Page 93 - Introduction to AI Robotics

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3 Biological Foundations of the Reactive Paradigm
A female digger wasp mates with a male, then builds a nest. Once it sees
the nest, the female lays eggs. The sequence is logical, but the important
point is the role of stimulus in triggering the next step. The nest isn’t built
until the female mates; that is a change in internal state. The eggs aren’t
laid until the nest is built; the nest is a visual stimulus releasing the next
step. Notice that the wasp doesn’t have to “know” or understand the
sequence. Each step is triggered by the combination of internal state and
the environment. This is very similar to Finite State Machines in computer
science programming, and will be discussed later in Ch. 5.

INNATE WITH MEMORY 3. to be born with behaviors that need some initialization (innate with mem-
ory). An animal can be born with innate behaviors that need customizing
based on the situation the animal is born in. An example of this is bees.
Bees are born in hives. The location of a hive is something that isn’t in-
nate; a baby bee has to learn what its hive looks like and how to navigate
to and from it. It is believed that the curious behavior exhibited by baby
bees (which is innate) allows them to learn this critical information. A
new bee will fly out of the hive for a short distance, then turn around and
come back. This will get repeated, with the bee going a bit farther along
the straight line each time. After a time, the bee will repeat the behavior
but at an angle from the opening to the hive. Eventually, the bee will have
circumnavigated the hive. Why? Well, the conjecture is that the bee is
learning what the hive looks like from all possible approach angles. Fur-
thermore, the bee can associate a view of the hive with a motor command
(“fly left and down”) to get the bee to the opening. The behavior of zoom-
ing around the hive is innate; what is learned about the appearance of the
hive and where the opening is requires memory.

LEARN 4. to learn a set of behaviors. Behaviors are not necessarily innate. In mam-
mals and especially primates, babies must spend a great deal of time
learning. An example of learned behaviors is hunting in lions. Lion
cubs are not born with any hunting behaviors. If they are not taught
by their mothers over a period of years, they show no ability to fend
for themselves. At first it might seem strange that something as funda-
mental as hunting for food would be learned, not innate. However, con-
sider the complexity of hunting for food. Hunting is composed of many
sub-behaviors, such as searching for food, stalking, chasing, and so on.
Hunting may also require teamwork with other members of the pride. It
requires great sensitivity to the type of the animal being hunted and the
terrain. Imagine trying to write a program to cover all the possibilities!