He conducted research into the effect of timing on conditioning with Charles B. Ferster, a fellow behavioral psychologist who worked at the Yerkes Laboratories of Primate Biology in Florida.
Ferster and Skinner found that schedules of reinforcement - the rate at which a reinforcement is repeated - can greatly influence operant conditioning. A number of types of schedules of reinforcement have been proposed by Skinner, Ferster and others, including:. A reward or punishment is provided every time an individual exhibits a particular mode of behavior. Through continuous reinforcement , the subject learns that the result of their actions will always be the same. However, the dependability of continuous reinforcement can lead to it becoming too predictable.
A subject may learn that a reward will always be provided for a type of behavior, and only carry out the desired action when they need the reward. For instance, a rat may learn that pushing a lever will always lead to food being provided. Given the security that this schedule of reinforcement provides, the rat may decide to save energy by only pressing the lever when it is sufficiently hungry. Instead of responding every time a person behaves in a particular way, partial reinforcement involves rewarding behavior only on some occasions.
A subject must then work harder to receive a reinforcement and may take longer to learn using this type of operant conditioning. Partial reinforcement can be used following a period of initial continuous reinforcement to prolong the effects of operant conditioning.
For example, an animal trainer might give a treat to a dog every time it sits on command. Once the animal has learnt that a reward provided for obeying the trainer, partial reinforcement may be used.
The dog may receive a treat only every 5 times it obeys a command, but the conditioned behavior continues to be reinforced and extinction is avoided. Partial reinforcement modifies the ratio between the conditioned response and reinforcement, or the interval between reinforcements:. Although classical and operant conditioning share similarities in the way that they influence behavior and assist in the learning process, there are important differences between the two types of conditioning.
During classical conditioning, a person learns by observation, associating two stimuli with each other. A neutral stimuli is presented in conjunction with another, unconditioned, stimulus.
Through repetition, the person learns to associate the first seemingly unrelated stimuli with the second. A person behaves in a particular manner and is subsequently rewarded or punished. They eventually learn to associate their original behavior with the reinforcement, and either increase, maintain or avoid their behavior in future in order to achieve the most desirable outcome. It explains why reinforcements can be used so effectively in the learning process, and how schedules of reinforcement can affect the outcome of conditioning.
An advantage of operant conditioning is its ability to explain learning in real-life situations. Praise following an achievement e. When a child misbehaves, punishments in the form of verbal discouragement or the removal of privileges are used to dissuade them from repeating their actions.
Operant conditioning can also be observed in its applications across a range of learning environments. Positive punishments - detention, exclusion or parents grounding their children until their behavior changes - serve to further influence behavior using the principles of operant conditioning.
And its uses are not limited to influencing human behavior: dog trainers use reinforcements to shape behavior in animals and to encourage obedience. However, it neglects individual differences and the cognitive processes that influence behavior.
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Moreover, the more predictive the situation, the more limited the repertoire might be, so that in the limit the subject may behave in persistently maladaptive way — just so long as it gets a few reinforcers.
Many of the behaviors termed instinctive drift are like this. When levels of arousal become too high, performance will decrease; thus there is an optimal level of arousal for a given learning task.
This bitonic relation seems to be the result of two opposed effects. On the one hand, the more predictive the situation the more vigorously the subject will behave — good. Autoshaping was so named because it is often used instead of manual shaping by successive approximations, which is one of the ways to train an animal to perform a complex operant task.
Shaping is a highly intuitive procedure that shows the limitations of our understanding of behavioral variation. The trainer begins by reinforcing the animal for something that approximates the target behavior.
If we want the pigeon to turn around, we first reinforce any movement; then any movement to the left say then wait for a more complete turn before giving food, and so on. But if the task is more complex than turning — if it is teaching a child to do algebra, for example — then the intermediate tasks that must be reinforced before the child masters the end goal are much less well defined.
