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.     

Neuropsychologic functioning in children with autism: further evidence for disordered complex information-processing.

A wide range of abilities was assessed in 56 high-functioning children with autism and 56 age- and IQ-matched controls. Stepwise discriminant analyses produced good group discrimination for sensory-perceptual, motor, complex language, and complex memory domains but lower agreement for the reasoning domain than previously obtained for adults. Group discrimination did not occur for attention, simple language, simple memory, and visuospatial domains. Findings provide additional support for a complex information-processing model for autism, previously based on adult data, demonstrating a pattern across domains of selective impairments on measures with high demands for integration of information and sparing when demands were low. Children as compared to adults with autism exhibited more prominent sensory-perceptual symptoms and less pronounced reasoning deficits reflecting brain maturation.     

Features and feedback: enhancing metamnemonic knowledge at retrieval reduces source-monitoring errors

Three experiments explored the issue of whether enhanced metamnemonic knowledge at retrieval can improve participants' ability to make difficult source discriminations in the context of the eyewitness suggestibility paradigm. The 1st experiment documented differences in phenomenal experience between veridical and false memories. Experiment 2 revealed that drawing participants' attention to these differences by pairing the ratings of the features with instructions about their utility was successful in reducing source misattributions of suggested items to the event. The results of Experiment 3 showed that participants can make online adjustments in the types of evidence used to make source judgments, as participants who received correct feedback during the training portion of the test reduced misattribution errors on the remainder of the test where feedback was not provided. Altogether, these studies suggest that people can discover and benefit from updated knowledge of the types of memorial evidence that discriminate between sources of information in memory.