Peter Frost

PREFERENCE FOR DARKER FACES IN PHOTOGRAPHS AT DIFFERENT PHASES OF THE MENSTRUAL CYCLE: PRELIMINARY ASSESSMENT OF EVIDENCE FOR A HORMONAL RELATIONSHIP

Six pairs of photographs showing human faces of both sexes were presented to 98 women who had to choose the more pleasing one of each pair. Faces within each pair were identical except for a slight difference in complexion. For women not taking oral contraceptives, skin-color preference differed significantly between two groups of subjects classified according to the current phase of their self-reported menstrual cycle: darker male faces were judged more positively by subjects in the phase when the estrogen/progesterone ratio was expected to be high than by those in the phase when this ratio was expected to be low. Female faces evoked no such cyclic response. Users of oral contraceptives showed no cyclic response to either male or female faces. These results suggest a mental mechanism whose inputs are (a) hormonal state, (b) visual identification of the sex of the face being observed, and (c) visual recognition of complexion, and whose output enters into evaluation of male and female faces. Replication with direct measures of hormonal state is recommended.

Trustworthy-Looking Face Meets Brown Eyes

We tested whether eye color influences perception of trustworthiness. Facial photographs of 40 female and 40 male students were rated for perceived trustworthiness. Eye color had a significant effect, the brown-eyed faces being perceived as more trustworthy than the blue-eyed ones. Geometric morphometrics, however, revealed significant correlations between eye color and face shape. Thus, face shape likewise had a significant effect on perceived trustworthiness but only for male faces, the effect for female faces not being significant. To determine whether perception of trustworthiness was being influenced primarily by eye color or by face shape, we recolored the eyes on the same male facial photos and repeated the test procedure. Eye color now had no effect on perceived trustworthiness. We concluded that although the brown-eyed faces were perceived as more trustworthy than the blue-eyed ones, it was not brown eye color per se that caused the stronger perception of trustworthiness but rather the facial features associated with brown eyes.

Vitamin D deficiency among northern Native Peoples: a real or apparent problem?

Vitamin D deficiency seems to be common among northern Native peoples, notably Inuit and Amerindians. It has usually been attributed to: (1) higher latitudes that prevent vitamin D synthesis most of the year; (2) darker skin that blocks solar UVB; and (3) fewer dietary sources of vitamin D. Although vitamin D levels are clearly lower among northern Natives, it is less clear that these lower levels indicate a deficiency. The above factors predate European contact, yet pre-Columbian skeletons show few signs of rickets—the most visible sign of vitamin D deficiency. Furthermore, because northern Natives have long inhabited high latitudes, natural selection should have progressively reduced their vitamin D requirements. There is in fact evidence that the Inuit have compensated for decreased production of vitamin D through increased conversion to its most active form and through receptors that bind more effectively. Thus, when diagnosing vitamin D deficiency in these populations, we should not use norms that were originally developed for European-descended populations who produce this vitamin more easily and have adapted accordingly. 1Published ‘ahead-of-print’ 10 November 2011 (at www.ijch.fi) in accordance with previous publishers routines.

Western Europe, State Formation, and Genetic Pacification:

Through its monopoly on violence, the State tends to pacify social relations. Such pacification proceeded slowly in Western Europe between the 5th and 11th centuries, being hindered by the rudimentary nature of law enforcement, the belief in a mans right to settle personal disputes as he saw fit, and the Churchs opposition to the death penalty. These hindrances began to dissolve in the 11th century with a consensus by Church and State that the wicked should be punished so that the good may live in peace. Courts imposed the death penalty more and more often and, by the late Middle Ages, were condemning to death between 0.5 and 1.0% of all men of each generation, with perhaps just as many offenders dying at the scene of the crime or in prison while awaiting trial. Meanwhile, the homicide rate plummeted from the 14th century to the 20th. The pool of violent men dried up until most murders occurred under conditions of jealousy, intoxication, or extreme stress. The decline in personal violence is usually attributed to harsher punishment and the longer-term effects of cultural conditioning. It may also be, however, that this new cultural environment selected against propensities for violence.

The Roman State and Genetic Pacification

Over the last 10,000 years, the human genome has changed at an accelerating rate. The change seems to reflect adaptations to new social environments, including the rise of the State and its monopoly on violence. State societies punish young men who act violently on their own initiative. In contrast, non-State societies usually reward such behavior with success, including reproductive success. Thus, given the moderate to high heritability of male aggressiveness, the State tends to remove violent predispositions from the gene pool while favoring tendencies toward peacefulness and submission. This perspective is applied here to the Roman state, specifically its long-term effort to pacify the general population. By imperial times, this effort had succeeded so well that the Romans saw themselves as being inherently less violent than the “barbarians” beyond their borders. By creating a pacified and submissive population, the empire also became conducive to the spread of Christianity—a religion of peace and submission. In sum, the Roman state imposed a behavioral change that would over time alter the mix of genotypes, thus facilitating a subsequent ideological change.

