A confluence of contexts: Asymmetric versus global failures of selective attention to Stroop dimensions.

In 6 experiments probing selective attention through Stroop classification, 4 factors of context were manipulated: (a) psychophysical context, the distinctiveness of values along the color and word dimensions; (b) set size context, the number of stimulus values tested; (c) production context the mode used to respond; and (d) covariate context, the correlation between the dimensions. The psychophysical and production contexts mainly caused an asymmetry in selective attention failure between colors and words, whereas the set size and covariate contexts contributed primarily to the average or global magnitudes of attentional disruption across dimensions. The results suggest that (a) Stroop dimensions are perceptually separable, (b) J. R. Stroop's (1935) classic findings arose from his particular combination of contexts, and (c) stimulus uncertainty and dimensional imbalance are the primary sources of task and congruity effects in the Stroop paradigm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The stimulus in information processing.

Argues that the nature of the stimulus is an important variable determining how information is processed. 2 major stimulus concepts are discussed: dimensional integrality vs. separability, and state vs. process limited stimuli. These concepts relate to the effects of stimulus redundancy on discrimination. There will be a gain with redundancy: (a) if the need for redundancy is due to a process limitation and the redundant dimensions are integral, or (b) if the need for redundancy is due to state limitation and the redundant dimensions are separable. Redundancy can also lead to improvement in discrimination if the stimulus elements can be integrated into a gestalt whole. (28 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The impact of stimulus and response variability on S-R correspondence effects.

Six experiments investigated how variability on irrelevant stimulus dimensions and variability on response dimensions contribute to spatial and nonspatial stimulus-response (S-R) correspondence effects. Experiments 1-3 showed that, when stimuli varied in location and number, S-R correspondence effects for location or numerosity occurred when responses varied on these dimensions but not when responses were invariant on these dimensions. These results are consistent with the response-discrimination account, according to which S-R correspondence effects should only arise for a dimension that is used for discriminating between responses in working memory. Experiments 4-6 showed that, when responses varied in location and number, both invariant and variable stimulus number produced correspondence effects in S-R numerosity. In summary, the present results indicate that the usefulness of a particular dimension for response discrimination can be sufficient for producing S-R correspondence effects, whereas variability of a stimulus dimension is not sufficient for producing such effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Uniformity in variety: Extension to three-element visual patterns and non-verbal measures.

Describes 4 experiments in which a total of 146 college and high school students rated visual patterns of 3 geometric elements, presented simultaneously or successively, for complexity, interestingness, and pleasingness. Exps. I and II showed that judged complexity generally varied inversely with the number of identical elements in a pattern and directly with the number of properties in which elements differed. Interestingness generally behaved like complexity with successive presentation, but showed no significant influence of any of the independent variables with simultaneous presentation. Pleasingness was heightened by the presence of similarities between elements when presentation was simultaneous, and by the presence of variety when elements appeared successively. Other findings, intercorrelations of scales, and comparisons with the results of previous experiments using 2-element patterns are discussed. Exp. III showed exploratory choice to favor 2-element patterns that had been judged more complex and more interesting but less pleasing. Exp. IV, using both 2- and 3-element patterns, revealed no effects of the independent variables on looking time. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Establishing global and local correspondence between successive stimuli: The holistic nature of backward alignment.

Reflection decisions on alphanumeric characters display systematic effects of disorientation, suggesting that subjects mentally rotate the stimulus to the upright (the uprighting process). However, response time also increases with increasing angular disparity between the current and preceding orientations. This occurs only when the current stimulus is a rotational transform of the preceding stimulus, suggesting that the current stimulus is brought into congruence with the preceding one (the backward alignment process). In the present study, we examined the hypothesis that the transformation that occurs in backward alignment is holistic even in tasks in which the uprighting process is likely to be piecemeal. Evidence supporting this hypothesis is presented on the basis of tasks requiring either classification of numbers (Experiments 1 and 3) and words (Experiment 2), or mirror image discrimination on letter pairs (Experiment 4). The results indicated that backward alignment establishes global correspondence between successive stimuli and is indifferent to local correspondence at the level of the constituent elements. The establishment of this global correspondence decreases with the number of elements in the stimulus (Experiment 5), but its effects are still observed for four-letter strings (Experiment 6). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The dimensionality of visual complexity, interestingness, and pleasingness.

Applied the Shepard-Kruskal multidimensional scaling technique to judgments of complexity, interestingness, and pleasingness with visual patterns as stimulus material. After a principal-axes rotation, 2 dimensions were found to account for 90% of the variance with respect to complexity and interestingness, and 3 dimensions accounted for almost 90% of the variance with respect to pleasingness. There was a high degree of inter-S consistency, and distance ratings with regard to the 3 properties were significantly intercorrelated. Values assigned to patterns on the 1st complexity dimension, which apparently represents "information content," were significantly correlated with values along the 1st interestingness and pleasingness dimensions. Values on the 2nd interestingness dimension were significantly correlated with values on the 2nd complexity dimension and on the 2nd pleasingness dimension. The results with 60 undergraduates confirm that judged complexity is a major determinant of judged interestingness and judged pleasingness and that Ss tend to agree on the relative locations of stimulus patterns in the spaces that govern interestingness and pleasingness judgments, even though the regions that they find most interesting or pleasing may differ. (French summary) (40 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus-response compatibility with relevant and irrelevant stimulus dimensions that do and do not overlap with the response.

