PSYC 340 1st Edition Lecture 6 Stimulus Preexposure Effects – Phenomena & InterferenceWhat you missed last class… (02.03.15)I. Clark Hull (1884-1952) A. Theory: Rp = (D * sHr * K * V) – (lr + slr) 1. Learning = S-R (stimulus – response)relationship 2. If any of the variables in (D * sHr * K * V) are zero, there is no response. 3. (lr + slr) – reduces Rp- Creates extinction I. Edward Tolman (1886-1959)A. Reacted against S-R view B. The theory: encoding S-S relations and S1-R-S2 expectancies1. S1 – stimulus; R – response; S2 – reinforcer 2. Unlike Hull’s rats, have expectations; there better be food at the end of the maze. C. Cognitive inferences 1. Tolman assumed contiguity (closeness of space and time) was all you needed to learn, rather than drive reduction a. If the elements were associated closely together, that’s all you needb. This is true for both S-S and S1-R-S2 2. Reinforcement only affects performanceD. Evidence of S-S learning 1. In S-R learning, no R = no learning 2. But, in S1-R-S2, no R = S-S b. Can use this information to make an inference; shows cognition c. Knows S1-R-S2; show it that S2-S* i. Taste aversion learning III. B.F. Skinner (1904-1990) A. Challenges to the S-R and cognitive views 1. Skinner said that sometimes we aren’t as flexible as Tolman suggestedB. Skinner’s solution 1. Distinction between respondent behavior (reflexively elicited; Pavlovian conditioning) and operant behavior(emitted, not elicited; animals can act on and adapt to their environment in any way they can; instrumental conditioning)a. Used operant rather than instrumentalb. All the stimulus does is set the occasion for the response. 2. Avoid theoretical speculation These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.3. Skinner said that there is not a stimulus; behavior is emitted, not eliciteda. Rate of responding – became his dependent variable rather than S-R strengthLearning After Watson I. B.F. Skinner (1904-1990)A. Pavlovian conditioning = respondent conditioning3. Can’t really help yourself 4. Stimulus occurs – you respond 5. Respondent behavior is elicited B. Operant conditioning (instrumental conditioning) 3. More flexible4. Animal can operate in its environment in whichever way 5. Operant behavior is emitted b. Essentially removes the stimulusc. Can no longer rely on the power of reflex C. New measure - Rate of response3. Functional analysis of behavior that identifies and isolates the environmental variables that control behavior D. According to Skinner, we don’t understand a pieces of behavior until we can train, control, and predict it 3. Reminiscent of WatsonE. Schedule of Reinforcement – biggest determinant of behavior3. Continuous reinforcement b. Every response receives a reward 4. Interval schedules (A & B)– reinforcement depends on time a. Fixed interval (A) – Reinforcement becomes available after a certain amount of timei. Food doesn’t come out for free; food is available at the certain time, so the animal has to respond to receive it ii. Distinct scallop-shape graphiii. Tells us about the capacity of the organism: - Has an internal clockiv. FI# - number = time requiredb. Variable interval (B) – reinforcement becomes available after a random amount of time i. Slow, steady rate of responding ii. When you check your email iii. VI# - number = average time required5. Ratio schedules (C & D) – reinforcement depends on how many responses b. Fixed ratio (C)– certain number of responses required i. Ratio run – working towards the reinforcement ii. Post reinforcement pause – receive reinforcement, then rest iii. FR# - number = responses requiredc. Variable ratio (D)– vary the number of responses requiredi. Produces highest sustained level of performance- However, people get burned out ii. VR# - number = average responses required iii. Slot machineF. By taking a behaviorist view and using these reinforcement schedules shows a vast host of empirical facts 1. Has stood the test of time 2. Approaches have proven very usefulStimulus Preexposure Effects I. Basic properties A. Potential outcomes (sensitization, no change, habituation) 1. Exposure to stimulus can affect you in certain ways: a. Habituation – get used to the stimulus b. Sensitization – become more sensitive to the stimulus B. Examples 1. Vary in stimulus and response complexity 2. Startle- dog may get less startled after they hear consistent fireworks 3. Perceptual learning – notice the faces? You can never unsee them. a. http://graulab.tamu.edu/J-Grau/Psyc340/Figures/SingStim-Forest%20Faces.jpeg4. Infant looking time – when a child habituates the stimulus, it looks elsewhere; only looks at the unexpected/novel stimulus a. Using habituation to determine how a baby perceives the world.5. Imprinting – baby ducky follows large moving object (such as human caretaker or mama duck.)a. Showing an attachment behaviori. Complex response b. Stimulus exposure is all you need to produce imprinting behavior 6. Social interaction – two dogs interact differently the first time they meet each other and the next few times; due to stimulus exposure 7. Recognition of a conspecific, emotions, pain (analgesia &hyperalgesia) II. Formal Properties A. Criteria for Stimulus Preexposure Effects 1. The behavioral modification depends on a form of neural plasticity 2. The modification depends on the organism’s experiential history. 3. The modification outlasts the environmental contingencies used to induceit; The experience has a lasting effect on performance 4. Exposure to a stimulus alters the response elicited by the target event, causing a decrement (habituation) or an enhancement (sensitization) in its behavioral and/or psychological consequence B. Inference 1. Direct: change in R magnitiudea. Must rule out sensory adaptation and motor fatigue i. Adapted to the stimulus; peripheral effect (leaving a loud club, everything sounds so quiet) ii. Could just be tirediii. Stimulus generalization- Shows that the animal can still hear and is not too tired to response; rules out sensory adaptation and motor fatigue 2. Indirect: inferred through its impact on another process a. Impact on acquisition of a Pavlovian CR i. Latent inhibition (CS habituation) - Extended CS preexposure hurts learning ii. Perceptual