Health status by gender, hair color, and eye color: Red-haired women are the most divergent

Red hair is associated in women with pain sensitivity. This medical condition, and perhaps others, seems facilitated by the combination of being red-haired and female. We tested this hypothesis by questioning a large sample of Czech and Slovak respondents about the natural redness and darkness of their hair, their natural eye color, their physical and mental health (24 categories), and other personal attributes (height, weight, number of children, lifelong number of sexual partners, frequency of smoking). Red-haired women did worse than other women in ten health categories and better in only three, being particularly prone to colorectal, cervical, uterine, and ovarian cancer. Red-haired men showed a balanced pattern, doing better than other men in three health categories and worse in three. Number of children was the only category where both male and female redheads did better than other respondents. We also confirmed earlier findings that red hair is naturally more frequent in women than in men. Of the ‘new’ hair and eye colors, red hair diverges the most from the ancestral state of black hair and brown eyes, being the most sexually dimorphic variant not only in population frequency but also in health status. This divergent health status may have one or more causes: direct effects of red hair pigments (pheomelanins) or their by-products; effects of other genes that show linkage with genes involved in pheomelanin production; excessive prenatal exposure to estrogen (which facilitates expression of red hair during fetal development and which, at high levels, may cause health problems later in life); evolutionary recentness of red hair and corresponding lack of time to correct negative side effects; or genetic incompatibilities associated with the allele Val92Met, which seems to be of Neanderthal origin and is one of the alleles that can cause red hair.

Health Status By Gender, Hair Color, And Eye Color: Red-Haired Women Are The Most Divergent With The Lowest Viability And The Highest Fertility

Red hair is associated with pain sensitivity, and more so in women than in men. Hair redness may thus interact with a female-specific factor. We tested this hypothesis on a large sample of Czech and Slovak respondents. They were asked about the natural redness and darkness of their hair, their natural eye color, their physical and mental health (24 categories), and other personal attributes (height, weight, number of children, lifelong number of sexual partners, frequency of smoking). We found that red-haired women did worse than other women in ten health categories and better in only three. In particular, they were more prone to colorectal, cervical, uterine, and ovarian cancer. Cancer risk increased steadily with increasing hair redness except for the reddest shade. Red-haired men showed a balanced pattern of health effects, doing better than other men in three categories and worse in three. Number of children was the only category where both male and female redheads did better than other respondents. Of the ‘new’ hair and eye colors, red hair diverges the most from the ancestral state of black hair and brown eyes. It is the most sexually dimorphic variant, not only in population frequency but also in health outcomes.

Reply to W.B. Grant 'Re: Vitamin D deficiency among northern Native Peoples'

Dr. Grant seems to assume that all humans share the same vitamin D metabolism, an assumption that is doubtful even on theoretical grounds (1). We know that natural selection can alter the way the human body synthesises, transports and uses this vitamin. We also know that the relevant selection pressures (from solar UV and skin color) vary from one human population to the next. So it is not necessarily unhealthy for a population to have low blood levels of vitamin D. The underlying metabolism may simply be different. (Published: 24 April 2012) Citation: Int J Circumpolar Health 2012, 71 : 18435 - http://dx.doi.org/10.3402/ijch.v71i0.18435

Reply to MacDonald

I wish to counter in this letter some of the arguments raised by Kevin MacDonald (1991) in his reply to several criticisms made by me of his essay on the history of European polygyny (1990). The main thrust of my first letter was that polygyny would have been less frequent as one goes back from historic to prehistoric times in Europe, the reason being that a hunting and gathering society offers fewer opportunities for men to amass wealth and extra wives. I then quoted the first-century historian Tacitus to show that polygyny was rare among the largely non-agricultural Germanic tribes outside the Roman empire. Kevin MacDonald criticizes this argument by first dismissing Tacitus as a credible witness, saying that the Roman historian probably twisted the facts to suit his own preconceived views. This kind of criticism, though valid, is sterile if concrete proof is lacking. It can in fact be used to dismiss written material left by almost any historical figure. On what grounds should the testimony of Tacitus be dismissed? MacDonald quotes several modern commentators according to whom Tacitus idealized the Germans as noble savages. From my own reading of the literature, this viewpoint is a minority one which furthermore ignores the many negative and derisory comments on the people Tacitus supposedly idealized. Take, for instance, the introduction to Germania in one standard reference volume (1958):