On the effects of signaling reinforcer probability and magnitude in delayed matching to sample

Two experiments examined whether postsample signals of reinforcer probability or magnitude affected the accuracy of delayed matching to sample in pigeons. On each trial, red or green choice responses that matched red or green stimuli seen shortly before a variable retention interval were reinforced with wheat access. In Experiment 1, the reinforcer probability was either 0.2 or 1.0 for both red and green responses. Reinforcer probability was signaled by line or cross symbols that appeared after the sample had been presented. In Experiment 2, all correct responses were reinforced, and the signaled reinforcer durations were 1.0 s and 4.5 s. Matching was more accurate when larger or more probable reinforcers were signaled, independently of retention interval duration. Because signals were presented postsample, the effects were not the result of differential attention to the sample.     

The cognitive effects of trauma: reversal of alpha function and the formation of a beta screen

Following a brief review of Freud's writings on trauma, the author discusses relevant theories of Bion, and in particular the concepts of the alpha function and the beta screen. A clinical example is presented in which the patient's relatively recent trauma in adulthood had become fused with prior related experiences, leading to a propensity for repeated enactments in analysis and a failure to learn from experience. Drawing on the analyst's alpha function, the patient was gradually able to use mentalization to transform her rigidly structured traumatic organization. The author highlights the roles of dreams/dream associations and of screen memories in the patient's analysis.     

Paralinguistic processing in children with callosal agenesis: emergence of neurolinguistic deficits

Recent research revealed impaired processing of both nonliteral meaning and affective prosody in adults with agenesis of the corpus callosum (ACC) and normal intelligence. Since normal children have incomplete myelination of the corpus callosum, it was hypothesized that paralanguage deficits in children with ACC would be less apparent relative to their peers. The Familiar and Novel Language Comprehension Test (FANL-C) and Prosody Test were given to 18 children with ACC and normal intelligence and 17 controls matched for age (7-13 years), education, and IQ (83-122). When controlling for age, children with ACC were significantly poorer in comprehension of the precise meaning of both literal and nonliteral items on the FANL-C. Adults with ACC had previously been shown to have difficulty only on nonliteral items. The effect size for nonliteral comprehension in children with ACC was smaller than that seen in adults. There was only a trend for the child ACC group to perform worse on the recognition of affective prosody. Thus, while deficits in paralinguistic processing were apparent, children with ACC were not as clearly different from age peers as adults, and were equally deficient at comprehending literal and nonliteral expressions. The differences in results between adults and children with ACC are thought to reflect incomplete callosal development in normal children, and the importance of the corpus callosum in the early stages of the development of the ability to process literal language.     

Development of upper limb proprioceptive accuracy in children and adolescents

This study was designed to determine differences in the proprioceptively guided movements of children (8-10 years) and adolescents (16-18 years). Participants were blindfolded and asked to actively match passively determined target positions of the elbow joint under three matching conditions. Overall, children were less accurate than adolescents in all matching tasks and utilized different kinematic strategies for making the matching movements. Specifically, children made larger absolute errors and utilized matching movements which, compared to adolescents, were of shorter duration and less irregular in terms of their velocity profiles. An assessment of limb asymmetry was also performed revealing a non-dominant arm matching advantage but only for children and only in the task requiring interhemispheric transfer of a memory-based model of limb position. The proprioceptive differences observed in this study are likely the result of experience-driven refinement in the utilization of somatosensory feedback throughout childhood and into adolescence.     

Serial recall and presentation schedule: a micro-analysis of local distinctiveness

According to temporal distinctiveness theories, items that are temporally isolated from their neighbours during presentation are more distinct and thus are recalled better. Event-based theories, which deny that elapsed time plays a role at encoding, explain isolation effects by assuming that temporal isolation provides extra time for rehearsal or consolidation of encoding. The two classes of theories can be differentiated by examining the symmetry of isolation effects: Event-based accounts predict that performance should be affected only by pauses following item presentation (because they allow time for rehearsal or consolidation), whereas distinctiveness predicts that items should also benefit from preceding pauses. The first experiment manipulated inter-item intervals and showed an effect of intervals following but not preceding presentation, in line with event-based accounts. The second experiment showed that the effect of following interval was abolished by articulatory suppression. The data are consistent with event-based theories but can be handled by time-based distinctiveness models if they allow for additional encoding during inter-item pauses.     

