Abstract # 5882 Event # 39:

Scheduled for Saturday, September 13, 2014 04:30 PM-04:45 PM: Session 10 (Henry Oliver) Oral Presentation


THE HYBRID DELAY TASK AND ASSESSMENTS OF SELF-CONTROL IN CAPUCHINS (SAPAJUS SPP.) AND CHIMPANZEES (PAN TROGLODYTES)

M. J. Beran1, T. A. Evans1, W. D. Hopkins1, E. Addessi2 and F. Paglieri2
1Georgia State University, Atlanta, GA, USA, 2Istituto di Scienze e Tecnologie della Cognizione, Rome, Italy
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     Inter-temporal choice tasks present smaller-sooner (SS) and larger-later (LL) options to assess self-control. Traditionally, the choices are presented as arbitrary stimuli. However, some research teams have instead presented food arrays as the choice options, and this introduces two problems: 1) choices of the LL option could result from animals’ difficulty with pointing to smaller amounts of food rather than reflect self-control; 2) there is no way to verify whether subjects would abandon their choice of the LL option at any time during the ensuing delay. The hybrid delay task combines the initial ITC choice with a subsequent accumulation phase in which selection of the SS option leads to its immediate delivery, but choice of the LL option then leads to one-by-one accumulation of those items that continues only as long as the subject does not eat the accumulated items. Choice of the LL option therefore only reflects self-control when the number of items obtained during the accumulation phase is higher than what was in the SS option. Data from capuchin monkeys (N = 18) indicated that previous ITC tasks may have over-estimated their general self-control abilities whereas data from chimpanzees (N = 19) demonstrated that their choices for the LL option in the ITC phase of the task often were matched by their ability to sustain delay of gratification during the accumulation phase.