Biomedical subjects

K Grammer

Publications and source records attributed to K Grammer.

9 recordsLinked to original sources

PubMed2001

Human (Homo sapiens) facial attractiveness in relation to skin texture and color.

The notion that surface texture may provide important information about the geometry of visible surfaces has attracted considerable attention for a long time. The present study shows that skin texture plays a significant role in the judgment of female facial beauty. Following research in clinical dermatology, the authors developed a computer program that implemented an algorithm based on co-occurrence matrices for the analysis of facial skin texture. Homogeneity and contrast features as well as color parameters were extracted out of stimulus faces. Attractiveness ratings of the images made by male participants relate positively to parameters of skin homogeneity. The authors propose that skin texture is a cue to fertility and health. In contrast to some previous studies, the authors found that dark skin, not light skin, was rated as most attractive.

Adult↗

PubMed2001

Human pheromones: integrating neuroendocrinology and ethology.

The effect of sensory input on hormones is essential to any explanation of mammalian behavior, including aspects of physical attraction. The chemical signals we send have direct and developmental effects on hormone levels in other people. Since we don t know either if, or how, visual cues might have direct and developmental effects on hormone levels in other people, the biological basis for the development of visually perceived human physical attraction is currently somewhat questionable. In contrast, the biological basis for the development of physical attraction based on chemical signals is well detailed.

Animals↗

PubMed2001

Homosexual orientation in males: evolutionary and ethological aspects.

Evolutionary theory proposes that adaptive traits are reproduced more successfully than maladaptive traits. Accordingly, natural selection should favor heterosexuality as it facilitates reproduction and the propagation of genes. However, the question becomes, what has maintained homosexuality in a small but consistent percentage of the human population? Research into the evolutionary and hormonal factors associated with a homosexual orientation have yielded provocative but inconsistent results. It also suggests that human sexual orientation, and in particular homosexual orientation, is too complex to be described by one simple model or a single research discipline. The current paper treads a new path and emphasizes an integrative approach for the understanding of homosexuality. The authors examine the combined effects of evolutionary factors and neurohormonal processes on the development of a homosexual orientation. It is suggested that research into the topic could benefit from an examination of and change in some of the assumptions upon which much past research has been based.

Adaptation, Physiological↗

PubMed2000

Non-verbal behavior as courtship signals: the role of control and choice in selecting partners.

In this work, we provide evidence based on direct observation of behavior in encounters of opposite-sexed strangers, that women initiate and "control" the outcome. In the first minute of these videotaped 10-min interactions, neither female "solicitation" behavior nor "negative" behavior is strongly related to professed interest in the man, while female "affirmative" behavior at this stage modulates male verbal output in later stages (4-10 min). Although the rate of female courtship-like behavior is significantly higher in the first minute, it is only in the fourth to tenth minute that the rate of female courtship-like behavior is correlated with professed female interest. We hypothesize that this serves as a strategic dynamic reflecting sexual asymmetry in parental investment and the potential cost of male deception to women. Ambiguous protean behavioral strategies veil individuals' intentions and make their future actions unpredictable. These behavioral strategies may result in men's overestimation of female sexual interest.

Journal Article↗

PubMed1999

Human body odour, symmetry and attractiveness.

Several studies have found body and facial symmetry as well as attractiveness to be human mate choice criteria. These characteristics are presumed to signal developmental stability. Human body odour has been shown to influence female mate choice depending on the immune system, but the question of whether smell could signal general mate quality, as do other cues, was not addressed in previous studies. We compared ratings of body odour, attractiveness, and measurements of facial and body asymmetry of 16 male and 19 female subjects. Subjects wore a T-shirt for three consecutive nights under controlled conditions. Opposite-sex raters judged the odour of the T-shirts and another group evaluated portraits of the subjects for attractiveness. We measured seven bilateral traits of the subject's body to assess body asymmetry. Facial asymmetry was examined by distance measurements of portrait photographs. The results showed a significant positive correlation between facial attractiveness and sexiness of body odour for female subjects. We found positive relationships between body odour and attractiveness and negative ones between smell and body asymmetry for males only if female odour raters were in the most fertile phase of their menstrual cycle. The outcomes are discussed in the light of different male and female reproductive strategies.

