The inter-association between face processing abilities, cognitive abilities, and autistic-like traits

There has been contention in the previous research regarding the association between face processing abilities (e.g. face detection, face perception, face memory and expression recognition) and cognitive abilities (i.e. intelligence). Some would contend that face processing abilities are unique and distinct from other cognitive abilities (Shakeshaft & Plomin, 2015; Wilmer et al., 2010). Whilst others have found moderate associations between these abilities (Connolly et al., 2019; Gignac et al., 2016; Hildebrandt et al., 2011; Schlegel et al., 2019). It would be greatly beneficial to explore the shared variance between face processing abilities and cognitive abilities, not only in improving our understanding of these abilities, but also the possibility of conceptualising face processing abilities within the contemporary models of cognitive ability, such as the Cattell-Horn-Carroll (CHC) model (Meyer et al., 2021). The majority of the recent research on the association between cognitive abilities and face identity processing has centred around face memory. Face memory is the ability to recognise a face that has previously been seen, a vital skill for socialisation (Oruc et al., 2019). Some studies have found a moderate, positive association between short-term face memory and other cognitive abilities, including general intelligence (Gignac et al., 2016; Hildebrandt et al., 2011; Shakeshaft & Plomin, 2015). However, other studies have failed to report a significant association (Davis et al., 2011; Palermo, Connor, Davis, Irons, & McKone, 2013; Peterson & Miller, 2012). The mixed results reported in the literature may be due to several factors, including small and range restricted samples (e.g., Davis et al., 2011; Peterson & Miller, 2012). Additionally, several studies measured cognitive abilities with only one or two subtests, which would only be described as ‘poor’ to ‘fair’ intelligence measurement, according to Gignac and Bate’s (2017) guidelines. Therefore, it is important to conduct a study that includes a large, representative sample with a balanced number of good quality cognitive abilities measures across the four core dimensions of cognitive ability: crystallised intelligence, visual/fluid intelligence, memory span, and processing speed. In comparison to face memory, there has been very minimal research conducted on face detection and cognitive abilities. Face detection is the process of locating a face within a visual scene. This ability is an essential prerequisite for higher-order face-specific processes, such as face memory (Garrido et al., 2008; Verhallen et al., 2017). To the authors’ knowledge, only one study has investigated the association between intelligence and face detection (Vigen et al., 1982). They found a moderate, positive correlation (r = .25) between the WAIS-R and a commonly used face detection task, the Mooney task. Therefore, it remains unknown the degree to which individual differences in face detection arise from a process specific to faces versus individual differences in visual processing more generally. On the one hand, there is neurophysiological evidence to suggest that face detection may be, at least to some degree, unique. For example, studies have shown that detection of a face in the visual space activates the highly face-selective fusiform face area, compared to when a face is not detected (Andrews & Schluppeck, 2004; Kriegeskorte et al., 2007; McKeeff & Tong, 2007). Whilst on the other hand face detection tasks are remarkably similar to tasks of visual closure, and an association between face detection and visual closure has been established (Walker et al., 2022). Therefore, an important aspect of this current study is to examine the association between face detection, other face processing abilities, specific cognitive abilities, and general cognitive ability. Face perception is considered a higher-level process than face detection (Verhallen et al., 2017). It’s the ability to either discriminated or individualised a person’s identity when viewing faces (Oruc et al., 2019). The ability to tell faces apart or individualise a face is important for day-to-day life. For example, being able to scan faces within a crowd and see each face as being distinct from each other. Previous research has shown a positive association between face perception and cognitive abilities (Connolly et al., 2019; Hildebrandt et al., 2011). However, only a small amount of empirical research has correlated individual differences in face perception with other cognitive ability dimensions, whether general or narrow in nature. This study aims to provide further evidence of the association between face perception and general cognitive ability, and specific cognitive abilities. Another very important face processing ability, especially for socialisation, is expression recognition, also known as face emotion recognition. The ability to accurately and efficiently recognise facial expressions is essential for effective interpersonal interaction and social cognition (Fox & Zougkou, 2011). Empirically, individual differences in expression recognition have been linked to cognitive abilities (Borod et al., 2000; Connolly et al., 2019). Schlegel et al. (2019) conducted a meta-analysis on the association between expression recognition and cognitive abilities. They found that general cognitive ability is positively correlated with expression recognition (r = .19). They also found that specific cognitive abilities (crystallized, fluid, spatial, memory, information processing speed and efficiency) also positively correlated with expression recognition to a similar extent. Schlegel et al. (2019) concluded that the effect size reported in the meta-analysis may be on the lower end of the true associations, due to psychometric limitations and limited complexity of the measures of expression recognition ability. Therefore, it is important that the association between expression recognition and cognitive abilities be examined when the measures have good psychometric properties and follow all steps outlined in recent test development guidelines (e.g. DeVellis, 2017). In doing so, the true association between expression recognition and cognitive abilities could be observed. It's also important to investigate the inter-association between the face processing abilities. Verhallen et al. (2017) and McCaffery et al. (2018) found highly significant correlations between their measures of face detection, face perception, and face memory. The correlations between measures differed in magnitude with shared variance ranging between 4% and 23%. Both studies concluded that a general ability of face processing may exist and underlies performance with a wide range of face tasks. Similarly, research into expression recognition and the other face processing abilities has seen considerable correlations between measures (Gignac et al., 2020; Hildebrandt et al., 2015; Palermo et al., 2013). Therefore, this study will aim to investigate the unique construct related variance associated with each of the four face processing abilities. One final aspect of this study is to investigate the shared variance between trait-autism and face processing abilities. To the authors’ knowledge, no individual difference study has yet examined all four dimensions of face processing (face detection, face perception, face memory and expression recognition) and trait-autism, simultaneously. There is evidence to suggest that higher trait-autism is associated with poor face processing abilities (Bothe et al., 2019; Davis et al., 2017; Halliday et al., 2014). Autistic-like traits (also known as the Broader Autism Phenotype) refers to milder forms of traits seen in neuro-typical individuals that are associated with the Autism Spectrum Disorder (ASD), such as communication deficits, restricted activities and poorer executive functioning (Deisinger, 2015). Specifically, previous research suggests that nonverbal communication, one dimension of trait-autism, is most likely to be associated with face processing ability compared to the other dimensions. For example, Bothe et al. (2019) found that nonverbal communication was negatively associated with discriminating and labelling emotions (r = -.24 & r = -.29, respectively). Davis et al. (2017) and Lewis et al. (2018) found that nonverbal communication and social aspects of trait-autism are negatively associated with face identity recognition. Therefore, it is predicted that the communication dimension of trait-autism, and potentially the social dimensions of trait-autism, is more likely to be negatively associated with face processing abilities. In conclusion, this study will provide the opportunity to determine the unique effects associated with each of the four face processing abilities, with respect to the dimensions of the trait-autism and cognitive abilities, in neuro-typical adults. In addition to enhancing our understanding of face processing, trait-autism, and cognitive abilities; the observation of one or more unique effects would suggest the possible benefits of experimental manipulation (i.e., face processing training may help ameliorate certain trait-autism behaviours). It will also be noted that cognitive abilities may be expected to associate positively with face processing ability, but unlikely with the trait-autism, thus, controlling for the effects of cognitive abilities on face processing abilities may increase the observed effects between face processing abilities and trait-autism (i.e., a suppressor effect).