A Role for Contrast Gain Control in Skin Appearance

Apparent contrast can be suppressed or enhanced when presented within surrounding images. This contextual modulation is typically accounted for with models of contrast gain control. Similarly, the appearance of one part of a face is affected by the appearance of the other parts of the face. These influences are typically accounted for with models of face-specific holistic processing. Here we report evidence that facial skin appearance is modulated by adjacent surfaces. In four experiments we measured the appearance of skin evenness and wrinkles in images with increased or decreased contrast between facial skin and adjacent image regions. Increased contrast with adjacent regions made facial skin appear more even and less wrinkled. We found the effect whether faces were presented upright or inverted, and also when facial features were not present, ruling out face-specific holistic processing as an explanation yet fully consistent with contrast gain control. Because the mechanism is not face specific, contrast between skin and any adjacent surface should affect skin appearance. This suggests that adornments such as makeup, hair coloring, clothing, and jewelry could also affect skin appearance through contrast suppression or enhancement, linking these cultural practices to the structure and function of the visual system

Which facial features are central in impression formation?

Which facial characteristics do people rely on when forming personality impressions from faces? Previous research has uncovered an array of facial features that influence people’s impressions. Even though some (classes of) features, such as facial width-to-height ratio or resemblances to emotional expressions, play a central role in theories of social perception, their relative importance in impression formation remains unclear. Here, we model faces along a wide range of theoretically important dimensions. We use machine learning to test how well 31 features predict impressions of trustworthiness and dominance in a diverse set of 597 faces. In line with overgeneralization theory, emotion resemblances were most predictive of both traits. Other features that have received a lot of attention in the literature, such as facial width-to-height ratio, were relatively uninformative. Our results highlight the importance of modeling faces along a wide range of dimensions to elucidate their relative importance in impression formation

Sequential effects in facial attractiveness judgments using cross-classified models: Investigating perceptual and response biases.

When evaluating items in a sequence, the current judgment is influenced by the previous item and decision. These sequential biases take the form of assimilation (shifting toward the previous item/decision) or contrast (shifting away). Previous research investigating facial attractiveness evaluations provides mixed results while using analytical techniques that fail to address the dependencies in the data or acknowledge that the images represent only a subset of the population. Here, we utilized cross-classified linear mixed-effects modeling across 5 experiments. We found compelling evidence of multicollinearity in our models, which may explain apparent contradictions in the literature. Our results demonstrated that the previous image’s rating positively influenced current ratings, and this was also the case for the previous image’s baseline value, although only when that image remained onscreen during the current trial. Further, we found no influence of the next face on current judgments when this was visible. In our final experiment, the response bias due to the previous trial remained present even when accounts involving motor effort were addressed. Taken together, these findings provide a clear framework in which to incorporate current and past results regarding the biases apparent in sequential judgments, along with an appropriate method for investigating these biases

Makeup Changes the Apparent Size of Facial Features

Makeup is a prominent example of the universal human practice of personal decoration. Many studies have shown that makeup makes the face appear more beautiful, but the visual cues mediating this effect are not well understood. A widespread belief holds that makeup makes the facial features appear larger. We tested this hypothesis using a novel reference comparison paradigm, in which carefully controlled photographs of faces with and without makeup were compared with an average reference face. Participants compared the relative size of specific features (eyebrows, eyes, nose, mouth) of the reference face and individual faces with or without makeup. Across three studies we found consistent evidence that eyes and eyebrows appeared larger with makeup than without. In contrast, there was almost no evidence that the lips appeared larger with makeup than without. In two studies using professionally applied makeup the nose appeared smaller with makeup than without, but in a study using self-applied makeup there was no difference. Thus makeup was found to alter the facial feature sizes in ways that are related to age and sex, two known factors of beauty. These results provide further evidence to support the idea that makeup functions in part by modifying biologically based factors of beauty

