ISSN : 1226-9654
Given parallel and independent processing stteams for color and motion, it is worth to investigate the mechanism for an isduminant chromatic motion, which has long been denied but now psychophysically demonstrated in many studies. I investigated characteristics of interation chromatic motion across cardinal axes and lurninacxe motion. Using a mufti-aperture pattern and a plaid canposed of isoltuninant duotnaric gratings and luminance grating, perceived direction, motion coherence/trarupamncy, and motion repulsion were psychophysically measured. Experimental results showed the existence of chromatic motion repulsion, vectore-sum computation for perceived motion direction of chromatic plaids, and the dependency of motion coherence/transparency on the angular differrnce of component motion ditections. There was the interaction of chromatic and luminance motion. These results indicate that chromatic motion processing is very analogous to luminance motion processing. It seems that there are two processing streams, one responsible for pure chromatic modulation and the other for 2nd-order chromatic contrast profile (at low temporal frequency), suggesting there is no reason to construct a 3rd-order structure for chromatic motion.
In the present study, 4 experiments were conducted in order to examine the similarity of underlying mechanisms for negative priming effects in a referent size-selection task and other selection tasks. The results were (1) negative priming effects were observed only when the same tasks were used in priming and probe trials, (2) regative priming effects were not observed when only a target stimulus was presented in probe trials, (3) negative priming effects were observed when only one word was presented for 33ms in prime trials, (4) response-stimulus incerval(RSI) did not affect negative priming effcts when RSI was manipulated between subjects. These results indicate that the underlying mechanisms for negative priming effects in the referent size-selecting task and other selection tasks are similar. These results may be explained more easily by the temporal discrimination accounts than by the inhibition and episodic retrieval accounts.
Processing unit of Hangul syllables was investigated by manipulating attention tasks to letters and congruity between consonants of Hangul syllables in four experiments. Two types of Hangul syllables, one with a vertical vowel(V) and the other with a horizontal vowel, were used as stimulus displays, where the first and the last letters were cocuonancs(that is, CVC). Response time condensation task was the longest in every experiment, which indicates integral or wholistic processing of Hangul letters is difficult. Regardless of the absence(Exp. 1) or the presence(Exp. 2) of a vowel in the display, Garner and Stroop interferences were observed in identification of C1 and C2. This means C1 and C2 were hard to be processed separably. Exp. 3 asked participanu to judge C1 and/or V, and observed Garner interference only in the display with a vertical vowel and no effett in the display with a horizontal vowel. This result conflicts with the 'syllable core' hypothesis suggesting that C1 and V would be integrated in syllable processing. There was no Garner interference in Exp. 4 requiring judgment of V and/or C2 in the display. This result is negative to the hypothesis suggesting V and C2 as a unit of syllable processing. With all the results, it was condudad Hangul letters in a syllable would be processed neither as an integrated whole nor as separate ones. Problems of stimulus set, conditions of stimulus presentation, and tasks, questions of fiuther study were discussed.
Two studies were conducted to test Shafir's(1993) response compatibility hypothesis in decision-making. These studies examined whether participants choose as well as reject the enriched option more frequently than the impoverished option. We constnacred five new decision-making problems in addition to Shafir's(1993) five problems in Study 1. Only one out of 10 problems produced the results consistent with the prediction of the response compatibility hypothesis. In Study 2, decision problems were modified to control for selettive attention each option's features, but the same pattern of results was obtained in this study. A new hypahesis wac presented to discuss our results.