exam 2 Flashcards
Operant Behavior
• Pavlovian responses are passive; they happen to you (reflexes, autonomic reactions).
• Operant behavior is active; it consists of the things you do.
Pavlovian responses are elicited(by stimuli) Operant behavior is emitted(by an organism)
• B. F. Skinner coined the term “operant behavior” to characterized the behavior studied by his influential predecessor, Edward Thorndike.
• Many of Skinner’s early ideas were derived from Thorndike’s work, but Skinner developed his own terminology and philosophical perspective (radical behaviorism).
Thorndike: The Law of Effect
- Thorndike’s research emphasized the effects on learning of the consequences that follow behavior.
- Law of Effect: Behavior followed by favorable outcomes will increase in frequency; behavior followed by undesirable outcomes will decrease.
- Therefore, he was the first scientist to systematically study operant behavior, although he called the changes that occurred trial-and error learning.
Skinner’s operant learning is not S-R (reflex) learning
• Early behaviorists like John Watson used the reflex terminology of stimulus-response (S-R) psychology to account for all behaviors.
• From this perspective, stimuli force responses much like meat in a dog’s mouth forces salivation.
• Using the reflexive, S-R approach leads to awkward, mechanistic explanations of voluntary, goal-oriented behaviors.
• Example on board of Clark Hull’s S-R chaining
– Every point in a maze is a stimulus that drives an organism reflexively to the reinforcement at the end of a maze.
Molecular vs Molar Behaviorism
Watson and Hull’s early Molecular approach:
All behavior, even operant behavior,is made up of S-R chains.Complex behavior = more complex chains.
Tolman & Skinner’s molar approach:
Behavior is made up of learned,whole, integrated acts that can be extended over time in complex ways. No need to describe or account for every twitch: just describe the final behavioral outcome—the rat runs to the end of the maze more rapidly than before.
S-R vs R-S learning
- Skinner agreed that classical (Pavlovian) conditioning could be characterized as S-R learning.
- But not all learning was S-R learning.
- Operant conditioning might be better described as R-S learning
- Complex behaviors are emitted first (R)
- This response leads to an environmental outcome (S), which then determines whether R is likely to be repeated.
The Selection of Operant Behavior
- Skinner preferred to describe operant conditioning in terms borrowed from Darwin’s natural selection.
- The principle of selection of behavior states that an individual emits behavior that produces effects, consequences, or outcomes.
- Based on these consequences,some behaviors increase in an organism’s behavioral repertoire while other behaviors decline or become extinct.
- (Analogous to physical traits increasing or decreasing in a population due to natural selection)
- Try something (behave); keep what works (i.e. what brings reinforcement)
Methodological Advances
• Discrete Trial Procedures: Behavior of an organism ends a trial (e.g., escape from box, or finding the end of a maze ends a trial; start again)
– Requires researchers to be present during task.
• Skinner introduced “Free Operant Procedures” : Ongoing operant behavior can be “freely” repeated any number of times; rates of responding automatically recorded by a cumulative recorder.
– Researchers can do other things while behavior is recorded automatically.
Operant Conditioning
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• Any procedure through which an operant behavior becomes stronger or weaker depending on the consequences of that behavior.
–Strength of behavior refers to its frequency, rate, probability of occurrence, intensity, or persistence.
Contingency
• In operant conditioning, we say that the strength of an operant behavior is contingent upon its consequences.
–Recall that contingency implies an if-then relationship.
• In operant conditioning, if I do this, then a certain consequence follows.
• If behavior, then consequence.
Operant Conditioning Procedures
- Reinforcement: providing consequences that increase or maintain the strength of an operant behavior.
- Punishment: providing consequences that reduce the strength of an operant behavior.
Environmental Consequences
• Consequences of a behavior can be described in terms of whether an environmental stimulus is presented or removed as a result of a behavior.
–Sometimes our actions result in something becoming present or available to us.
–Think (+) (addition)
–Sometimes our action result in something being removed or taken from us.
–Think (−) (subtraction)
Two types of Reinforcement
Positive Reinforcement: A response is strengthened by adding a stimulus or increasing its intensity
(e.g., + food, praise)
The stimulus is called a positive reinforcer.
Negative Reinforcement: A response is strengthened by subtracting a stimulus or decreasing its intensity
(e.g.,—shock, nagging)
The stimulus is called a negative reinforcer.
Positive reinforcers as rewards
- Positive reinforcers are often things we seek out, things that bring us pleasure or satisfaction, things that might be called rewards for our behavior.
- Sometimes positive reinforcement is called reward learning.
