Fear Motivation 41Figure 2.2 Having “captured” the ball bearing, the
rat attempts to engage in consummatory behavior.movement and the increased probability of predatory appeti-
tive behaviors like chase and capture.
Timberlake (1993; Timberlake & Silva, 1995) suggested
that within the predatory subsystem, functional behaviors are
organized by motivational modes into response tendencies
based on the temporal, spatial, and psychological distance to
the prey. This view is complementary to the predatory immi-
nence continuum developed by Fanselow (1989; Fanselow &
Lester, 1988) in describing the functional behavior systems of
defensive behavior that will be described more fully later.
These modes describe the relative probability of particular re-
sponses given the appropriate environmental support stimuli
and create the underlying organization of feeding behavior.
Following initiation of a predatory foraging sequence, be-
haviors such as motor search, visual search, target tracking,
or substrate investigation are motivated by a general search
mode that also specifies stimulus selectivities such as in-
creased responding to novelty or movement. Environmental
cues related to an increase in prey imminence cause a quali-
tative shift in stimulus and motor selectivity described as the
focal search mode. Within the focal search mode, behavior
patterns may shift to include responses such as chase and
capture, stalking, or area-restricted search. Timberlake and
Washburne (1989) investigated behavioral responses to artifi-
cial moving prey stimuli in seven different rodent species and
noted that the topography of chase and capture behaviors di-
rected toward the artificial prey stimulus were based on the
subject’s species-typical predatory behavior. When food is
present, the animal engages in behaviors directed toward the
food item and again makes a qualitative shift to the stimulus
selection and motor properties organized by the handling/
consuming mode. At this point, stimulus characteristics such
as taste, odor, and orotactile stimulation are the predominant
influences on behavior and motivation, as suggested by
Garcia (1989) in his description of the factors involved in
feeding cathexes, described earlier. Motor patterns are those
typically described as consummatory behaviors, including
the various kinds of ingestion and oral rejection behaviors.
The behavior systems model just outlined suggests that
feeding response organization is governed by motivational,
but not behavioral, modes. The exact nature of the behavior in
any sequence is determined by the interaction of the animal’s
motivational mode, its behavioral repertoire, and the affor-
dances of the stimuli in the environment. Just as ethological
theories of response organization suggest that chains of be-
havior are organized into relatively independent subunits
with their own intermediate goals (Morris, 1958; Tinbergen,
1951), this behavior systems approach also separates be-
havior chains into functional subunits with related stimulus
and motor preparedness and particular stimulus-response
transactions that function as transitions between them.FEAR MOTIVATIONFear motivation reverses the perspective of feeding, as we
focus on prey and not predators. Because the goal of the preda-
tor is to consume the prey, the selection pressure on defense is
powerful because injured or dead individuals have infinitely
diminished reproductive success. Thus it is not surprising that
prey species have evolved elaborate behavioral strategies to
deal with such threats. Fear is a motivational system that is
provoked by danger signals in the environment, and when ac-
tivated this system triggers defensive reactions that protect
individuals from environmental dangers. In this section we
examine fear from a behavioral systems perspective.
Because of this enormous selection pressure, species have
several lines of defense. Some species rely on primary defen-
sive strategies that “operate regardless of whether or not a
predator is in the vicinity” (Edmunds, 1974, p. 1). Primary de-
fense strategies include camouflage (the animal’s body color
blends into environment) and Batesian mimicry (the animal’s
body color and form resemble another species that has dan-
gerous or unpleasant attributes). Although primary defenses
contribute to survival, these strategies are relatively inflexible
and insensitive to feedback. For example, green insects avoid
wild bird predation more often when they are tethered to a
green environment compared to a brown environment (Di
Cesnola, 1904). Thus, the insect’s camouflage contributes to
survival only when it rests in the matching green-colored en-
vironment, and the camouflage is ineffective elsewhere. In
contrast to primary defense, secondary defensive strategies