Abstract
Canonical adult change-detection tasks utilize button-press responses, and memory is inferred based on accuracy. However, infant change-detection tasks must rely on passive visual responses to infer change-detection, making between-age comparisons difficult. Importantly, recent work revealed adults and infants scanned 4-item change-detection arrays similarly, dwelling longer on the color-changed circle (i.e., change-preference); however only if they had fixated that circle during the sample array (Eschman & Ross-Sheehy, in press). This is surprising, as adults should have been able to remember all four circles. These results raise two questions: First, do passive, free-viewing tasks elicit the same memory/performance as tasks that incorporate a button-press? Second, do these effects persist if arrays exceed capacity? To examine this, 11-mo-old infants and adults (n=15 each) were tested in a passive change-detection task, and adults completed an additional block of active trials (i.e., button-press to indicate same/different). Gaze was sampled at 500Hz using EyeLink 1000+. Change-detection arrays consisted of colored circles (ss3, ss6, ss9), each trial included 1500ms sample array, 500ms retention interval, and 3000ms test array. Circle colors either stayed the same from sample to test (No-Change) or varied by one color based on scanning during the sample array (N-back1=last fixated circle, N-back2=second-to-last fixated circle, Change-Other=non-fixated circle). Results revealed higher change-preference for adults, F(1,28)=9.198, p=.005. However, both ages showed condition effects, F(2,56)=88.48, p<.001, with higher change-preference for N-back1 than N-back2 (p=.006) and for N-back2 than Change-Other (p<.001). Change-preference was also higher for larger set sizes, F(2,56)=8.95, p<.001, suggesting visual load influenced scanning and/or encoding. Importantly, adult change-preference did not differ for passive and active blocks (all ps>.05.), although additional analyses revealed more scanning during active block, F(1,14)=6.141, p=.027. This suggests that adding an explicit response altered scanning, but not circle preference during the test array. Additional performance measures and implications for active/passive task designs discussed.