No / A current, popular, theory of spatial localization holds that the visual system represents the location of simple objects by a single positional tag, the accuracy of which is largely independent of the internal properties of the object. We have already presented evidence of the limitations of such a view (Keeble & Hess (1998). Vision Research, 38, 827-840) in that 3-micropattern alignment performance was found to be dependent on the orientation of the micropatterns. We tested whether this was caused by a local anisotropy in positional coding by conducting 3-micropattern bisection experiments with varying patch orientation. No corresponding effect of patch orientation was found, implying a difference in the mechanisms used for the two tasks. In a further experiment we show that alignment task performance is very similar to the otherwise identical 2-patch orientation discrimination task. We conclude that the 3-micropattern alignment task is mediated by orientational mechanisms. We therefore present a 2nd-order orientation model for 3-patch alignment.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/2847 |
| Date | 24 June 2009 |
| Creators | Keeble, David R.T., Nishida, S. |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Article, No full-text in the repository |
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