Male chacma baboons (Papio hamadryas ursinus) discriminate loud call contests between rivals of different relative ranks

Males in multi-male groups of chacma baboons (Papio hamadryas ursinus) in Botswana compete for positions in a linear dominance hierarchy. Previous research suggests that males treat different categories of rivals differently; competitive displays between males of similar rank are more frequent and intense than those between disparately ranked males. Here we test whether males also respond differently to male–male interactions in which they are not directly involved, using playbacks of the loud wahoo calls exchanged between competing males in aggressive displays. We played paired sequences of vocal contests between two adjacently ranked and two disparately ranked males to ten subjects, half ranking below the signalers in the call sequences and half above. Subjects who ranked above the two signalers showed stronger responses than lower-ranking subjects. Higher-ranking subjects also responded more strongly to sequences involving disparately ranked, as opposed to adjacently ranked opponents, suggesting that they recognized those individuals relative ranks. Strong responses to sequences between disparately ranked opponents might have occurred either because such contests typically involve resources of high fitness value (defense of meat, estrous females or infants vulnerable to infanticide) or because they indicate a sudden change in one contestants condition. In contrast, subjects who ranked lower than the signalers responded equally strongly to both types of sequences. These subjects may have been able to distinguish between the two categories of opponents but did not respond differently to them because they had little to lose or gain by a rank reversal between males that already ranked higher than they did.     

The leg-to-body ratio as a human aesthetic criterion

There are surprisingly few empirical studies on the aesthetic appeal of human legs, examining such variables as length or shape. The human legs are conspicuous in erotic contexts, but few studies have experimentally tested preferences for longer legs. This study examined the utility of the human leg-to-body ratio (LBR) as a specific aesthetic criterion among 71 British undergraduates. Participants rated for physical attractiveness line drawings that varied in five levels of LBR. The results showed that a longer LBR was preferred as maximally attractive in women, whereas a shorter LBR was preferred in men. Evolutionary psychological and socio-cultural explanations for this aesthetic preference are discussed, and the study's limitations are considered.     

Psychophysical design influences frequency discrimination performance in young children

We investigated how different psychophysical procedures affect frequency discrimination performance in children. Four studies used a design in which listeners heard two tone pairs and had to identify whether the first or second pair contained a higher frequency target tone. Thresholds for 6- and 7-year-olds were higher than those for 8- and 9-year-olds and adults. Two manipulations led to lower (better) thresholds in young children: (a) moving the standard comparison tone before the target tone and (b) using three target comparison tone pairs. It is suggested that young children benefit from designs that help cue them to when they need to attend to a target tone. The two-interval, forced-choice procedure that is widely used in studies of developmental disorders led to variable performance even in adults and did not give a realistic picture of the perceptual capabilities of children under 8 years of age.     

Experience and materials affect combinatorial construction in tufted capuchin monkeys (Cebus apella)

Three movement procedures can combine nesting cups into seriated structures. Reliance on these procedures changes with age in human children, and the putatively most advanced emerges as a predominant procedure at 3 or more years. Six monkeys' (Cebus apella) combinatorial procedures and successes at nesting seriated cups were evaluated. The current study examined whether the procedures used (a) shift toward more efficient procedures after unguided experience, (b) are dependent on the type of object being combined, and (c) can be altered by specific training history. All factors produced a change in procedure for some individuals, suggesting that combinatorial procedure is a product of the dynamic influences of preexisting tendencies to act in certain ways, of environmental circumstances, and of prior experiences. Some monkeys preferred the putatively most cognitively complex procedure.     

Hegel, Women, and Hegelian Women on Matters of Public and Private

This paper introduces America's first women Idealists and discusses their appropriation and reconfiguration of Hegel's public/private distinction. Through their philosophies of education two of these women, Susan E. Blow (1843--1916) and Anna C. Brackett (1836--1911), legitimized women's active involvement in public life. A third, Marietta Kies (1853--1899), put forth a political theory of altruism. Her theory anticipates feminist critiques of male-centered political theory and has important implications for today's ethic of care. Blow and Brackett were associates of William T. Harris (1835--1909) in the St. Louis Philosophical Movement (ca. 1860--1880) and contributors to The Journal of Speculative Philosophy. Kies was associated with Harris through the Concord Summer School of Philosophy (1879--1888). She was also a student of John Dewey at the University of Michigan.