Object recognition and laterality: null effects.

In two experiments, normal subjects named briefly presented pictures of objects that were shown either to the left or to the right of fixation. The net effects attributable to hemifield were negligible: naming RTs were 12 msec lower for pictures shown in the left visual field but error rates were slightly lower, by 0.8%, for pictures shown in the right visual field. In both experiments, a second block of trials was run to assess whether hemifield effects would be revealed in object priming. Naming RTs to same name--different shaped exemplar pictures were significantly longer than RTs for identical pictures, thus establishing that a component of the priming was visual, rather than only verbal or conceptual, but hemifield effects on priming were absent. Allowing for the (unlikely) possibility that variables with large differential left-right hemifield effects may be balancing and cancelling each other out, we conclude that there are no differential hemifield effects in either object recognition or object priming.