Gender differences in the sensitivity to posttraumatic stress disorder: An epidemiological study of urban young adults

The authors examine the relationship between 2 separate but interrelated findings in the epidemiology of posttraumatic stress disorder (PTSD): women's greater PTSD risk following traumatic events and the sensitizing effects of a prior trauma on the PTSD response to a subsequent trauma. Data come from a representative sample of 1,698 young adults from a large U.S. city. Analysis was conducted on the subset exposed to traumatic events. Women's risk for PTSD following assaultive violence was higher than men's. When assaultive violence preceded a later nonassaultive trauma in women, there was an increased risk (relative risk = 4.9) for PTSD, which was not observed in men. The relative risk estimate in women was significantly higher than in men. These findings suggest that assaultive violence elicits women's PTSD response directly and by sensitizing them to the effects of subsequent traumatic events of lesser magnitude.     

A method for describing preschoolers' activity preferences

We designed a series of analyses to develop a measurement system capable of simultaneously recording the free-play patterns of 20 children in a preschool classroom. Study 1 determined the intermittency with which the location and engagement of each child could be momentarily observed before the accuracy of the measurement was compromised. Results showed that intervals up to 120 s introduced less than 10% measurement error. Study 2 determined the extent of agreement between two observers who simultaneously collected data for 20 children using 30-, 60-, 90-, and 120-s momentary time sampling (MTS) intervals. The three larger intervals resulted in high levels of interobserver agreement (above 90%), whereas the 30-s interval resulted in unacceptably low levels of agreement (less than 80%). By allowing observers to select from among the different MTS intervals via a datasheet array and then collect data with the chosen system, Study 3 determined observers' preferences for the remaining MTS intervals. Both data collectors preferred the 90-s MTS procedure. The sensitivity of the 90-s MTS procedure, which was shown to be accurate, reliable, and preferred, was then demonstrated by its use to describe activity preferences of a classroom of children in Study 4. This system identified high- and low-preference activities for individual children and revealed interesting patterns of response allocation by the group.     

Preschoolers' aggression, affiliation, and social dominance relationships: An observational, longitudinal study

This study of 61 preschool children used an observational, longitudinal design to examine the degree to which social dominance relationships account for time-related change in rates of aggression and affiliation across a school year. Specific hypotheses reflected the view that, over time, behavioral function should change in accord with the stability of social dominance relationships, social norms, and on-going developmental processes. Results showed that change in rates of aggression was non-linear (i.e., increasing then decreasing over the year), that physical and verbal forms of aggression were associated with distinct longitudinal trajectories, and that these trajectories were related to rates of affiliation and visual regard. As predicted, social dominance accounted for significant variation in these patterns. Implications for theory, future research, and school practitioners are discussed.     

Integrating Behavioral and Social Sciences in the Medical School Curriculum: Opportunities and Challenges for Psychology

The Institute of Medicine has reviewed and made recommendations concerning current teaching approaches, content, and barriers to the incorporation of behavioral/social sciences in medical school curricula (Cuff & Vanselow, 2004). This paper discusses those recommendations, the history of medical education reform, the barriers to and evolution of behavioral/social sciences’ inclusion, and the implications for psychology’s future role in academic medicine. Psychological concepts and technology permeate medical practice, but little progress has been made in integrating psychological and biological sciences. Looking to its basic science domains (e.g. cognition, learning, development, neuroscience), psychology can take scientific leadership in illuminating the mechanisms by which behavioral/social processes interact with biological functions in health, thereby providing the empirical basis for a truly integrated bio-behavioral curriculum. This article is based upon a symposium, “IOM Report on Enhancing Behavioral & Social Science in Medical Education: Impact and Opportunities for Psychology,” presented at the Annual meeting of the American Psychological Association, Washington, D.C., August 21, 2005. Suzanne Bennett Johnson, Chair; Elena Reyes, John E. Carr, and Anthony Errichetti, participants; Eugene K. Emory, Discussant.     

Hippocampal differentiation without recognition: an fMRI analysis of the contextual cueing task

A central role of the hippocampus is to consolidate conscious forms of learning and memory, while performance on implicit tasks appears to depend upon other structures. Recently, considerable debate has emerged about whether hippocampal-dependent tasks necessarily entail task awareness. In the contextual cueing task, repetition facilitation is implicit, but impaired in patients with amnesia. Whether the hippocampus alone or other MTL structures are required is unclear. Event-related functional magnetic resonance imaging revealed hippocampal activity that differentiates novel from repeated arrays. This pattern of results was observed without recognition of the repeating arrays. This finding provides support for the claim that the hippocampus is involved in processes outside the domain of conscious learning and memory.     

