Transsaccadic perception of translating objects: effects of landmark objects and visual field position.

Previously Gysen, De Graef, and Verfaillie [Vision Research 42 (2002) 379] showed that, with stimulus displays presenting one stationary and one translating object, sensitivity for intrasaccadic displacements was higher for translating than for stationary objects. In the present paper the importance of the relative encoding of the path of the translating object towards the stationary object is investigated. In three experiments we compared detection of intrasaccadic displacements of translating objects in relative motion (moving towards the landmark object) and translating objects moving in isolation. No 'facilitatory' effect of relative motion was found. However a visual field effect was present. Performance was always better for the translating object presented in the lower part in comparison to the upper part of the visual field. A fourth experiment investigated the sensitivity for intrasaccadic displacements of stationary and translating objects presented in the upper as well as in the lower visual field. A lower visual field advantage was observed. The superior performance for translating objects, as was found previously, was confirmed in the lower and upper visual field.