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Intentionality as measured in the persistence and elaboration of communication by chimpanzees (Pan troglodytes).
TLDR
The chimpanzees exhibited persistence in and elaboration of their communication in every condition except when the banana was delivered, demonstrating that both intentionality and nonverbal reference are capacities shared by humans with the authors' nearest living relatives, the great apes.
Hand preferences for a coordinated bimanual task in 110 chimpanzees (Pan troglodytes): cross-sectional analysis.
  • W. Hopkins
  • Psychology, Biology
    Journal of comparative psychology
  • 1 September 1995
TLDR
The results suggest that coordinated bimanual tasks elicit strong hand preferences at the individual level and elicit population level right-handedness.
Asymmetric Broca's area in great apes
TLDR
The findings suggest that the neuroanatomical substrates for left-hemisphere dominance in speech production were evident at least five million years ago and are not unique to hominid evolution.
Recognizing facial cues: individual discrimination by chimpanzees (Pan troglodytes) and rhesus monkeys (Macaca mulatta).
TLDR
Chimpanzees and rhesus monkeys are able to use facial cues to discriminate unfamiliar conspecifics and the feature-masking task showed that the eyes were the most important cue for individual recognition.
On the Other Hand: Statistical Issues in the Assessment and Interpretation of Hand Preference Data in Nonhuman Primates
  • W. Hopkins
  • Psychology, Biology
    International Journal of Primatology
  • 2004
I describe methodological and statistical issues in the assessment of hand preference in nonhuman primates and discuss them in the context of a recent paper by McGrew and Marchant (1997) in which
Comparative and familial analysis of handedness in great apes.
  • W. Hopkins
  • Psychology, Biology
    Psychological bulletin
  • 1 July 2006
TLDR
Overall, the proportion of right handedness is lower in great apes compared with humans, and various methodological and theoretical explanations for this discrepancy are discussed.
The Distribution and Development of Handedness for Manual Gestures in Captive Chimpanzees (Pan troglodytes)
TLDR
The collective results suggest that left-hemisphere specialization for language may have evolved initially from asymmetries in manual gestures in the common ancestor of chimpanzees and humans, rather than from hand use associated with other, noncommunicative motor actions, including tool use and coordinated bimanual actions, as has been previously suggested in the literature.
Wild chimpanzees show population-level handedness for tool use.
  • E. Lonsdorf, W. Hopkins
  • Biology, Psychology
    Proceedings of the National Academy of Sciences…
  • 30 August 2005
TLDR
It is demonstrated that population-level handedness is evident in wild chimpanzees and suggested that the antecedents of lateralization of function associated with hand use were present at least 5 million years ago, before the Pan-Homo split.
Understanding the Point of Chimpanzee Pointing
TLDR
If pointing by captive chimpanzees is so variably expressed in different rearing environments, this suggests that pointing by humans may also be attributable to situational factors that make pointing effective in certain developmental contexts.
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