Should he do problems by rote in the hope that understanding eventually arrives? And, if it does, why? Or should we let the pupil flounder, and learn from his mistakes? A few behaviorists deny there even is such a thing. These examples show, I think, that understanding behavioral variation is one of the most pressing tasks for learning psychologists.
If our aim is to arrive at knowledge that will help us educate our children, then the overwhelming emphasis in the history of this field on selection reinforcement , which was once appropriate, may now be failing to address some of the most important unsolved problems.
It should be said, however, that the study of operant conditioning is not aimed only at improving our education systems. The recent combination of operant conditioning with neuroscience methods of investigating the neural structures responsible for learning and expression of behavior, has contributed considerably to our current understanding of the workings of the brain.
In this sense, even a partial understanding of how learning occurs once the sought-after behavior has spontaneously appeared, is a formidable goal. Skinner made three seminal contributions to the way learning in animals is studied: the Skinner box also called an operant chamber -- a way to measure the behavior of a freely moving animal Figure 2 ; the cumulative recorder -- a graphical way to record every operant response in real time; and schedules of reinforcement -- rules specifying how and when the animal must behave in order to get reinforcement.
The combination of an automatic method to record behavior and a potentially infinite set of rules relating behavior, stimuli e. Moreover, automation meant that the same animal could be run for many days, an hour or two a day, on the same procedure until the pattern of behavior stabilized. The reinforcement schedules most frequently used today are ratio schedules and interval schedules.
In interval schedules the first response after an unsignaled predetermined interval has elapsed, is rewarded. The interval duration can be fixed say, 30 seconds; FI30 or randomly drawn from a distribution with a given mean or the sequence of intervals can be determined by a rule -- ascending, descending or varying periodically, for example.
If the generating distribution is the memoryless exponential distribution, the schedule is called a random interval RI , otherwise it is a variable interval VI schedule. The first interval in an experimental session is timed from the start of the session, and subsequent intervals are timed from the previous reward. In ratio schedules reinforcement is given after a predefined number of actions have been emitted. The required number of responses can be fixed FR or drawn randomly from some distribution VR; or RR if drawn from a Geometric distribution.
Schedules are often labeled by their type and the schedule parameter the mean length of the interval or the mean ratio requirement. For instance, an RI30 schedule is a random interval schedule with the exponential waiting time having a mean of 30 seconds, and an FR5 schedule is a ratio schedule requiring a fixed number of five responses per reward.
Researchers soon found that stable or steady-state behavior under a given schedule is reversible; that is, the animal can be trained successively on a series of procedures — FR5, FI10, FI20, FR5,… — and, usually, behavior on the second exposure to FR5 will be the same as on the first. The apparently lawful relations to be found between steady-state response rates and reinforcement rates soon led to the dominance of the so-called molar approach to operant conditioning.
Molar independent and dependent variables are rates, measured over intervals of a few minutes to hours the time denominator varies. In contrast, the molecular approach — looking at behavior as it occurs in real time, has been rather neglected, even though the ability to store and analyze any quantity of anything and everything that can be recorded makes this approach much more feasible now than it was 40 years ago.
The most well-known molar relationship is the matching law, first stated by Richard Herrnstein in For instance when one lever is reinforced on an RI30 schedule, while the other is reinforced on an RI15 schedule, rats will press the latter lever roughly twice as fast as they will press the first lever.
Although postulated as a general law relating response rate and reinforcement rate, it turned out that the matching relationship is actually far from being universally true. In fact, the matching relationship can be seen as a result of the negative-feedback properties of the choice situation concurrent variable-interval schedule in which it is measured.
Because the probability a given response will be reinforced on a VI schedule declines the more responses are made — and increases with time away from the schedule — almost any reward-following process yields matching on concurrent VI VI schedules. Hence matching by itself tells us little about what process is actually operating and controlling behavior. And indeed, molecular details matter.
Immediately it did so a food pellet would drop into a container next to the lever. The rats quickly learned to go straight to the lever after a few times of being put in the box. The consequence of receiving food if they pressed the lever ensured that they would repeat the action again and again. Positive reinforcement strengthens a behavior by providing a consequence an individual finds rewarding.
