Kelly Hughes

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Animals signal their reproductive status in a range of sensory modalities. Highly social animals, such as primates, have access not only to such signals, but also to prior experience of other group members. Whether this experience affects how animals interpret reproductive signals is unknown. Here, we explore whether familiarity with a specific female(More)
The fields of developmental and comparative psychology both seek to illuminate the roots of adult cognitive systems. Developmental studies target the emergence of adult cognitive systems over ontogenetic time, whereas comparative studies investigate the origins of human cognition in our evolutionary history. Despite the long tradition of research in both of(More)
Strong evidence indicates that non-human primates possess a numerical representation system, but the inherent nature of that system is still debated. Two cognitive mechanisms have been proposed to account for non-human primate numerical performance: (1) a discrete object-file system limited to quantities <4, and (2) an analog system which represents(More)
The effect that treatment with stimulant medication has on the intellectual performance of children with attention deficit hyperactivity disorder (ADHD) was examined. Thirty-one children diagnosed with ADHD were given a WISC-III before any treatment was implemented. At least 1 year later, children were retested. At this time, 24 of the children were taking(More)
Food sharing among nonkin-one of the most fascinating cooperative behaviors in humans-is not widespread in nonhuman primates. Over the past few years, a large body of work has investigated the contexts in which primates cooperate and share food with unrelated individuals. This work has successfully demonstrated that species-specific differences in(More)
Over the past few decades, research in judgment and decision-making has revealed that decision-makers, though not always rational, are often quite predictable. Here, we attempt to explore the nature of this systematicity with a different approach to decision-making. Specifically, we propose that some of the systematicity of human decision-making may result(More)
Rotational displacement tasks, in which participants must track an object at a hiding location within an array while the array rotates, exhibit a puzzling developmental pattern in humans. Human children take an unusually long time to master this task and tend to solve rotational problems through the use of nongeometric features or landmarks as opposed to(More)
Humans' ability to count by verbally labeling discrete quantities is unique in animal cognition. The evolutionary origins of counting algorithms are not understood. We report that nonhuman primates exhibit a cognitive ability that is algorithmically and logically similar to human counting. Monkeys were given the task of choosing between two food caches.(More)
Some researchers have recently argued that humans may be unusual among primates in preferring to use landmark information when reasoning about some kinds of spatial problems. Some have explained this phenomenon by positing that our species’ tendency to prefer landmarks stems from a human-unique trait: language. Here, we test this hypothesis—that preferring(More)
Basic quantitative abilities are thought to have an innate basis in humans partly because the ability to discriminate quantities emerges early in child development. If humans and nonhuman primates share this developmentally primitive foundation of quantitative reasoning, then this ability should be present early in development across species and should(More)