J Hum Evol. 2016 Sep;98:27-35. doi: 10.1016/j.jhevol.2016.07.001. Epub 2016 Aug 10.
- 1Department of Anatomy and Neurobiology, NEOMED, United States. Electronic address: cvinyard@neomed.edu.
- 2Department of Biomedical Sciences, Grand Valley State University, United States.
- 3WWAMI Medical Education Program, University of Wyoming, United States.
- 4Southwest Wildlife Conservation Center, United States.
Abstract
Non-human
primates demonstrate food preferences much like humans. We have little
insight, however, into how those preferences impact oral processing in
primates. To begin describing this relationship, we conducted a
preliminary analysis measuring food preference in two tufted capuchins
(Cebus apella) and comparing ranked preference to physiological
variables during chewing of these foods. Food preference was assessed
for each monkey across 12 foods, including monkey biscuits and 11 foods
consumed by humans (e.g., various fruits and nuts). Animals chose from
randomized pairs of foods to generate a ranked scale across the 12
foods. Contemporaneous with preference testing, electromyographic (EMG)
activity was measured for the jaw-closing muscles to assess oral
physiology during chewing of these foods. As expected, these capuchins
exhibited clear preferences among these 12 foods. Based on their
preferences, we identified sets of preferred and non-preferred brittle
(i.e., almond versus monkey chow) and ductile (i.e., dates and prunes
versus apricots)
foods for physiological comparisons that broadly control variation in
food mechanical properties (FMPs). As expected, oral physiology varied
with FMPs in each animal. Within brittle and ductile groupings, we
observed several significant differences in chewing cycle length and
relative muscle activation levels that are likely related to food
preference. These differences tended to be complex and individual
specific. The two capuchins chewed non-preferred apricots
significantly faster than preferred dates and prunes. Effect sizes for
preference were smaller than those for FMPs, supporting the previous
focus on FMPs in primate dietary research. Although preliminary, these
results suggest that food preference may influence oral physiology in
non-human primates. The prospect that this relationship exists in
monkeys raises the possibility that a link between food preference and
oral processing in humans may be based on shared tendencies with
non-human primates, such as aversion to bitter items or preference for
sweet foods.
Copyright © 2016 Elsevier Ltd. All rights reserved.
KEYWORDS:
Electromyography; Feeding; Food mechanical properties; Food preference; Muscle
