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kind of emotions they can feel and thereby help to refine regulations designed
to safeguard animal welfare.
Alteration of the Judgment and Decision Making by Emotions
While cognitive processes are at the origin of emotions, emotions can in turn
influence cognitive processes. Here again, a significant body of work in
human psychology has shown how emotions can temporarily bias the proces-
sing of information coming from the situation that is attention, memory, and
judgment. For example, anxiety induces a shift in attention towards potential
threats (
Bradley et al., 1997
), emotionally charged events are more readily
remembered than neutral ones (
Reisberg and Heurer, 1995
), and people
exposed to strongly negative events tend to judge all subsequent ambiguous
events negatively (
Wright and Bower, 1992
). Such cognitive biases induced
by an emotion may have adaptive value by helping individuals to pay atten-
tion and to memorize threatening circumstances. They are not restricted to
humans (
Paul et al., 2005
). In rodents, the startle response induced by expo-
sure to a sudden event is faster and larger under negative emotional states
(
Lang et al., 1998
). Heifers subjected to a potent stressor were unable to
abandon a previously learned behavior that was no longer rewarded; this
prevented them acquiring a new, more appropriate behavior (
Lensink et al.,
2006
). Sheep experiencing repeated aversive events demonstrated learning
deficits (
Destrez et al., 2013
). In contrast, rats given a catecholamine injec-
tion mimicking the physiological component of a moderate emotion are
more attentive and display improved memory (
Sandi et al., 1997
).
The evidence that an emotion has an immediate and temporary repercus-
sion for cognitive functions suggests that it would be worthwhile to study
how an accumulation of emotions modifies an animal's cognitive functions
in a long-lasting manner. Rats or mice previously subjected to repeated
frightening events respond less readily to an ambiguous stimulus signaling
the delivery of a positive event long after the last exposure to a frightening
event, thus revealing a persistent reduction of the capacities for judgment
and decision-making (
Harding et al., 2004
;
Pardon et al., 2000
). Similarly,
rats housed under social stress show less behavioral agitation after the
presentation of a conditioned stimulus predicting the delivery of sucrose
reward, suggesting reduced anticipation due to impaired judgment (
von Frijtag
et al.,2000
). Likewise, sheep submitted to repeated unpredictable aversive
events for several weeks are less prone to respond to a stimulus signaling the
delivery of a positive or negative event, especially when the signal is ambigu-
ous, i.e. between a positive and a negative signal (
Doyle et al.,2011
;
Harding
et al.,2004
). These findings suggest that the accumulation of negative experi-
ences affects the way the animal appraises the environment to which it is
exposed, making it less aware of positive cues and more susceptible to nega-
tive ones. Such persistent biases (optimistic versus pessimistic) guide the
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