Mechanisms underlying cognitive bias in nonhuman primates

Recent research in nonhuman animals highlights the exciting possibility that performance on cognitive bias tasks might indirectly measure an individual’s subjective, affective state. Subjects first learn to perform a conditional discrimination task with two differentially reinforced responses, and then intermediate, unreinforced stimuli are introduced. Differences in affective state have been related to changes in the […]

Preferences among four species of local browse offered to Colobus guereza kikuyuensis at the Central Park Zoo

Abstract 10.1002/zoo.20051.abs The objective of this study was to document the browse preferences of five adult Colobus monkeys (one male and four females, fed a nutritionally sound diet) among four local and readily available temperate browse types at the Central Park Zoo. The four browse species used in part A of the study were nasturtium […]

Decrease in nasal temperature of rhesus monkeys (Macaca mulatta) in negative emotional state

We established an infrared thermographic system for the detection of emotion-related temperature changes in rhesus monkeys (Macaca mulatta). We continuously measured temperatures of various facial regions of four rhesus monkeys during the presentation of a potentially ‘threatening’ person, i.e., a person in a laboratory coat with a catching net, who entered the experimental room and […]

Estradiol effects on behavior and serum oxytocin are modified by social status and polymorphisms in the serotonin transporter gene in female rhesus monkeys

Despite the well-documented relation between estradiol (E2) and behavior, exposure to stressors may modify sensitivity to E2. The effects of E2 on behavior are, in part, likely related to their modulation of the serotonin (5HT) and oxytocin systems. The short allele (s-variant) polymorphism found in the promoter region of the SLC6A4 gene that encodes the […]

Prenatal origins of individual variation in behavior and immunity

The in utero environment plays a critical role in initiating the normal ontogeny of many physiological systems. As a consequence, disturbances during prenatal life can affect the baby’s maturational trajectory and sometimes cause chronic alterations that influence health postpartum. Our review summarizes a series of studies in rhesus monkeys supporting these conclusions. Psychological disturbance or […]

Relational Matching in Baboons (Papio papio) With Reduced Grouping Requirements

Analogical reasoning is a corner stone of human cognition, but the phylogenetic origins of this skill are still unknown. Recent animal studies have suggested that only apes can solve the 2- by 2-item relational matching (RMTS) analogy problem, with potential benefits of language- (Premack, 1983) or token-training procedures (Thompson, Oden, & Boysen, 1997). In this […]

Conceptual thresholds for same and different in old-(Macaca mulatta) and new-world (Cebus apella) monkeys

Learning of the relational same/different (S/D) concept has been demonstrated to be largely dependent upon stimulus sets containing more than two items for pigeons and old-world monkeys. Stimulus arrays containing several images for use in same/different discrimination procures (e.g. 16 identical images vs. 16 nonidentical images) have been shown to facilitate and even be necessary […]

Artificially Generated Cultural Variation Between Two Groups of Captive Monkeys, Colobus guereza kikuyuensis

The majority of studies of social learning in primates have tested subjects in isolation and investigated the effects of learning over very short periods of time. We aimed to test for social learning in two social groups of colobus monkeys, Colobus guereza kikuyuensis. Subjects were shown video footage of familiar monkeys either pushing or pulling […]

Social awareness in monkeys

Tests of self-awareness in nonhuman primates have to date been concerned almost entirely with the recognition of an animal’s reflection in a mirror. By contrast, we know much less about non-human primates’ perception of their place within a social network, or of their understanding of themselves as individuals with unique sets of social relationships. Here […]

Analysing small-scale aggregation in animal visits in space and time: the ST-BBD method

Movement behaviour plays an important role in many ecological interactions. As animals move through the environment, they generate movement patterns, which are a combined result of landscape characteristics and species-specific behaviour. Measuring these ranging patterns is being facilitated by technological advances in collection methods, such as GPS collars, that are capturing movement on finer spatial […]