Model Gender Interacts With Expressed Emotion to Enhance Startle: Angry Male and Happy Female Faces Produce the Greatest Potentiation.

Several studies have implied gender differences in startle reaction to emotional facial expressions. However, few studies have been designed to investigate the difference between responding to emotional female vs. male faces, nor gender differences in responses. The present experiment investigated startle EMG responses to a startle probe while viewing pictures of neutral, happy, angry, fearful, and sad facial expressions presented by female and male models. Participants were divided into female and male groups. Results showed that emotional facial expressions interact with model gender to produce startle potentiation to a probe: greater responses were found while viewing angry expressions by male models, and while viewing happy faces by female models. There were no differences in responses between male and female participants. We argue that these findings underline theimportance of controlling for model gender in research using facial expressions as stimuli.

Correction: Filtered beauty in Oslo and Tokyo: A spatial frequency analysis of facial attractiveness.

[This corrects the article DOI: 10.1371/journal.pone.0227513.].

Filtered beauty in Oslo and Tokyo: A spatial frequency analysis of facial attractiveness.

Images of European female and male faces were digitally processed to generate spatial frequency (SF) filtered images containing only a narrow band of visual information within the Fourier spectrum. The original unfiltered images and four SF filtered images (low, medium-low, medium-high and high) were then paired in trials that kept constant SF band and face gender and participants made a forced-choice decision about the more attractive among the two faces. In this way, we aimed at identifying those specific SF bands where forced-choice preferences corresponded best to forced-choice judgements made when viewing the natural, broadband, facial images. We found that aesthetic preferences dissociated across SFs and face gender, but similarly for participants from Asia (Japan) and Europe (Norway). Specifically, preferences when viewing SF filtered images were best related to the preference with the broadband face images when viewing the highest filtering band for the female faces (about 48-77 cycles per face). In contrast, for the male faces, the medium-low SF band (about 11-19 cpf) related best to choices made with the natural facial images. Eye tracking provided converging evidence for the above, gender-related, SF dissociations. We suggest greater aesthetic relevance of the mobile and communicative parts for the female face and, conversely, of the rigid, structural, parts for the male face for facial aesthetics.

The Tromso Infant Faces Database (TIF): Development, Validation and Application to Assess Parenting Experience on Clarity and Intensity Ratings.

Newborns and infants are highly depending on successfully communicating their needs; e.g., through crying and facial expressions. Although there is a growing interest in the mechanisms of and possible influences on the recognition of facial expressions in infants, heretofore there exists no validated database of emotional infant faces. In the present article we introduce a standardized and freely available face database containing Caucasian infant face images from 18 infants 4 to 12 months old. The development and validation of the Tromsø Infant Faces (TIF) database is presented in Study 1. Over 700 adults categorized the photographs by seven emotion categories (happy, sad, disgusted, angry, afraid, surprised, neutral) and rated intensity, clarity and their valance. In order to examine the relevance of TIF, we then present its first application in Study 2, investigating differences in emotion recognition across different stages of parenthood. We found a small gender effect in terms of women giving higher intensity and clarity ratings than men. Moreover, parents of young children rated the images as clearer than all the other groups, and parents rated "neutral" expressions as more clearly and more intense. Our results suggest that caretaking experience provides an implicit advantage in the processing of emotional expressions in infant faces, especially for the more difficult, ambiguous expressions.

In Your Face: Startle to Emotional Facial Expressions Depends on Face Direction.

Although faces are often included in the broad category of emotional visual stimuli, the affective impact of different facial expressions is not well documented. The present experiment investigated startle electromyographic responses to pictures of neutral, happy, angry, and fearful facial expressions, with a frontal face direction (directed) and at a 45° angle to the left (averted). Results showed that emotional facial expressions interact with face direction to produce startle potentiation: Greater responses were found for angry expressions, compared with fear and neutrality, with directed faces. When faces were averted, fear and neutrality produced larger responses compared with anger and happiness. These results are in line with the notion that startle is potentiated to stimuli signaling threat. That is, a forward directed angry face may signal a threat toward the observer, and a fearful face directed to the side may signal a possible threat in the environment.

Nocebo hyperalgesia and the startle response.

BACKGROUND: The literature on the effects of nocebo on pain is sparse. The present experimental study investigated whether suggestions of nocebo hyperalgesia modified the startle response and whether increased startle contributed to the nocebo hyperalgesic effect. METHODS: A design with four groups was employed; the participants were randomized into either a placebo group, a natural history group, or into two nocebo groups. The participants in the placebo and nocebo groups received suggestions of pain decrease or pain increase, together with a placebo or nocebo cream applied to the lower arm, respectively. Heat pain was induced by a PC-controlled thermode before and after the treatment. White noise was used to elicit startle responses. Startle was assessed by measuring eye blink electromyographic responses recorded from the right orbicularis oculi muscle. RESULTS: The results showed that nocebo suggestions increased reports of pain and startle responses. Increased startle was significantly associated with the nocebo hyperalgesic response. CONCLUSIONS: The results of the present study suggest that verbally induced expectations of increased pain engage cortical physiological defensive systems that in turn mediate the experience of increased pain.

Invisible expressions evoke core impressions.

Participants viewed "hybrid" faces that showed a facial expression (anger, fear, happiness, or sadness) only in the lowest spatial frequency (1-6 cycles/image), which was blended with the same face's neutral expression in the rest of the bandwidth (7-128 cycles/image). Participants rated the portrayed persons (compared to neutral images) as "friendly" when the lowest spatial frequencies showed a positive expression and "unfriendly" when the lowest spatial frequencies showed negative expressions. In contrast, the same hybrid images were explicitly judged as neutral and their "hidden" emotional expressions could not be explicitly recognized, as also confirmed by d' sensitivity measures. Finally, one patient (SS) who had the left anterior temporal lobe surgically resected (including the amygdala), failed to show the above described unconscious effects on friendliness judgments when viewing "afraid" and "sad" hybrid faces. We conclude that the lowest spatial frequencies of facial expressions can evoke "core" emotions without knowledge or awareness of a specific emotion but these core emotions can convey a clear "impression" of a person's character.

Anchoring gaze when categorizing faces' sex: evidence from eye-tracking data.

Previous research has shown that during recognition of frontal views of faces, the preferred landing positions of eye fixations are either on the nose or the eye region. Can these findings generalize to other facial views and a simpler perceptual task? An eye-tracking experiment investigated categorization of the sex of faces seen in four views. The results revealed a strategy, preferred in all views, which consisted of focusing gaze within an 'infraorbital region' of the face. This region was fixated more in the first than in subsequent fixations. Males anchored gaze lower and more centrally than females.

Remembering 1500 pictures: the right hemisphere remembers better than the left.

We hypothesized that the right hemisphere would be superior to the left hemisphere in remembering having seen a specific picture before, given its superiority in perceptually encoding specific aspects of visual form. A large set of pictures (N=1500) of animals, human faces, artifacts, landscapes, and art paintings were shown for 2s in central vision, or tachistoscopically (for 100ms) in each half visual field, to normal participants who were then tested 1-6 days later for their recognition. Images that were presented initially to the right hemisphere were better recognized than those presented to the left hemisphere. These results, obtained with participants with intact brains, large number of stimuli, and long retention delays, are consistent with previously described hemispheric differences in the memory of split-brain patients.