September 2005
Volume 5, Issue 8
Free
Vision Sciences Society Annual Meeting Abstract  |   September 2005
Sequential effects and stimulus-response dependencies in an orientation identification task: characterization of the class 2 oblique effect
Author Affiliations
  • Andrew M. Haun
    Department of Psychological and Brain Sciences, University of Louisville
  • Bruce C. Hansen
    Department of Psychological and Brain Sciences, University of Louisville
  • Yeon-Jin Kim
    Department of Psychological and Brain Sciences, University of Louisville
  • Edward A. Essock
    Department of Psychological and Brain Sciences, University of Louisville, and Department of Ophthalmology and Visual Science, University of Louisville
Journal of Vision September 2005, Vol.5, 158. doi:10.1167/5.8.158
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      Andrew M. Haun, Bruce C. Hansen, Yeon-Jin Kim, Edward A. Essock; Sequential effects and stimulus-response dependencies in an orientation identification task: characterization of the class 2 oblique effect. Journal of Vision 2005;5(8):158. doi: 10.1167/5.8.158.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

The Class 2 oblique effect (C2OE) refers to poorer performance for obliquely oriented stimuli compared to horizontal or vertical (“cardinal”) stimuli on memory-related tasks (Essock, Perception, 1980). This effect is thought to stem from a greater confusability of obliques and is distinct from the poorer visibility of oblique stimuli (i.e., the Class 1 oblique effect). In the present study several aspects of the C2OE obtained on a timed orientation identification task were examined. Subjects reported the orientation of a brief (200 msec) presentation of an oriented pattern (0°, 45°, 90°, or 135°) via the four fingers of the right hand (one mapped to each orientation). Results indicated that the C2OE arises from trials for which the preceding trial was a stimulus of the other category (oblique/cardinal). The increase in RT associated with the presented stimulus having changed category was much greater for oblique stimuli than cardinal stimuli. Other findings suggest that for a large (5°) central patch of broadband noise, this effect was large for finger/orientation pairings where oblique and cardinal stimuli were assigned to laterally grouped fingers (e.g. 45-135-0-90), and was not significant for alternating finger/orientation pairings (e.g. 45-0-135-90). When smaller (.5°) line or patch stimuli were presented randomly at one of eight locations (2° outer boundary), a C2OE was found for both types of finger/orientation pairings. Finally, when the smaller line stimuli were presented randomly at locations arranged vertically or horizontally, a C2OE was found only in the horizontal displacement condition. Together these findings suggest that the greater confusion of obliques observed when identification of stimulus orientation is required occurs when the category of the stimulus (oblique/cardinal) is switched on sequential trials, and, secondly, that this effect is altered by factors such as spatial configuration of the stimuli and stimulus/response pairings.

Haun, A. M. Hansen, B. C. Kim, Y.-J. Essock, E. A. (2005). Sequential effects and stimulus-response dependencies in an orientation identification task: characterization of the class 2 oblique effect [Abstract]. Journal of Vision, 5(8):158, 158a, http://journalofvision.org/5/8/158/, doi:10.1167/5.8.158. [CrossRef]
Footnotes
 This work was supported by a grant from the Office of Naval Research (grant # N00014-03-1-0224) and from the Kentucky Space Grant Consortium (KSGC - NASA EPSCOR).
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