Pre- and poststimulus activation of response channels: a psychophysiological analysis

To examine mechanisms of response activation, we asked subjects to respond differentially to the central letter of one of four arrays--HHHHH, SSHSS, SSSSS, and HHSHH--and measured event-related brain potentials (ERPs) and electromyographic activity (EMG). For very fast responses, accuracy was at chance level for all arrays, suggesting that subjects were guessing. For intermediate latency responses, accuracy was above chance if the noise was compatible with the targets and below chance if it was incompatible, suggesting that these responses were based on partial stimulus analysis. For slow responses, accuracy was above chance for all arrays, suggesting that these responses were based on complete stimulus analysis. The occurrence and accuracy of fast responses could be predicted by examining motor potentials preceding the presentation of the array. Measures of the motor potentials in the period following the presentation of the array suggested that partial analysis of stimulus information could activate responses and that the level of response activation at the time of the EMG response was constant for trials with different response latencies. The data are discussed in terms of a response channel conception.     

Filtering versus parallel processing in RSVP tasks.

An experiment of McLean, D. E. Broadbent, and M. H. P. Broadbent (1983) using rapid serial visual presentation (RSVP) was replicated. A series of letters in one of 5 colors was presented, and the subject was asked to identify the letter that appeared in a designated color. There were several innovations in our procedure, the most important of which was the use of a response menu. After each trial, the subject was presented with 7 candidate letters from which to choose his/her response. In three experimental conditions, the target, the letter following the target, and all letters other than the target were, respectively, eliminated from the menu. In other conditions, the stimulus list was manipulated by repeating items in the series, repeating the color of successive items, or even eliminating the target color. By means of these manipulations, we were able to determine more precisely the information that subjects had obtained from the presentation of the stimulus series. Although we replicated the results of McLean et al. (1983), the more extensive information that our procedure produced was incompatible with the serial filter model that McLean et al. had used to describe their data. Overall, our results were more compatible with a parallel-processing account. Furthermore, intrusion errors are apparently not only a perceptual phenomenon but a memory problem as well.     

Filtering versus parallel processing in RSVP tasks

An experiment of McLean, D. E. Broadbent, and M. H. P. Broadbent (1983) using rapid serial visual presentation (RSVP) was replicated. A series of letters in one of 5 colors was presented, and the subject was asked to identify the letter that appeared in a designated color. There were several innovations in our procedure, the most important of which was the use of a response menu. After each trial, the subject was presented with 7 candidate letters from which to choose his/her response. In three experimental conditions, the target, the letter following the target, and all letters other than the target were, respectively, eliminated from the menu. In other conditions, the stimulus list was manipulated by repeating items in the series, repeating the color of successive items, or even eliminating the target color. By means of these manipulations, we were able to determine more precisely the information that subjects had obtained from the presentation of the stimulus series. Although we replicated the results of McLean et al. (1983), the more extensive information that our procedure produced was incompatible with the serial filter model that McLean et al. had used to describe their data. Overall, our results were more compatible with a parallel-processing account. Furthermore, intrusion errors are apparently not only a pereptual phenomenon but a memory problem as well.     

Selective encoding from multielement visual displays

When a multiletter display is preceded by a bar designating one of the letters for report, reaction time (RT) to voice the indicated letter decreases. Previous research had indicated that the efficiency of this selective mechanism decreases as the number of display elements increases. Two experiments were conducted to determine whether the effect of display size could be eliminated when the indicator precedes the display at long intervals. Results indicated that the display size effect was maintained. The results could not be attributed to eye movements, but were interpreted in terms of a central encoding mechanism that is limited in its precision of localization and exclusion.     

The extent of processing of noise elements during selective encoding from visual displays

Circular visual displays of 12 elements, consisting of A, H, M, and U, were presented to S. She responded with a lever movement in one direction if a given letter designated by a bar indicator was a member of the set A-U and in the opposite direction if it was from the other set. The principal experimental variables were the SOA by which the indicator preceded the display and whether the target letter was flanked by letters of the same or opposite set. The results indicated that the interference produced by noise letters is primarily on the response as opposed to the processing side. Also, there is a limit to the precision of selective attention in the visual field. The interference of opposite-set letters was inversely proportional to their distance from the target.     

Information processing in visual search: A continuous flow conception and experimental results

This paper reexamines the visual search process, and visual information processing more generally, from a perspective of the continuous flow of information and responses through the visual system. The results from three experiments are reported which support the continuous flow conception: Information accumulates gradually in the visual system, with concurrent priming of responses. The first two experiments investigated the processing of display stimuli which varied in size and figure-ground contrast in a nonsearch task, and provided evidence confirming a continuous flow model. Experiment 3 employed an asynchronous onset of target and noise and provided convergent evidence of the accumulative nature of information and response priming in visual processing.     

Temporal luminance summation effects in backward and forward masking

Two experiments tested six predictions derived from the assumptions underlying the luminance summation-contrast reduction explanation for certain instances of forward and backward masking effects. The predictions concerned the circumstances under which masking would occur and also that forward masking would be more extensive than backward masking under specified luminance arrangements. All six predictions were confirmed.     

“Subliminal cues” and the Miiller-type illusion

Using the viewing box from a 2-field tachistoscope, feathers-arrows from 1 field were superimposed upon line-pairs from the other field to construct the Muller-Lyer illusion. 6 Os were tested for the illusory effects under 4 conditions of feather-arrow detectability: (a) d′=O, (no luminance); (b) d′=.42; (c) d′=1.00 and (d) d′=3.7. The length differences of lines of any given pair were a in., 1/64 in., 2/64 in., or 6/64 in. The illusion effect was observed when the feather-arrow d’ equaled 3.7. No significant nor suggestive illusion effects were found for the other feather-arrow detectability conditions.     

Computer-assisted self-interviews: A cost effectiveness analysis

Computer-assisted self-interview (CASI) questionnaires are being used with increased frequency to deliver surveys that previously were administered via self-administeredpaper-and-pencil questionnaires (SAQs).Although CASI may offer a number of advantages, an important consideration for researchers is the assessment modality's immediate and long-term costs. To facilitate researchers' choice between CASI and SAQ, this article provides theoretical cost models with specific parameters for comparing the costs for each assessment type. Utilizing these cost models, this study compared the cost effectiveness in a health behavior study in which both CASI (n = 100) and SAQ (n = 100) questionnaires were administered. Given the high initial costs, CASI was found to be less cost effective than SAQ for a single study. However, for studies with large sample sizes or when CASI software is to be used for multiple studies, CASI would be more cost effective and should be the assessment mode of choice.     

Factors associated with a positive attitude towards change among employees during the early phase of a downsizing process

Most research on organizational changes in working life, including downsizing, focuses on the negative attitudes and negative consequences of the change. The aim of this study was to evaluate if the employee's previous learning experience and characteristics of the working environment were associated with positive attitudes towards organizational change. The 467 employees (73.5% males) working in a global oil company in the early phases of a downsizing process were asked to answer a questionnaire with demographic variables, perception of the working environment, and attitude to change (93% response rate). Corporate social responsibility (CSR), involvement and participation, team leadership and team effectiveness were important factors related to positive attitudes towards organizational change. Non-leaders and older employees were positive to change. We conclude that employees' perceptions of their psychosocial working environment, in particular the CSR, were highly related to their attitude to organizational change.