Skinner Schedules of Reinforcement

Skinner Schedules of Reinforcement

Skinner likes to tell about how he “accidentally -- i.e. operantly -- came across his various discoveries.
For example, he talks about running low on food pellets in the middle of a study. Now, these were the
days before “Purina rat chow” and the like, so Skinner had to make his own rat pellets, a slow and
tedious task. So he decided to reduce the number of reinforcements he gave his rats for whatever
behavior he was trying to condition, and, lo and behold, the rats kept up their operant behaviors, and at
a stable rate, no less. This is how Skinner discovered schedules of reinforcement!
Continuous reinforcement is the original scenario: Every time that the rat does the behavior (such as
pedal-pushing), he gets a rat goodie.

The fixed ratio schedule was the first one Skinner discovered: If the rat presses the pedal three times,
say, he gets a goodie. Or five times. Or twenty times. Or “x” times. There is a fixed ratio between
behaviors and reinforcers: 3 to 1, 5 to 1, 20 to 1, etc. This is a little like “piece rate” in the clothing
manufacturing industry: You get paid so much for so many shirts.

The fixed interval schedule uses a timing device of some sort. If the rat presses the bar at least once
during a particular stretch of time (say 20 seconds), then he gets a goodie. If he fails to do so, he doesn’t
get a goodie. But even if he hits that bar a hundred times during that 20 seconds, he still only gets one
goodie! One strange thing that happens is that the rats tend to “pace” themselves: They slow down the
rate of their behavior right after the reinforcer, and speed up when the time for it gets close.

Skinner also looked at variable schedules. Variable ratio means you change the “x” each time -- first it
takes 3 presses to get a goodie, then 10, then 1, then 7 and so on. Variable interval means you keep
changing the time period -- first 20 seconds, then 5, then 35, then 10 and so on.

In both cases, it keeps the rats on their rat toes. With the variable interval schedule, they no longer
“pace” themselves, because they can no longer establish a “rhythm” between behavior and reward.
Most importantly, these schedules are very resistant to extinction. It makes sense, if you think about it.
If you haven’t gotten a reinforcer for a while, well, it could just be that you are at a particularly “bad”
ratio or interval! Just one more bar press, maybe this’ll be the one!

This, according to Skinner, is the mechanism of gambling. You may not win very often, but you never
know whether and when you’ll win again. It could be the very next time, and if you don’t roll them dice,
or play that hand, or bet on that number this once, you’ll miss on the score of the century!

Multiple Choice

Choose the term that best describes the following statement:  "Every time the rat does the behavior, he gets a rat goodie."

• continuous reinforcement

• fixed ratio

• fixed interval

• variable interval

Multiple Choice

Choose the term that best describes the following statement:  "If the rat presses the pedal three times, he gets a goodie."

• continuous reinforcement

• fixed ratio

• fixed interval

• variable interval

Multiple Choice

Choose the term that best describes the following statement:  "If the rat presses the bar at least once during a particular stretch of time, then it gets a goodie."

• continuous reinforcement

• fixed ratio

• fixed interval

• variable interval

Multiple Choice

Choose the term that best describes the following statement:  "You change the "x" each time--first it takes 3 presses to get a goodie, then 10, then 1, then 7, and so on."

• variable ratio

• fixed ratio

• fixed interval

• variable interval

Multiple Choice

Choose the term that best describes the following statement:  "You keep changing the time period -- first 20 seconds, then 5, then 35, then 10, and so on."

• variable ratio

• fixed ratio

• fixed interval

• variable interval