Referential Communication by Chimpanzees (Pan troglodytes)

Two experiments were conducted to assess the referential function of chimpanzee (Pan troglodytes) gestures to obtain food. The chimpanzees received 1 trial per condition. In Experiment 1 (N 101), in full view of the chimpanzee, a banana was placed on top of 1 of 2 inverted buckets or was hidden underneath 1 of the buckets. […]

Observing Conspecifics Scratching Induces a Contagion of Scratching in Japanese Monkeys (Macaca fuscata)

Although a large number of studies have examined self-directed behaviors (SDBs) such as scratching and self-grooming as nonverbal leakage of negative emotional arousal in humans, few studies have investigated the informative function of SDBs in nonhuman primates. The present study investigated whether viewing another monkey scratching itself elicited negative arousal from conspecific observers in Japanese […]

Modified Prenatal Sensory Stimulation Influences Postnatal Behavioral and Perceptual Responsiveness in Bobwhite Quail Chicks (Colinus virginianus)

Asynchronous bimodal stimulation during prenatal development elicits higher levels of behavioral and physiological arousal in precocial avian embryos than does unimodal sensory stimulation. To investigate whether the increased arousal associated with prenatal bimodal stimulation has enduring effects into postnatal development, bobwhite quail (Colinus virginianus) embryos received no supplemental stimulation, unimodal auditory stimulation, or bimodal (audiovisual) […]