Wanting or having children predicts age preferences in online dating

When dating, women seek men slightly older than themselves while men typically prefer younger women. Such patterns reflect differences in parental investment and age-related fertility, which are both concerned with maximizing reproductive outcomes. Using large samples of online daters, we considered whether having or wanting children was associated with the perceived importance of age as a matching criterion when dating (Study 1; N = 119,361), as well as how these two factors related to the preferred age of a match (Study 2; N = 486,382). Men without children (or those who wanted children) rated age as more important than those with children (or those who did not want children), and also selected a preferred age range that incorporated younger women. In contrast, women’s preferences showed little association with having or wanting children. Taken together, these findings demonstrate that age preferences may depend on factors in addition to those previously investigated, and that the relationships with the number of current children and the desire to have children are consistent with evolutionary predictions

No credible evidence for links between 2D:4D and COVID-19 outcomes: A probabilistic perspective on digit ratio, ACE variants, and national case fatalities

Research into COVID-19 susceptibility and outcomes are critical, but claims must be carefully evaluated to inform policy decisions. In a recent series of articles, Manning and Fink [1–3] use national-level data to describe associations between case-fatality ratios and male and female finger ratios (2D:4D), a suggested measure of prenatal androgen exposure, as well as angiotensin-converting enzyme (ACE) allele and genotype frequencies. The authors suggest that 2D:4D is linked with ACE variant prevalence, and that higher male 2D:4D is associated with higher case fatality ratios, and point to 2D:4D as a useful prognostic measure for COVID-19 susceptibility. A critical review and robust Bayesian analysis of the hypothesis is described here, finding no conclusive evidence of COVID-19 mortality and 2D:4D, nor associations between 2D:4D and ACE1 allele or ACE2 genotype frequency. This absence of evidence is present for data taken from the second wave of COVID-19 in October 2020. Problematic theoretical grounding, individual-level conclusions drawn from national-level data, and issues with statistical inference in the original articles are discussed. Taken together, the current data offer no clear utility of 2D:4D in determining COVID-19 outcomes

What Does Women's Facial Attractiveness Signal? Implications for an Evolutionary Perspective on Appearance Enhancement.

In their Target Article, Davis and Arnocky (2020) suggest that evolutionary theories of mate preferences can contribute to our understanding of why appearance-enhancement behaviors are seemingly ubiquitous. We support their argument that an interdisciplinary approach, in which evolutionary and other perspectives are fully integrated, will give us a more complete understanding of appearance-enhancement behaviors. We also agree that evolutionary theories of mate preferences have the potential to provide new insights into why such behaviors are so common. Here, we use the literature on women’s facial attractiveness to highlight an important limitation of this argument: uncertainty about precisely what is signalled by physical attractiveness

PREDICTORS OF PELVIC ACCELERATION DURING TREADMILL RUNNING AT DIFFERENT STRIDE FREQUENCIES

The aim of this study was to examine predictors of peak vertical and anteroposterior pelvic acceleration during treadmill running. Participants ran at 9 km∙h-1 at their preferred stride frequency and at ± 5% of their preferred stride frequency. Coordinate and acceleration data were collected using a motion capture system and inertial measurement units. Linear mixed models showed that for every one standard deviation increase in the anteroposterior displacement from knee to ankle at initial contact, vertical pelvic acceleration increased by 2.18 m∙s-2 (p = 0.046). Additionally, for every one standard deviation increase in stride frequency, peak anteroposterior pelvic acceleration increased by 0.68 m∙s-2 (p = 0.035). Runners who suffer from injuries or pain at the pelvis may benefit from decreasing the anteroposterior displacement from their knee to their ankle at initial contact and reducing their stride frequency

Individual differences in face and voice matching abilities: The relationship between accuracy and consistency

Deciding whether two different face photographs or voice samples are from the same person represent fundamental challenges within applied settings. To date, most research has focussed on average performance in these tests, failing to consider individual differences and within‐person consistency in responses. Here, participants completed the same face (Experiment 1) or voice matching test (Experiment 2) on two separate occasions, allowing comparison of overall accuracy across the two timepoints as well as consistency in trial‐level responses. In both experiments, participants were highly consistent in their performances. In addition, we demonstrated a large association between consistency and accuracy, with the most accurate participants also tending to be the most consistent. This is an important result for applied settings in which organisational groups of super‐matchers are deployed in real‐world contexts. Being able to reliably identify these high performers based upon only a single test informs regarding recruitment for law enforcement agencies worldwide