Negative reinforcement is the termination of an unpleasant state following a response. Negative reinforcement strengthens behavior because it stops or removes an unpleasant experience. Skinner showed how negative reinforcement worked by placing a rat in his Skinner box and then subjecting it to an unpleasant electric current which caused it some discomfort.
As the rat moved about the box it would accidentally knock the lever. Immediately it did so the electric current would be switched off. The consequence of escaping the electric current ensured that they would repeat the action again and again.
In fact Skinner even taught the rats to avoid the electric current by turning on a light just before the electric current came on. The rats soon learned to press the lever when the light came on because they knew that this would stop the electric current being switched on. These two learned responses are known as Escape Learning and Avoidance Learning.
Punishment is defined as the opposite of reinforcement since it is designed to weaken or eliminate a response rather than increase it. It is an aversive event that decreases the behavior that it follows. The behavior has been extinguished. Behaviorists discovered that different patterns or schedules of reinforcement had different effects on the speed of learning and extinction.
Ferster and Skinner devised different ways of delivering reinforcement and found that this had effects on. The Response Rate - The rate at which the rat pressed the lever i. The Extinction Rate - The rate at which lever pressing dies out i.
Skinner found that the type of reinforcement which produces the slowest rate of extinction i. The type of reinforcement which has the quickest rate of extinction is continuous reinforcement. Behavior is reinforced only after the behavior occurs a specified number of times.
For example, a child receives a star for every five words spelled correctly. One reinforcement is given after a fixed time interval providing at least one correct response has been made. An example is being paid by the hour. Another example would be every 15 minutes half hour, hour, etc. For examples gambling or fishing. Providing one correct response has been made, reinforcement is given after an unpredictable amount of time has passed, e.
An example is a self-employed person being paid at unpredictable times. The main principle comprises changing environmental events that are related to a person's behavior.
For example, the reinforcement of desired behaviors and ignoring or punishing undesired ones. This is not as simple as it sounds — always reinforcing desired behavior, for example, is basically bribery. There are different types of positive reinforcements. Primary reinforcement is when a reward strengths a behavior by itself. Behavior modification uses the principles of operant conditioning to accomplish behavior change so that undesirable behaviors are switched for more socially acceptable ones.
Some teachers and parents create a sticker chart, in which several behaviors are listed [link]. Sticker charts are a form of token economies, as described in the text. Each time children perform the behavior, they get a sticker, and after a certain number of stickers, they get a prize, or reinforcer. The goal is to increase acceptable behaviors and decrease misbehavior. Remember, it is best to reinforce desired behaviors, rather than to use punishment.
In the classroom, the teacher can reinforce a wide range of behaviors, from students raising their hands, to walking quietly in the hall, to turning in their homework. At home, parents might create a behavior chart that rewards children for things such as putting away toys, brushing their teeth, and helping with dinner.
In order for behavior modification to be effective, the reinforcement needs to be connected with the behavior; the reinforcement must matter to the child and be done consistently. Sticker charts are a form of positive reinforcement and a tool for behavior modification.
Once this little girl earns a certain number of stickers for demonstrating a desired behavior, she will be rewarded with a trip to the ice cream parlor. Time-out is another popular technique used in behavior modification with children. It operates on the principle of negative punishment. When a child demonstrates an undesirable behavior, she is removed from the desirable activity at hand [link]. For example, say that Sophia and her brother Mario are playing with building blocks. Sophia throws some blocks at her brother, so you give her a warning that she will go to time-out if she does it again.
A few minutes later, she throws more blocks at Mario. You remove Sophia from the room for a few minutes. There are several important points that you should know if you plan to implement time-out as a behavior modification technique. First, make sure the child is being removed from a desirable activity and placed in a less desirable location. If the activity is something undesirable for the child, this technique will backfire because it is more enjoyable for the child to be removed from the activity.
