Effects of the menstrual cycle on looking preferences for faces in female rhesus monkeys

Fluctuations of ovarian hormones across the menstrual cycle influence a variety of social and cognitive behaviors in primates. For example, female rhesus monkeys exhibit heightened interest for males and increased agonistic interactions with other females during periods of high estrogen levels. In the present study, we hypothesized that females’ preference for males during periods of high estrogen levels is also expressed at the level of face perception. We tested four intact females on two face-tasks involving neutral portraits of male and female rhesus monkeys, chimpanzees and humans. In the visual preference task (VP), monkeys had to touch a button to view a face image. The image remained on the screen as long as the button was touched, and the duration of pressing was taken as an index of the monkey's looking time for the face stimulus. In the Face-Delayed Recognition Span Test (Face-DRST), monkeys were rewarded for touching the new face in an increasing number of serially presented faces. Monkeys were tested 5 days a week across one menstrual cycle. Blood was collected every other day for analysis of estradiol and progesterone. Two of the four females were cycling at the time of testing. We did not find an influence of the cycle on Face-DRST, likely due to a floor effect. In the VP however, the two cycling individuals looked longer at conspecific male faces than female faces during the peri-ovulatory period of the cycle. Such effects were absent for human and chimpanzee faces and for the two noncycling subjects. These data suggest that ovarian hormones may influence females’ preferences for specific faces, with heightened preference for male faces during the peri-ovulatory period of the cycle. Heightened interest for stimuli of significant reproductive relevance during periods of high conception risk may help guide social and sexual behavior in the rhesus monkey.     

Executive functioning: Developmental consequences on adolescents with histories of maltreatment

Research suggests that children exposed to maltreatment have deficits in executive functioning (EF) but few studies have focused on the adolescent age group. We investigated whether maltreated adolescents had lower EF abilities compared to a group of non‐maltreated adolescents. Forty adolescents with histories of child maltreatment, together with a comparison group of 40 non‐maltreated adolescents matched for age, completed a comprehensive battery of EF tasks. Hierarchical multiple regression analyses, controlling for IQ, were carried out using each of the EF measures as dependent variables to examine group differences. Maltreated adolescents had significantly lower performance than non‐maltreated adolescents on tasks assessing executive loaded working memory, fluency, and inhibition, although switching was not impaired. Emotional and behavioural difficulties (EBD) were included in additional regression analyses to examine whether these variables would explain the group differences. The inclusion of EBD variables had some effect on group differences, as expected, but did not eliminate them. These findings support the theory that impairments in EF may be one underlying reason why adolescents with histories of maltreatment struggle to cope both inside and outside the classroom.     

Infants' use of social partnerships to predict behavior

The experiences of social partners are important motivators of social action. Can infants use such experiences to make predictions about how social agents will behave? Sixteen‐month‐old infants were introduced to two social pairs. Initial events established within‐pair cooperation as well as between‐pair conflict involving an individual from each pair. Following these events, infants looked longer when between‐pair members who had never previously interacted now cooperated – instead of conflicted – with each other. Thus, infants tracked the third‐person allegiances and inferred that the conflict would generalize across social partnerships. These findings demonstrate a critical feature of early social cognition and promote needed, further research on the role of social allegiances in social cognition across development.     

SCIENCE'S CONCEPTION OF HUMAN BEINGS AS A BASIS FOR MORAL THEORY

Abstract. Niels Bohr stated, and Werner Heisenberg reiterated, that “in the great drama of existence we ourselves are both actors and spectators.” Their emphasis stems from the fact that the entry of human beings into physics as actors constitutes the most fundamental philosophical departure of twentieth‐century basic physics from its eighteenth‐ and nineteenth‐century forerunners. Those earlier theories claimed that our human conscious thoughts are mere witnesses to, or by‐products of, essentially mechanically determined brain processes. In stark contrast, certain conscious decisions that are made by human beings, but that are not determined by any known law, statistical or otherwise, enter irreducibly into orthodox contemporary physical theory. These actions are required to counteract effects of Heisenberg's Uncertainty Principle, which ordains that the physically described process of nature, acting alone, produces not a physical world of the kind we experience but rather a continuous smear of potential possible worlds of the kind we know. This contradiction between theory and experience is resolved in orthodox contemporary physical theory by bringing certain effects of our conscious human choices into the dynamics in essentially the way that we intuitively feel that our conscious intentions affect the physical world, namely, via the effects of our intentional efforts on our physically described bodies. The moral implications of this profound change in physics are discussed.     

How are habits formed: Modelling habit formation in the real world

To investigate the process of habit formation in everyday life, 96 volunteers chose an eating, drinking or activity behaviour to carry out daily in the same context (for example ‘after breakfast’) for 12 weeks. They completed the self‐report habit index (SRHI) each day and recorded whether they carried out the behaviour. The majority (82) of participants provided sufficient data for analysis, and increases in automaticity (calculated with a sub‐set of SRHI items) were examined over the study period. Nonlinear regressions fitted an asymptotic curve to each individual's automaticity scores over the 84 days. The model fitted for 62 individuals, of whom 39 showed a good fit. Performing the behaviour more consistently was associated with better model fit. The time it took participants to reach 95% of their asymptote of automaticity ranged from 18 to 254 days; indicating considerable variation in how long it takes people to reach their limit of automaticity and highlighting that it can take a very long time. Missing one opportunity to perform the behaviour did not materially affect the habit formation process. With repetition of a behaviour in a consistent context, automaticity increases following an asymptotic curve which can be modelled at the individual level. Copyright © 2009 John Wiley & Sons, Ltd.