196 CHAPTER 5
A variable ratio schedule of reinforcement is one in which the number of responses
changes from one trial to the next. In the rat example, the rat might be expected to push the
bar an average of 20 times to get reinforcement. That means that sometimes the rat would
push the lever only 10 times before a reinforcer comes, but at other times it might take 30
lever pushes or more.
Figure 5.8 shows a purple line that is just as rapid a response rate as the fixed ratio
schedule because the number of responses still matters. But the graph is much smoother
because the rat is taking no rest breaks. It can’t afford to do so because it doesn’t know how
many times it may have to push that lever to get the next food pellet. It pushes as fast as
it can and eats while pushing. It is the unpredictability of the variable schedule that makes
the responses more or less continuous—just as in a variable interval schedule.
In human terms, people who shove money into the one-armed bandit, or slot
machine, are being reinforced on a variable ratio schedule of reinforcement (they hope).
They put their coins in (response), but they don’t know how many times they will have
to do this before reinforcement (the jackpot) comes. People who do this tend to sit there
until they either win or run out of money. They don’t dare stop because the “next one”
might hit that jackpot. Buying lottery tickets is much the same thing, as is any kind of
gambling. People don’t know how many tickets they will have to buy, and they’re afraid
that if they don’t buy the next one, that will be the ticket that would have won, so they
keep buying and buying.
Regardless of the schedule of reinforcement one uses, two additional factors con-
tribute to making reinforcement of a behavior as effective as possible. The first factor
is timing: In general, a reinforcer should be given as immediately as possible after the
desired behavior. Delaying reinforcement tends not to work well, especially when deal-
ing with animals and small children. (For older children and adults who can think about
future reinforcements, such as saving up one’s money to buy a highly desired item,
some delayed reinforcement can work—for them, just saving the money is reinforcing
as they think about their future purchase.) The second factor in effective reinforcement
is to reinforce only the desired behavior. This should be obvious, but we all slip up at
times; for example, many parents make the mistake of giving a child who has not done
some chore the promised treat anyway, which completely undermines the child’s learn-
ing of that chore or task. And who hasn’t given a treat to a pet that has not really done
the trick?The Role of Punishment in Operant Conditioning
5.7 Identify the effect that punishment has on behavior.
So I think I get reinforcement now, but what about punishment?
How does punishment fit into the big picture?Let’s go back to the discussion of positive and negative reinforcement. These strategies
are important for increasing the likelihood that the targeted behavior will occur again. But
what about behavior that we do not want to recur?DEFINING PUNISHMENT People experience two kinds of things as consequences in the
world: things they like (food, money, candy, sex, praise, and so on) and things they
don’t like (spankings, being yelled at, and experiencing any kind of pain, to name a
few). In addition, people experience these two kinds of consequences in one of two
ways: Either people experience them directly (such as getting money for working or
getting yelled at for misbehaving) or they don’t experience them, such as losing an
allowance for misbehaving or avoiding a scolding by lying about misbehavior. These
four consequences are named and described in Ta b l e 5. 2.variable ratio schedule
oH rGKPHorEGmGPt
schedule of reinforcement in which
the number of responses required for
reinforcement is different for each
trial or event.
Slot machines provide reinforcement in
the form of money on a variable ratio
schedule, making the use of these
machines very addictive for many people.
People don’t want to stop for fear the
next pull of the lever will be that “magic”
one that produces a jackpot.