Monday, June 21, 2004

Shy blue eyed boys

In book `survival of the prettiest'

psychologist Jerome Kagan has found that children with pale pigment, in particular children with blue eyes, are far more likely to be shy and inhibited than dark-eyed children. They are the most likely to be fearful of new situations, hesitant in approaching someone, quiet with a new person, and the most likely to stay close to their mothers. Brown-eyed children are bolder. Kagan speculates that fear of novelty, melanin production and corticorsteroid levels share some of the same genes.

His theory is speculative, suggesting that when people migrated to northern Europe they were faced with the problem of keeping up a body temperature that was used to a warmer climate. A mutation that increased the efficiency of the sympathetic nervous system and upped the level of norepinephrine...would have also raised the body temperature and offered a survival advantage. Unfortunately, it would have left them with a more reactive nervous system and a more timorous temperament. Where does the pigment come in? High levels of norepinephrine can inhibit the production of melanin in the iris and can increase the level of circulating glucosteroids that can inhibit melanin production as well. So blond hair and blue eyes and shyness may be a common biological package....
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Another study:

Physical and physiological correlates of behavioral inhibition.

Rosenberg AA, Kagan J.

University of California, Berkeley 94708.

Previous investigations have suggested that the temperamental quality of inhibition is related to the threshold of reactivity to unfamiliar events within certain limbic structures. In earlier work, children in three independent samples who had been selected to be inhibited were more likely to have blue than brown eyes, whereas uninhibited children were more likely to have brown eyes. The present study, which selected two-year-old children on the basis of eye color (blue or brown) rather than behavior, found a significant association between blue eyes and behavioral inhibition, and between brown eyes and an uninhibited style. Although the inhibited children were more likely to have a high and stable heart rate than were the uninhibited children, there was no relation between eye color and these cardiac measures. Several interpretations of the association between these temperamental categories and iris pigmentation are proposed.

PMID: 2636201 [PubMed - indexed for MEDLINE]

Another again:

Shyness and little boy blue: iris pigmentation, gender, and social wariness in preschoolers.

Coplan RJ, Coleman B, Rubin KH.

Department of Psychology, Carleton University, Ottawa, Ontario, Canada.

In recent years, researchers have uncovered a link between iris pigmentation and inhibition/social wariness among young children (e.g., Rosenberg & Kagan, 1987, 1989; Rubin & Both, 1989). In the present study, 152 Caucasian preschool-aged (Mage = 54.09 months, SD = 5.84) children (77 males) with either blue (n = 84) or brown (n = 68) eyes, were compared in terms of parental and teacher ratings of social wariness, social play, and aggression. A significant Eye Color x Gender Interaction was found in terms of indices of social wariness; blue-eyed males were rated as more socially wary than brown-eyed males, while blue- and brown-eyed females did not differ in this regard. These results supported the notion that eye color is a marker variable for social wariness in young children.

PMID: 9452906 [PubMed - indexed for MEDLINE]



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