Adult↗

PubMed1999

Fuzziness of nonverbal courtship communication unblurred by motion energy detection.

A new method for the assessment of qualitative description of nonverbal behavior (automatic movie analysis) is introduced. This model-free method does not use any assumptions on the structure and organization of nonverbal behavior. Cross-cultural comparison (Germany, Japan) of unobtrusively filmed initial interactions between 2 opposite-sex strangers revealed no consistent courtship repertoire of directly observable behavior categories. Furthermore, an extensive analysis of gaze behavior and speech revealed differences between the countries but also showed no consistent relation to interest. Motion energy detection demonstrated in both cultures that female movement quality score (number of movements, duration, size, speed, and complexity) covaries with female interest. This effect is in concordance with the theory that in early stages of interactions manipulative efforts occur in order to avoid possible deception in high-risk situations.

Adolescent↗

PubMed1999

Human evolutionary aspects and urban dwelling features.

Planning and architecture of modern housing projects should take into account the fact that human well-being depends very much on needs derived from the natural history of human evolutionary aspects, which include territoriality, security, and a balance between privacy and communal activity. Although model housing projects should consider space, all to often the need for privacy and the importance of the residential environment has been neglected. Putative consequences are a loss of social coherence, resulting in anonymity, vandalism and an increase in crime rates. On a game theoretical basis, we predict that a tendency for cooperation grows with the increasing probability of future meetings among inhabitants. The higher the probability to re-meet co-residents, the more interactions are to be expected. Frequent meetings lead to reciprocal recognition and enable the inhabitants to control their environment by identifying straners. This mechanism results in the identification with a common territory. Friendly interactions between residents are a motor for and an indicator of satisfactory living conditions. For this study, six different Viennese residential apartment blocks were selected and their quality measured using a checklist. The behavior of the residents was recorded using ethological standard methods (N = 1653), their subjective evaluation was assessed by on-site interviews (N = 300), and the frequency of physical incivilities was counted. The results support the hypotheses. The classification of urban environments relating to the presence of the above-listed features indicates that high habitat quality covaries with differences in preference for the site, extent of friendly interactions and familiarity with other residents, and occurrences of incivilities. One may conclude that the importance of the quality of the habitat environment cannot be overestimated, as its socially integrative potential is a means to counteract anonymity and crime incidence in cities.

Adult↗

PubMed1997

[Battle of odors: significance of pheromones for human reproduction].

The significance of odours for human reproduction is partially neglected by medical sciences. Nevertheless, it can be shown that male pheromones (androstenol/androstenone) from male sweat have a direct impact on female menstrual cycles and ovulation. Furthermore, female pheromones (copulins), which are present in vaginal secretions, influence male perception of females and may induce hormonal changes in males. The mutual pheromonal influence between the sexes is discussed as a result of sex-specific reproductive interests which are a consequence of evolutionary constraints.

Animals↗

PubMed1994

Human (Homo sapiens) facial attractiveness and sexual selection: the role of symmetry and averageness.

We hypothesized from the parasite theory of sexual selection that men (Homo sapiens) would prefer averageness and symmetry in women's faces, that women would prefer averageness and symmetry in men's faces, and that women would prefer largeness (not averageness) of the secondary sexual traits of men's faces. We generated computer images of men's and women's faces and of composites of the faces of each sex, and then had men and women rate opposite-sex faces for 4 variables (attractive, dominant, sexy, and healthy). Symmetry, averageness, and the sizes of facial features were measured on the computerized faces. The hypotheses were supported, with the exception of the hypothesized effects of averageness of female and male faces on attractiveness ratings. This is the first study to show that facial symmetry has a positive influence on facial attractiveness ratings.

Adult↗