Information transmission for one-dimensional stimuli: The role of strategies

Important evidence about the information flow between perceptual and motor processes has been obtained from the lateralized readiness potential (LRP) recorded in two-choice go/nogo tasks. Here, we investigated the effect of time pressure on information transmission for one-dimensional stimuli (four squares differing in size). In between- and within-subject designs, respectively, Experiments 1 and 2 showed that under time pressure partial information initiates hand decision and response preparation before complete size information is available. These findings appear to be at odds with the asynchronous discrete coding model. Experiment 3 assessed the mechanisms behind these effects by manipulating the relative difficulty of extracting hand- and go/nogo-specific information from the size of the stimuli. Consistent with asynchronous coding, our results suggest that serial-consecutive processes in extracting partial and full size information may occur also for one-dimensional stimuli. Our data are inconclusive as to the question of discreteness or continuity of information transmission. On a more general level, our data support the notion of flexibility in the coding of perceptual dimensions to adapt performance to environmental conditions.     

Perceptual identification across the life span: a dissociation of early gains and late losses

The age-correlated gains and losses in visual identification under backward pattern masking were studied in a representative sample of 226 individuals ranging from 6 to 88 years of age. Participants identified masked symbols at leisure under high and low stimulus quality and at varying Stimulus Onset Asynchronies. Performance increased from childhood to early adulthood and then decreased, describing the common inverted U-shaped function. However, measures of general processing speed accounted for the gains in childhood and adolescence but not for losses in older age. This asymmetry between child development and aging is inconsistent with general-factor lifespan theories of cognitive development and suggests that specific mechanisms underlying visual identification during child development and aging are different.     

Alcohol and Acquaintance Rape in Australia: Testing the Presupposition Model of Attributions About Responsibility and Blame1

According to the presupposition model of attributions about responsibility and blame (Bradbury & Fincham, 1990), an attribution of blame presupposes an attribution of responsibility. Both constructs share the dimensions of choice, intention, and accountability, but an additional dimension of liability relates only to blame. Reactions of 260 university students to acquaintance‐rape scenarios portraying different levels of alcohol intoxication were examined. Results showed that the model's dimensions explained much of the variance in attributions of responsibility and blame, although the hierarchical structure was not supported. Mediational analyses suggest that different attributional principles apply when assigning victim and perpetrator responsibility, which may explain why intoxicated victims are assigned more responsibility than sober victims, but intoxicated perpetrators are assigned less responsibility than sober perpetrators.     

Increases in language lateralization in normal children as observed using magnetoencephalography

Previous functional magnetic resonance imaging (fMRI) studies investigating hemispheric dominance for language have shown that hemispheric specialization increases with age. We employed magnetoencephalography (MEG) to investigate these effects as a function of normal development. In sum, 22 healthy children aged 7-16 years were investigated using two language tasks: a verb-generation (VG) task and a vowel-identification (VI) task. Significant hemispheric differences were found for both tasks in cerebral language areas using oscillatory MEG spectral analyses, confirming the MEG's ability to detect hemispheric specialization for language in children. Additionally, a significant increase of this lateralization as a function of age was observed for both tasks. As performance in the VI task showed no correlation with age, this increase seems to be unrelated to performance. These results confirm an increase in hemispheric specialization as a function of normal brain maturation.     

Individual differences in components of reaction time distributions and their relations to working memory and intelligence

The authors bring together approaches from cognitive and individual differences psychology to model characteristics of reaction time distributions beyond measures of central tendency. Ex-Gaussian distributions and a diffusion model approach are used to describe individuals' reaction time data. The authors identified common latent factors for each of the 3 ex-Gaussian parameters and for 3 parameters central to the diffusion model using structural equation modeling for a battery of choice reaction tasks. These factors had differential relations to criterion constructs. Parameters reflecting the tail of the distribution (i.e., tau in the ex-Gaussian and drift rate in the diffusion model) were the strongest unique predictors of working memory, reasoning, and psychometric speed. Theories of controlled attention and binding are discussed as potential theoretical explanations.     

Preceding stimulus awareness augments offset-evoked potentials: Evidence from motion-induced blindness

Event-related potentials (ERPs) were measured in response to the objective offset of a visual disk under two physically similar conditions: (1) visible conditions in which the target disk was well perceived and (2) invisible conditions in which participants reported to have not seen the target because of motion-induced blindness (Bonneh, Cooperman, & Sagi in Nature 411:798-801, 2001). Electrophysiological responses to the physical offset of the target disk were almost completely absent in the invisible conditions (Experiment 2). In the same conditions, the physical offset was almost completely invisible (Experiment 1). Results suggest an augmenting function of prior awareness of a stimulus for the offset-triggered ERP of that stimulus.     

Is word perception in a second language more vulnerable than in one's native language? Evidence from brain potentials in a dual task setting

We assessed the effect of additional tasks on language perception in second-language and native speakers. The N400 component of the event-related potential was recorded to spoken nouns that had to be judged for synonymity with a preceding word, while additional choice responses were required to visual stimuli. In both participant groups N400 was delayed as a function of temporal overlap with the additional task. In second-language speakers there was a global delay of N400 independent of additional task load and a decrease of accuracy at highest overlap. These findings are interpreted within a single channel account of language perception.     

Why cast shadows are expendable: insensitivity of human observers and the inherent ambiguity of cast shadows in pictorial art

The kinds of visual cues artists choose to use or not use in their work can offer insight into perceptual processes. On the basis of the observed paucity of the use of cast shadow in pictorial art, we hypothesized that cast shadows might be relatively expendable as pictorial cues. In this study, we investigated two potential reasons for this expendability: first, viewers might be insensitive to much of the information that cast shadows provide; and, second, ambiguities about what is shadow and what is pigment can often be resolved only through motion-something that static media are ill-equipped to deal with. In experiment 1, we used a visual-search paradigm in which viewers had to determine if there were odd cast shadows in sets of 4, 8, 16, and 32 objects. In experiment 2, viewers had to discriminate between shadow/pigment ambiguities in both still and moving images. Our results demonstrate that viewers are neither particularly sensitive to static cast-shadow incongruities, nor are they able to disambiguate cast shadow from pigment without continuous motion information. Taken together, these results may help explain why cast shadows are relatively rare in static pictorial work.     

A longitudinal study of relational aggression, physical aggression, and children's social-psychological adjustment

Although great strides have recently been made in our understanding of relational aggression and its consequences, one significant limitation has been the lack of prospective studies. The present research addressed this issue by identifying and assessing groups of relationally aggressive, physically aggressive, relationally plus physically aggressive (co-morbid), and nonaggressive children during their third grade year in elementary school and then reassessing them a year later, during fourth-grade (N = 224, 113 girls). Two aspects of social-psychological adjustment were assessed during both assessment periods including internalizing difficulties (i.e., withdrawal, depression/anxiety, and somatic complaints) and externalizing problems (i.e., aggressive behavior, delinquency). It was revealed that the strongest predictor of future social-psychological adjustment problems and increases in these problems from third to fourth was the combination of relational and physical aggression. Relational aggression also contributed unique information, relative to physical aggression, in the prediction of future maladjustment. Implications of these findings for future research and prevention efforts, particularly for aggressive girls, are discussed.