Route-based travel and shared routes in sympatric spider and woolly monkeys: cognitive and evolutionary implications

Many wild primates occupy large home ranges and travel long distances each day. Navigating these ranges to find sufficient food presents a substantial cognitive challenge, but we are still far from understanding either how primates represent spatial information mentally or how they use this information to navigate under natural conditions. In the course of a long-term socioecological study, we investigated and compared the travel paths of sympatric spider monkeys (Ateles belzebuth) and woolly monkeys (Lagothrix poeppigii) in Amazonian Ecuador. During several field seasons spanning an 8-year period, we followed focal individuals or groups of both species continuously for periods of multiple days and mapped their travel paths in detail. We found that both primates typically traveled through their home ranges following repeatedly used paths, or “routes”. Many of these routes were common to both species and were stable across study years. Several important routes appeared to be associated with distinct topographic features (e.g., ridgetops), which may constitute easily recognized landmarks useful for spatial navigation. The majority of all location records for both species fell along or near identified routes, as did most of the trees used for fruit feeding. Our results provide strong support for the idea that both woolly and spider monkey use route-based mental maps similar to those proposed by Poucet (Psychol Rev 100:163–182, 1993). We suggest that rather than remembering the specific locations of thousands of individual feeding trees and their phenological schedules, spider and woolly monkeys could nonetheless forage efficiently by committing to memory a series of route segments that, when followed, bring them into contact with many potential feeding sources for monitoring or visitation. Furthermore, because swallowed and defecated seeds are deposited in greater frequency along routes, the repeated use of particular travel paths over generations could profoundly influence the structure and composition of tropical forests, raising the intriguing possibility that these and other primate frugivores are active participants in constructing their own ecological niches. Building upon the insights of Byrne (Q J Exp Psychol 31:147–154, 1979, Normality and pathology in cognitive functions. Academic, London, pp 239–264, 1982) and Milton (The foraging strategy of howler monkeys: a study in primate economics. Columbia University Press, New York, 1980, On the move: how and why animals travel in groups. University of Chicago Press, Chicago, pp 375–417, 2000), our results highlight the likely general importance of route-based travel in the memory and foraging strategies of nonhuman primates.

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This contribution is part of the Special Issue “A Socioecological Perspective on Primate Cognition” (Cunningham and Janson 2007).     

Using TD learning to simulate working memory performance in a model of the prefrontal cortex and basal ganglia

Delayed-response tasks (DRTs) have been used to assess working memory (WM) processes in human and nonhuman animals. Experiments have shown that the basal ganglia (BG) and dorsolateral prefrontal cortex (DLPFC) subserve DRT performance. Here, we report the results of simulation studies of a systems-level model of DRT performance. The model was trained using the temporal difference (TD) algorithm and uses an actor-critic architecture. The matrisomes of the BG represent the actor and the striosomes represent the critic. Unlike existing models, we hypothesize that the BG subserve the selection of both motor- and cognitive-related information in these tasks. We also assume that the learning of both processes is based on reward presentation. A novel feature of the model is the incorporation of delay-active neurons in the matrisomes, in addition to DLPFC. Another novel feature of the model is the subdivision of the matrisomal neurons into segregated winner-take-all (WTA) networks consisting of delay- versus transiently-active units.Our simulation model proposes a new neural mechanism to account for the occurrence of perseverative responses in WM tasks in striatal-, as well as in prefrontal damaged subjects. Simulation results also show that the model both accounts for the phenomenon of time shifting of dopamine phasic signals and the effects of partial reinforcement and reward magnitude on WM performance at both behavioral and neural levels. Our simulation results also found that the TD algorithm can subserve learning in delayed-reversal tasks.     

"They" as a gender-unspecified singular pronoun: eye tracking reveals a processing cost

The plural pronouns they and them are used to refer to individuals with unknown gender and when a random allocation of gender is undesirable. Despite this apparently felicitous usage, “singular they/them” should raise processing problems under the theory that pronouns seek gender- and number-matched antecedents. Using eye-tracking, we investigated whether there was any processing cost associated with using singular they/them. There was a clear cost of number incompatibility for they/them. Thus, although singular they/them is in current usage, it does not appear that they/them is immediately tolerant of a plural antecedent, though such may be rapidly accommodated. The data are consistent with the search account of pronoun resolution and preserve the semantics of they/them as denoting plurality.     

The Nature of Preschool Phonological Processing Abilities and Their Relations to Vocabulary, General Cognitive Abilities, and Print Knowledge

The development of reading-related phonological processing abilities (PPA) represents an important developmental milestone in the process of learning to read. In this cross-sectional study, confirmatory factor analysis was used to examine the structure of PPA in 129 younger preschoolers (M = 40.88 months, SD = 4.65) and 304 older preschoolers (M = 56.49 months, SD = 5.31). A 2-factor model in which phonological awareness and phonological memory was represented by one factor and lexical access was represented by a second factor provided the best fit for both samples and was largely invariant across samples. Measures of vocabulary, cognitive abilities, and print knowledge were significantly correlated with both factors, but phonological awareness/memory had unique relations with word reading. Despite significant development of PPA across the preschool years and into kindergarten, these results show that the structure of these skills remains invariant.