For the second phase of the experiment, with P1-Time for each individual set to the value found in Phase 1, the effect of cue on change detection was investigated. Overall, despite the expectation of at least 71% correct detection, the presence of a cue did not manifestly increase the overall detection performance (
Figure 3A). More strikingly, for the No Cue condition mean correct detection was 44 ± 3 %, against an expectation of 71% (a significant difference for each of the experimental groups, single sample t-test,
P < .001 in each case). The provision of a cue 200 ms before the presentation of the second stimulus gave no advantage for change detection over a cue appearing only 50 ms before, for any of the groups, and thus these two cue conditions were combined for the purpose of analysis. Repeated measures ANOVA between Cue and No Cue conditions showed significantly reduced change detection performance (in the no cue condition) as illustrated in
Figure 3A (
F(1, 83) = 46.5,
P < .0001), with a significant interaction between Group and Cue conditions (F(2, 83) = 4.7, P =.01). The DDs performed worse overall in both cued and uncued conditions, and post-hoc comparisons revealed a significant difference in the performance of the DDs and NRs (Fisher’s PLSD, P = .0057).
Performance for all groups was highly reliable under conditions when there was no change (
Figure 3B) as illustrated by a mean overall correct rejection rate of 0.93 with no differences between groups.