Biomedical Engineering Reference
In-Depth Information
research: the use of anecdotes and the use of initial obser-
vations to confirm a hypothesis.
The last two sections of this chapter present general
statements about the study and use of behavior techniques
with special reference to nonhuman primates in a labora-
tory or other experimental setting. Each nonhuman primate
species has a unique set of social and environmental needs
that must be met for the animal to thrive in the laboratory.
The suggested applications reflect the authors' own
perspectives; a rapidly growing body of literature outlines
the suggestions and ideas of many others now interested in
this area of study. This chapter is thus intended to be an
introduction to, rather than a synopsis of, the available
literature.
Knowledge of behavior is critical for anyone who plans
to work with nonhuman primates. Knowing how a species
lives in its natural environment helps in establishing an
appropriate captive environment. The major adaptive thrust
in the evolution of nonhuman primates has been their ability
to interact socially and use behavior to adjust to new envi-
ronments.
Kummer (1971)
suggested that nonhuman
primates have few ecological specializations other than
sociality; therefore, nonhuman primates may be expected to
act jointly in response to environmental challenges, and
providing opportunities for joint social action could help
most nonhuman primates adjust to a captive environment.
Many nonhuman primates show physiological and psycho-
logical manifestations of stress in the absence of multiple
social partners with which to interact (
Pond and Rush, 1983;
Levine and Coe, 1988; Barnett and Hemsworth, 1990; Lutz
et al., 2003; Baker et al., 2007
). On the other hand, species
of Callitrichidae, which are adapted to life in monogamous
pairs, may not flourish when housed in large groups with
multiple members of each sex present. In primates like
langurs (e.g. Presbytis), callitrichids, and Aotus, a great deal
of infant care is provided by individuals other than the
mother. In these species, an isolated female and infant may
not thrive even though isolation may reduce the chances of
other animals' aggressive behavior toward the infant.
Behavioral analysis not only is important in housing
nonhuman primates for experimental use but also can be
equally important in a clinical or diagnostic setting. In
a natural setting, animals that act atypically are the ones
most likely to be targeted by predators. This leads to
a stoicism among animals that makes spotting a sick animal
very difficult. However, familiarity with the behavioral
patterns of an animal and with how it ordinarily reacts to
the presence of certain stimuli may make it possible to
recognize a sick animal before gross signs appear.
(1955, 1963)
stated that biological processes, including
behavior, should first be described in terms of observable
structure and then analyzed with regard to proximal
(immediate) causes, function (adaptive significance),
ontogeny or development, and evolution. Each of these
types of analysis focuses on the same act but is viewed from
a different perspective. An ethogram is often used in
behavioral analysis and begins as a dictionary or catalog
describing an animal's typical behavioral acts. Ethograms
are often organized by classifying acts that may serve
similar functions, such as maternal care, reproduction, self-
maintenance, or aggressive behavior. Ethograms help to
standardize discussions about the behavior of a species.
The first task in building an ethogram is to describe
what the animal does. The physical movements individuals
make and how they relate to each other to form sequences
of actions are the basis for all later descriptions of social
roles and organizations. Once single acts are described,
investigations may then focus on sequences of actions or
complex social interactions and patterns, such as social
roles and the structure of social groups. When examining
the basic behavioral units and searching for the functional
significance of behavior, one might assume that when two
or more actions occur in the same types of exchanges, these
actions serve similar functions. For example, nonhuman
primates in some species may stare at each other with their
mouths gaping open to indicate hostility, whereas
nonhuman primates in other species may flash their genitals
at each other. These patterns, although very different
visually, signal the same kind of information
hostility
e
to the appropriate receiver. When describing behavior, one
might focus on the physical movements or postures of the
animal; for example, terms like “open-mouth stare” or “hip
touch” denote the actual movement the animal makes. An
alternative is to describe these patterns in terms of their
presumed functions or consequences. A stare that often
precedes a chase may be labeled a “threat face,” or
a grimace may be called a “fear signal” or “submissive
gesture.” Although one may begin by describing the
structure of the behavior of the animal, the function of the
behavior is often more interesting. One should be aware,
however, that functional labels are subjective interpreta-
tions and that not all observers will agree on the function of
a particular behavioral act.
As
Tinbergen (1963)
explained, one can seek to find the
immediate or proximal cause of behavior (a first level of
“Why?”) in the environmental events that serve as triggers
or stimuli eliciting a behavioral act. This cause can be
a social stimulus, such as the presence of a higher-ranking
animal; a physical stimulus, such as an object in the envi-
ronment; or an endogenous stimulus, such as a neuro-
chemical or hormonal condition. In any case, the response
is linked to an immediately preceding event that provokes
the subject
e
LEVELS OF BEHAVIORAL ANALYSIS
A common phenomenon in describing behavior is a focus
on totally different aspects of the same action.
Tinbergen
to act
in a predictable way. For example,
