using a clicker and food rewards to choose a rewarded image, S+, out of two images displayed on computer screens. The generalization step consisted in the presentation of a large sample of paired images of heads of dogs from different breeds and cross-breeds with those of other mammal species, included humans. A reversal phase followed the generalization step. Each of the nine subjects was able to group all the images of dogs within the same category. Thus, the dogs have the capacity of species discrimination despite their great phenotypic variability, based only on visual images of heads.     

Does a salient distractor capture attention early in processing?

Kim and Cave (1999) used spatial probes in order to measure the effects of bottom-up and top-down factors on the allocation of spatial attention over time. Subjects searched for a target with a unique shape, with a uniquely colored distractor present on each trial. The singleton distractor captured attention early in processing, whereas attention homed in on the target’s location later on. Kim and Cave (1999) concluded that top–down factors cannot prevent the presence of a salient distractor from delaying target selection. The present study tested the idea that such results were obtained only because subjects adopted the strategy of searching for the most salient item. Kim and Cave’s (1999) finding was replicated in Experiment 1. In Experiment 2, instead of a feature search, subjects performed a conjunction search—that is, a task that could not be performed using a salience–based strategy. Probe response times were longest at the salient distractor’s location at both the short and the long stimulus onset asynchronies. These results suggest that, early in processing, top–down factors can exert their influence and prevent the capture of attention by a salient distractor.     

Mimicry and propagation of prosocial behavior in a natural setting

This study tested, in a natural setting, the effect of mimicry on people's disposition toward helping others and the extent to which this helping behavior is extended to people not directly involved in the mimicry situation. In the main street of a busy town, men (n = 101) and women (n = 109) passersby were encountered and asked for directions. These passersby were subjected to mimicry by na?ve confederates who mimicked either verbal behavior alone or verbal and nonverbal behaviors together, including arm, hand, and head movements. In the control condition, passersby were not mimicked. Following this first encounter, each subject was then met further down the street by a second confederate who asked for money. The results show that people who had been mimicked complied more often with a request for money and gave significantly more, suggesting they were more helpful and more generous toward other people, even complete strangers.     

A national survey of U.S. statutes on juvenile transfer: implications for policy and practice

A survey of the statutes on juvenile transfer and cecertification in the U.S. federal and 50 state jurisdictions, and the District of Columbia, was performed. Relevant information was obtained on the procedures in each jurisdiction by which a juvenile can be tried in criminal court, whether there are applicable decertification (“transfer back”) procedures in jurisdictions permitting criminal court processing through automatic file or prosecutorial discretion, and the burden and allocation of proof in relevant proceedings. We also identified four criteria relevant to the mental, emotional, and developmental functioning of juveniles that are used in various jurisdictions in making transfer and decertification decisions: treatment needs and amenability, risk assessment of future criminality, the presence of mental retardation or mental illness, and certain kinds of offense characteristics. The majority of jurisdictions now allow 14-year-old juveniles to be tried in criminal court. Treatment needs/amenability and risk assessment are set forth as criteria relevant to transfer in the majority of jurisdictions as well, with the presence of mental retardation or mental illness explicitly relevant in a small number of jurisdictions. The patterns of these findings are discussed in their implications for social policy and for the forensic mental health assessment of juvenile transfer and decertification, with needed areas of research identified within each. ©1997 John Wiley & Sons, Ltd.     

Dopamine,depressive symptoms,and decision-making: the relationship between spontaneous eye blink rate and depressive symptoms predicts Iowa Gambling Task performance

Depressive symptomatology has been associated with alterations in decision-making, although conclusions have been mixed, with depressed individuals showing impairments in some contexts but advantages in others. The dopaminergic system may link depressive symptoms with decision-making performance. We assessed the role of striatal dopamine D₂ receptor density, using spontaneous eye blink rates, in moderating the relationship between depressive symptoms and decision-making performance in a large undergraduate sample that had not been screened for mental illness (N?=?104). The regression results revealed that eye blink rate moderated the relationship between depressive symptoms and advantageous decisions on the Iowa Gambling Task, in which individuals with more depressive symptomatology and high blink rates (higher striatal dopamine D₂ receptor density) performed better on the task. Our computational modeling results demonstrated that depressive symptoms alone were associated with enhanced loss-aversive behavior, whereas individuals with high blink rates and elevated depressive symptoms tended to persevere in selecting options that led to net gains (avoiding options with net losses). These findings suggest that variation in striatal dopamine D₂ receptor availability in individuals with depressive symptoms may contribute to differences in decision-making behavior.     

We can do it: the interplay of construal orientation and social comparisons under threat

The authors investigated how a collective self-construal orientation in combination with positive social comparisons "turns off" the negative effects of stereotype threat. Specifically, Experiment 1 demonstrated that stereotype threat led to increased accessibility of participants' collective self ("we"). Experiment 2 showed that this feeling of "we-ness" in the stereotype threat condition centered on the participants' stereotyped group membership and not on other important social groups (e.g., students). Experiment 3 indicated that in threat situations, when participants' collective self is accessible, positive social comparison information led to improved math test performance and less concern, whereas in nonthreat situations, when the collective self is less accessible, positive comparison information led to worse test performance and more concern. Our final experiment revealed that under stereotype threat, only those comparison targets who are competent in the relevant domain (math), rather than in domains unrelated to math (athletics), enhanced participants' math test performance.     

Effects of top-down guidance and singleton priming on visual search

Recent literature suggests that observers can use advance knowledge of the target feature to guide their search but fail to do so whenever the target is reliably a singleton. Instead, they engage in singletondetection mode—that is, they search for the most salient object. In the present study, we aimed to test the notion of a default salience-based search mode. Using several measures, we compared search for a known target when it is always a singleton (fixed-singleton search) relative to when it is incidentally a singleton (multiple-target search). We examined the relative contributions of strategic factors (knowledge that the target is a singleton) and intertrial repetition effects (singleton priming, or the advantage of responding to a singleton target if the target on the previous trial had also been a singleton). In two experiments, singleton priming eliminated all the differences in performance between fixed-singleton and multiple-target search, suggesting that search for a known singleton may be feature based rather than salience based.