Multiple Measures of Handedness and Laterality in Three Species of Lemur Lemur Catta, Eulemur Mongoz and Eulemur Fulvus Rufus

Date of Award

2004

Document Type

Thesis

Degree Name

Bachelors

Department

Social Sciences

Second Department

Natural Sciences

First Advisor

Harley, Heidi

Keywords

Laterality, Handedness, Lemur

Area of Concentration

Biological Psychology

Abstract

The present study investigated handedness as an indicator of lateralization of hemispheric function in three species of lemur, L. catta, E. Mongoz and E. fulvus rufus. Semi-free-ranging subjects were assessed for hand preference over multiple behavioral measures including hand and limb use: (1) in reaching with discrete food presentation on twelve subjects, (2) in foraging using four subjects, (3) by leading limb in locomotion with three subjects, and (4) in a sequential food extraction task tested on four subjects. Significant individual hand preferences occurred in discrete food presentation; about half of the lemurs preferentially used their right hands, and the other half, their left. Posture affected food-related tasks, such that dominant hand preference increased as posture shifted from a quadrupedal to a bipedal stance. Position of food affected hand preference in foraging, such that lemurs tended to use the hand closest to the food item; therefore, hand preferences were lacking in this measure. A population-level weak left preference was expressed for leading limb in walking, but no overall preference was found for leading limb in climbing. For the sequential tube task, all subjects exhibited strong right preferences, which indicated a left hemisphere specialization for sequential hand movements, thereby supporting the Task Complexity theory. Stability was not found across tasks; individuals did not always use the same hand or limb for each behavioral measure and thus, are categorized as a Level 2 population (McGrew & Marchant, 1997).

Rights

This bibliographic record is available under the Creative Commons CC0 public domain dedication. The New College of Florida, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.

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