Fig. 1.

Stimuli for the delayed match-to-sample task. Children were presented with the sample stimulus for 250 ms, followed by a 1000 ms retention interval during which they are instructed to remember the initial stimulus. A second, test stimulus was then presented for up to 2000 ms, or until the child responded. The inter-stimulus interval (ISI) period varied between 1100 and 1400 ms. The upper panel shows an example of the "same" condition, as the colour of the squares in the sample and test stimulus match. The lower panel shows the "different" condition, as the colour of one square has changed (from yellow to green). Task adapted from Palva et al. (2010).