Memory of disguised faces: the effects of eyebrows and congruence of encoding

• Main Author: Ang, Wei Xuan
• Other Authors: Charles Or
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Social Sciences
• Online Access: https://hdl.handle.net/10356/177447
• Institution: Nanyang Technological University

People are remarkably good at recognising faces they are familiar with, yet recognising unfamiliar faces seem to pose major difficulties for many especially under various visual conditions. This study investigated whether occluding eyebrows alongside the eyes affect face memory performance. Participants (n = 84) were presented with stimuli depicting faces of individuals without disguise (full faces), with small sunglasses and big sunglasses. Small sunglasses conceal only the eyes while big sunglasses conceal both the eyes and eyebrows. They were instructed to perform face memory tasks, whereby they study a series of faces and differentiate whether the studied and new distractor faces are familiar or unfamiliar to them. It was found that there were no significant differences in sensitivity of observers for faces with occluded eyebrows compared to faces with unoccluded eyebrows. We additionally tested the effect of congruence by adding sunglasses to faces in either study or test phase only (i.e., study full faces, test with disguised faces; or study disguised faces, test with full faces) and found that incongruent disguises led to lower sensitivity for observers compared to congruent disguises. Furthermore, significant liberal response biases were detected consistently in the presence of disguise, particularly evident under congruent presentation of faces. Altogether, findings suggesting the lack of effect of occlusion of eyebrows on face memory support holistic processing of faces while significant congruence effect on face memory aligns with encoding specificity principle. Law enforcement agencies can incorporate this knowledge into eyewitness identification protocols as a practical implication.