- Skinner objected: “People are rewarded, but behavior is reinforced.”
- What is positively reinforcing must be determined empirically: does its presentation increase the strength of behavior?
Negative reinforcement and escape
- Negative reinforcers are often things we find aversive, things we would normally avoid.
- Sometimes negative reinforcement is called escape-avoidance learning.
- We will do something more often (strengthen a behavior) to avoid or escape something we don’t like.
- As with positive reinforcement, the stimuli that act as negative reinforcers must be determined empirically for a particular species or organism.
Punishment
Any stimulus or outcome that decreases the strength of an operant behavior.
–Positive Punishment: Decreases the likelihood of a behavior by presenting (adding) a stimulus (usually aversive).
–Negative Punishment: Decreases the likelihood of a behavior by removing (subtracting) a stimulus (usually a desirable one).
Kinds of Reinforcers: Primary & Secondary
• Primary reinforcer: any reinforcer that is not dependent on another reinforcer for its reinforcing properties.
–Often biologically based; innately or naturally reinforcing for members of a species.
–Food, water, sexual stimulation, or relief from pain, cold, or other aversive conditions.
• Secondary Reinforcer: Any reinforcer that has acquired its reinforcing properties through its association with other reinforcers.
–Also called “conditioned reinforcers”
• e.g., pair a buzzer with food (classical conditioning)
• Then the buzzer can be used to reinforce operant behavior (such as pressing a bar).
Generalized Reinforcers
- Any secondary reinforcer that has been paired with a variety of other reinforcers.
- Money: Paired with almost every imaginable reinforcer in consumer societies.
- In prisons, cigarettes are generalized reinforcers.
- In some institutions, tokens are generalized reinforcers (token economies).
Kinds of Reinforcers
–Contrived (“extrinsic”) reinforcers: Any reinforcing event that has explicitly been designed to modify behavior.
• Almost all reinforcements in research and applied behavior analysis.
–Natural (“intrinscic”) reinforcers: Any reinforcing event that follows automatically, i.e., naturally from a behavior.
• Pleasure from succeeding on a task.
• Scratching an itch.
• Reading for intrinsic pleasure (natural) vs. reading to earn a star in class (contrived).
Social Reinforcers
• Social reinforcers are consequences that involve personal communication from others
– Praise, touch, compliments
– Many mammals respond to these social reinforcers( Limbic System): “good dog” in a happy, warm tone. ‘
• Social reinforcers are easy to deliver, can be applied immediately, and are not very disruptive
Shaping & Chaining
• By definition, reinforcement must come after a behavior is emitted (a reinforcer is a consequence of the behavior).
Shaping
• Shaping involves reinforcing successive approximations to the desired (target) behavior.
– Hot, warmer, cold
Chaining
- A behavior chain is a connected (and usually ordered) sequence of distinct behaviors
- e.g., Cooking
- Once a chain has been learned, it can be considered one extended act.
Chaining Methods
– 1st Step: Task Analysis—identify each link in the chain and their order
– Forward chaining begins with the first link in a task; when a link is mastered, the next link is added as a new requirement for reinforcement. And so on.
• If any link does not readily occur, use shaping.
– Backward chaining begins with the last link and works backward toward the first link.
Prompting
Prompts are any stimuli that help an organism to initiate the desired behavior.
Some prompts are simply verbal or visual cues or reminders (sticky notes, or saying “Wash your hands.”)
Modeling (showing how) is another type of prompting.
Physical (or manual) prompting means physically guiding the organism to engage in the correct behavior.
e.g., If a dog simply will not spontaneously sit, push its rear end down, then reinforce.
Variables Affecting Reinforcement
- Contingency
- Contiguity
- Characteristics of Reinforcers
- Behavior Characteristics
- Motivating Operations
• Other odds and ends
Contingency
• Remember? If A, then B
- In operant conditioning, contingency refers to the degree of correlation between a behavior and its consequences.
- The rate of learning depends on the degree to which a behavior is followed by a reinforcer.
More contingency, more learning
- Smaller reinforcers with high contingency are generally better at producing learning than larger reinforcers with low contingency.
- Organisms will often work for a smaller “sure thing” than for a larger “long shot.”
Contiguity
- In operant conditioning, contiguity refers to the time between a behavior and its consequences.
- In general, the faster a reinforcer is delivered after a behavior, the stronger the learning.
Shorter delay, faster learning
• If a delay is too long, other behaviors might occur before reinforcement.
Characteristics of Reinforcers: Size
- All else being equal, larger reinforcers (e.g., more food) strengthen behavior more than smaller reinforcers.
