Unit 6 Flashcards
Learning
is the process of acquiring new understanding, knowledge, behaviors, skills, values, attitudes, and preferences. At the neural level, learning occurs through strengthening and weakening of specific synapses.
Behaviorism
Behaviorism is a psychological field that seeks to explain how the behavior of humans and other animals develop through types of learning. It assumes that behavior is either a reflex evoked by the pairing of certain antecedent (prior) stimuli in the environment [e.g., classical conditioning], or a consequence of that individual’s history, including especially reinforcement and punishment contingencies, together with the individual’s current motivational state and controlling stimuli [operant conditioning]. It was initially proposed by Watson. Although behaviorists now generally accept the important role of genetic heredity in determining behavior, they focus primarily on environmental events, usually in an experimental and/or laboratory setting.
Finding ways to change behavior
Psychoanalytic theory
Also known as depth psychology, psychoanalytic theory was developed by Freud, Jung, and Adler. For Freud, a central premise was thus that we are driven by unconscious wishes that we are unaware of, and this lack of awareness results in driven or self-defeating behavior. Freud believed we delude ourselves about reasons for our behaviors and this self-deception limits our choices. By becoming aware of our unconscious wishes and our defenses against them, we increase the choices available to us. Thus, as we decrease the extent to which we are driven by unconscious factors, we assume a greater degree of agency. This theory was not typically tested experimentally.
Law of Effect
Any stimulus/action/context associated with positive reinforcement will tend to be repeated, while those that produce a discomforting or negative effect become less likely to occur again in that situation. This theory competed with Freud’s psychoanalysis-based “depth psychology,” which could not usually be tested experimentally. Developed by Thorndike in the late 1890s.
Ethology
Ethology is the scientific and objective study of animal behavior, usually with a focus on behavior under natural conditions, and viewing behavior as an evolutionarily adaptive trait. This contrasts with behaviorism, which studies behavior under controlled, experimental settings.
Classical conditioning
is a type of learning that had a major influence on behaviorism. Discovered by Russian physiologist Ivan Pavlov, classical conditioning is a learning process that occurs through associations between an environmental, neutral, unrelated stimulus and a naturally occurring, unconditioned stimulus. Applies to reflexive behaviors
Higher order classical conditioning
A series of neutral stimuli that is happening close together in time can be associated with the behavioral response by conditioning them in stages
Neutral stimulus
In classical conditioning, a neutral stimulus (NS) is a stimulus that initially does not evoke a response until it is paired with the unconditioned stimulus. For example, in Pavlov’s experiment the bell was the neutral stimulus, and only produced a response when it was paired with food.
Unconditioned stimulus
In classical conditioning, the unconditioned stimulus is a stimulus that causes a natural and automatic unconditioned response. In Pavlov’s study, the unconditioned stimulus was food, which already made the dog salivate. [Note that salivation to food may have already been conditioned as a response when the dog was very young, but that was considered to be outside of the experimental setting and viewed as an instinct or reflex.]
Unconditioned response:
In classical conditioning, an unconditioned response is an unlearned response that occurs automatically when the unconditioned stimulus is presented. Pavlov showed the existence of the unconditioned response by presenting a dog with a bowl of food and the measuring its salivary secretions
Conditioned stimulus
In classical conditioning, the conditioned stimulus (CS) is a substitute stimulus that triggers the same response in an organism as an unconditioned stimulus. Simply put, a conditioned stimulus makes an organism react to something because it is associated with something else. For example, Pavlov’s dog learned to salivate at the sound of a bell.
Conditioned response
In classical conditioning, the conditioned response (CR) is the learned response to the previously neutral stimulus. In Ivan Pavlov’s experiments in classical conditioning, the dog’s salivation was the conditioned response to the sound of a bell.
Classical conditioning in humans
Person has a stomach bug (US) causing nausea (UR)
Person eats chocolate (NS)
Person vomits from stomach bug after eating chocolate (acquisition)
Person now feels disgust/nausea (CR) for chocolate (CS)
Operant Conditioning
(sometimes referred to as instrumental conditioning) is a method of learning that employs rewards and punishments for behavior. Through operant conditioning and repeated experience, an association is made between a behavior and a consequence (whether negative or positive) for that behavior. The response is then increased or decreased. Applies to voluntary behaviors.
Reward/reinforcement increases desired behavior
Punishment decreases behavior
Skinner’s classic pigeon experiment: operant conditioning
1) Pigeon presented with colored dot (stimulus)
2) Pigeon pecks dot (response)
3) Pigeon receives food (Pos. reinforcement)
Pigeon learns association that pecking dot predicts food
Key: food reward must occur immediately after the peck in order for association to be learned
Reinforcement
is a term used in operant conditioning to refer to anything that increases the likelihood that a response will occur. Reinforcement can include anything that strengthens or increases a behavior, including specific tangible rewards, events, and situations. Primary reinforcements occur naturally and tend to have an evolutionary basis in that they aid in the survival of the species (e.g., air, food, sleep, sex, water). Secondary reinforcements involve stimuli that have become rewarding by being paired with another reinforcing stimulus
Positive reinforcement
adds something to increase desired `response/behavior
Negative reinforcement
removes something in order to increase desired response/behavior
Punishment
is a term used in operant conditioning to refer to any change that occurs after a behavior that reduces the likelihood that that behavior will occur again in the future. While positive and negative reinforcements are used to increase behaviors, punishment is focused on reducing or eliminating unwanted behaviors. The difference: Reinforcement increases the chances that a behavior will occur and punishment decreases the chances that a behavior will occur.
