Transcript LT2Ch10
PSY402 Theories of Learning Chapter 10 – Animal Misbehavior Operant Conditioning Nature of reinforcement: Premack’s probability differential theory Response deprivation theory Behavioral economics: Behavioral allocation – blisspoint Choice behavior – Herrnstein’s matching law. Momentary maximization theory Delay-reduction theory Probability-Differential Theory Premack – a reinforcer can be any activity that is more likely to occur than the reinforced behavior. Manipulators vs eaters High probability behaviors can be used as reinforcers of low probability behaviors. Frequency of the reinforcer decreases when it is made contingent on another response. Response Deprivation Theory Timberlake & Allison – deprivation occurs when an activity is used as a reinforcer and is not freely emitted. The activity is reinforcing because it satisfies the deprivation created. The animal tries to return to its predeprivation level of responding. Activities can be reinforcing even if their baselines were not higher. Behavioral Allocation Blisspoint (paired basepoint) – the free operant level of two responses. Unrestricted responding with two choices of behaviors. Blisspoint is used to figure out how much behavior an animal will engage in to obtain a reward. Animals try to get as close to the blisspoint as possible. Problems with Contingencies Blisspoint is established by looking at behavior before a contingency is established. The established contingency must take blisspoint into account or it may not increase desired behavior. Choice Behavior Herrnstein’s matching law – describes how animals act when they have two or more choices. Different responses have different schedules of reinforcement. Responding to each choice is proportionate to the reinforcement for each choice – after learning. This can be expressed mathematically. Delayed Gratification Why does anyone choose a smaller reward part of the time? Animals and people typically choose a small immediate reward over a larger delayed reward. Large rewards are selected when: The choice is made in advance of reward. Reinforcers are not visible or reward is already present (pleasurable activity). Complexities of the Matching Law Maximizing law – sometimes the aim is to obtain as many rewards as possible. Explains FR-10 vs FR-40 schedules. Doesn’t work for VI vs VR schedules. Momentary maximization theory – choose best alternative at the time. Delay reduction theory – choose what will get the reward the fastest. Limits to Learning How general are the laws of learning? Skinner’s rules work in both lab and real-world settings, across species. Learning doesn’t explain all aspects of behavior. Organization of behavior already exists within an organism. Learning modifies that organization. Behavior Systems Approach Timberlake – learning changes the integration, tuning, instigation or linkages within a behavior system. Different cues are salient to different behavior modes. Variations in learning occur across species because their behavior systems are different. Variations in behavior are the result of predispositions and constraints. Animal Misbehavior Breland & Breland – trained 38 species of animals for Busch Gardens. Elicitation of foraging and foodhandling instincts interferes with performance of operant routines. Instinctive drift Pig and piggy bank Raccoons and food-washing Explaining Misbehavior Does misbehavior result from operant food reinforcement or classical conditioning? Timberlake’s appetitive structure view – both kinds of learning contribute to animal misbehavior. Pairings with food are necessary but not sufficient to evoke misbehavior. Schedule-Induced Behavior Superstitious behavior – induced by FI schedules. Animal associates whatever it is doing at the time with the reinforcement. Ritualistic, stereotyped behavior during the interval. Two kinds of behavior: Terminal – reinforcer-oriented Interim – follows reinforcement. Effects with Humans Superstitious gambling behavior. Schedule-induced behavior may be related to alcoholism: Excessive drinking, eating, smoking may occur immediately after reinforcement. Weak and inconsistent in humans. Develops rapidly in humans, stops quickly Flavor-Aversion Learning Long-delay learning – does not depend on contiguity. Preparedness – certain stimuli are innately more likely to be associated with a UCS than others. Visual cues more salient to birds Taste cues more salient to rats Salience depends on when the animals seeks its food (nocturnal or not). Applications Cancer chemotherapy (UCS) causing nausea may be associated with hospital food (CS). Preexposure to food without the toxic drug or drug without food may help prevent food aversions. Coyotes and wolves can be taught to avoid attacking and eating sheep using flavor-aversion learning. Explanations Learned-Safety theory – an evolved mechanism unique to flavoraversion to protect animal. Ingestional neophobia – small quantities consumed at first. Concurrent-Interference view – long delay occurs because the animal doesn’t eat anything else for a while Imprinting Lorenz – social attachment process where young ducks follow their mother. Ducks imprint to: Moving objects with lifelike motion Vocalizing objects, short rhythmic sounds, not high-pitched Objects that are the right size Other Factors in Imprinting Harlow – baby primates attach to soft terry cloth rather than wire. Rocking rather than stationary Warm rather than cold Ainsworth – attachment to a responsive mother. Occurs more easily during sensitive period of animal’s life. 6 to 12 months for humans Other Kinds of Imprinting Sexual preferences – occurs early in development, long before sexual maturity, not modifiable later. Food preferences – preferences established early and permanent. People prefer familiar foods Food aversions develop between 6 & 12 yrs Nature of Imprinting Both instinctive and associative processes are involved. Associative-learning view – objects become familiar before fear system matures Familiar objects reduce fear later, so become preferred due to relief. Harlow’s studies contradict this. Some objects are more imprintable. Instinctive View of Imprinting Organisms contain an innate schema of the imprinting object Evolutionary pressure to learn the right thing. Response is hard to change. Extinction does not lead to loss of preference. Abused primates and children cling to abusive mothers despite punishment. Avoidance of Aversive Events Species-specific defense reactions (SSDR) – instinctive responses to specific dangers. Rats – running, freezing, fighting. Cues predicting danger also select the specific response. Escape and avoidance behaviors are learned more readily when they incorporate SSDR.