Fig 1. Experimental task.

(a) Experiment 1. Two orientation stimuli were presented followed by a delay, then one location was probed at random and subjects adjusted the probe bar to match the remembered orientation at that location. Stimuli varied in contrast. Participants were subsequently asked for a confidence rating. (b) Experiment 2. Two composite stimuli were presented each containing four orientations. After a delay, one location was probed and participants reported the average orientation they recalled at that location. Stimuli differed in the variability of their component orientations.