Relation between Visual Search Time and Peripheral Visual Acuity

Abstract

An experiment conducted at the U.S. Naval Ordnance Test Station investigated the relationship between peripheral visual acuity and time required to locate a target in a static structured display. Sixteen male observers were used in the tests.

Peripheral acuity measured at 3.6 degrees and 4.8 degrees off the visual axis correlated significantly at the 0.01 level with time required to find a target in displays containing 16 or 32 rings and correlated at the 0.05 level with search time on displays of 16 and 32 blobs. Almost all correlations involving search times from object densities of 48 and/or acuity measurements made at 6.0 degrees off the visual axis were not significant.

In addition to the results concerning peripheral visual acuity, other relationships between variables were suggested by an analysis of the data. An analysis of variance established that the shape of the objects in the display (blobs or rings) and the number of objects in the display (16, 32, or 48) had a significant effect (p< 0.01) upon search time. The interaction of shape and object density was also found to be significant at the 0.01 level. There were no significant intercorrelations between observer age, foveal acuity as measured in a naval eye examination, and peripheral acuity. Furthermore, age and foveal acuity did not correlate significantly with search performance.

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