Gender, gender relations, and the social dynamics of children's conversations

The authors investigated the effects of gender on the social dynamics and outcomes of conversations involving 120 children (mean age = 8 years 7 months). Children were taught particular values for different shaped counters and placed in same-gender or mixed-gender pairs with children who were taught different values. Pairs were asked to add the counters together to make a total of 100. Conversations were coded in terms of communication acts and simultaneous speech acts. Boys used more controlling acts overall and more negative interruptions in mixed-gender pairs. Girls used more affiliating acts. All children used more collaborative communication in same-gender pairings. Children whose perspective dominated used more controlling and comparatively fewer affiliating acts. When children reached a compromise, conversations were more collaborative.     

Understanding the structural determinants of object confusion in memory: an assessment of psychophysical approaches to estimating visual similarity

Computer-generated shapes varying on visual dimensions such as curvature, tapering, and thickness have been used to investigate identification deficits in the category-specific visual agnosia (CSVA) Patient E.L.M.. However, whether the implemented variations on each of these dimensions were perceived by novice observers as "similar amounts of change" is unknown. To estimate distance in psychophysical shape space, sets of shapes were developed using two different scaling methods--an objective method based on visual search, and a subjective method based on judgments of similarity--and a third approach that did not involve scaling. How well each method estimated psychophysical shape space was assessed by measuring the confusions within memory among the shapes. The results suggested that, although neither of the approaches perfectly reflected psychophysical shape space, subjective scaling was a better estimator of distance in psychophysical shape space than were other approaches. The number of confusions produced on each set of shapes was used to develop a new set of shapes that accurately estimated distance in psychophysical shape space. These results suggest that a combination of approaches is preferable in order to accurately estimate distance in psychophysical shape space.     

A meta-analytic review of prospective memory and aging

A meta-analysis of prospective memory (PM) studies revealed that in laboratory settings younger participants outperform older participants on tests of both time- and event-based PM (rs=-.39 and -.34, respectively). Event-based PM tasks that impose higher levels of controlled strategic demand are associated with significantly larger age effects than event-based PM tasks that are supported by relatively more automatic processes (rs=-.40 vs. -.14, respectively). However, contrary to the prevailing view in the literature, retrospective memory as measured by free recall is associated with significantly greater age-related decline (r=-.52) than PM, and older participants perform substantially better than their younger counterparts in naturalistic PM studies (rs=.35 and.52 for event- and time-based PM, respectively).     

Braking reaching movements: a test of the constant tau-dot strategy under different viewing conditions

Following F. Zaal and R. J. Bootsma (1995), the authors studied whether the decelerative phase of a reaching movement could be modeled as a constant tau-dot strategy resulting in a soft collision with the object. Specifically, they investigated whether that strategy is sustained over different viewing conditions. Participants (N = 11) were required to reach for 15- and 50-mm objects at 2 different distances under 3 conditions in which visual availability of the immediate environment and of the reaching hand were varied. Tau-dot estimates and goodness-of-fit were highly similar across the 3 conditions. Only within-participant variability of tau-dot estimates was increased when environmental cues were removed. That finding suggests that the motor system uses a tau-dot strategy involving the intermodal (i.e., visual, proprioceptive, or both) specification of information to regulate the decelerative phase of reaching under restricted viewing conditions. The authors provide recommendations for improving the derivation of tau;(x) estimates and stress the need for further research on how time-to-contact information is used in the regulation of the dynamics of actions such as reaching.     

Size of the neocerebellar vermis is associated with cognition in healthy elderly men

Cerebellar volumes show small positive correlations with cognitive ability in young adults, but no studies have examined this relationship in older adults. Furthermore, no studies have examined relationships between sizes of subareas of the cerebellum and cognitive ability. We hypothesized that size of the two areas of the neocerebellar vermis would correlate with a battery of eight cognitive tests in 50 men aged 65-70. Size of the neocerebellar areas of the vermis correlated positively with several cognitive tests (r's=.29-.37, p<.05), whilst sizes of other parts of the vermis did not correlate with any cognitive tests. Total cerebellar volumes correlated significantly with a test of nonverbal reasoning (r=.030, p=.42). These findings suggest a specific association of neocerebellar vermis size with variations in cognitive ability in older adults.     