Second, the length of the time-out is important. Sophia is five; therefore, she sits in a time-out for five minutes. Setting a timer helps children know how long they have to sit in time-out. Finally, as a caregiver, keep several guidelines in mind over the course of a time-out: remain calm when directing your child to time-out; ignore your child during time-out because caregiver attention may reinforce misbehavior ; and give the child a hug or a kind word when time-out is over.
Time-out is a popular form of negative punishment used by caregivers. When a child misbehaves, he or she is removed from a desirable activity in an effort to decrease the unwanted behavior.
For example, a a child might be playing on the playground with friends and push another child; b the child who misbehaved would then be removed from the activity for a short period of time. Remember, the best way to teach a person or animal a behavior is to use positive reinforcement. For example, Skinner used positive reinforcement to teach rats to press a lever in a Skinner box. At first, the rat might randomly hit the lever while exploring the box, and out would come a pellet of food.
After eating the pellet, what do you think the hungry rat did next? It hit the lever again, and received another pellet of food. Each time the rat hit the lever, a pellet of food came out. When an organism receives a reinforcer each time it displays a behavior, it is called continuous reinforcement. This reinforcement schedule is the quickest way to teach someone a behavior, and it is especially effective in training a new behavior.
Now, each time he sits, you give him a treat. Timing is important here: you will be most successful if you present the reinforcer immediately after he sits, so that he can make an association between the target behavior sitting and the consequence getting a treat. Watch this video clip where veterinarian Dr.
Once a behavior is trained, researchers and trainers often turn to another type of reinforcement schedule—partial reinforcement. In partial reinforcement , also referred to as intermittent reinforcement, the person or animal does not get reinforced every time they perform the desired behavior. There are several different types of partial reinforcement schedules [link]. These schedules are described as either fixed or variable, and as either interval or ratio.
Fixed refers to the number of responses between reinforcements, or the amount of time between reinforcements, which is set and unchanging. Variable refers to the number of responses or amount of time between reinforcements, which varies or changes. Interval means the schedule is based on the time between reinforcements, and ratio means the schedule is based on the number of responses between reinforcements.
A fixed interval reinforcement schedule is when behavior is rewarded after a set amount of time. For example, June undergoes major surgery in a hospital. During recovery, she is expected to experience pain and will require prescription medications for pain relief.
June is given an IV drip with a patient-controlled painkiller. Her doctor sets a limit: one dose per hour. June pushes a button when pain becomes difficult, and she receives a dose of medication. Since the reward pain relief only occurs on a fixed interval, there is no point in exhibiting the behavior when it will not be rewarded. With a variable interval reinforcement schedule , the person or animal gets the reinforcement based on varying amounts of time, which are unpredictable.
Say that Manuel is the manager at a fast-food restaurant. Manuel never knows when the quality control person will show up, so he always tries to keep the restaurant clean and ensures that his employees provide prompt and courteous service. His productivity regarding prompt service and keeping a clean restaurant are steady because he wants his crew to earn the bonus.
With a fixed ratio reinforcement schedule , there are a set number of responses that must occur before the behavior is rewarded. Carla sells glasses at an eyeglass store, and she earns a commission every time she sells a pair of glasses. She always tries to sell people more pairs of glasses, including prescription sunglasses or a backup pair, so she can increase her commission.
She does not care if the person really needs the prescription sunglasses, Carla just wants her bonus. This distinction in the quality of performance can help determine which reinforcement method is most appropriate for a particular situation. Fixed ratios are better suited to optimize the quantity of output, whereas a fixed interval, in which the reward is not quantity based, can lead to a higher quality of output.
In a variable ratio reinforcement schedule , the number of responses needed for a reward varies. This is the most powerful partial reinforcement schedule. An example of the variable ratio reinforcement schedule is gambling. Imagine that Sarah—generally a smart, thrifty woman—visits Las Vegas for the first time. She is not a gambler, but out of curiosity she puts a quarter into the slot machine, and then another, and another. Nothing happens.
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