PS251, Lec 3, Final: 12/02/2013
Extinction: when you do something for a long time and then it fades away. When the rewarding element
is removed, the behavior gets extinguished. Ex. when siblings bug each other and one ignores the other,
the bugging gets extinguished.
Shaping a behavior: gradually reinforce an organism to get to target behavior. Ex. a rat will press a
bar to feed itself.
Contingency Based Reward/Reinforcement: chain behaviors together to teach an animal
Any stimuli similar to the original one will elicit a similar response.
Conditioned Reinforcer: stimuli associated with a primary reward. Meaningful for the organism. Ex.
money, doesn’t work very well because you have to give more every time. Any less than the previous time
and it’s considered a punishment.
Delay of reinforcement: when we give the reward after the behavior, more immediate, the better it is
(more powerful for reinforcing the behavior). The more delay the less someone cares about this reinforcer.
Critical for learning. Schedules of reinforcement follow predicted outcome:
Schedules of Reinforcement: Two types:
Ratio schedules: more effective than interval. Based on number of behavior outputs that the individual
has to do to get reinforced. Organism has to be involved.
Fixed ratio: Rat has to press a bar a specific number of times to get food. ex. frequent flyer miles causes
people to fly more with a specific airline. When they get the reward, they don’t give a behavior (flat part). As
you get closer, you give more behavior output.
Variable Ratio: Highest behavior output. Reward comes on an irregular schedule. Ex. Slot machine.
You put in a lot for a chance to win. I’m so close, and you keep putting money. When you get a reward,
you’re happy for a bit, but then you continue.
Interval: Based on time. Organism has to wait. Two types:
Fixed Interval: Reinforcement is based on time. ex. mail. You check for mail at a specific time, once you
get it, you don’t check for another 24 hours. Called scallops.