- $1 vs. $100 after each A on report card.
- However, there are diminishing returns: as the size of the reinforcer increases, the rate of learning (while increasing) becomes less pronounced.
- i.e., a nonlinear relationship between size and learning.
Characteristics of Reinforcers: Quality
- Species, and individuals within a species, often have different “tastes.”
- e.g. Food is not interchangeable; some reinforce better than others.
- Rats prefer bread or milk over sunflower seeds: bread and milk strengthen behavior more than seeds.
- Reptiles do not respond to social reinforcers.
Behavior Characteristics
• Behavior that is a part of a normal repertoire for a species also affects reinforcement:
–Birds that peck for seeds in the wild (e.g., pigeons) learn to peck a disk for reinforcers much more readily than do birds of prey (e.g., hawks).
Motivating Operations
• Also called Establishing Operations
• MOs are anything that establishes conditions that improve the effectiveness of areinforcer.
–e.g. Thorndike’s work: animals were deprived of food to motivate them to find a way out of the puzzle box.
–Food deprivation established food as an effective reinforcer.
• Water (make thirsty)
• Social contact (keep isolated from others)
• Physical stimulation (sensory deprivation/boredom)
• Rest (make them tired)
• Warmth (keep in cold room)
Alternative reinforcers
• Reinforcement is weaker if there are alternative reinforcers easily available in the environment.
–A rat might not work hard for a particular type of food if there are other types lying around “for free.”
Extinction in Operant Conditioning
- In classical conditioning, if the CS (bell) is continually presented without the US (food), you get extinction: the CS will no longer elicit salivation.
- In operant conditioning, you find a similar process:
- If you withhold the reinforcing consequences of a behavior that has been reinforced in the past, the behavior will be weakened.
Another extinction phenomenon…
• When extinction begins, organism will begin to vary the previous behavior
–“try something different.”
• This can be useful in shaping: if the behavior gets “stuck” at one point, try withholding reinforcement.
• The organism will often begin variations in their behavior, perhaps offering a better approximation to the final target behavior.
Extinction and Emotion
- During the initial period of extinction, an organism will frequently increase its emotional behavior,especially aggression.
- Example: Rats who have been frequently reinforced with food for pressing a lever.
- Stop delivery of the food: Rats will become aggressive, biting at the lever, attacking other nearby rats.
Extinction-Induced Aggression
• Most organisms will attack when they are shocked, prodded, or subjected to other aversive stimuli.
• Apparently, removal of positive reinforcement is an aversive event.
– Extinction periods from previous reinforcement can been used as punishments to weaken other behaviors.
Spontaneous Recovery
- During extinction, it is typical for a behavior to continue decreasing until it reaches a pre-reinforced level or ultimately ceases.
- However, a phenomenon commonly associated with extinction is the reappearance of the behavior, after a delay,even though it has not be reinforced.
- This is called“spontaneous recovery,” just as in classical conditioning.
- Spontaneous recovery is short-lived and limited if the extinction procedure remains in effect.
Resurgence
- Condition Behavior A through reinforcement, then extinguish the behavior by withholding the reinforcement.
- Now condition Behavior B using the same reinforcer, then start to extinguish it.
- What happens?
- Subject engages in Behavior A again.
Resistance to Extinction
• The rate at which a behavior is extinguished by non-reinforcement depends on many factors.
• Continued responding during extinction is termed resistance to extinction.
• As a rule of thumb, any factor that strengthens reinforcement might also produce resistance to extinction.
• The number of times a behavior has been reinforced in the past affects resistance to extinction.
• A behavior with a long history of reinforcement will be more resistant to extinction than a behavior with fewer reinforcements.
– Number of bar presses during extinction varies by number of previous reinforcements.
Effort and Resistance to Extinction
• If a response requires greater effort, it may decrease more quickly during extinction than a response requiring less effort.
Guidelines for the Use of Extinction for Eliminating Unwanted Behavior
- Identify & withhold all sources of reinforcement for the unwanted target behavior.
- Withhold Consistently
- Consistency is important to all behavior change procedures; it is absolutely essential to extinction.
- Use Instructions (with children)
Guidelines for Extinction
• Expect Common Extinction Phenomena:
–The behavior might get worse, not better, at first.
• Extinction bursts will occur
–The behavior might come back briefly.
• Spontaneous recovery will occur
–Aggressive and immature behavior might appear
• Resurgence and extinction-induced aggression
• These are indicators that extinction is working
–so don’t get dismayed, and stay with the plan.