The Relationship Between Temperament and Adult Behavior in Non-Human Primates
Kellejian, A., Coleman, K., & Island, H.
National Primate Research Center, 2Pacific University of Oregon.
Results (con’t)
Method (con’t)
Traditionally, temperament refers to the emotional, physiological, and behavioral
response to a novel stimulus or situation (Gosling & John, 1999).). An individual’s
temperamental response to novelty is along a continuum from shy or reserved to
bold and exploratory (Itoh, 2002). Behavioral trends consistent with a shy
temperament consist of avoiding and not exploring novel stimuli or new environment
(Clarke, Boinski , 1995). Behavioral trends consistent with a bold temperament
consist of approaching and exploring unfamiliar stimuli or unknown environment
(Clarke, Boinski , 1995). Among primates, the diversity of behaviors attributed to
temperament are analogous to the nonhuman primates. However, the consistency of
these behaviors throughout the lifespan of the macaque is less well known.
Procedure
Early Temperament Test. The novel stimuli temperament test was used to
establish each subject’s early temperament during 3-6 months of age. Coleman (n.d.)
developed this particular segment of this study while conducting a larger battery of
temperament tests for a previous study. An examiner took each subject into a new
cage, then introduced a novel piece of fruit and recorded the duration of time it took for
the subject to approach the novel fruit. The time it took for the subject to approach the
fruit was indicative of the subject’s temperament. If the subject never approached the
novel fruit, their temperament was recorded as shy..
Adult behavior Assessment. Once the subjects reached 9-11 years of age, their
behaviors were recorded, in their known environment. The examiner recorded subjects
from 7:00am to 11:00 am, during the months June and July. To measure behavior of the
monkeys in the corral, the examiner used instantaneous sampling techniques in which
the social and non-social behavior of the subject was recorded at 15sec intervals for the
10 min. Any events that occurred within the 15sec intervals were also recorded.
Despite what we know about temperament among humans and other apes,
there is a paucity of research exploring the stable long-term behavior of snow
macaques from childhood to maturity. Given the Oregon National Primate
Research Center houses the largest and oldest, captive snow monkey colony in
the world, the OPRNC provides an ideal population to answer this question.
The goal of this project was to explore the possible connection between
temperament (measured early in life) and adult behavior in a troop of Japanese
macaques. The behavioral ethogram included social interactions, anxious
behavior, and environmental exploration. We anticipated that
Hypothesis 1: Subjects with a shy temperament would spend more time alone
compared to subjects with a bold temperament; therefore, spending less time
grooming or in close social contact.
Hypothesis 2: Subjects with a shy temperament will exhibit more anxiety-like
(e.g., scratching) behaviors compared to subjects with a bold temperament.
Hypothesis 3: Subjects with a shy temperament will spend less time exploring
than subjects with a bold temperament.
Method
Results
Subjects
Female (n=7) and male (n=9) Japanese Macaques (Macaca fuscata) (n=16)
from Oregon National Primate Research Center were observed. All subjects
lived in an outdoor corral, with roughly 220 conspecific adults and juveniles .
• females with a shy temperament did not spend more of their time exploring than
females with a bold temperament. However, the data approached significance
suggesting that females with a shy temperament spend more of their time exploring
than females with a bold temperament (p-value= .074).
Materials
A stop watch, ethogram, writing instrument and clipboard were used to record
behavior. The ethogram explained three different classes of behavior, social
behavior, non-social behavior, and events. Behaviors such as grooming,
nursing, playing, restraining, touching, proximity, or ventral contact, or an
absence were considered social behaviors. In the absences of these behaviors,
the subject was recorded as being alone. During observation of social behavior,
modifiers were also recorded to include whether the subject initiated or received
the behavior, as well as the indentifier of the other primate involved in the social
exchange. Drinking, eating, exploring, foraging, locomotion, sleeping, and selfplay were recorded as non-social behaviors. Events were recorded during the
15 second interval of the event occurrence. Behaviors such as aggressing,
chasing, displacing, fear grimacing, lip smacking, scratching, threating, were
recorded as events.
Table 1.1: Percent of time spent alone by temperament and sex.
PERCENT OF TIME ALONE
90
80
70
60
50
40
30
20
10
0
SHY
TEMPERAMENT
5
4
3
2
1
0
TEMPERAMENT
Hypothesis 1:
• males with a shy temperament did not spend more of their time alone compared to
males with a bold temperament (p-value= .827)
• females with a shy temperament did not spend more of their time alone compared to
females with a bold temperament (p-value= .157)*
Hypothesis 2:
• males with a shy temperament did not exhibit more anxiety like behaviors than males
with a bold temperament (p-value= .127)*
• females with a shy temperament did not exhibit more anxiety like behaviors than
• females with a bold temperament (p-value= .827)
Hypothesis 3:
• males with a shy temperament did not spend less time exploring than males with a
bold temperament (p-value= .376).
BOLD
Table 1.2: Percent of time exhibiting anxiety like behaviors
compared by temperament and sex.
PERCENT OF TIME SCRATCHING
Introduction
F
M
F
M
Table 1.3: Percent of time exploring compared by temperament
and sex.
4
PERCENT OF TIME EXPLORING
1Oregon
3
2
1
0
BOLD
SHY
F
M
TEMPERAMENT
Discussion
The results reveal trends inconsistent with the predicted temperament and
behavior relationships, but a small sample size prevents meaningful
conclusions about the data. Dominance ranking and number of relatives
could have confounded the result, which further prevents meaningful
conclusions about the data. The possible confound effect of dominance
ranking or number of relatives could influence the perceived security of
primates. For example, a higher ranking primate would perceive a lower level
of risk, thus may explore the environment more. However, the primate might
have a temperament, therefore explore the environment less. Even though
the study yielded results inconsistent with predicted trends, it yielded
behaviors of key interest. Primatologists should examine these behaviors
with a larger population, in order to make more meaningful conclusions
regarding the relationship between temperament and behavior.