The time course of object encoding

Four experiments examined the effects of encoding time on object identification priming and recognition memory. After viewing objects in a priming phase, participants identified objects in a rapid stream of non-object distracters; display times were gradually increased until the objects could be identified (Experiments 1-3). Participants also made old/new recognition judgments about previously viewed objects (Experiment 4). Reliable priming for object identification occurred with 150 ms of encoding and reached a maximum after about 300 ms of encoding time. In contrast, reliable recognition judgments occurred with 75 ms of encoding and continued to improve for encoding times of up to 1200 ms. These results suggest that recognition memory may be based on multiple levels of object representation, from rapidly activated representations of low-level features to semantic knowledge associated with the object. In contrast, priming in this object identification task may be tied specifically to the activation of representations of object shape.     

The Role of Teacher Cognition and Behavior in Children’s Peer Relations

This study explored the role of the classroom teacher in peers’ evaluations of liking and disliking of their classmates. Teacher cognitions about children (teacher liking of students, teacher attributions for aggressive student behavior) and teacher behavior toward children (positive, corrective/negative) were examined as mediators in the link between children’s own behavior (aggression, prosocial behavior) and peer liking and disliking. Participants were 127 second-graders in 12 classrooms (64 males, 63 females). Data on child behavior were collected through peer and teacher report, data on teacher cognitions about children were collected through self report, data on teacher behavior toward children were collected through naturalistic classroom observations, and data on peer liking and disliking were collected through peer nominations. Data were analyzed using path analysis. Results indicated that teacher cognitions about children and corrective/negative teacher behavior toward children mediated the relations between aggressive and prosocial child behavior and peer disliking.     

Intergroup and intragroup competition and cooperation

This study examined the effects on group performance and evaluation of three factors: intergroup competition or cooperation, intragroup competition or cooperation, and task means-interdependence. Intragroup cooperation was related positively to performance on a high means-interdependent task and was related negatively to performance on a low means-interdependent task. However, this relationship held only when there was intergroup cooperation rather than intergroup competition. These results were discussed in terms of their implications for the relative magnitude of the motives produced by the intragroup and intergroup reward structure. Evaluations of ingroup members were higher when there was intragroup cooperation than when there was intragroup competition. To foster ingroup liking, it was not necessary to introduce intergroup competition.     

Classroom behavior and children with mental retardation: Comparison of children with and without ADHD

Thirty-four children (ages 6–12 years) with moderate to borderline mental retardation were studied in a laboratory classroom setting to determine whether children identified as having attention deficit hyperactivity disorder on the basis of Conners Questionnaires differed in classroom behavior. Half of the children scored 15 or greater on both the Parent and Teacher Conners; the remaining children scored 11 or less. All were participants in a Saturday Education Program serving children with mental retardation. Direct observation of the laboratory classroom documented significant differences between groups on measures of on-task behavior and fidgetiness, especially during situations where little direct teacher feedback or supervision was available. Saturday Education Program staff, while blind as to group designation, rated the two groups as differing significantly on all scales of two standardized behavior problem checklists. Checklists by parents and teachers appear to be valid measures of classroom behavior of children with moderate to borderline mental retardation.This research was supported by a grant to the first author from the National Institutes of Child Health and Human Development, U.S. Department of Health and Human Services, grant No. 1R29HD26186-01A1. The authors gratefully acknowledge the assistance of the staff of Children's Hospital of Pittsburgh's Saturday Education Program: Nancy Hall, Aimee Hart, Phyllis Loeffler, Robin Nelson, Christina Poljak, Kelley Sacco, Sarah Stewart, and Mary Zuberbuehler.     

Long-Term Follow-Up of Children with Mental Retardation/Borderline Intellectual Functioning and ADHD

Fifty-two children (ages 7 to 14 years) with moderate mental retardation to borderline intellectual functioning were recontacted 12 to 65 months following participation in a double-blind, placebo-controlled trial of methylphenidate (MPH). Sixty-nine percent of subjects continued to be prescribed medication for behavior control at follow-up. While 72% of the sample evidenced improvement, over two-thirds continued to be rated at or above the 98th percentile on the Hyperactivity Index of the Parent Conners. In fact, 22% of subjects had received inpatient psychiatric treatment between the time of the initial MPH trial and follow-up. Finally, subjects with high initial ratings on the Parent Conners Conduct Problems scale were more likely to be suspended from school or receive inpatient psychiatric treatment than subjects with low initial ratings. The results suggested that children with ADHD and mental retardation or borderline intellectual functioning continued to exhibit significant symptoms associated with attention deficit hyperactivity disorder (ADHD) at follow-up and that early conduct problems were predictive of continuing behavioral difficulties.     

Differences in attentional set between athletes and nonathletes

The purpose of this study was to determine if the ability to set attention is different between athletes and nonathletes. University volleyball players were compared with nonathletes on a spatial cuing task similar to that of C. L. Folk, R. W. Remington, and J. C. Johnston (1992). As expected, both groups showed evidence of entering into a specific attentional set because attentional cuing effects were found only when cues and targets shared a task-relevant feature (onset or color). In addition, the cuing effects when the cues matched the targets were greater for the athletes than for the nonathletes. The results are discussed in terms of the orienting of attention and athletic performance.     

Long-term retinotopic priming in object identification

An important result in perception research is that priming in an object naming task is invariant with translation and left-right reflection. A more sensitive object recognition paradigm was used in three experiments in order to investigate the extent to which priming of object identification is affected by changes in left-right orientation and position. In a prime phase, participants viewed consecutively presented object images. In a subsequent probe phase, participants identified familiar objects in rapid visual streams of nonobject distractors. In Experiment 1, images previously viewed in the same left-right orientation were primed more than images previously viewed in the opposite orientation (i.e., a left-right reflection). This reflection-sensitive priming was replicated in Experiment 2 using a brief (300-msec) prime exposure. In Experiment 3, when the retinal locations of prime and probe images matched, reflection-sensitive priming was also obtained, but when the retinal locations of prime and probe images differed, no reflection-sensitive priming was observed. These results suggest that a single prime exposure can produce long-term priming that is sensitive to left-right reflection, but that this priming is specific to a retinal location.     

Does effort influence inequity aversion in cotton-top tamarins (Saguinus oedipus)?

The human sense of fairness entails sensitivity not just to equality, the equal division of resources, but also to merit, the relationship between an individual’s share of resources and how hard they worked for their share. Recent evidence suggests that our sensitivity to equality has deep phylogenetic roots: several nonhuman animal species show an aversion to unequal reward distributions. However, the extent to which nonhuman animals share sensitivity to merit remains poorly understood, largely because previous studies have failed to properly manipulate work effort in inequity aversion tasks. Here, we tested whether cotton-top tamarins (Saguinus oedipus) would exhibit a differential response to inequity when acquiring rewards was either (1) effortful or (2) effortless. Subjects engaged in a pulling task in which they had an opportunity to deliver a disadvantageously unequal distribution of food to themselves and a partner (one piece for self, four pieces for partner). We made delivery effortful by adding a weight to the pulling handle. Critically, effort was calibrated to each individual. Results show that individuals varied markedly in their response to effort, highlighting the importance of manipulating work effort at the individual level. Overall, subjects showed little aversion to inequity. However, subjects were slightly less likely to accept inequity when doing so was effortful, although this effect was pronounced in only one individual. Our findings suggest a new method for capturing individual variation in effort and for studying the roots of the concept of merit in nonhuman animals.