Who Needs Emotions? The Brain Meets the Robot

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emerged through decades of study (Petrovich, Canteras, & Swanson, 2001;
Risold, Thompson, & Swanson, 1997; Swanson, 2000). One important feature
of this model and very relevant to the current chapter is the notion of
behavior control columns. Swanson (2000) proposes that very specific and
highly interconnected sets of nuclei in the hypothalamus are devoted to
the elaboration and control of specific behaviors necessary for survival:
spontaneous locomotor behavior, exploration, and ingestive, defensive, and
reproductive behaviors. Animals with chronic transections above the hypothalamus
can more or less eat, drink, reproduce, and show defensive behaviors,
whereas if the brain is transected below the hypothalamus, the animal
displays only fragments of these behaviors, enabled by motor pattern generators
in the brain stem. Stimulation and lesion studies during the first half
of the 20th century indicated that the motor instructions for species-specific
motivated behaviors were instantiated within the hypothalamic circuitry
and its brain-stem motor targets. Indeed, such investigations were the hallmark
of early physiological psychology. Hess’s (1957) extensive treatise on
hypothalamic stimulation in the cat provides numerous compelling examples.
Aggressive, exploratory, ingestive, and oral responses as well as sleep and
many autonomic responses (defecation, blood pressure, respiratory changes,
and pupillary dilation) were observed upon electrical stimulation of various
hypothalamic sites. The affective component associated with the displays is
also vividly described by Hess:
Perhaps the most striking example is one type of behavior of
the cat, in which it looks like it were being threatened by a dog. The
animal spits, snorts, or growls at the same time; the hair stands on end
and its tail becomes bushy; its pupils widen . . . ears lie back (to frighten
the nonexistent enemy) . . . when the stimulation is maintained or
intensified, the cat makes an “actual” attack. The cat turns towards
a person standing in its vicinity and leaps on him or strikes a wellaimed
blow at him with its paw. This can only mean that the somatic
movement is accompanied by a corresponding psychic attitude.
(Hess, 1957, p. 23, original italics)
Many instances of evoked motivated behavior by direct electrical chemical
stimulation—eating, drinking, grooming, attack, sleep, maternal behavior,
hoarding, copulation—have been described in the literature. Such examples
of remarkably specific evoked responses suggest that the “potential” for behaviors
that are often associated with emotion (using Buck’s term) is hardwired
within the hypothalamic and brain-stem circuitry.
The major divisions of the behavior control column constitute a rostral
segment containing nuclei involved in ingestive and social behaviors (reproductive
and defensive) and a more caudal segment involved in general for-