Acquisition (Psychology): Definition and Examples

Acquisition refers to the initial stage of learning when a behavior is first being acquired. The term is used in both classical and operant conditioning. 

In classical conditioning, a stimulus that naturally triggers a response (e.g., food that makes a dog salivate), is presented along with a second stimulus that is neutral (e.g., the sound of a bell).

During the acquisition phase, the two stimuli are repeatedly paired. Eventually, the previously neutral stimulus (bell) will also trigger the response (salivation).

Acquisition in Psychology Definition and Overview

Learning through response acquisition is sometimes referred to as Pavlovian conditioning, named after the Russian physiologist that first discovered this fundamental principle of learning.

During his studies, Pavlov demonstrated that a dog could be trained to salivate in response to the sound of a bell that had been repeatedly associated with food.

There are 4 key terms to know when discussing response acquisition.

• Unconditioned stimulus (UCS): This is the stimulus that naturally triggers a response. Food is a UCS because it naturally triggers a biological response such as salivation.
• Conditioned stimulus (CS): This is the stimulus that is initially neutral in that it does not trigger a response. However, by being associated with the UCS, it begins to trigger the response as well.
• Unconditioned response (UCR): This is the response that is triggered by the UCS. There is no learning by association needed.
• Conditioned response (CR): This is the term for the response that is triggered by the UCS after it has been associated with the CS.

The Acquisition Process in Classical Conditioning

There are several factors that affect acquisition.

1. Number of Pairings: Generally speaking, as the number of times the UCS and the CS are paired increases, the stronger the acquired behavior (CR). There is such a thing as one-trial acquisition, in which it only takes one pairing, but that only occurs in unusual situations.
2. Intensity of the UCS: The greater the magnitude of the UCS, the stronger the response, up to a point. For example, if Pavlov only presented a small amount of food to the dog, then it would salivate less. As the amount of food increases, so does the response.
3. Reliability of Pairing: The more times that the UCS and the CS are not paired, the longer it takes for acquisition to occur. The CS must have a predictive quality to it. The less reliable the pairing, the less predictive is the CS.
4. Contiguity: The closer in time the CS is followed by the UCS, the quicker the acquisition process. Although there are some variations of this basic principle.

The Acquisition Process in Operant Conditioning

Operant conditioning is a theory of learning which postulates that the consequences that follow a behavior determine the likelihood of it happening again.

Behaviors that are rewarded are strengthened and more likely to occur again.

Behaviors that are punished are weakened and less likely to occur again.

The term acquisition in operant conditioning refers to how long it takes for the target behavior to be established.

For example, if a target behavior is rewarded every time it occurs, which is called continuous reinforcement, then the organism will acquire that behavior quickly.

The contingency between the target behavior and the reward is consistent and contiguous, so it is quickly perceived by the organism. This leads to quick acquisition.

Because the organism wants the reward, it engages in the target behavior frequently.

However, if the target behavior is only rewarded occasionally, referred to as partial reinforcement, then it takes a while for the animal to perceive the contingency. This results in slow acquisition.

There are four intermittent reinforcement schedules:

• Fixed ratio – reinforcement occurs after a regular number of occurrences of the response (i.e. once every five responses)
• Variable ratio – reinforcement occurs after a variable number of occurrences of the response (i.e. playing bingo)
• Fixed interval – reinforcement occurs after a regular time interval (i.e. pay day every 2nd Thursday)
• Variable interval – reinforcement occurs after a random time interval

Each reinforcement schedule rewards behavior after a set number of responses (ratio schedules) or after a certain interval of time has elapsed (interval schedules).

The different schedules lead to different patterns of behavior and each contain unique strengths and weaknesses.

The schedules of reinforcement were delineated by B. F. Skinner (1965) as part of operant conditioning and based in part on Edward Thorndike’s Law of Effect (1898; 1905).

