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C82MPR – Practical Methods 2 Dr Mark Haselgrove Blocking and Associative learning. Please log in with Windows 7. Structure of the Practical. Week 1: Introduction to the topic, background information Homework: Reading Week 2: Further background. Set up Experiment
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C82MPR – Practical Methods 2 Dr Mark Haselgrove Blocking and Associative learning Please log in with Windows 7
Structure of the Practical Week 1: Introduction to the topic, background information Homework: Reading Week 2: Further background. Set up Experiment Homework: Test Participants Week 3: Introduction to Excel and SPSS, data exploration Homework: Test more participants and explore data Week 4: Data analysis, Introduction to PowerPoint, begin preparing presentations Homework: Prepare presentation Week 5: Present your finding, Q & A Homework: Write-up practical report. Hand in by 4pm, 7th April
Conditioning and Learning A reminder of some terminology and facts… Unconditioned Stimulus (US): Biologically significant event (e.g. food, pain) Unconditioned Response (UR): The response evoked by the US Conditioned stimulus (CS): Previously neutral stimulus (e.g. tone) that acquires a response by being paired with a US Conditioned response (CR): The response evoked by the CS Clicker → Shock Jumping → Jumping (US) → (UR) (CS) → (CR)
Learning mechanism Response generator Sensory register Event CS CS CS CS-US US US US Observed behaviour Conditioning and Learning Hebb (1949) Pairing a CS with a US is sufficient for learning to take place “Whatever fires together, wires together”
No fear of the Light Lots of fear of the Light Conditioning and Learning Kamin (1968) Shock conditioning experiment with rats Only learn about a CS if it followed by A SURPRISING US
Monkeys expressed more interest in Y than X Conditioning and Learning Other examples of blocking…. Waelti, Dickinson & Schultz (2001): Blocking in Macaques
Participants rated X as safer than Y Conditioning and Learning Other examples of blocking…. LePelley, Oakshott & McLaren (2005) Blocking in Cambridge undergraduates
Conditioning and Learning Rescorla & Wagner (1972) • A mathematical theory of learning and surprise CS US Learning = intensity of CS x intensity of US x surprisingness of US ΔV = α x β x (λ - ΣV) Surprise = The difference betweenwhat you get and what you expect to get
Conditioning and Learning Rescorla & Wagner model applied to blocking: ΔV = α x β x (λ - ΣV) A US X
ΔV = α x β x (λ - ΣV) Conditioning and Learning Your turn…
More fear X in Control group than Blocking group: Conditioning and Learning Surprise brought about by a QUALITATIVE change in the US Bakal, Johnson & Rescorla (1974) – Conditioned fear in rats When blocking persists, despite a qualitatitive change in the nature of the US, we call the effect: TRANS-REINFORCER BLOCKING
Conditioned eye blink to X in both groups: UN-BLOCKING Conditioning and Learning Surprise brought about by a QUALITATIVE change in the US Stickney & Donahoe (1983) – Eye blink conditioning in rabbits When blocking disappears, with a qualitatitive change in the nature of the US, we call the effect: TRANS-REINFORCER UN-BLOCKING
Conditioning and Learning How do we explain this discrepancy in the literature? Bakal et al (1974) – Conditioned fear in rats (TRB) Stickney & Donahoe (1983) – Eye blink conditioning in rabbits (TRuB) Could be an effect of: (1) different species, (2) different experimental procedure, (3) different apparatus, (4) different measure of behaviour. Betts, Brandon & Wagner (1996) – Blocking in rabbits No blocking when eye blink conditioning was measured But, blocking was observed when “startle” was measured HOMEWORK: Read: Betts, Brandon & Wagner (1996) Paper to be found on Mark Haselgrove’s website
References Bakal, C. W., Johnson, R. D., & Rescorla, R. A. (1974). The effect of change in US quality on the blocking effect. Pavlovian Journal, 9, 97-103. Betts, S. L., Brandon, S. E., & Wagner, A. R. (1996). Dissociation of the blocking of conditioned eyeblink and conditioned fear following a shift in US locus. Animal Learning & Behavior, 24(4), 459-470. Hebb, D. O. (1949). The organisation of behaviour. New York: Wiley. Kamin, L. J. (1968). Attention-like processes in classical conditioning. In M. R. Jones (Ed.), Miami symposium on the prediction of behvior: Aversive stimulation (pp. 9-32). Coral Gables, Fl: University of Miami Press. Le Pelley, M. E., Oakeshott, S. M., & McLaren, I. P. L. (2005). Blocking and unblocking in human causal learning. Journal of Experimental Psychology-Animal Behavior Processes, 31(1), 56-70. Rescorla, R. A., & Wagner, A. R. (1972). A theory of Pavlovian learning: Variations in the effectiveness of reinforcement and nonreinforcement. In A. H. Black & W. F. Prokasy (Eds.), Classical Conditioning II (pp. 64-99). New York: Appleton-Century-Crofts. Stickney, K. J., & Donahoe, J. W. (1983). Attenuation of Blocking by a Change in Us Locus. Animal Learning & Behavior, 11(1), 60-66. Waelti, P., Dickinson, A., & Schultz, W. (2001). Dopamine responses comply with basic assumptions of formal learning theory. Nature, 412, 43-48.