Incomplete faces are completed using a more average face

Kramer and Jones Cognitive Research: Principles and Implications https://doi.org/10.1186/s41235-022-00429-y (2022) 7:79 Cognitive Research: Principles and Implications Open Access ORIGINAL ARTICLE Incomplete faces are completed using a more average face Robin S. S. Kramer1*   and Alex L. Jones2 Abstract Facial first impressions are known to influence how we behave towards others. As a result of the COVID-19 pandemic, we often view incomplete faces due to the commonplace wearing of face masks. Previous research has shown that perceptions of attractiveness are often increased due to these coverings, with initial evidence suggesting that this may be caused by viewers using a mental representation of the average face to complete any missing information. Here, we directly address this hypothesis by presenting participants with incomplete faces (either the lower or upper half removed) and asking them to decide how they thought the actual, full face looked. Participants were able to manipulate the missing half of the face onscreen by increasing or decreasing the averageness of its shape. Our results demonstrated that participants did not select the original versions of the faces but instead chose more average versions when manipulating both the lower and upper face. Further, the typicality of the original image influenced responses, with less typical faces (in comparison with more typical ones) being completed using an even more average version of the missing half of the faces. Taken together, these findings provide the first direct evidence that people utilise an average/typical internal representation when inferring information about incomplete faces. This result has theoretical importance in terms of visual perception, as well as real-world relevance in a time where face masks are commonplace due to the COVID-19 pandemic. Keywords: Facial attractiveness, Facial typicality, Positivity bias, Upper- and lower-face, Face morph, Face average Introduction Due to the COVID-19 pandemic and the everyday use of face masks (Rab et al., 2020), we have now become accustomed to forming facial first impressions based on incomplete information. Recent studies have begun to address how the wearing of face masks may have impacted our rapid and automatic judgements of others (Olson & Marshuetz, 2005; Ritchie et al., 2017; Willis & Todorov, 2006), given that our initial impressions of strangers can have significant implications for how we behave towards them. The ‘halo effect’ (Dion et al., 1972), for example, describes how socially desirable traits are indiscriminately applied to attractive people, who in turn, *Correspondence: 1 School of Psychology, University of Lincoln, Brayford Pool, Lincoln LN6 7TS, UK Full list of author information is available at the end of the article may benefit from receiving more help (Benson et al., 1976), getting more lenient sentences in court (Erian et al., 1998), and earning higher wages (Pfeifer, 2012). A growing body of research has focussed on the nature of attractiveness perceptions when faces are either partly obscured by masks or entirely visible to the viewer. Prior to the pandemic, Miyazaki and Kawahara (2016) showed that faces originally categorised as middle- or high-attractiveness suffered a decrease in ratings when presented with face masks. The authors argued that this pattern of results supported the ‘sanitary-mask effect’, whereby the presence of masks primed perceptions of illness/poor health. In contrast, when the lower face was occluded by a notebook instead, high-attractiveness faces were rated lower, while low-attractiveness faces were rated higher. Here, the underlying mechanism was argued to be the result of the occlusion itself. Covering the lower part of unattractive faces caused an increase in © The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Kramer and Jones Cognitive Research: Principles and Implications (2022) 7:79 ratings (e.g., by hiding signs of low symmetry and rough skin) while the same occlusion caused a decrease in ratings for attractive faces (e.g., by hiding signs of high symmetry and smooth skin). Subsequent research has taken place since the onset of the pandemic, where our exposure to face masks has presumably negated the above-mentioned negative primes associated with mask-wearing. Indeed, studies have tended to show an overall increase in attractiveness perceptions with the presence of face masks, or at least, no overall decrease in ratings. For instance, Hies and Lewis (2022) found that face masks increased ratings of attractiveness, and this was equally true for both unattractive and attractive faces. Further, when faces were considered without categorising into low and high groups, no overall differences were found when rating faces with versus without face masks (Bennetts et al., 2022; Guo et al., 2022). Interestingly, many researchers have also identified different patterns of results for low- and high-attractiveness faces, perhaps supporting the mechanism described above (Miyazaki & Kawahara, 2016). For example, Patel et al. (2020) found that faces when presented with masks were rated as more attractive in general, although this was particularly true for the most unattractive faces (which saw the largest increase). In addition, Kamatani et al. (2021) showed that high-attractiveness faces decreased in their ratings when presented with masks, while low-attractiveness faces showed an increase in their ratings. Finally, Pazhoohi and Kingstone (2022) also found that unattractive faces were rated as more attractive when presented with masks, although attractive faces saw no change in how they were perceived. This pattern was also present in a study by Oldmeadow and Koch (2021), although these researchers initially categorised their stimuli based upon trustworthiness rather than attractiveness: only low-trustworthiness faces increased in attractiveness ratings when presented wearing masks, which is consistent with previous research that has established a strong correlation between facial trustworthiness and attractiveness perceptions (e.g., Oosterhof & Todorov, 2008). How might we account for th (...truncated)