The Law of Effect states that:

“Responses that produce a satisfying effect in a particular situation become more likely to occur again in that situation, and responses that produce a discomforting effect become less likely to occur again in that situation” (Gray, 2007, p. 106).

For a detailed description of the reinforcement schedules, click here.

Acquisition vs. Extinction

While acquisition refers to the process of a behavior being learned, extinction refers to the process of the behavior being unlearned.

Taking Pavlov’s experiment as an example…

After repeated pairings, the dog salivates in response to the bell. If Pavlov were to then remove the contingency between the bell and the food and present the bell alone without the food, eventually the dog would stop salivating in response to the bell.

The bell no longer has any predictive quality, so the dog stops salivating. This is called extinction.

Extinction can also occur in operant conditioning. For example, with continuous reinforcement, extinction of the target behavior can occur quickly. The contingency between the target behavior and reward is eliminated, and this is perceived quickly by the organism.

Extinction takes longer with a partial schedule of reinforcement. Because the target behavior was sometimes rewarded, and sometimes not, it takes longer for the organism to detect the changed contingency.

Applications of Acquisition

1. In Gambling

It would be unprofitable for games of chance to reward behavior on a continuous schedule of reinforcement to establish quick acquisition.

Games such as slot machines utilize a partial reinforcement schedule (variable ratio usually) that is designed to maintain behavior and make it less susceptible to extinction.

2. In Classroom Behavior

Keeling young students on-task is always difficult. This is even more challenging with students that have learning disabilities.

For this reason, teachers will often implement a continuous schedule of reinforcement in the beginning so that students acquire the target behavior quickly.

Once acquisition has occurred, a teacher will gradually taper the reinforcement schedule, called thinning. This maintains the target behavior over time and allows the teacher to focus their efforts on other instructional goals.  

3. In Treatment of Phobias

Some programs for treating phobias rely on classical conditioning. Let’s use fear of an elevator as an example.

The elevator was initially neutral (CS). Then one day, the elevator falls several floors (UCS) and triggers intense fear (UCR). Now, the elevator also triggers fear (CR).

The goal of therapy is for the patient to associate a new conditioned response (relaxation) with the elevator.

Because both therapist and patient want this new response to be acquired quickly, the two are paired repeatedly and often.

This involves the therapist teaching the patient how to use a relaxation technique whenever they encounter the stimulus. The stimulus and relaxation are paired each and every time so that the learned response will be acquired quickly.

Conclusion

Acquisition refers to the process of a behavior being learned. In classical conditioning, this means that a previously neutral stimulus eventually evokes a response that was once naturally triggered by another stimulus.

The more frequently and contiguously the two stimuli are paired, the quicker the acquisition.

Acquisition also applies to operant conditioning. When a target behavior is rewarded continuously, the organism will acquire that behavior quickly. But, if the reward contingency is terminated, the target behavior will extinguish quickly as well.

Quick acquisition of behavior is desired in many circumstances. Teachers want their students to stay on-task as quickly as possible, while a patient wants to overcome their phobia as soon as possible as well.

Although quick acquisition is often desirable, in some circumstances it is better to make a behavior last longer. This is why slot machines and other games of chance rely on a partial schedule of reinforcement.

References

Cooper, L. (1991). Temporal factors in classical conditioning. Learning and Motivation, 22, 129-152. https://doi.org/10.1016/0023-9690(91)90020-9

Gray, P. (2007). Psychology (6^th ed.). Worth Publishers, NY.

Skinner, B. F. (1953). Science and human behavior. New York: Macmillan.

Staddon, J. E., & Cerutti, D. T. (2003). Operant conditioning. Annual Review of Psychology, 54(1), 115-144.

Thorndike, E. L. (1898). Animal intelligence: An experimental study of the associative processes in animals. The Psychological Review: Monograph Supplements, 2(4), i.

Thorndike, E. L. (1905). The elements of psychology. New York: A. G. Seiler.

Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158-177.