Chapter 9 Learning and Conditioning 323always work best when they capitalize on inborn
tendencies.
Years ago, two psychologists who became ani-
mal trainers, Keller and Marian Breland (1961),
learned what happens when you ignore biological
constraints on learning. They found that their
animals were having trouble learning tasks that
should have been easy. One animal, a pig, was
supposed to drop large wooden coins in a box.
Instead, the animal would drop the coin, push at
it with its snout, throw it in the air, and push at
it some more. This odd behavior actually delayed
delivery of the reinforcer (food, which is very rein-
forcing to a pig), so it was hard to explain in terms
of operant principles. The Brelands finally real-
ized that the pig’s rooting instinct—using its snout
to uncover and dig up edible roots—was keeping
it from learning the task. They called such a rever-
sion to instinctive behavior instinctive drift.
In human beings, too, operant learning is af-
fected by genetics, biology, and the evolutionary
history of our species. As we discuss in Chapter 3,
human children are biologically disposed to learn
language and to understand rudimentary numbers,
spatial relations, and certain features of the physical
world (Izard et al., 2009). Further, temperaments
and other inborn dispositions may affect how a
person responds to reinforcers and punishers. Itinstinctive drift During
operant learning, the
tendency for an organism
to revert to instinctive
behavior.the robot requires, and so on until the cow finally
learns to milk herself. The key is that as each ap-
proximation is achieved, the next one becomes
more likely, making it available for reinforce-
ment. Cows allowed to milk themselves do so
three or four times a day instead of the traditional
twice a day, and show fewer signs of stress than
other cows.
Using shaping and other techniques, Skinner
was able to train pigeons to play Ping-Pong with
their beaks and to “bowl” in a miniature alley,
complete with a wooden ball and tiny bowling
pins. (Skinner had a great sense of humor.) Today,
animal trainers routinely use shaping to teach
animals their parts in movies and TV shows.
Animals also act as the “eyes” of the blind and the
“limbs” of people with spinal cord injuries, do-
ing such daily tasks as turning on light switches,
opening refrigerator doors, and reaching for
boxes on shelves.
Biological Limits on Learning. LO 9.13 All
principles of operant conditioning, like those of
classical conditioning, are limited by an animal’s
genetic dispositions and physical characteristics.
If you try to teach a fish to dance the samba,
you’re going to get pretty frustrated (and wear
out the fish). Operant-conditioning procedures
Behavioral techniques such as shaping have many useful applications. Monkeys have been trained to assist their
paralyzed owners by opening doors, helping with feeding, and turning the pages of books. Miniature horses have been
trained to help blind people navigate everywhere, from crowded subways to rocky, uneven terrain. Note the horse’s
cool little protective sneakers!