Five experiments were conducted using 4- and 6-choice stimulus–response compatibility tasks with graphic and alphabetic stimuli, and keypress and verbal responses. A comparison of performance with compatible, incompatible, and neutral conditions shows that when a stimulus set is perceptually, conceptually, or structurally similar to a response set, (a) mean reaction times (RTs) are faster when individual stimuli and responses match than when they do not match, (b) this is true whether the stimulus and response sets are similar on relevant or irrelevant dimensions, (c) this "compatibility effect" is greater when the dimensions are relevant than when they are irrelevant, and (d) whether the dimensions are relevant or irrelevant, the faster RTs are due to a facilitative process and the slower RTs to an interfering process. These results are accounted for by the dimensional overlap model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Startle amplitude and fear in an acoustic startle paradigm: Lesions to the brachium of the inferior colliculus or the lateral tegmental tract.

In 2 Experiments, startle amplitude and startle stimulus-induced freezing (an index of fear) were measured in an acoustic startle response (ASR) paradigm in rats. Lesions to lateral tegmental tract (LTG), a pathway medial to brachium of the inferior colllciulus (BIC), significantly decreased freezing and produced a persistent 5-fold increase in ASR amplitude compared with sham-operated controls. Lesions to BIC increased both ASR amplitude (2-fold) and freezing. Neither BIC not LTG lesions affected startle amplitude when startle was elicited by a brief footshock stimulus. Characteristics of the lesion effects were tested with manipulations of interstimulus interval, stimulus intensity, and prepulse inhibition. The data suggest (a) an ascending pathway medial to BIC that carries the fear-inducing dimensions of an acoustic stimulus and (b) a descending pathway that provides tonic inhibition of the sensory input to the ASR circuitry. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hedonic effects of uniformity in variety.

Describes 2 experiments with a total of 148 undergraduates, using visual patterns consisting of 2 elements that differed in 0-4 properties but were otherwise alike. Different Ss rated the patterns for pleasingness, interestingness, liking, and complexity. With successive, but not with simultaneous, presentation of elements, pleasingness and liking reached maxima when there were both differences and similarities. Interestingness increased with the number of differences in both modes of presentation. Judged complexity increased with the number of differences but was significantly higher when elements appeared simultaneously. It is suggested that when hedonic ratings are plotted against judged complexity, results can be related to findings of previous experiments on hedonic effects of complexity. (French summary) (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative modeling of visual attention processes in patients with Parkinson's disease: Effects of stimulus integrality on selective attention and dimensional integration.

Parkinson's disease (PD) patients and normal controls (NCs) were administered a series of visual attention tasks. The dimensional integration task required integration of information from 2 stimulus dimensions. The selective attention task required selective attention to 1 stimulus dimension while ignoring the other stimulus dimension. Both integral- and separable-dimension stimuli were examined. A series of quantitative models of attentional processing was applied to each participant's data. The results suggest that (a) PD patients were not impaired in integrating information from 2 stimulus dimensions, (b) PD patients were impaired in selective attention, (c) selective attention deficits in PD patients were not due to perceptual interference, and (d) PD patients were affected by manipulations of stimulus integrality and separability in much the same way as were NCs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychophysiological responses to changes in workload during simulated air traffic control

In this investigation, eight Air Force air traffic controllers (ATCs) performed three scenarios on TRACON (Terminal Radar Approach Control), a computer-based air traffic control (ATC) simulation. Two scenarios were used each with three levels of difficulty. One scenario varied traffic volume by manipulating the number of aircraft to be handled and the second scenario varied traffic complexity by manipulating arriving to departing flight ratios, pilot skill and mixture of aircraft types. A third scenario, overload, required subjects to handle a larger number of aircraft in a limited amount of time. The effects of the manipulations on controller workload were assessed using performance, subjective (TLX), and physiological (EEG, eye blink, heart rate, respiration, saccade) measures. Significant main effects of difficulty level were found for TRACON performance, TLX, eye blink, respiration and EEG measures. Only the EEG was associated with main effects for the type of traffic. The results provide support for the differential sensitivity of a variety of workload measures in complex tasks, underscore the importance of traffic complexity in ATC workload, and support the utility of TRACON as a tool for studies of ATC workload.     

Mental rotation: Effects of stimulus complexity and familiarity.