Positive punishment
involves presenting an aversive stimulus after a behavior has occurred in order to decrease that behavior.
Negative punishment
involves taking away a desirable stimulus after a behavior has
occurred in order to decrease that behavior.
Reinforcement schedules
In situations when present reinforcement is controlled, such as during training, the timing of when a reinforcer is presented can be manipulated. During the early stages of learning, continuous reinforcement is often used, such as when you first teach your dog a new trick. However, during later stages of learning, variable partial reinforcements tend to lead to a fast response rate and slow extinction rate.
Continuous Reinforcement
This schedule involves reinforcing a response each and every time it occurs. Learning tends to occur relatively quickly, yet the response rate is quite low. Extinction also occurs very quickly once reinforcement is halted.
Partial Reinforcement
Once a behavior has been acquired, it’s often a good idea to switch to a partial reinforcement schedule. The four main types of partial reinforcement include: Fixed interval, fixed ratio, variable interval and variable ratio
Fixed-interval schedules
Reinforcing a behavior after a specific period of time has elapsed. Response rates remain fairly steady and start to increase as the reinforcement time draws near, but slow immediately after the reinforcement has been delivered.
Fixed-ratio schedules
Reinforcing a behavior after a specific number of responses have occurred. This typically leads to a fairly steady response rate.
Variable-interval schedules
Reinforcing the behavior after an unpredictable period of time has elapsed. This tends to lead to a fast response rate and slow extinction rate.
Variable-ratio schedules
Reinforcing the behavior after an unpredictable number of responses. This also leads to both a high response rate and slow extinction rates.
Acquisition
apply to both classical and operant conditioning: In the initial period of learning, acquisition describes when an organism learns to connect a neutral stimulus and an unconditioned stimulus.
Extinction
apply to both classical and operant conditioning: In psychology, extinction refers to gradual weakening of a conditioned response by breaking the association between the conditioned and the unconditioned stimuli. For example, when the bell was repeatedly rung and no food presented Pavlov’s dog gradually stopped salivating at the sound of the bell.
Spontaneous recovery
apply to both classical and operant conditioning: Spontaneous Recovery is a phenomenon of Pavlovian conditioning that refers to the return of a conditioned response (in a weaker form) after a period of time following extinction. For example, when Pavlov waited a few days after extinguishing the conditioned response, and then rang the bell once more, the dog salivated again.
Generalization
apply to both classical and operant conditioning: In psychology, generalization is the tendency to respond in the same way to stimuli that are similar but not identical to the conditioned stimulus. For example, in Pavlov’s experiment, if a dog is conditioned to salivate at the sound of a bell, it may later salivate to a higher pitched bell.
Discrimination
apply to both classical and operant conditioning: In classical conditioning, discrimination is a process through which individuals learn to differentiate among similar stimuli and respond appropriately to each one. For example, eventually Pavlov’s dog learns the difference between the sounds of the 2 bells and no longer salivates at the sound of the non-food bell.
Temporal contiguity
occurs when two stimuli are experienced close together in time and, as a result, an association may be formed. The repeated co-activation of circuits increases the likelihood that if one of those circuits is activated the other will also activate (Circuits that fire together, wire together). In Pavlovian conditioning the strength of the association between the conditioned stimulus (CS) and the unconditioned stimulus (US) is largely affected by temporal contiguity. If the CS and UC are too far apart in time, no association will be made.
Hebbian theory
is a neuroscientific theory based on the idea that an increase in synaptic efficacy arises from a presynaptic cell’s repeated and persistent stimulation of a postsynaptic cell. It is an attempt to explain synaptic plasticity, the adaptation of brain neurons during the learning process
Synaptogenesis/Dendritization
Increase in number of dendritic branches (more surface area for more receptors to increase chance of AP)
Hebbian synapse
is a junction between neurons that is strengthened when it successfully fires the postsynaptic cell.
Long-term potentiation (LTP)
is a persistent strengthening of synapses based on recent patterns of activity. These are patterns of synaptic activity that produce a long-lasting increase in signal transmission between two neurons. It is one of several phenomena underlying synaptic plasticity, the ability of chemical synapses to change their strength. As memories are thought to be encoded by modification of synaptic strength, LTP is widely considered one of the major cellular mechanisms that underlies learning and memory. One of the key indicators of LTP induction is the increase in the ratio of AMPAR to NMDARs following high-frequency stimulation. The idea is that AMPARs are trafficked from the dendrite into the synapse and incorporated through some series of signaling cascades.
Long term potentiation leads to the increased likelihood of a neuronal response (AP) along repeatedly co-activated circuits in post synaptic cell
LTP Process
Glutamate binds to postsynaptic AMPARs and another glutamate binds the NMDAR. Ligand binding causes the AMPARs to open, and Na+ flows into the postsynaptic cell, resulting in a depolarization. NMDARs, on the other hand, do not open directly because their pores are occluded at resting membrane potential by Mg2+ ions (Mg++ blocks ion gates). NMDARs can open only when a depolarization from the AMPAR activation leads to Mg2+ cation being kicked out into the extracellular space, allowing the pore to pass current. Unlike AMPARs, however, NMDARs are permeable to both Na+ and Ca2+. The Ca2+ that enters the cell triggers the upregulation of AMPARs to the membrane, which results in a long-lasting increase in EPSP size underlying LTP. The calcium entry also phosphorylates the enzyme CaMKII, which phosphorylates AMPARs, increasing their single-channel conductance. Prolonged activity along the circuit leads to other structural changes such as building new dendritic branches.
