This comprehensive, ten volume reference work reflects the interdisciplinary influences on evolutionary psychology and serves as a major resource for its history, scientific contributors and theories.
White fat is the body’s main energy store and is deposited in two main reservoirs: as visceral fat in the abdomen and as subcutaneous fat on the thighs and buttocks. The visceral component of abdominal fat is more detrimental to long-term health than subcutaneous fat. This may be for partly mechanical reasons; the deposition of fat around the organs in the abdominal cavity may interfere with their normal function. Additionally, the development of insulin resistance (which contributes to diabetes and vascular disease) is attributed to an adipokine called retinol-binding protein 4 (RBP4), which is generated by fat cells. Visceral fat generates greater amounts of RBP4 than subcutaneous fat, and so visceral fat potentially has a disproportionate impact on health.
Recognition of older people’s body expressions is a crucial social skill. We here investigate how age, not just of the observer, but also of the observed individual, affects this skill. Age may influence the ability to recognize other people’s body expressions by changes in one’s own ability to perform certain action over the life-span (i.e., an own-age bias may occur, with best recognition for one’s own age). Whole body point light displays of children, young adults and older adults (>70 years) expressing six different emotions were presented to observers of the same three age-groups. Across two variations of the paradigm, no evidence for the predicted own-age bias (a cross-over interaction between one’s own age and the observed person’s age) was found. Instead, experience effects were found with children better recognizing older actors’ expressions of ‘active emotions,’ such as anger and happiness with greater exposure in daily life. Together, the findings suggest that age-related changes in one own’s mobility only influences body expression categorization in young children who interact frequently with older adults.
A popular scale for assessing knowledge about Alzheimer‘s disease is the Alzheimer‘s Disease Knowledge Scale (ADKS). The aim of the study was to investigate the effect of adding ‗don‘t know‘ to the original ‗true‘ or ‗false‘ response option. It was assumed that this modification would provide insight into the reasons underlying incorrect responses and could distinguish between misconceptions and knowledge gaps. To investigate this, carers (care home carers and informal carers) and members of the general population were recruited. The results showed that percentage correct responses was lower than previously reported, suggesting potential inflation of knowledge by guesses without the ‗don‘t know‘ option. Moreover, care-home workers were more likely to select the incorrect response than ‗don‘t know‘ compared to informal carers for several items related to the earlier stages of AD, suggesting a higher level of misconceptions around this topic and highlighting potential training needs for care home carers.
Biases in facial expression recognition can be reduced successfully using feedback-based training tasks. Here we investigate with event-related potentials (ERPs) at which stages of stimulus processing emotion-related modulations are influenced by training. Categorization of subtle facial expressions (morphed from neutral to happy, sad or surprise) was trained with correct-response feedback on each trial. ERPs were recorded before and after training while participants categorized facial expressions without response feedback. Behavioral data demonstrated large improvements in categorization of subtle facial expression which transferred to new face models not used during training. ERPs were modulated by training from 450 ms post-stimulus onward, characterized by a more gradual increase in P3b/Late Positive Potential (LPP) amplitude as expression intensity increased. This effect was indistinguishable for faces used for training and for new faces. It was proposed that training elicited a more fine-grained analysis of facial information for all subtle expressions, resulting in improved recognition and enhanced emotional motivational salience (reflected in P3b/LPP amplitude) of faces previously categorized as expressing no emotion.
Eye tracking has been used during face categorisation and identification tasks to identify perceptually salient facial features and infer underlying cognitive processes. However, viewing patterns are influenced by a variety of gaze biases, drawing fixations to the centre of a screen and horizontally to the left side of face images (left-gaze bias). In order to investigate potential interactions between gaze biases uniquely associated with facial expression processing, and those associated with screen location, face stimuli were presented in three possible screen positions to the left, right and centre. Comparisons of fixations between screen locations highlight a significant impact of the screen centre bias, pulling fixations towards the centre of the screen and modifying gaze biases generally observed during facial categorisation tasks. A left horizontal bias for fixations was found to be independent of screen position but interacting with screen centre bias, drawing fixations to the left hemi-face rather than just to the left of the screen. Implications for eye tracking studies utilising centrally presented faces are discussed.