Sexual victimization in relation to perceptions of risk: mediation, generalization, and temporal stability

There is evidence that personal experience with trauma is associated with increases in both personal and comparative risk perception. This study investigates this relation in terms of sexual victimization among women, focusing on three potential mediators: perceived control over sexual assault, perceived similarity to a typical sexual assault victim, and psychological distress. Mediational analyses were investigated using structural equation modeling. Although victimization experience was not related to comparative risk perception, it was associated with greater personal risk perception. This relation was mediated by perceived similarity to a typical sexual assault victim. Prospective analyses indicated that personal risk perception does change in response to sexual victimization but also indicated that heightened risk perception may be an accurate assessment of risk that actually precedes victimization experience. Implications for the meaning of perceived similarity and perceptions of risk for sexual assault victims are discussed.     

Dying to be thin: the effects of mortality salience and body mass index on restricted eating among women

Following terror management theory, the authors suggest women's striving to attain a thin physique is fueled in part by existential concerns. In three studies, women restricted consumption of a nutritious but fattening food in response to reminders of mortality (mortality salience; MS). When conducted in private (Study 1), this effect was found among women but not men; when replicated in a group setting in which social comparison was likely (Studies 2 and 3), only women who were relatively less successful attaining the thin ideal (i.e., high body mass index; BMI) restricted eating after MS. In Study 3, MS caused high BMI women to perceive themselves as more discrepant from their ideal thinness; this perceived failure mediated the effects of MS and BMI on eating behavior. Findings are discussed from a self-regulatory framework, which considered in the context of pressures for women to be thin, can shed light on health risk behavior.     

Assessing aggression in adolescent romantic relationships: can we do it better?

Almost all research on aggression in adolescent romantic relationships makes use of 1-time, retrospective assessment methods. In the present research, the authors compared data on the experience of adolescent relationship aggression (physical aggression and threatening behavior) collected from 125 high school students via 2 methods: (a) a 1-time, 2-month retrospective assessment and (b) a cumulative method based on four 2-week retrospective assessments, each spaced 2 weeks apart. For the cumulative method, data from the 4 assessments were aggregated to cover the same time period as the single, 2-month retrospective assessment. A greater proportion of the sample (48.0%) reported experiencing physical aggression using the cumulative method compared with the single, 2-month retrospective method (27.0%). The prevalence of threatening behavior was also higher using the cumulative method (48.8% vs. 24.8%). Adolescent trauma and anxiety symptoms correlated more strongly with physical aggression data derived from the cumulative method than from the 1-time assessment method.     

Expectancies for Sexually Abused Children: Evidence of Perceiver Bias

We investigated perceiver bias in relation to children labeled as sexually abused. Building on recent research indicating that adults perceive children with such a label as having more behavioral problems and lower achievement, we replicated and expanded upon an earlier study. We tested undergraduate students (N = 699), who judged a six-year old child's aggressive behavior in vignettes that varied on severity of the aggressive behavior, child gender, and family history (sexually abused, mother dying of cancer, normal). Perceiver bias was related to family history label for internalizing behavior problems and competence issues and child gender for internalizing behavior problems and externalizing behavior problems. Implications for educators and practitioners are discussed as well as routes for future research.     

Cross-cultural similarities and differences in North Americans’ geographic location judgments

We examined some potential causes of bias in geographic location estimates by comparing location estimates of North American cities made by Canadian, U.S., and Mexican university students. All three groups placed most Mexican cities near the equator, which implies that all e influenced by shared beliefs about the locationthree groups wers of geographical regions relative to global reference points. However, the groups divided North America into different regions and differed in the relative accuracy of the estimates within them, which implies that there was an influence of culture-specific knowledge. The data support a category-based system of plausible reasoning, in which biases in judgments are multiply determined, and underscore the utility of the estimation paradigm as a tool in cross-cultural cognitive research.