Brain areas sensitive to coherent visual motion

Detection of coherent motion versus noise is widely used as a measure of global visual-motion processing. To localise the human brain mechanisms involved in this performance, functional magnetic resonance imaging (fMRI) was used to compare brain activation during viewing of coherently moving random dots with that during viewing spatially and temporally comparable dynamic noise. Rates of reversal of coherent motion and coherent-motion velocities (5 versus 20 deg s-1) were also compared. Differences in local activation between conditions were analysed by statistical parametric mapping. Greater activation by coherent motion compared to noise was found in V5 and putative V3A, but not in V1. In addition there were foci of activation on the occipital ventral surface, the intraparietal sulcus, and superior temporal sulcus. Thus, coherent-motion information has distinctive effects in a number of extrastriate visual brain areas. The rate of motion reversal showed only weak effects in motion-sensitive areas. V1 was better activated by noise than by coherent motion, possibly reflecting activation of neurons with a wider range of motion selectivities. This activation was at a more anterior location in the comparison of noise with the faster velocity, suggesting that 20 deg s-1 is beyond the velocity range of the V1 representation of central visual field. These results support the use of motion-coherence tests for extrastriate as opposed to V1 function. However, sensitivity to motion coherence is not confined to V5, and may extend beyond the classically defined dorsal stream.     

Examining the effectiveness of a community-based self-help program to increase women's readiness for smoking cessation

This study investigated the effectiveness of two components of a smoking cessation intervention: a reading manual and a series of televised programs. Female smokers in the Chicago metropolitan area with a high school education or less were interviewed at 4 different times: baseline, immediate postintervention, and 6 and 12 months. We examined the effects of several baseline measures (race, age, number of cigarettes smoked, and stage of readiness to change) and exposure to the intervention components on subsequent stage of change. Race, baseline smoking rate, baseline stage, and exposure to both intervention components had direct effects on stage at immediate postintervention, with both intervention components increasing readiness to quit. Furthermore, exposure to the manual interacted with baseline stage, such that the manual benefited women at earlier stages more than women at later stages. Effects of both components were sustained at 6 months, and the effects of the manual were sustained at 12 months.     

A Note on (K)Nots: Response to Robert W. Kentridge''s Commentary

GY, an extensively studied human hemianope, is aware of salient visual events in his cortically blind field but does not call this "vision." To learn whether he has low-level conscious visual sensations or whether instead he has gained conscious knowledge about, or access to, visual information that does not produce a conscious phenomenal sensation, we attempted to image process a stimulus s presented to the impaired field so that when the transformed stimulus T(s) was presented to the normal hemifield it would cause a sensation similar to that caused by s in the impaired field. While degradation of contrast, spatio-temporal filtering, contrast reversal, and addition of smear and random blobs all failed to match the response to a flashed bar s(f), moving textures of low contrast were accepted to match the response to a moving contrast-defined bar, s(m). Orientation and motion direction discrimination of the perceptually matched stimuli [s(m) and T(s(m))] was closely similar. We suggest that the existence of a satisfactory match indicates that GY has phenomenal vision.     

Age-of-acquisition and cumulative frequency have independent effects

Lewis (1999) argued that effects of age of acquisition (AoA) are entirely attributable to cumulative frequency. He reported an instance-based model in which the number of instances of the stimulus stored in memory predicts reaction time. We note four aspects of the literature on AoA that cannot be explained by this instance-based approach. Firstly, an effect of AoA has been observed in the absence of an effect of frequency. Secondly, an effect of AoA has been observed when cumulative frequency has been controlled. Thirdly, the effect of AoA is dependent on task. Fourthly, the effect of word frequency is dependent on stimulus modality. Lewis reported an experiment in which participants make a decision based on identity-specific semantic information to celebrity faces to demonstrate an effect of the number of instances in memory, which he interpreted as an effect of AoA. We note that effects of AoA have been found in lexical and perceptual tasks, but to date all attempts to demonstrate an advantage for early-acquired items in semantic classification tasks have failed. We conclude that the effects of AoA cannot be attributed solely to the effects of cumulative frequency.     

Influences of age, performance, and item relatedness on verbatim and gist recall of verb-noun pairs

Age differences in adults' memory for performed actions (e.g., wave hand) are sometimes smaller than age differences in memory for nonperformed phrases. In this study, we examined the conditions under which performance reduces age differences in recall. Younger and older adults performed or read verb-noun phrases that were either related (e.g., actions performed in a kitchen) or unrelated. Performance did not reduce age differences in recall of the exact verbs and nouns used to describe an action, but performance did reduce age differences in memory for the gist of related actions. Older adults especially had difficulty recalling the exact verb used to describe the action. These results suggest that older adults may have better memory for actions than is revealed by tests of verbatim recall. They may remember performing the action but not remember the exact words used to describe the action.     

Recent Developments in Close-Relationships Theory

A selective review of some recent theoretical developments in the field of close relationships is presented. We describe demographic developments reflecting flux in relationships and the family and what may be viewed as a revolution in gender relations and the family over the past three to four decades. Also reviewed are theories on the development, maintenance, and ending of relationships, as well as the “dark side" of closerelationships. We conclude that the close-relationships field is likely to continue to develop and prosper as people search for answers to daunting relationship problems.     

Antisocial Behavior and the Continuing "Tragedy of the Commons"

The influence of individuals' antisocial tendencies and risk perceptions on a simulated managerial decision are examined in the study. Subjects accepting and rejecting a hypothetical scenario were found to be significantly different in terms of aggression, lack of empathy, and degree of individualism. Situational influences were not significantly related to subjects' decision. Limitations and future research are discussed.