The tell-tale tasks: a review of saccadic research in psychiatric patient populations

This review focuses on saccade research with adult psychiatric patients. It begins with an introduction of the various types of saccades and the tasks used to evoke them. The functional significance of the different types of eye movements is briefly discussed. Research findings regarding the saccadic performance of different adult psychiatric patient populations are discussed in detail, with particular emphasis on findings regarding error rates, response latencies, and any specific task parameters that might affect those variables. Findings regarding the symptom, neurocognitive, and neural correlates of saccadic performance and the functional significance of patients’ saccadic deficits are also discussed. We also discuss the saccadic deficits displayed by various patient groups in terms of circuitry (e.g. cortical/basal ganglia circuits) that may be implicated in the underlying pathophysiology of several of these disorders. Future directions for research in this growing area are offered.     

Variability in Adaptive Behavior in Autism: Evidence for the Importance of Family History

Adaptive behavior in autism is highly variable and strongly related to prognosis. This study explored family history as a potential source of variability in adaptive behavior in autism. Participants included 77 individuals (mean age = 18) with average or better intellectual ability and autism. Parents completed the Family History Interview about the presence of broader autism phenotype symptoms and major psychiatric disorders in first degree relatives. Adaptive behavior was assessed via the Vineland Adaptive Behavior Scales (VABS). Based on family history variables, age, and intelligence quotient (IQ), 87% of participants were correctly classified as having impaired or average VABS scores. Family history of depression and shyness accounted for the most variance in VABS scores, and they had the greatest influence on VABS Socialization scores in particular. Possible underlying mechanisms include genetics, psychosocial factors, and social resources. This study provides initial evidence of the importance of family history to adaptive behavior in autism and has implications for genetics and treatment.     

Developmental differences in error-related ERPs in middle- to late-adolescent males

Although there are some studies documenting structural brain changes during late adolescence, there are few showing functional brain changes over this period in humans. Of special interest would be functional changes in the medial frontal cortex that reflect response monitoring. In order to examine such age-related differences, the authors analyzed event-related potentials following errors in a visual flanker task and a go/no-go task in adolescent males, 15-16 and 18-20 years old. Response times and accuracy were comparable between groups on each task, but the younger group made more go/no-go errors, suggesting this task was more difficult. Error-related negativity, thought to be generated in the anterior cingulate cortex (ACC), had greater amplitude for the older adolescents on both tasks; thus the increased errors are not simply due to performance level differences. Results from this study suggest that the ACC, which supports response monitoring, is late to mature due to age-related structural or neurochemical changes.     

Regularity of symmetry verticality guides perceptual judgments of objects

Previous research indicated that most salient, real-world objects possess natural regularities that observers commonly assume in perceptual judgments of figural orientation and interpretation. Regularities include 3-dimensionality, bilateral symmetry, and the tendency for object tops to possess more salient information than bottoms. Thus, when observers interpret randomly shaped figures, they reliably impose volume, bilateral symmetry, and top and front orientation directions, even when figures are 2-dimensional and asymmetric. We confirmed generalizability for observers to assume these regularities with stimuli that vary in complexity, and we found evidence supporting another regularity, that of symmetry verticality (symmetry about a vertical axis). Findings support use of a family of perceptual heuristics corresponding to natural regularities that constrain stimulus indeterminacy and help guide judgment of object orientation and interpretation.     

Providing information about diagnostic features at retrieval reduces false recognition

In the following study, participants encoded blocked DRM word lists and we varied whether they received information before test about the utility of mnemonic features that potentially discriminate between veridical and false memories. The results of three experiments revealed that this manipulation successfully reduced false recognition of critical theme words. We also found that this manipulation was effective for younger but not older adults. Furthermore, calling attention to the features in test instructions alone was sufficient for reducing false recognition and its effectiveness was not enhanced by also asking participants to rate their phenomenal experience. We argue that providing diagnostic information before test allows participants to establish more accurate expectations about the task and thus improves the efficacy of retrieval and monitoring processes that are subsequently engaged.     

State of Multicultural Neuropsychological Assessment in Children: Current Research Issues

Scientific attention to cultural considerations in child neuropsychological assessment has not developed parallel to the focus these issues have received in adult and elderly neuropsychological assessment. There are limited data on the presence, magnitude, etiology, and implications of culture-related differences in cognitive test performance among children. This preliminary report reviews the available empirical literature on the current state of multicultural neuropsychological assessment in children. The review identified articles by searching PubMed and PsycINFO databases, and the tables of contents of Developmental Neuropsychology and Child Neuropsychology from 2003-2008. Of the 1,834 abstracts reviewed, ten papers met inclusion criteria for the review. Five studies were completed in America; four of these compared performance between ethnic groups while the fifth examined neighborhood level poverty indicators exclusively within African-American children. Of the five international studies, all established local normative data and/or were exploratory investigations of neuropsychological functions in specific cultural groups, including Taiwanese infants, South African youth, and bilingual British children. Taken together, the results yield important clinical and research data that begin to inform many of the complex and fascinating mechanisms by which ethnic identity and culture impact cognitive development and the neuropsychological assessment of children. A critique of the existing literature and directions for future research are provided.     

Interpreting dissociations between regular and irregular past-tense morphology: Evidence from event-related potentials

Neuropsychological dissociations between regular and irregular English past-tense morphology have been reported using a lexical decision task in which past-tense primes immediately precede present-tense targets. We present N400 event-related potential data from healthy participants using the same design. Both regular and irregular past-tense forms primed corresponding present-tense forms, but with a longer duration for irregular verbs. Phonological control conditions suggested that differences in formal overlap between prime and target contribute to, but do not account for, this difference, suggesting a link between irregular morphology and semantics. Further analysis dividing the irregular verbs into two categories (weak irregular and strong) revealed that priming for strong verbs was reliably stronger than that for weak irregular and regular verbs, which were statistically indistinguishable from one another. We argue that, although we observe a regular-irregular dissociation, the nature of this dissociation is more consistent with single- than with dual-system models of inflectional morphology.     

STEREOTYPE THREAT AND THE GENDER GAP IN POLITICAL KNOWLEDGE

Men tend to achieve higher response accuracy than women on surveys of political knowledge. We investigated the possibility that this performance gap is moderated by factors that render the communicative context of a survey intellectually threatening to women and thereby induce stereotype threat. In a telephone survey of college students' political knowledge, we manipulated two factors of the survey context: the alleged diagnosticity of the question set (i.e., whether it was portrayed as being sensitive to potential gender differences) and the gender of the interviewer. Consistent with previous studies of political knowledge, men scored higher than women overall. However, as predicted, this difference was reliably moderated by the manipulated factors. Women's scores were not reliably different from men's when the survey was portrayed as nondiagnostic and when women were interviewed by female interviewers. Diagnosticity and interviewer gender had no effects on men's scores. Consistent with previous research on stereotype threat, these results suggest that explicit and implicit cues reminding women of the possibility that they might confirm a negative gender stereotype can impair their retrieval of political knowledge.