The times required for encoding, mental rotation, and comparison of unfamiliar stimuli (patterns of filled-in squares in a 3?×?3 matrix) were found to increase with stimulus complexity (as measured, for example, by the number of separated pieces constituting each figural pattern). However, with continued practice on particular stimuli, rotation time, though still dependent on angle of rotation, became independent of the complexity of those stimuli for most subjects. Subjects may represent a stimulus and imagine its rotation piece by piece, if it is unfamiliar, and as a whole, if (as, presumably, in the experiments by Cooper & Podgorny, 1976) it is sufficiently well learned. However, for a few subjects, who reported using a more analytic, verbally supported strategy throughout, the effects of stimulus complexity were only partially reduced by continuing practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of groups' variety and disparity on groups' cognitive complexity.

This study examined the influence of group diversity conceptualized as disparity and as variety on group cognitive complexity. Data on individual cognitive complexity and group cognitive complexity were collected in 44 groups using a conceptual mapping technique. Also data on the quality of teamwork processes and satisfaction were collected using an individual questionnaire. The results indicate that (a) gender variety has a positive impact on group cognitive complexity, (b) cognitive disparity has a negative impact on group cognitive complexity, and (c) groups with a high average individual cognitive complexity have the highest cognitive complexity as a group only if the quality of their interactions is high. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Holistic and analytic modes of processing: The multiple determinants of perceptual analysis.

With the use of the criterion of privileged axes, 6 experiments with 96 undergraduates showed that analytic processing of saturation and brightness, prototypical integral dimensions, does sometimes occur. However, it was less frequent and less successful than the analytic processing of separable dimensions. Findings identify several factors that influence whether analytic processing occurs: (a) stimulus factors such as the magnitude of dimensional differences; (b) task factors, including the degree to which analytic processing is encouraged by instructions or by implicit task demands and the amount of time available for processing; and (c) S factors, particularly the amount of experience that the perceiver has had with the stimuli in tasks that encourage stimulus analysis. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Motor preparation and the effects of practice: Evidence from startle.

To examine sequential movement preparation, participants practiced unimanual movements that differed in amplitude and number of elements for 4 days in either a simple (Experiment 1) or choice (Experiment 2) reaction time (RT) paradigm. On Day 1 and 4, a startling stimulus was used to probe the preparation process. For simple RT, we found increased premotor RT for the two component movement during control trials on Day 1, which was minimized with practice. During startle trials, all movements were triggered at a short latency with similar consistency to control trials, suggesting full advance preparation of all movements. For choice RT, we also found increased premotor RT for control trials for the two component movement. As advance preparation could not occur, the startling stimulus did not trigger any of the movements. We hypothesized that complexity may relate to the neural commands needed to produce the movement, rather than a sequencing requirement. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Choice reaction time: An analysis of the major theoretical positions.

This report analyzes and evaluates (against experimental findings) contemporary theories of choice reaction time (CRT). The influence of Donders' subtraction method on current theory is assessed, followed by a review of experimental findings concerned with the effects on CRT of (a) number of alternatives, (b) stimulus probability, (c) stimulus value, (d) repetition of stimulus or response, (e) stimulus discriminability, (f) stimulus-response compatibility, (g) practice, and (h) emphasis on speed vs. accuracy. A 3-state conceptualization of the central mechanisms operative during the latent period-stimulus preprocessing, stimulus categorization, and response selection-is proposed. The theories are dichotomized on the basis of the process-template matching vs. feature testing-which is assumed to underlie stimulus categorization. The analysis indicates that current theories have neglected response-selection processes and are consequently unable to account for several experimental findings. A final section deals with the relation of CRT theories to perceptual recognition theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus determinants of social attraction in rats.

Conducted 5 experiments on the stimulus characteristics mediating 1 rat's attraction for another. 120 Sprague-Dawley and 12 Wistar male albino rats were tested for attraction (physical approach) to (a) a variety of stimulus objects (familiar and unfamiliar objects; stuffed, anesthetized, tethered, and free-moving stimulus rats), (b) rats varying in static stimulus qualities (normal, dyed, shaven, or perfumed), and (c) rats under varying degrees of sensory impairment (normal, blinded, shaven, whiskerless, or anosmic). Variations in sensory capacity or static stimulus characteristics had little effect on social attraction; variations in the dynamic quality of the other rat had large effects. Ss were more attracted to rats which could move and respond to them than to stuffed or anesthetized rats. Results suggest that the quality of behavior and the possibility of interaction between animals mediates gregariousness in rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exposure and affect: Overview and meta-analysis of research, 1968–1987.

A review and meta-analysis of methodological and subject variables influencing the exposure–affect relationship was performed on studies of the mere exposure effect published in the 20 years following R. B. Zajonc's (see record 1968-12019-001) seminal monograph. Stimulus type, stimulus complexity, presentation sequence, exposure duration, stimulus recognition, age of subject, delay between exposure and ratings, and maximum number of stimulus presentations all influence the magnitude of the exposure effect. Implications of these findings are discussed in the context of previous reviews of the literature on exposure effects and with respect to prevailing theoretical models of the exposure–affect relationship. Modifications of the 2-factor model of exposure effects that increase the heuristic value of the model are described. A possible evolutionary basis of the exposure effect is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)