PSYC 4750 Lecture Notes - Lecture 14: Nicotine, Classical Conditioning, Operant Conditioning
17 May 2018
School
Department
Course
Professor
03/20/2018 Lecture 14: Individual Differences in Addiction: Novelty, Sensation Seeking, Impulsivity,
Compulsivity
Cumulative Record
• Role of paper with moving pen used to record behaviour
• Used to observe the pattern of behaviour over time
Schedules of Reinforcement
• Two types of response requirements
o Ratio – number (r)
o Interval – time (i)
• Variable or fixed ratios/intervals
o Variable – different ratio or interval throughout
o Fixed – same ratio or interval throughout
• Fixed ratio scales – we see a pattern of post-reinforcement pauses by animal followed by
reengagement of steadily-paced behaviour
o After a fixed amount of presentations (can be every presentation, would just mean ratio
is 1), you engage in the response and will get the reinforcement
• Fixed interval scales – we see scallop pattern of pausing (rat does not pause in the same way,
but does slow for a little) followed by reengagement of less steadily-paced behaviour
o After a fixed amount of time has passed, you engage in the response and will get the
reinforcement
• Variable ratio scales – e do not see this pause eause the don’t kno eatl hen the ill
be rewarded
o Reinforcement is not given after a fixed amount of trials, it only occurs sometimes
• Variable interval scales – we see steady responding as with VR scales
o Reinforcement is not given after a fixed amount of time, it only occurs sometimes
• Also progressive ratio scales – progressively increasing the response requirement
• Highest rates of responding evoked by ratio schedules rather than interval schedules
• These responses are relatively conserved across species
Extinction
• Extinction: reduction in the strength or probability of a learned behavior that occurs when the
CS is presented without the US (in classical conditioning) or when the behavior is no longer
reinforced (in operant conditioning)
• Study on acquisition of nicotine administration in rats – rats press lever to get nicotine
• When we switch rats from a FR1 to FR2 schedule rats get reward every time compared to every
other time they press lever
o Rats increase pressing of lever because they have to work harder to get the same
amount of nicotine
• After all of the training rats behaviour is high and stable
• Then we take the nicotine away
• Over repeated sessions there is a decrease in the amount of lever pressing
• The reward they are looking for is no longer there
Extinction is Not Competing Learning
• Extinction does not eliminate learning it is competing learning
find more resources at oneclass.com
find more resources at oneclass.com