Anomaly detection in the right hemisphere: The influence of visuospatial factors

Previous research with both brain-damaged and neurologically intact populations has demonstrated that the right cerebral hemisphere (RH) is superior to the left cerebral hemisphere (LH) at detecting anomalies (or incongruities) in objects (Ramachandran, 1995; Smith, Tays, Dixon, & Bulman-Fleming, 2002). The current research assesses whether the RH advantage for anomaly detection is due to the RH superiority for visuospatial skills or is a distinct cognitive process. Sixty undergraduate participants completed tasks assessing anomaly detection, mental rotation, and global and local perceptual abilities. The results demonstrate that anomaly detection is negatively correlated with mental rotation. These findings suggest that anomaly detection is not simply a function of visuospatial skills.     

Attendance probabilities of participants in a human experiment

This study investigated how different prompting strategies affected the attendance probabilities of 60 undergraduate students participating in an experiment. Subjects were randomly assigned to one of three conditions: no prompt, phone-message prompt, or phone-voice prompt. Analysis showed that participants in the no-prompt condition attended the study at a rate of 50%. Participants who received a phone-message prompt attended at a rate of 55%, while participants who received a phone-voice prompt attended at a rate of 100%.     

Seeing double: the role of meaning in alphanumeric-colour synaesthesia

When PD, an alphanumeric-colour synaesthete, is shown black digits or letters, each grapheme elicits a highly specific colour, called a "photism" (e.g., a 2 induces green, a Z induces brown). Previous experiments showed that photisms interfere with video-colour naming when the photism colour and the video colour are incongruent. Here we used coloured ambiguous graphemes that could be interpreted as either digits or letters depending on context (e.g., an ambiguous grapheme was interpreted as a 2 if presented within a block of digit trials, but as a Z if presented within a block of letter trials). Ambiguous graphemes were presented in video colours that were either congruent or incongruent with PD's photisms. Crucially, what was a congruent trial in one context was an incongruent trial in the other context. PD's pattern of response times indicated that identical graphemes could induce differently coloured photisms depending on their interpretation. This suggests that the meaning of graphemes ultimately determines their synaesthetic colour.     

Synaesthetic photisms guide attention

We evaluated whether synaesthetic colour experiences (i.e., photisms) guide or attract attention. An alphanumeric-colour synaesthete, J, and seven non-synaesthetes searched for target digits presented against backgrounds that were either congruent or incongruent with the colours of J's photisms for the target digits. For J, the slope of the search function for detecting the target digits on incongruent trials was shallower than the slope of the search function for detecting the target digits on congruent trials. In contrast, for the seven non-synaesthetes, the slopes of the search functions for detecting the target digits on congruent and incongruent trials were equivalent. These findings suggest that synaesthetic colour experiences influence the efficiency of visual search by guiding or attracting attention.     

Latent change models of adult cognition: are changes in processing speed and working memory associated with changes in episodic memory?

The authors used 6-year longitudinal data from the Victoria Longitudinal Study (VLS) to investigate individual differences in amount of episodic memory change. Latent change models revealed reliable individual differences in cognitive change. Changes in episodic memory were significantly correlated with changes in other cognitive variables, including speed and working memory. A structural equation model for the latent change scores showed that changes in speed and working memory predicted changes in episodic memory, as expected by processing resource theory. However, these effects were best modeled as being mediated by changes in induction and fact retrieval. Dissociations were detected between cross-sectional ability correlations and longitudinal changes. Shuffling the tasks used to define the Working Memory latent variable altered patterns of change correlations.