Background. In recent years, researchers have investigated the relationship between facial width-to-height ratio (FWHR) and a variety of threat and dominance behaviours. The majority of methods involved measuring FWHR from 2D photographs of faces. However, individuals can vary dramatically in their appearance across images, which poses an obvious problem for reliable FWHR measurement.
Methods. I compared the effect sizes due to the differences between images taken with unconstrained camera parameters (Studies 1 and 2) or varied facial expressions (Study 3) to the effect size due to identity, i.e., the differences between people. In Study 1, images of Hollywood actors were collected from film screenshots, providing the least amount of experimental control. In Study 2, controlled photographs, which only varied in focal length and distance to camera, were analysed. In Study 3, images of different facial expressions, taken in controlled conditions, were measured.
Results. Analyses revealed that simply varying the focal length and distance between the camera and face had a relatively small effect on FWHR, and therefore may prove less of a problem if uncontrolled in study designs. In contrast, when all camera parameters (including the camera itself) are allowed to vary, the effect size due to identity was greater than the effect of image selection, but the ranking of the identities was significantly altered by the particular image used. Finally, I found significant changes to FWHR when people posed with four of seven emotional expressions in comparison with neutral, and the effect size due to expression was larger than differences due to identity.
Discussion. The results of these three studies demonstrate that even when head pose is limited to forward facing, changes to the camera parameters and a person’s facial expression have sizable effects on FWHR measurement. Therefore, analysing images that fail to constrain some of these variables can lead to noisy and unreliable results, but also relationships caused by previously unconsidered confounds.
Research has demonstrated that wearing red can have significant effects on perceptions of the wearer. However, these findings are based on impressions formed while viewing static images. Here, I focus on perceptions of political leaders and show participants short videos in order to investigate color effects in stimuli with increased ecological validity. Viewers watched videos of politicians and made judgments regarding how dominant, how good a leader, and how believable the politicians appeared to be. The colors of the politicians’ ties were digitally manipulated to be red or blue. Whether the politician was familiar (Study 1) or unfamiliar to viewers (Study 2), tie color had no effect on perceptions. Even when the sound was muted in order to increase the influence of visual cues (Study 3), I found no clothing color effect. Finally, when only presented with a static image (Study 4), wearing red still had no effect on judgments. These results suggest that, at least in a political setting, wearing red has no effect on perceptions. Therefore, real-world applications associated with red clothing may be limited.
Although several studies in recent years have provided evidence of a relationship between month of birth and height during childhood, the association remains less clear for adult (final) height. Here, I investigated this relationship using a large international sample of adult actors. Analyses considered both the sample as a whole, as well as subsamples based on nationality, and treated men and women separately. In all instances, I found no relationship between birth month or season and height, even after controlling for year of birth. This may be due to the particular nature of samples of actors, who are taller than the general population, or could suggest more broadly that birth month effects are minimal or absent in adults.
Could a simple pair of glasses really fool us into thinking Superman and Clark Kent are two different people? Here, we investigated the perception of identity from face images with a task that relies on visual comparison rather than memory. Participants were presented with two images simultaneously and were asked whether the images depicted the same person or two different people. The image pairs showed neither image with glasses, both images with glasses, and ‘mixed’ pairs of one image with and one without glasses. Participants’ accuracies, measured by both percentage correct and d′ sensitivity, were significantly lower for ‘mixed’ trials. Analysis of response bias showed that when only one face wore glasses, people tended to respond ‘different’. We demonstrate that glasses affect face matching ability using unconstrained images, and this has implications for both disguise research and authenticating identity in the real world.