JRM Vol.19 No.4 pp. 416-422
doi: 10.20965/jrm.2007.p0416


Linear Discrimination Analysis of Monkey Behavior in an Alternative Free Choice Task

Kazuhito Takenaka*,**, Yasuo Nagasaka*, Sayaka Hihara*,
Hiroyuki Nakahara***, Atsushi Iriki*, Yasuo Kuniyoshi**,
and Naotaka Fujii*

*Laboratory for Symbolic Cognitive Development, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan

**Intelligent Systems and Informatics Lab., Dept. of Mechano-Informatics, School of Information Science and Technology, The Univ. of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

***Laboratory for Integrated Theoretical Neuroscience, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan

January 11, 2007
February 23, 2007
August 20, 2007
action prediction, decision making, monkey behavior, motion capture, discriminant analysis

When we observe people, we can often comprehend their intention from their behaviors. The intentions expressed by individuals can be considered as existing in interpersonal space and from a current social context. In our daily activity, choosing socially correct behavior through the observation of such social context is essential. However, it is not known how we can decode intention from another’s behavior. Here, we show how we can retrieve the intention of monkeys through external observation of their behavior patterns while performing alternative free choice tasks. We found that linear discriminant analysis on a monkey’s motion parameters could provide a discriminant score that appears to reflect the internal decision making process. The score showed a clear flexion point that we defined as a moment of outward expression of intention (OEI). This suggests that an alternative decision is made just before an OEI and that intention is expressed in the environment after this OEI in behavior, which in turn suggests that discriminant analysis may be useful in indicating how the brain implements nonverbal social communication. If we could embed the function in a human-machine interfaces, it could enable intuitive, smooth communication between machines and humans.

Cite this article as:
K. Takenaka, Y. Nagasaka, S. Hihara, <. Nakahara, A. Iriki, Y. Kuniyoshi, and <. Fujii, “Linear Discrimination Analysis of Monkey Behavior in an Alternative Free Choice Task,” J. Robot. Mechatron., Vol.19, No.4, pp. 416-422, 2007.
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Last updated on Dec. 18, 2018