Why is visual search superior in autism spectrum disorder?

This study investigated the possibility that enhanced memory for rejected distractor locations underlies the superior visual search skills exhibited by individuals with autism spectrum disorder (ASD). We compared the performance of 21 children with ASD and 21 age‐ and IQ‐matched typically developing (TD) children in a standard static search task and a dynamic search task, in which targets and distractors randomly changed locations every 500 ms, precluding the use of memory in search. Children with ASD exhibited overall faster reaction time (RT) relative to TD children, and showed no disruption in search efficiency in the dynamic condition, discounting the possibility that memory for rejected distractors augments their visual search abilities. Analyses of RT x set size functions showed no group differences in slopes but lower intercepts for the ASD group in both static and dynamic search, suggesting that the ASD advantage derived from non‐search processes, such as an enhanced ability to discriminate between targets and distractors at the locus of attention. Eye‐movement analyses revealed that the ASD and TD groups were similar in the number and spatial distribution of fixations across the search array, but that fixation duration was significantly shorter among children with ASD. Lower intercepts in static search were related to increased symptom severity in children with ASD. In summary, ASD search superiority did not derive from differences in the manner in which individuals with ASD deployed their attention while searching, but from anomalously enhanced perception of stimulus features, which was in turn positively associated with autism symptom severity.     

Human brain activity time-locked to narrative event boundaries

Readers structure narrative text into a series of events in order to understand and remember the text. In this study, subjects read brief narratives describing everyday activities while brain activity was recorded with functional magnetic resonance imaging. Subjects later read the stories again to divide them into large and small events. During the initial reading, points later identified as boundaries between events were associated with transient increases in activity in a number of brain regions whose activity was mediated by changes in the narrated situation, such as changes in characters' goals. These results indicate that the segmentation of narrated activities into events is a spontaneous part of reading, and that this process of segmentation is likely dependent on neural responses to changes in the narrated situation.     

Dimensions of DSM-IV personality disorders and life-success

This study examined associations between dimensional representations of DSM-IV personality disorders and life-success in a community sample of 304 men at age 48. Measures included a standardized social interview and the SCID-II for assessment of personality disorders. The identified indicators of life-success were factor-analyzed resulting in two moderately correlated components representing "status and wealth" and "successful intimate relationships." Avoidant, obsessivecompulsive, and narcissistic dimensional scores were positively associated with "status and wealth." Inverse relationships were found between dependent, schizotypal, schizoid, and adult antisocial personality disorder dimensions and this domain of life-success. Avoidant, schizoid, and borderline personality disorder dimensions were negatively associated with "successful intimate relationships." The findings suggest that although most personality disorders are associated with impaired psychosocial functioning and life-failure, some personality disorder traits (even if considered as pathological) can contribute positively to one important aspect of life-success: status and wealth.     

Trait expectancies and stereotype expectancies have the same effect on person memory

Two studies examined whether trait expectancies and stereotype expectancies similarly affected memory for expectancy-relevant behaviors. The results of both studies showed that, when activated in identical ways, trait expectancies and stereotype expectancies had similar effects on recall. Better recall was obtained for expectancy-incongruent items when expectancies were activated in relatively overt ways, while better recall for expectancy-congruent items was obtained when expectancies were activated in less overt ways. Additional analyses examining the order of events that emerged in the recall protocols provided little evidence that participants attempted to reconcile the items, as would be predicted by some earlier models of person memory (e.g., Srull, 1981). The implications of these findings for how social expectancies guide social information processing are discussed.     

Mere effort and stereotype threat performance effects

Although the fact that stereotype threat impacts performance is well established, the underlying process(es) is(are) not clear. Recently, T. Schmader and M. Johns (2003) argued for a working memory interference account, which proposes that performance suffers because cognitive resources are expended on processing information associated with negative stereotypes. The antisaccade task provides a vehicle to test this account because optimal performance requires working memory resources to inhibit the tendency to look at an irrelevant, peripheral cue (the prepotent response) and to generate volitional saccades to the target. If stereotype threat occupies working memory resources, then the ability to inhibit the prepotent response and to launch volitional saccades will be impaired, and performance will suffer. In contrast, S. Harkins's (2006) mere effort account argues that stereotype threat participants are motivated to perform well, which potentiates the prepotent response, but also leads to efforts to counter this tendency if participants recognize that the response is incorrect, know the correct response, and have the opportunity to make it. Results from 4 experiments support the mere effort but not the working memory interference account.     

