4/19/2012 3:25:00 PM Learning - Learning is important for virtually all animal life. - A textbook definition of learning: Adaptation through experience. - In what ways do humans and other animals adapt to changing environments? o 1. They can change their behavior. o 2. They can change the cognitive processes that give rise to behavior. Behavioral definition of learning: - Learning is an enduring change in behavior. - Behavioral definitions must distinguish changes in behavior due to learning from those due to physical, physiological and developmental changes. Cognitive definition of learning: - Learning is the formation of a novel mental structure [that is only indirectly manifest in behavior] What selection pressures could have generated a common learning process? - As fish have evolved a similar body shape to move efficiently in water and birds to move efficiently in air, a common learning process could have evolved in all species because the physical laws that constrain the environment are the same for all species: - A critical constraint that could have produced a common learning mechanism is the structure of causal relations which are the same for all species in all niches and are constrained by physics not biology: o effects never occur without a cause o effects never occur before the cause  1. Causal relations are neither arbitrary, accidental, or indiscriminate.  2. Events do not stand in causal relations because of an animal’s biology, but because of environmental constraints.  3. Sensitivity to these relations is critical for survival and reproductive fitness.  Therefore selection pressures ensured that animals developed a general learning mechanismsensitive to the causal texture of the specific environment to which their biology was specifically tuned to respond Elicited Behavior and Nonassociative Learning Types of Reflexes - Patellar reflex - Pupillary reflex - Withdrawal/Flexion Reflex - Head turning reflex in infants - Respiratory occlusion reflex Habituation - is a decrease in response to a stimulus after repeated presentations; an extremely simple form of learning, in which an animal, after a period of exposure to a stimulus, stops responding - Distinction from Sensory Adaptation and Response Fatigue: o Response- and Stimulus-Specific o Dishabituation: the ability to re-introduce the stimulus that was hadbituated in such a way that it once again elicits a response BACK TO CLASSICAL CONDITIONING: - Learning the relationship between two or more stimuli/actions. - Two basic types of associative learning. o Classical Conditioning (Pavlovian learning) o Instrumental Conditioning NOTE THAT: exposure to the CS can cause changes in behavior… - How can we tell? - One way is to use a control group that gets the light presented alone. - If a similar change occurs to the light when it is not paired with food then we should doubt that this change in behavior is due to associative learning … Appetitive excitatory conditioning (or just appetitive conditioning) Aversive excitatory conditioning (or just aversive conditioning) describes learning about stimuli that are paired with aversive US’s- These are events which are noxious; that we and other animals have a natural tendency to avoid and that, generally, are damaging to the health of the animal. - Again there are many examples: things that threaten the animal with imminent death, tissue damage, pain, severe or even mild discomfort or toxin induced malaise - A standard example of aversive conditioning in the animal laboratory is the study of conditioned fear: - e.g. little Albert or studies examining CS -> shock in rats - Freezing is an adaptive response in rats to a distal predator - Measure of learning is the amount of behavioral suppression during the light prior to the shock presentation (e.g. freezing) Factors Controlling Pavlovian Learning: 1. Preexposure Effects 2. Stimulus Salience 3. CS-US Belongingness - For example: CS taste would be paired with CS illness because they “go together”-are associated- not taste and foot