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PSYC 1010 Lecture Notes - Reinforcement, Operant Conditioning

Course Code
PSYC 1010
Rebecca Jubis

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(US) X-raynausea (UR)
solution (after 7 hours) paired with X-ray (two stimuli were not contiguous)
(CS) solution nausea (CR)
Since there was such a long time gap, Garcia began wondering whether organisms have
prepared learning.
X-ray nausea
water/light/noise + X-ray
If you were to take the water, light, or noise on its own, would you get a conditioned nausea
(US) shock fear (UR)
water/light/noise + shock
light fear (CR)
noisefear (CR)
Garcia concluded that organisms are more prepared to associate certain stimuli with each
other than others. For example, since mice consumed water, its more unlikely for them to
develop fear for it.
Operant Conditioning (Skinner)
learning through consequences
3 Elements:
1)Stimulus (S)
2)Response (R) VOLUNTARY response
a)positive reinforce
b)negative reinforce
c)negative punishment
d)positive punishment
Positive Reinforcer (Sr+)
when something pleasant is added to the situation and thus increases the
probability of the R reoccurring
Factors that Influence the Effectiveness of a Sr+:
1) Magnitude of the Sr+
2)Immediacy of the Sr+
3)The Pattern of Reinforcement
Continuous Sr +
a R is reinforced every single time it occurs (i.e. every single time you make your bed,
I will give you a dollar; all of a sudden he doesnt get it one day and decides not to make
his bed until he gets his dollar)
Partial Sr +
a R is reinforced only some of the time (i.e. every once in a while, like 5 days or so,
you receive a dollar for making your bed for the past couple of days; but one day I dont
give it to you, but its only one of the many other days you dont get it, so it is more
likely you will still make your bed that day)
partial Sr+ schedule leads to more persistent behaviour than does a continuous
Cumulative Recorder would record the mices performance and every step would represent
it pressed the button for food.
Ratio Schedule
Sr+ depends on the # of times a behaviour occurs
Fixed Ratio
the # of Rs required for a Sr+ is always the same or fixed (FR10 fixed ratio 10:
means the number of times you would have to perform the action to receive the reward;
the number does not change)
Pattern of Responding
a high rate of activity
responding is quite consistent
get a post-reinforcement pause (If a mice has to press the button 100 times before it
gets one measly pellet, then it will hold on to it for a longer time b/c it knows it must
do it ANOTHER 100 times before getting another reward)
Variable Ratio Schedule
Sr+ is given for an average # of Rs emitted (VR10 variable ratio 10: means average
of times you would have to perform the action to receive the reward; individual tries
may not be 10)
Pattern of Responding
high rate of activity
responding is quite consistent
NO post-reinforcement pause
Interval Schedule
Sr+ is delivered for the first R that occurs after a given time period has elapsed
Fixed Interval Schedule
Sr+ is given for the 1st R that occurs at the end of a fixed time interval (FI 2 min no
matter how many times mice hits button, it will not receive the reward until 2 min is