Visual change with moving displays: more evidence for color feature map inhibition during preview search

Preview search with moving stimuli was investigated. The stimuli moved in multiple directions, and preview items could change either their color or their shape before onset of the new (search) displays. In Experiments 1 and 2, the authors found that (a) a preview benefit occurred even when more than 5 moving items had to be ignored, and (b) color change, but not shape change, disrupted preview search in moving stimuli. In contrast, shape change, but not color change, disrupted preview search in static stimuli (Experiments 3 and 4). Results suggest that preview search with moving displays is influenced by inhibition of a color map, whereas preview search with static displays is influenced by inhibition of locations of old distractors.     

Teenagers and illicit drug use—expanding the ‘user vs non-user’ dichotomy

The present study examines proximal and distal factors associated with the use and non-use of illegal substances within a sample of 860 teenagers in North Wales. Arguing that there is predictive utility in expanding the traditional ‘users vs non-users’ design dichotomy, four groups are identified — resistant and vulnerable non-users and experimental and repeated users. ‘Person’ variables (life satisfaction, deviance, hopelessness and drug-related attributions) appeared to primarily differentiate the vulnerable group from their resistant counterparts and identify this, as yet non-using group, with user samples. It is suggested that these variables might represent ‘risk’ factors for illicit substance use and that the group design employed suggests they precede, rather than follow as a consequence of, illicit drug use. Like their resistant counterparts however, the vulnerable group are differentiated from user samples on some lifestyle and context indices. It is argued that these represent ‘protective’ influences in an otherwise at-risk group of non-users. Variables associated with an escalation of illicit drug use are discussed in considering the differences between the experimental and repeated user groups. Apart from the more proximal factor of drug-related attributions, ‘person’ variables appeared less involved here. Repeated users did however, tend to use a greater number of drugs, have a greater proportion of friends who also used illegal substances and significantly fewer had a Welsh cultural identity.     

Uniform connectedness and classical gestalt principles of perceptual grouping

We assessed whether uniform connectedness (UC; Palmer & Rock, 1994) operates prior to effects reflecting classical principles of grouping: proximity and similarity. In Experiments 1 and 2, reaction times to discriminate global letters (H vs. E), made up of small circles, were recorded. The small circles were respectively grouped by proximity, similarity of shapes, and by UC. The discrimination of stimuli grouped by similarity was slower than those grouped by proximity, and it was speeded up by the addition of UC. However, the discrimination of stimuli grouped by proxhnity was unaffected by connecting the local elements. In Experiment 3, similar results occurred in a task requiring discrimination of the orientation of grouped elements, except that the discrimination of stimuli grouped by UC was faster than that of those grouped by weak proximity. Experiment 4 further showed that subjects could respond to letters composed of discriminably separate local elements as fast as to those without separated local elements. The results suggest that grouping by similarity of shapes is perceived slower than grouping by UC, but grouping by proximity can be as fast and efficient as that by UC.     

Genetic Testing Considerations in Breast Cancer Patients

Genetic testing is now feasible for a growing number of cancers. Although the implications for unaffected relatives have been widely described, the impact of the tests on affected individuals are often not recognized. We present and discuss four cases that highlight some of the issues—for example, feelings of guilt and anxiety, intrafamilial conflict, and support needs—that may arise in testing affected individuals. We offer some suggestions to aid in the approach to such testing.     

Flexibility of attention between stimulus dimensions

Three experiments examined the flexibility of attention to the color and location dimensions of visual stimuli. Displays typically consisted of two curved lines, one a target and the other a distractor. Subjects were precued to the location of the target, and they made a speeded response to that item’s direction of curvature. In Experiment 1, a color difference between the stimuli facilitated selective attention to targets. Experiment 2 demonstrated that this effect was not automatic. Although component color differences were necessary for selective attention, they were not sufficient unless they reliably specified the target. Furthermore, when color was informative but the target was in an unexpected color, performance was markedly impaired. A third experiment, using a response-deadline technique, showed that stimulus color was resolved before stimulus location and that attention can be exclusive to the color dimension. The results were interpreted in terms of a model assuming that stimulus color and location are processed independently. Subjects attend to the dimension resolved most quickly which can reliably specify the target.     

