Psychophysiology
During acquisition, the SCR showed a significant Stimulus x Time
interaction, F (1,255) = 13.99, p < .001,R 2 = .114, and a significant Stimulus x Group
interaction, F (2,255) = 3.71, p = .026,R 2 = .024, but the Stimulus x Group x Time
interaction was not significant, F (2,255) = 0.23, p =
.792, R 2 = .002. Follow-up analyses showed that
the difference between CS+ and CS- was larger in group HU compared to
LU, bGroup(HU-LU)*Stimulus = -0.02 , SE = 0.01,t (261.00) = 2.48, p = .014 but there was no difference
between groups HU-MU, bGroup(HU-MU)*Stimulus =
-0.007 , SE = 0.01, t (261.00) = 0.67, p = .501 or LU-MU,bGroup(LU-MU)*Stimulus = 0.02 , SE = 0.01,t (261.00) = 1.87, p = .062 (Bonferroni correction α
< .017). Furthermore, as shown in Figure 3, averaged across
groups, participants showed increased differential SCR responding in
Acq1 compared to Acq2, bTime*Stimulus = -0.03 , SE
= 0.01, t (261.00) = 3.77, p < .001.
For ssVEPs in acquisition, there was no significant main effect of
Stimulus or Group (all p values >.331) indicating
that participants’ visuocortical engagement was similar for the two
stimuli across the three groups, see Table 3 for means and standard
deviations per test stimulus. There was a significant main effect for
Time, F (1,255) = 8.30, p = .004,R 2 = .033 with overall stronger responses in
Acq1 (M = 1.19, SD = 1.40) than Acq2 (M = 1.03,SD = 1.24). No interaction effects were found (all pvalues >.393). Consequently, there was no difference in
visuocortical engagement for either of the two faces and no group
differences (HU: CS+: M = 1.29, SD = 1.34, CS-:M = 1.19, SD = 1.06, MU: CS+: M = 0.79, SD =
0.94, CS-: M = 0.84, SD = 1.00, LU: CS+: M =
1.30, SD = 1.76, CS-: M = 1.20, SD = 1.65)
but there was more visuocortical engagement to both faces during Acq1
than Acq2.