scholarly journals An analysis of bimanual actions in natural feeding of semi-wild chimpanzees

2015 ◽  
Vol 159 (1) ◽  
pp. 85-92 ◽  
Author(s):  
Gillian S. Forrester ◽  
Bruce Rawlings ◽  
Marina Davila-Ross
Keyword(s):  
Author(s):  
Amy C. Ulinski ◽  
Zachary Wartell ◽  
Paula Goolkasian ◽  
Evan A. Suma ◽  
Larry F. Hodges
Keyword(s):  

Behaviour ◽  
2015 ◽  
Vol 152 (3-4) ◽  
pp. 461-492 ◽  
Author(s):  
William D. Hopkins ◽  
Jennifer Schaeffer ◽  
Jamie L. Russell ◽  
Stephanie L. Bogart ◽  
Adrien Meguerditchian ◽  
...  

The evolutionary origins of human right-handedness remain poorly understood. Some have hypothesized that tool use served as an important preadaptation for the eventual evolution of population-level right-handedness. In contrast, others have suggested that complex gestural and vocal communication served as prerequisite for the evolution of human right-handedness. In this study, we tested these competing hypotheses by comparing the handedness of bonobos and chimpanzees, two closely related species of Pan, on three different measures of hand use including simple reaching, manual gestures and coordinated bimanual actions. Chimpanzees are well known for their tool using abilities whereas bonobos rarely use tools in the wild. In contrast, many have suggested that bonobos have a more flexible gestural and vocal communication system than chimpanzees. The overall results showed that chimpanzees were significantly more right-handed than bonobos for all three measures suggesting that adaptations for tool use rather than communication may have led to the emergence of human right-handedness. We further show that species differences in handedness may be linked to variation in the size and asymmetry of the motor-hand area of the precentral gyrus. The results are discussed within the context of evolutionary theories of handedness, as well as some limitations in the approach to handedness measurement in nonhuman primates.


2005 ◽  
Vol 93 (2) ◽  
pp. 801-812 ◽  
Author(s):  
Jörn Diedrichsen ◽  
Timothy Verstynen ◽  
Steven L. Lehman ◽  
Richard B. Ivry

Anticipatory postural adjustments (APA) during bimanual actions can be observed when participants hold an object in one hand and then lift it with the other hand. The postural force used to hold the object is reduced in anticipation of unloading, indicating an accurate prediction of the change in load. We examined patients with unilateral or bilateral cerebellar damage as well as two individuals lacking the corpus callosum on the bimanual unloading task. The acallosal patients showed an intact APA, suggesting subcortical integration of motor signals for anticipatory adjustments during bimanual actions. Contrary to the hypothesis that the cerebellum is critical for predicting and compensating for the consequences of our actions, we found that the well-learned APA in this task was largely intact in cerebellar patients. However, cerebellar damage abolished short-term adaptation of the APA, and the patients were unable to acquire an APA in a similar but previously untrained situation. These results indicate that while over-learned anticipatory adjustments are preserved after cerebellar lesions, adaptation of this response and the acquisition of a novel coordination requires the cerebellum ipsilateral to the postural hand. Furthermore, this structure appears to be essential for the accurate timing of previously learned behaviors. The patients with cerebellar damage showed poorly timed adjustments with the APA beginning earlier than in healthy participants.


2013 ◽  
Vol 225 (4) ◽  
pp. 559-567 ◽  
Author(s):  
Stacey L. Gorniak ◽  
Jay L. Alberts

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