Date of Award

Summer 8-2016

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Psychology

Committee Chair

Tammy Greer

Committee Chair Department

Psychology

Committee Member 2

Alen Hajnal

Committee Member 2 Department

Psychology

Committee Member 3

Bonnie Smith

Committee Member 3 Department

Anthropology and Sociology

Abstract

In an effort to explain the underlying mechanisms of number representation, both the object-file and the approximate number system have been proposed. Despite the recognition in animals, both nonhuman and human, it remains unclear how numbers are represented cognitively or what system is employed. Furthermore, primate numerosity research has been almost exclusively conducted within haplorhine species (monkeys and apes). Within the strepsirhines (lemurs, lorises, and galagos), it has only been investigated in 15 diurnal and cathermal Malagasy primate species. No study to date has looked at this ability in either African strepsirhines or nocturnal primates. To examine the extent of numerical representation among the strepsirhines, the current study examined a nocturnal African primate, Garnett’s Greater Bushbaby (Otolemur garnettii). Using a modified search task developed by Lewis et al. (2005), bushbabies searched for raisins in an opaque pail across 10 paired trials. Each pair consisted of one “honest” presentation (number observed = number retrievable) and one “deceitful” presentation (number observed > number retrievable), with trial conditions consisting of 1 vs. 2, 2 vs. 3, and 3 vs. 4. False bottoms in the pails allowed for “deceitful” presentations. A 5 (1:1, 2:4. 4:8, 2:3, 3:4) X 2 (honest vs deceitful) fully repeated measures analysis of variance examined the within-subject effects of trial type and ratio of raisins revealing longer search times on deceitful versus honest trials only with ratios of 1:2 and 2:4.

ORCID ID

orcid.org/0000-0001-8645-9442

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