Biological determinants of individual differences in face cognition

Ljudi se razlikuju u uspješnosti kojom percipiraju i pamte nepromjenjive aspekte lica, kao i promjenjive aspekte lica kao što su emocionalni izrazi. Muškarci su u tome često manje uspješni od žena, što može upućivati na djelovanje spolnih hormona na obradu lica. Cilj ovog istraživanja jest ispitati pretpostavku o postojanju aktivacijskih i organizacijskih učinaka spolnih hormona na točnost percepcije emocionalnih izraza lica. Diferencijalni doprinos ovih učinaka moguće je ispitati u okviru teorije latentnih crta i stanja (Steyer i sur., 1992, 1999). Provedeno je istraživanje u dvije točke mjerenja na 305 studentica koje su se razlikovale po fazama menstrualnog ciklusa u trenutku mjerenja, odnosno karakterističnim razinama spolnih hormona, kao indikatorima aktivacijskih učinaka. Također je bio izmjeren i omjer drugog i četvrtog prsta kao indikator organizacijskih učinaka te primijenjena baterija testova koja uključuje mjere obrade emocionalnih izraza na licima te mjere obrade nepromjenjivih aspekata lica, opće kognitivne sposobnosti i emocionalne inteligencije, koje su omogućile definiranje obrade emocionalnih izraza kao specifične sposobnosti. Naši rezultati ne potkrepljuju pretpostavku o postojanju aktivacijskih učinaka, odnosno faza ciklusa nije objašnjavala varijacije u situacijskoj komponenti rezultata na mjerama percepcije emocionalnih izraza, a točnost percepcije emocionalnih izraza nije bila različita u folikularnoj fazi u odnosu na lutealnu fazi. Indikator organizacijskih učinaka bio je pozitivno povezan s dispozicijskom komponentom rezultata na mjerama percepcije emocionalnih izraza za jednu od korištenih mjera percepcije emocionalnih izraza (r = .13, p = .047). Ovi zaključci su ograničeni niskom specifičnošću korištenih mjera percepcije emocionalnih izraza. Istraživanje upućuje na potrebu za daljnjim razvojem mjera percepcije emocionalnih izraza da bi se utvrdilo u kojoj mjeri se može razlikovati kognitivna obrada nepromjenjivih i promjenjivih aspekata lica.Face cognition is an important part of everyday communication. The contemporary models of face cognition differentiate between perception and memory of face aspects, as well as between processing invariant facial aspects, pertaining to a person’s facial identity, and changeable facial aspects, such as emotional expressions (Bruce & Young, 1986; Fitousi & Wenger, 2013). These aspects are partly processed together and partly independently, although the stage at which the processing separates is not well established. The processing of emotion expressions is also considered as one of the basic branches of emotional intelligence Individual differences exist in the ability to accurately perceive and memorize both faces and facial expressions, which cannot be explained by general cognitive abilities, mental speed, complex visual stimuli cognition, and immediate and delayed memory (Hildebrandt, Sommer, Schacht, & Wilhelm, 2015; Wilhelm, Herzmann i sur., 2010). It has also been established that women often outperform men in face cognition (Herlitz & Lovén, 2013; Sommer, Hildebrandt, KuninaHabenicht, Schacht, & Wilhelm, 2013), which might indicate that sex hormones partly determine the face cognition ability. Sex hormones could exert their influence on face cognition via organisational effects, i.e., permanent changes in cortical structures that lead to certain behaviours, and via activational effects, i.e., reversible changes due to hormone levels fluctuations. The differential contribution of these effects can be determined using the latent state-trait theory (Steyer, Ferring, & Schmitt, 1992; Steyer, Schmitt, & Eid, 1999). Face cognition was therefore analysed in terms of latent state–trait theory, which enabled us to determine the transsituational component of face cognition (expected to be related to indicators of organisational effects), and situation specific component (expected to be related to indicators of activational effects). The aim of this research was to investigate the activational and organisational effects of sex hormones on the accuracy of the facial emotion perception, taking into account the specificity of this face cognition ability Methodology The sample consisted of Croatian female students (Mage = 21.2). The data for each participant were collected on two occasions on average five months apart (n1 = 305, n2 = 255). The measurement points differed regarding the menstrual cycle phase, indicative of typical sex hormones levels, i.e., activational effects, which was established using a backward counting method. Part of the sample was measured in the same menstrual phase both times (n = 70), while part of the sample was first measured in the phase when hormones are supposed to be at their highest, and then in the phase when they are supposed to be at their lowest (n = 42). At each measurement we collected data on face cognition of emotional expressions and invariant aspects, general cognitive ability and emotional intelligence. We also collected data on the second-to-fourth-digit ratio as an indicator of organisational effects. Results and discussion The data preparation included exploratory factor analyses, tests of measurement models and measurement invariance, as well as the formation of new variables defined as to reflect the component specific to emotion expression in regard to face cognition of invariant aspects, general cognitive ability, and emotional intelligence. These abilities completely explained the common variance of the emotion expression measures. Therefore variables formed to reflect the specific component were defined for each of the emotion expression measures, and not for the common factor of emotion expression measures as was planned. The variables reflecting the specific emotion expressions variance had a significant trait and situation specific component. The situation specific component of the variables did not have a significant correlation with either menstrual phase or second-to-fourth-digit ratio. The second-to-fourthdigit ratio had a marginally significant correlation with the trait component of one of the emotion expression variables, r = .13, p = .047. There were no differences in accuracy of emotion expressions recognition due to menstrual phase for any of the measures. Our results indicate that both activational or organisational effects of sex hormones on processing of emotion expressions are either very weak or nonexistent. Other possible explanations of sex differences should be investigated, e.g., other hormones or environmental characteristics such as gender inequality. It is also possible that these sex differences are better explained by sex differences in the face cognition of invariant aspects. However, our conclusions are limited by the validity and low specificity of the measures of emotion expressions processing. Special attention should be given to further development of these measures, which would enable researchers and practitioners alike to have a measure of this specific ability. This would help establish the degree of (in)dependence of face cognition of invariant and changeable aspects