Abstract
Introduction. Visual adaptation occurs after a sustained exposure to a visual stimulus. Aftereffects form after fixating a variety of visual stimuli, and the duration of the aftereffect varies depending on the visual stimulus (Burton et al., 2016; Leopold et al., 2005; Rhodes et al., 2007; Kloth & Rhodes, 2016; Kloth, & Schweinberger, 2008). The current study tests opposing aftereffects for Christian and Muslim faces 7 days after adaptation. Methods. Thirty-four participants underwent an opposing after effect paradigm. First, participants viewed 48 face pairs, one compressed by 10% and one expanded by 10%, and on each trial selected which face looked more attractive. Next, participants were adapted to Muslim and Christian faces altered by 60%. After adaptation, participants again viewed and selected from the original 48 face pairs. Participants returned 7 days later and viewed and selected from the same 48 face pairs to determine if aftereffects were still measurable. Next, participants were re-adapted to Christian and Muslim faces distorted in the opposite direction and tested to see whether aftereffects could be reversed. Results. Using a mean change score for contracted faces selected from baseline as the dependent variable, there was a significant interaction between adaptation condition and religious face type (F(1, 32)=6.18, p=0.018) 7 days after adaptation. Examining adaptation conditions separately, opposing aftereffects were observed for those who adapted to Christian contracted and Muslim expanded faces, 7 days after adaptation (t(17)=2.98, p= 0.009). Opposing aftereffects could not be reversed by exposure to faces distorted in the opposite direction after 7 days, as no significant interaction between adaptation condition and religious face type was observed (F(1, 32)=2.018, p=0.165). Discussion. Results revealed evidence of opposing aftereffects adaptation persisting for 7 days. Furthermore, the aftereffect could not be reversed 7 days after adaptation.