Shape constancy: The effects of changing shape orientation and the effects of changing the position of focal features

Five experiments examined the time taken to judge that two consecutive elongated geometrical shapes had the same structure, irrespective of their orientation. Shape transformations either changed the orientation of the principal axis while maintaining the relative locations of focal features or maintained the orientation of the principal axis while changing the relative locations of focal features, or they changed both. Experiment 1 demonstrated that changes in the orientation of the principal axis were more detrimental to matching than were changes in the locations of the shape’s focal features. Indeed, the time taken to match same-orientation shapes was the same as that taken to match shapes that maintained the same position in the visual field. Further experiments showed that this result was not due to differential apparent motion in the transformation conditions, that it was not due to response bias, and that it generalized across shapes. However, the result was different when subjects could predict the location of the to-be-matched stimulus. In this case, performance was principally affected by the position of the focal feature of the shape and not by the shape’s orientation. It is suggested that the results reflect the efficiency with which subjects can construct matching representations for the stimuli When subjects cannot predict stimulus locations, they generate representations by describing shape structure relative to the shape’s principal axis. When the axis of the to-be-matched shapes is constant, subjects can use the same procedure in generating this representation for both shapes, facilitating matching relative to the case in which the orientation of the axis changes. When subjects can predict the stimulus location, they selectively attend to the focal features of shapes, minimizing the effects of shape orientation.     

Loss of control by a less valid or by a less salient stimulus compounded with a better predictor of reinforcement

An unsalient stimulus, or one imperfectly correlated with reinforcement, may acquire significant control over responding, provided that it is the only available signal for reinforcement, but may fail to acquire control if it is reinforced only in conjunction with a second, more salient or more valid stimulus. A stimulus imperfectly correlated with reinforcement may also lose control over responding if having initially been reinforced in isolation, it is subsequently reinforced only in conjunction with another, more valid stimulus. If the effects of relative salience are to be explained in exactly the same way as those of relative validity, we should expect a similar loss of control by an unsalient stimulus, A, if, after initial consistently reinforced trials to A alone, subjects subsequently receive reinforcement only in the presence of a compound stimulus, A + B. Two experiments on discrete-trial discrimination learning in pigeons and one on conditioned suppression in rats confirm this expectation. The results have implications for theories of selective association in conditioning and discrimination learning.     

View-specific effects of depth rotation and foreshortening on the initial recognition and priming of familiar objects

In a series of three experiments, we examined, first, the effects of viewpoint in depth on the efficiency of initial picture naming and, second, the effects of priming on subsequent naming. On initial presentation, foreshortened views were harder to name than were more typical (nonforeshortened) views. In addition, priming increased as a function of the similarity of the prime and target. Indeed, if a foreshortened view of an object had already been named, the subjects named a subsequent foreshortened view of that object as fast as or faster than they named a subsequent, more typical view. These results provide evidence against theories that predict full view-invariant object recognition and view-invariant priming of object recognition. Instead, the results support theories that suggest that object recognition is mediated by stored representations that are both view- and object-specific.     

The Hong Kong version of the Oxford Cognitive Screen (HK-OCS): validation study for Cantonese-speaking chronic stroke survivors

This study reports the validation of the Hong Kong version of Oxford Cognitive Screen (HK-OCS). Seventy Cantonese-speaking healthy individuals participated to establish normative data and 46 chronic stroke survivors were assessed using the HK-OCS, Albert’s Test of Visual Neglect, short test of gestural production, and Hong Kong version of the following assessments: Western Aphasia Battery, MMSE, MoCA, Modified Barthel Index, and Lawton Instrumental Activities of Daily Living scale. The validity of the HK-OCS was appraised by the difference between the two participant groups. Neurologically unimpaired individuals performed significantly better than stroke survivors on the HK-OCS. Positive and significant correlations found between cognitive subtests in the HK-OCS and related assessments indicated good concurrent validity. Excellent intra-rater and inter-rater reliabilities, fair test–retest reliability, and acceptable internal consistency suggested that the HK-OCS had good reliability. Specific HK-OCS subtests including semantics, episodic memory, number writing, and orientation were the best predictors of functional outcomes.     

4～6岁儿童人物画结构比例影响因素的比较研究

本研究旨在探索不同文化背景下影响 4～ 6岁儿童人物画结构比例的因素及认知发展的规律。研究分为自由画人与按照规定要求画人两部分。发现多因素导致儿童自由画人结构失调 ,如绘画顺序、空间统筹安排能力、头躯包含的器官以及对其重要性的认识等均会影响儿童自由人物画的头躯比值。儿童能按要求事先安排规定人物画的结构比例 ,根据细节多寡相应加大或缩小人体有关部分 ,如增大躯干部分以容纳夹克衫的纽扣、口袋等细节 ,或相应缩小头的轮廓以示背影等。此外 ,注意与重要性等因素也会对规定人物画结构产生影响。