Familiarity from orthographic information: Extensions of the recognition without identification effect

Two experiments were conducted to investigate the effect of letter location information in recognition memory judgments. The experiments used the recognition without identification paradigm (Peynircioglu, 1990), in which participants first attempt to identify the test item and then make a recognition decision as to whether or not the item was studied. In these studies, items that are not identified but that correspond to items that were presented are typically still rated as more likely to have been studied than those that were not presented. The present experiments demonstrated this finding with a variant of the conjunction lure paradigm. In Experiments 1 and 2, participants were tested with word fragments that were made from the letters of two words. When the letters were from studied items, fragments were rated higher than when the test items were derived from two unstudied items, or one studied item and one unstudied item, suggesting that recognition without identification is prone to the same types of errors as recognition with identification. Results are discussed in terms of familiarity effects in recognition memory.     

Self-monitoring and mimicry of positive and negative social behaviors

This study examined the role that self-monitoring plays in behavioral mimicry. Participants were exposed to videotaped targets who were laughing, yawning, frowning, or neutral in their expression. Participants’ behavioral mimicry while viewing the targets was recorded. It was hypothesized that higher self-monitors would show greater mimicry than lower self-monitors. It was also hypothesized that participants would respond differently to positive and negative target expressions. Participants who scored higher in self-monitoring did mimic the targets’ behaviors more often, and participants showed less mimicry of frowns than of laughs or yawns.     

Speech-associated gestures, Broca's area, and the human mirror system

Speech-associated gestures are hand and arm movements that not only convey semantic information to listeners but are themselves actions. Broca's area has been assumed to play an important role both in semantic retrieval or selection (as part of a language comprehension system) and in action recognition (as part of a "mirror" or "observation-execution matching" system). We asked whether the role that Broca's area plays in processing speech-associated gestures is consistent with the semantic retrieval/selection account (predicting relatively weak interactions between Broca's area and other cortical areas because the meaningful information that speech-associated gestures convey reduces semantic ambiguity and thus reduces the need for semantic retrieval/selection) or the action recognition account (predicting strong interactions between Broca's area and other cortical areas because speech-associated gestures are goal-direct actions that are "mirrored"). We compared the functional connectivity of Broca's area with other cortical areas when participants listened to stories while watching meaningful speech-associated gestures, speech-irrelevant self-grooming hand movements, or no hand movements. A network analysis of neuroimaging data showed that interactions involving Broca's area and other cortical areas were weakest when spoken language was accompanied by meaningful speech-associated gestures, and strongest when spoken language was accompanied by self-grooming hand movements or by no hand movements at all. Results are discussed with respect to the role that the human mirror system plays in processing speech-associated movements.     

Walking patterns change rapidly following asymmetrical lower extremity loading

The purpose of this study was to determine the amount of time needed for individuals to become well accommodated to asymmetrical changes in lower extremity inertial properties. Participants walked at 1.57 m s(-1) during four separate data collection sessions over the period of eight days. On days 1 and 7, participants completed a 60 min treadmill protocol consisting of both overground (motion and ground reaction force recorded) and treadmill (vertical ground reaction force recorded) walking. On day 1, 1.95 kg was attached distally to one shank prior to the start of the 60 min treadmill protocol and was not removed until day 7. On day 7, the load was permanently removed prior to the 60 min treadmill protocol. On days 2 and 8 participants completed three overground walking trials and walked on the treadmill for approximately 5 min. Stance and swing time asymmetries appeared immediately and were complete following initial assessment after the load was attached. Net joint moments at the knee and hip were altered and continued to change beyond initial exposure to the load, but these changes were complete within 5 min. Overall, results suggest that changes in walking symmetry due to asymmetrical lower extremity loading are immediate and complete within 5 min of exposure to the load. We recommend that at least 5 min of walking or other normal activity be used to accommodate individuals to novel asymmetrical lower extremity loading.