Object permanence in common marmosets (Callithrix jacchus)

A series of 9 search tasks corresponding to the Piagetian Stages 3-6 of object permanence were administered to 11 common marmosets (Callithrix jacchus). Success rates varied strongly among tasks and marmosets, but the performances of most subjects were above chance level on the majority of tasks of visible and invisible displacements. Although up to 24 trials were administered in the tests, subjects did not improve their performance across trials. Errors were due to preferences for specific locations or boxes, simple search strategies, and attentional deficits. The performances of at least 2 subjects that achieved very high scores up to the successive invisible displacement task suggest that this species is able to represent the existence and the movements of unperceived objects.     

Beyond the individual: the impact of ethnic context and classroom behavioral norms on victims' adjustment

With a sample of 1,630 sixth-grade students from 77 classrooms, the authors used hierarchical linear modeling to examine how ethnicity within context and classroom social disorder influenced the association between peer victimization and social-psychological adjustment (loneliness and social anxiety). Victimized students in classrooms where many classmates shared their ethnicity reported feeling the most loneliness and social anxiety. Additionally, classroom-level social disorder served as a moderator such that the association between victimization and anxiety was stronger in classrooms with low social disorder. Both findings were interpreted as evidence that problem behavior deviating from what is perceived as normative in a particular context heightens maladjustment. The authors discuss implications for studying ethnicity and classroom behavioral norms as context variables in peer relations.     

Knowledge about the probability of change affects change detection performance

The visual system continually selects some information for processing while bypassing the processing of other information, and as a consequence, participants often fail to notice large changes to visual stimuli. In the present studies, the authors investigated whether knowledge about the probability of particular changes occurring over time increased the likelihood that changes that were likely to occur in the real world (probable changes) would be detected. The results of two experiments showed that participants were more likely to detect probable changes. This occurred whether or not they were processing the scene in a meaningful manner or actively searching the scene for changes. Furthermore, participants were unable to accurately predict change detection performance for probable and improbable changes.     

Associative change in the representations acquired during conditional discriminations: further analysis of the nature of conditional learning

Three experiments with rats investigated how the associative strengths of the representations that underlie conditional learning change when they are conditioned in compound. The results of each experiment suggest that the representation whose associative strength is most discrepant from the asymptote supported by the outcome of the trial undergoes the greatest change in associative strength. These results parallel those from simple Pavlovian conditioning (e.g., R. A. Rescorla, 2000). are inconsistent with unique-cue and configural accounts of conditional learning, and support a connectionist analysis of learning in which a "winner-takes-all" rule applies to the hidden units that can be activated and acquire associative strength at a given point in time.     

Cue-focused and reflexive-associative processes in prospective memory retrieval

Several theories of event-based prospective memory were evaluated in 3 experiments. The results depended on the association between the target event and the intended action. For associated target-action pairs (a) preexposure of nontargets did not reduce prospective memory, (b) divided attention did not reduce prospective memory, (c) prospective memory was better than when the target event and intended action were not associated, and (d) prospective memory was characterized by retrieval of the precise intended action. These results converge on the view that retrieval is mediated by a reflexive-associative process. In contrast, for unassociated pairs (a) preexposure of nontargets reduced prospective memory, and (b) divided attention reduced prospective memory. These results implicate cue-focused retrieval processes and are most consistent with a discrepancy-plus-search model. The entire pattern implicates both cue-focused and reflexive-associative processes and more generally supports a multiprocess framework of prospective memory (M. A. McDaniel & G. O. Einstein, 2000).     

Pigeons use item-specific and category-level information in the identification and categorization of human faces

Three experiments examined the pigeon's ability to adapt to the specific tasks of identification and categorization of complex visual stimuli by attending to information at different levels of abstraction. In Experiment 1, pigeons were successively trained to discriminate first between pairs of human faces from the same sex and then between male and female faces. A final test revealed that the associations formed in the first training phase did not survive categorization training, indicating that the pigeons used item-specific information to discriminate faces of the same sex, but shifted their attention to category-level information for discriminating between the male and female categories. Two further experiments disproved alternative explanations. The results support the feature-learning account of open-ended categorization in animals.     

Teachers' screening for attention deficit/hyperactivity disorder: comparing multinational samples on teacher ratings of ADHD

This study evaluates a measurement model for Attention Deficit/Hyperactivity Disorder (ADHD). The DSM-IV divides 18 symptoms into two groups, inattentive and hyperactive/impulsive. Elementary school teachers rated 21,161 children in 4 locations: Spain, Germany, urban US, and suburban US. Confirmatory factor analysis suggested that the 2-factor model (inattention, hyperactivity/impulsivity) shows the best fit. A third factor, impulsivity, was too slight to stand-alone. Children with academic performance problems were distinguished by inattention, but children with behavior problems typically had elevations in inattention, hyperactivity, and impulsivity. Between-site differences were statistically significant, but so small that we conclude that same measurement model fits all 4 samples in 2 continents.     

Now you feel it, now you don't: frontal brain electrical asymmetry and individual differences in emotion regulation

Recent theoretical accounts of emotion regulation assign an important role in this process to the prefrontal cortex, yet there is little relevant data available to support this hypothesis. The current study assessed the relation between individual differences in asymmetric prefrontal activation and an objective measure of uninstructed emotion regulation. Forty-seven participants 57 to 60 years old viewed emotionally arousing and neutral visual stimuli while eyeblink startle data were collected. Startle probes were also presented after picture presentation to capture the persistence or attenuation of affect following the offset of an emotional stimulus. Subjects with greater relative left-sided anterior activation in scalp-recorded brain electrical signals displayed attenuated startle magnitude after the offset of negative stimuli. This relation between resting frontal activation and recovery following an aversive event supports the idea of a frontally mediated mechanism involved in one form of automatic emotion regulation.     

Information search in the laboratory and on the Web: With or without an experimenter

The focus of this study is the effect of the location (laboratory vs. Web) of experiments on active information searchin decision-making tasks. In two experiments, participants were confronted with two different search method versions (list vs. keyword) for acquiring information about a task from a database. The amount and type of information gathered and the time required for task completion were measured. In Experiment 1, significantly more information was searched for in the laboratory than on the Web when the list version was employed, whereas there was no difference between locations in the keyword version. In Experiment 2, the participants were assigned randomly to the Web or the laboratory condition. The results of Experiment 1 were replicated. Whereas location (and the presence or absence of an experimenter) had an effect on the absolute amount of information gathered in both experiments, the relative distribution and type of information items did not differ.