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ERIC Number: EJ844420
Record Type: Journal
Publication Date: 2005
Pages: 8
Abstractor: As Provided
Reference Count: 17
ISSN: ISSN-0211-2159
Reaction Time Asymmetries between Expansion and Contraction
Lopez-Moliner, Joan
Psicologica: International Journal of Methodology and Experimental Psychology, v26 n1 p139-146 2005
Different asymmetries between expansion and contraction (radial motions) have been reported in the literature. Often these patterns have been regarded as implying different channels for each type of radial direction (outward versus inwards) operating at a higher level of visual motion processing. In two experiments (detection and discrimination tasks) we report reaction time asymmetries between expansion and contraction. Power functions were fitted to the data. While an exponent of 0.5 accounted for the expansion data better, a value of unity yielded the best fit for the contraction data. Instead of interpreting these differences as corresponding to different higher order motion detectors, we regard these findings as reflecting the fact that expansion and contraction tap two distinct psychophysical input channels underlying the processing of fast and slow velocities respectively. (Contains 1 table and 2 figures.)
University of Valencia. Dept. Metodologia, Facultad de Psicologia, Avda. Blasco Ibanez 21, 46010 Valencia, Spain. Tel: +34-96-386-4100; Web site:
Publication Type: Journal Articles; Reports - Evaluative
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A