Figure 1.

Visual learning task and experimental timeline. (a) Binocular disparity was used to differentiate two types of stimuli (near versus far). (b) The task was performed in the lower visual field, except for the Generalization test, which was performed in the matching upper visual field. Each subject participated in two sessions (A/B), the order of which was balanced. In one of the sessions, the task was performed mainly in the left visual field, in the other on the right. (c) In each session, three phases (Warmup, Baseline and Training) were followed by a retention interval and three further task phases (Refresher, Retrieval and Generalization). One of the two sessions started in the morning, the other one in the evening, such that the retention interval contained a period of night sleep or not. Auditory feedback (indicated by the speaker symbol) was given only before the retention period. Phases used to assess performance are colour-coded as in figure 2.