Transcript 85% Weight Calculations

BF Skinner
• American Behaviorist
• Operant conditioning
• “Skinner Box”
Skinner
• Operant chamber
– permits precise control
of stimuli
– typical behavior is a
key peck or bar press
• Behavior units
– small, measurable,
behaviors
FREE-OPERANT PROCEDURES
• responses made by the animal at a pace which they set
(i.e., they are “free” to operate on their environment by
responding whenever they would like and however often they
would like).
Skinner eliminated the maze altogether
designed a chamber with start box and the goal box in
the same place so the animal didn't have to run
anywhere
DISCRETE TRIALS PROCEDURES = during training,
1) each trial ends when you remove the animal from the apparatus
2) the instrumental response is performed only once during each trial.
Usually, discrete trial procedures use some type of maze.
Skinner
• Magazine Training
– preliminary phase of conditioning
– pairing food delivery devise with food
• Shaping
– sequence of training
steps in training:
1ST STEP = MAGAZINE TRAINING =
sound of being delivered:
teach the rat to associate the "click" produced by the
feeding mechanism with the delivery of food
(classical conditioning)
2ND STEP = SHAPING = rewarding
successive approximations to the desired
behavior (operant conditioning)
Differential Reinforcement
Successive Approximations
(MSA)
• Shaping: A technique
for training responses that are
initially unlikely to occur. The first step is to
reinforce whatever aspect of an individual’s
behavior is closest to the desired response. As this
behavior begins to occur more often, the trainer
withholds reinforcement until some closer
approximation to the desired response occurs, and
so on
» Lieberman (2001)
Lever Shaping
• Begin differential reinforcement of
behaviors that most resemble, or could lead
to, the desired behavior (lever pressing)
• These behaviors are known as successive
approximations because they gradually
approximate the desired behavior
RESPONSE-OUTCOME CONTINGENCIES
Some definitions:
APPETITIVE STIMULUS = A pleasant event.
AVERSIVE STIMULUS = An unpleasant event.
POSITIVE CONTINGENCY = a response "turns on" a
stimulus = a rat can press the bar which will activate the
food magazine and he will get some food.
NEGATIVE CONTINGENCY = a response "turns off" a
stimulus = a rat can be sitting in the Skinner box and the
experimenter can deliver a loud noise – if the rat presses the
bar the noise will be turned off.