Effect of visual stimulus velocity on the acquisition of a task of tracking a sequence of light stimuli

Maria Teresa Cattuzzo
LACOM-EEFE-USP/ESEF-UPE

Luciano Basso
LACOM-EEFE-USP

Cleverton Jos? Farias de Souza
CEST-UEA/LACOM-EEFE-USP

Go Tani
LACOM-EEFE-USP

Guilherme Laurentino Lima-Filho
ESEF-UPE

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     Last modified: May 13, 2007

Abstract
The study investigated the effect of visual stimulus rate on the acquisition of a task of tracking a sequence of light stimuli with the aim to know the uncertainly level caused for them. A hundred twenty male adults (X=24.2 years; SD=3.56) participated in this study. The experimental design involved six experimental groups: G1 ? 300 ms of the inter-stimuli interval (ISI); G2=400 ms of ISI; G3=500 ms of ISI; G4=600 ms of ISI; G5=700 ms of ISI and G6=800 ms of ISI. The task consisted of touching six response keys in a given order performed in association with the lightening of the LEDs in a specific sequence, which the aim to recognize the pattern of this series. All groups performed 10 blocks of 60 trials; the first block, the middle block and the last one were used in the statistical tests. Global performance was evaluated by four types of response: anticipatory, correct, incorrect and omission responses. A repeated measures analysis of variance tests for multiple dependent variables (6 groups X 3 blocks) was used; in terms of the tests of hypotheses for interaction effects the results of the analysis de variance were significant to the anticipatory responses (df=5; F=3.85; p=0.0001) as well as to the correct (df=5; F=8.17, p<0.0001), incorrect (df=5, F= 3.70, p<0.0001) and omission responses (df=5, F=2.46, p<0.0081). The Ryan-Einot-Gabriel-Welsch (R-E-G-W) multiple range post hoc test was used to evaluate differences among specific means. As was expected the distinct rates of visual stimulus invocated a level of uncertainty in the system which responded with the distinct changes in the four types of responses. The ISI in the first two groups was considered very exigent, causing high level of uncertainty during the practice; in another extreme, in the last two groups, the ISI permitted the system to use all types of responses, since the first block of trials, and it were considered not very exigent. The ISI of G3 (500 ms) was one which cause uncertainty sufficient to press the system to change the performance by searching to increase the functional responses (correct and antecipatory responses) during the practice, which could attend to aim of the task.