The development of responses to people and a toy in infants with down syndrome

The behavior of eight infants with Down syndrome was observed biweekly from 8 to 24 weeks and monthly up to 48 weeks. At each visit the infants were presented with their mother, a female stranger, and a rattle puppet that were alternately active and passive. Each condition lasted 60 s. The results showed that by 4 months of age the infants began to differentiate, in the proportion of time they looked, smiled, and vocalized, between people and the toy. They did not discriminate, however, between mother and female stranger and between the active and passive adults until the second half of the first year. In particular, whereas normal infants usually show distress toward passive or “still-face” adults, the infants in this study continued to vocalize, at times even with smiling faces. The implications of these atypical aspects of the social development of infants with Down syndrome for their subsequent nonverbal communicative development are discussed.     

Recognition of color-form compounds by 4-month-old infants

In two studies, a paired-comparison procedure was used to investigate whether 4-month-old infants can perceive and remember correlations of color and form. In Study 1, infants were shown simultaneous presentations of two different colored shapes until two criteria for familiarization had been met. They were then offered a simultaneous choice between a colored form that they had already seen and one that was a new combination of a familiar color and a familiar shape. The infants looked significantly longer at the new combination than at the familiar combination on the test trial. In Study 2, the same procedure was used, except that the familiarization criteria were less stringent and additional analyses of the infants' test trial behavior were conducted. Infants again exhibited a significant preference for the new combination, both when looking time accumulated during the entire test-trial was analyzed and when looking just up to the “first look away” was considered. These findings that 4-months-olds can perceive and remember compounds of visual attributes conflict with the results of several studies in which the habituation and test stimuli were presented sequentially rather than simultaneously. Differences in the nature of the information processing that may be evoked by the two methods are discussed.     

Perception of ensemble statistics requires attention

To overcome inherent limitations in perceptual bandwidth, many aspects of the visual world are represented as summary statistics (e.g., average size, orientation, or density of objects). Here, we investigated the relationship between summary (ensemble) statistics and visual attention. Recently, it was claimed that one ensemble statistic in particular, color diversity, can be perceived without focal attention. However, a broader debate exists over the attentional requirements of conscious perception, and it is possible that some form of attention is necessary for ensemble perception. To test this idea, we employed a modified inattentional blindness paradigm and found that multiple types of summary statistics (color and size) often go unnoticed without attention. In addition, we found attentional costs in dual-task situations, further implicating a role for attention in statistical perception. Overall, we conclude that while visual ensembles may be processed efficiently, some amount of attention is necessary for conscious perception of ensemble statistics.     

视知觉无意识加工的脑机制及其研究进展

本文从脑的解剖和功能结构、神经网络联结及其突触活动基础角度,对视知觉无意识加工脑内可能存在的信息加工方式进行了探讨。视知觉无意识加工既是一个不同特征在大脑的不同区域被平行分布加工的过程,也是一个涉及正向和反向的信息序列加工及意识与无意识相互转化的过程。     

Effect of facial stimuli exposure time on evaluation of facial attractiveness

Facial attractiveness has advantages both socially and sexually, and the human brain has evolved to perceive specific facial characteristics as attractive. The current research examined the effect of facial stimuli exposure time on facial attractiveness evaluations. In Experiment 1, 86 students observed 44 facial stimuli in short and long amounts of time. To eliminate any influence of repeated stimuli on the second observations, Experiment 2 was performed on 84 participants who observed the facial stimuli in either short or long durations. Differences in both experiments were significant. These studies showed that exposure time has an influence on the evaluation of facial attractiveness. Participants who were exposed to facial stimuli for a short amount of time perceived greater facial attractiveness than when they were exposed for a longer time to the same stimuli. In other words, faces were more beautiful when they were observed in a short amount of time, and this effect occurred regardless of gender.     

Aging and performance on an everyday-based visual search task

Research on aging and visual search often requires older people to search computer screens for target letters or numbers. The aim of this experiment was to investigate age-related differences using an everyday-based visual search task in a large participant sample (n=261) aged 20-88 years. Our results show that: (1) old-old adults have more difficulty with triple conjunction searches with one highly distinctive feature compared to young-old and younger adults; (2) age-related declines in conjunction searches emerge in middle age then progress throughout older age; (3) age-related declines are evident in feature searches on target absent trials, as older people seem to exhaustively and serially search the whole display to determine a target's absence. Together, these findings suggest that declines emerge in middle age then progress throughout older age in feature integration, guided search, perceptual grouping and/or spreading suppression processes. Discussed are implications for enhancing everyday functioning throughout adulthood.