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.     

Experimental manipulation of prior experience: Effects on item and associative recognition

Frequency of exposure to very low- and high-frequency words was manipulated in a three-phase (familiarisation, study, and test) design. During familiarisation, words were presented with their definition (once, four times, or not presented). One week (Experiment 1) or one day (Experiment 2) later, participants studied a list of homogeneous pairs (i.e., pair members were matched on background and familiarisation frequency). Item and associative recognition of high- and very low-frequency words presented in intact, rearranged, old-new, or new-new pairs were tested in Experiment 1. Associative recognition of very low-frequency words was tested in Experiment 2. Results showed that prior familiarisation improved associative recognition of very low-frequency pairs, but had no effect on high-frequency pairs. The role of meaning in the formation of item-to-item and item-to-context associations and the implications for current models of memory are discussed.     

Experimental measures of cognitive privilege/deprivation and some of their correlates

An operational definition of intellectual privilege and deprivation was used to develop measures of that construct in each sex from information furnished by 10th-grade students in Project Talent about their family and health background. Information such as reports of high school grades that directly reflected the ability of the students was excluded. The correlation between the experimental measure and the Talent intelligence composite is about .65 in contrast to the usual value of about .40 for a traditional measure of socioeconomic status. Sex differences in the items keyed are minimal. Using a similar definition, measures were also developed for Vernon's mechanical-spatial major group factor (1960), but the level of validity achieved is lower. The measures of privilege/deprivation developed for the two criteria show some degree of differential validity, but there is more generality in the two kinds of privilege than in tested abilities. The measures of intellectual privilege are almost congeneric measures of general intelligence, but there are significant departures from parallel profiles of relationships with other cognitive tests in Talent. The measures of intellectual privilege for both sexes add to the accuracy of prediction obtained from the intelligence criterion of scores on verbal academic and aesthetic information, but add nothing in predicting scores on measures of spatial visualization and rote memory. The possibility of constructing a test of general intelligence using item types that would minimize the correlation with privilige/deprivation is discussed.     

Attenuated hypothesis or attenuated test of hypothesis?

After discussing several of the criticisms made by Professor Jensen, it is concluded that the Spearman hypothesis, as currently worded, has been disconfirmed. The near-zero correlation between blacks and low socio-economic status (SES) whites is not an artifact of the methodology. Neither is it a sampling fluke. The logic of sampling error does not apply to the arbitrary selection of intercorrelated tests from an undefined population. It is important also that low and high SES white differences are highly correlate with general factor loadings in a very heterogeneous selection of tests. Research attention should be turned to the difference in outcome of the race and SES comparisons.     

Sequential validation of cluster analytic subtypes of homeless veterans

To identify subgroups within the homeless population, a number of researchers have employed cluster analytic statistical procedures. Although this is an appropriate application of cluster analysis, many studies have not employed important statistical safeguards against arbitrary results. This study demonstrates a cluster analytic procedure—sequential validation—that enhances the replicability, external validity, and cross-validity of cluster solutions. The procedure is applied to a nationwide sample of 745 homeless veterans. After 12 different clustering procedures were subjected to derivation, replication, external validation, and cross-validation phases, a 4-cluster Ward solution emerged as the most sound. Substantively, the clusters were an alcoholic subtype, a psychiatrically impaired subtype, a best functioning subtype, and a multiproblem subtype. The generalizability of these subgroups to other contexts was assessed by comparing them to subgroups identified in other homelessness research. Suggestions were made for improving the quality of cluster analytic research in community psychology.     

Interactions between perceptual organization based on Gestalt laws and those based on hierarchical processing

Our recent research with compound stimuli (Han, Humphreys, & Chen, 1999a) suggests that grouping between local elements facilitates the perception of global structure, whereas encoding closure in local elements enhances their segmentation. The present study presents further evidence supporting this assertion. Experiment 1 first developed a new paradigm in which grouping between local elements was manipulated. Subjects responded to the orientations of perceptual groups consisting of local arrows or triangles embedded in background crosses. Responses to the orientations of the groups were slowed as a function of the increased contrast of the crosses, indicating that the strength of grouping between local arrows or triangles was gradually weakened by increasing the contrast of the crosses. Using a similar paradigm, Experiments 2 and 3 investigated the role of Gestalt factors in hierarchical analysis. Global arrows or triangles made up of local arrows, or triangles were embedded in background crosses. Subjects responded to global or local stimuli in terms of orientation or closure. Increasing the contrast of the background crosses produced stronger effects on global responses than on local responses and resulted in elimination of the global precedence effect and emerging of a local precedence effect, which was stronger for closure discrimination than for orientation discrimination. These results provide new evidence supporting our previous claim about the role of Gestalt factors in hierarchical analysis.     

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.     

Beyond the search surface: visual search and attentional engagement.

Treisman (1991) described a series of visual search studies testing feature integration theory against an alternative (Duncan & Humphreys, 1989) in which feature and conjunction search are basically similar. Here the latter account is noted to have 2 distinct levels: (a) a summary of search findings in terms of stimulus similarities, and (b) a theory of how visual attention is brought to bear on relevant objects. Working at the 1st level, Treisman found that even when similarities were calibrated and controlled, conjunction search was much harder than feature search. The theory, however, can only really be tested at the 2nd level, because the 1st is an approximation. An account of the findings is developed at the 2nd level, based on the 2 processes of input-template matching and spreading suppression. New data show that, when both of these factors are controlled, feature and conjunction search are equally difficult. Possibilities for unification of the alternative views are considered.