Recency effects and lesion effects in delayed non-matching to randomly baited samples by monkeys.

Monkeys' memory for 3-dimensional junk objects was tested in a task which required them to discriminate objects which had recently been presented in an acquisition list from new objects which had not. The accuracy of this discrimination was shown to depend on the recency of presentation of the old object. The discrimination was not significantly affected by lesions of either the foveal pre-striate cortex, the fundus of the superior temporal sulcus, or the anterior inferior temporal area. A substantial impairment was caused by transection of the fornix.