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Hand preference is well observed in humans and some primates. Unlike many other primates, however, humans show a consistent hand preference across a variety of tasks, and a distinct right-handed skew at the population level. Although there are a moderate number of published studies, primate hand preference literature is unbalanced by the large number of studies on only a few species. No previous studies have addressed hand preference in white-faced sakis (WFS; Pithecia pithecia). We followed three habituated groups of wild WFS in Suriname and recorded individual hand preference for six different manual behaviors. There was no consistent hand preference across a range of uni-manual behaviors for any individual. Likewise, there were significantly more ambidextrous individuals in the population than expected (χ(2) (df = 2) = 11.2, P = 0.004) and thus, no population level hand preference. Our findings contribute baseline data to the debate of primate hand lateralization, and support the notion that lateralization of hand function does not characterize all species.

A film technique was developed to obtain children's self-estimates of selected aspects of their own body dimensions under static and dynamic conditions. Subjects were 40 children, ranging in age from 6.10 to 10.10 yr. They estimated their own heights and shoulder widths while viewing projected images of themselves in two conditions, static and dynamic. The condition films displayed the projected image of the subject from 6 in. below to 6 in. above his or her actual height. The subject responded by stopping a remote-controlled projector when the projected image was perceived by the subject to be his or her own body dimension. A nested factorial design was utilized to determine significant main effects of age, sex, condition, and mode (direction of trials). A paired difference test indicated whether the subjects' estimates were in fact significantly different from the actual body dimensions. Analysis showed no significant differences in main effects of age or sex. Self-estimates of selected body dimensions were significantly different from actual, measured, body dimensions. The motion-picture technique was considered successful in obviating several difficulties encountered in the past by workers using other techniques and was effective in introducing dynamics as a condition under which subjects could make self-estimates of their own body dimensions.

Substance P (SP) modulates the activity of taste-responsive neurons in the gustatory zone of the nucleus of the solitary tract (NST) in the hamster. The distribution of the neurokinin-1 (NK1) receptor (i.e. the SP receptor) was mapped and compared with the distribution of SP immunoreactivity to identify the sites of ligand-receptor interactions. NK1-immunoreactive puncta and somata were located mostly in the rostral lateral, upper half of the rostral central and medial NST subnuclei. These subnuclei also contained intense SP-immunoreactive puncta, and are known to receive substantial inputs via gustatory and somatosensory afferent fibers. The ventral subnucleus, which is involved in visceromotor reflexes accompanying ingestion, contained little NK1 or lighter SP-immunoreactivity. These findings suggest that SP modulates taste activity destined for the ascending gustatory pathway at the level of the first central synapse in the gustatory pathway.

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