Proactive Interference (A Comprehensive Guide)

In this article we will discuss proactive interference.

To dial a number not saved on the phone, we tend to read the number and keep on repeating it until we dial it.

But as soon as we stop repeating the information, we tend to forget it.

Many cognitive psychologists have tried to explain how we store information and with it forgetting that why we tend to forget the information we have memorized.

The most prevalent and valid model of memory is one given by Atkinson and Sheriff.

They explained the memory by forming an analogy with information processing in computers.

A person takes up the information through sensory memory, processes the information in short term memory, also known as working memory and stores the information in long term memory for future use. 

In the above mentioned example as long as a person keeps on repeating the information it stays in the working memory but due to lack of elaborative rehearsal, the information does not consolidate in long term memory and individual’s forgets it. As with memory, there are two major theories to explain forgetting known as interference theory and decay theory. 

According to interference theory, a person forgets the particular information because of the competing information while according to decay theory forgetting of information is considered as the function of time. 

Interference theory:

According to interference theory forgetting occurs because recall of information some information interferes with the recall of other information.

This theory has been studied for over a half century and has been validated by experiment. 

Experimentation on interference theory:

An experiment was conducted by Peterson and Peterson in 1959, in which participants were asked to recall the three letters for example K P L.

The combinations of three letters were called trigram. They varied the retention period between the display of trigram and recall of letters.

Participants were asked to recall trigram after 3, 6, 9, 12, 15 or 18 seconds.

The test the interference theory, Peterson and Peterson asked the participants to backward count by three from any number they said after the display.

According to them this backward counting acted as interfering information which kept the participants from rehearsing the information.

The results of the experiment showed that recall declined tremendously with the increase of time between the display of letters and recall.

It was to their surprise that even verbal counting of numbers interfered with the consolidation of information in long term memory.

Their experiment supported interference theory. 

There are two types of interference studied by psychologist:

  1. Retroactive interference: This occurs when newly learned information interferes with the recall of previously learned material. 
  2. Proactive interference: This occurs when information learned in past interferes with the newly learned information. 

Proactive interference: 

Proactive interference refers to the type of forgetting where the information learned before interferes with the memorization or retrieval of new information.

For example if you have studied French in College and then you learn Spanish in University, you will find yourself using many words of French in Spanish essay.

This phenomenon is known as proactive interference. 

Factors affecting Proactive interference:

There are two major factors which affects proactive interference: 

  1. Amount of time between the encoding of information and its retrieval. As the time increases, more and more previously learned information will interfere with it. 
  2. The amount of previously learned information. If a person has learned something new very recently, such as a language in the above mentioned example, he will be experiencing more proactive interference.

Age and Proactive interference: 

If a person had experience with his or her grandparents, he might have experienced that their grandparents remember the information of their past very accurately and tend to forget what they had in their last meal.

This can be explained by the phenomenon of proactive interference, as proactive interference is more apparent in older adults in younger adults.

Older adults have so much previously learned information that it interferes greatly with the newly learned information so they tend to forget it shortly after encoding it. 

Alcoholic and Proactive interference:

 Studies have found that individuals addicted to alcohol experience lesser proactive interference than those who are not.

It can be explained with the observation that alcoholics have difficulty in relating past information to the new one.

The lack the capability to cluster information in meaningful units and relate them with each other which makes them less prone to proactive interference. 

Brain and Proactive interference:

Through Magnetic imaging resonance technology, it has been found that an area known as Brodmann 45 in the left hemisphere is responsible for proactive interference.

It has been hypothesized, based on the observation of proactive interference in alcoholics, that area Brodmann 45 is responsible for clustering of information.

When new information is learned, it is clustered and related to past information which takes up most of the cognitive resources of an individual.

This consumption of cognitive resources in developing relation between different pieces of information, limits the resources for learning new information thus resulting in the phenomenon of proactive information. 

Proactive interference and Focus of Attention:

Focus of attention refers to the stimulus to which a person is attending to currently.

This focus of attention tends to release the individual from the effective proactive interference. .

It should be noted here the capacity of focus of attention is very limited. A person can attend to only 3-4 stimuli at one time.

With this range of stimuli, there is a minimum chance of observing proactive interference but if more stimuli are involved, more cognitive resources will be used to retain the information in working memory which will exacerbate the function of proactive interference. 

Proactive interference and Long Term Memory:

Long term memory has been divided into two types known as declarative memory and nondeclarative memory.

Former is associated with learning facts and figures while latter is associated with procedural memory and perceptual representation systems.

Procedural memory is about learning skills set such as how to ride a bicycle. Proactive interference is observed in both types of non-declarative memory. 

Proactive interference and Procedural Memory:

As mentioned above procedural memory is associated with cognitive motor skills.

Different experiments have shown proactive interference in procedural memory for example Cook in 1941 asked participants in an experiment to draw a reflection in a mirror.

In the first five trials the image was the same but in the next five trials the image was inverted.

Results of his experiment indicated that due to proactive interference, participants’ performance declined drastically.

In another study, Fittz and Jones (1961) analyzed plane crashes in WWII indicated that in most plane crashes, pilots had a history of switching between different planes which required different motor skills to control. 

Proactive interference and Declarative memory:

Declarative memory is associated with learning about something that it is the reality existing out there.

It further has been divided into two types that is semantic memory and episodic memory.

Semantic memory is the memory of facts and figures about the world while on the other hand episodic memory is associated with the memory of a particular event.

Again proactive interference has been observed in both.

Proactive interference and Semantic Memory:

Proactive interference can be observed widely in semantic memory such as the case when a person switches from leaning one type of language to another, he would be using mingling between the words of two languages.

It can also be observed when a person switches from one type of problem solving to another type of problem solving. 

Proactive interference and Episodic memory:

In addition to semantic memory, proactive interference can also be observed in episodic memory.

An experiment was conducted by Greenberg and Underwood (1950) in which they studied the effects of previously learned material on newly learned information as a function of long term memory.

Participants were asked to memorize the list of words for four successive days with the time interval of 24 hours rendering it an experiment of long term memory.

On each day, they were asked to recall the previous list and memorize a new list.

On the second day, when they only had to retrieve one list, the recall percentage was 75% but on the fourth day when participants had to recall three lists, recall lowered to 25%.

Results of the experiments showed the role of proactive interference in retrieval of information from long term memory. 

Release from proactive interference:

It should be noted that not every information leads to decline in memory.

For example if a person is learning a list of numbers, according to proactive interference, performance will eventually decline.

But if the person switches from list of numbers to list of words, performance will rebound back.

This enhancement in performance is known as release from proactive interference.

This release from proactive interference is more effective in a condition when there is more delay between encoding the stimulus and its recall. 

Effect of proactive interference on recall:

Some early psychologists such as Bartlet (1932) recognized the flaw in memory experiments.

According to him in real life, individuals do not need to remember some nonsense syllables or words from the list.

Rather they need to remember the information which is connected with each other or is in chunks.

Thus he conducted an experiment in which he asked participants to learn complete text and recall it.

Results showed that participants distorted the text which was alien to them as per their own understanding.

He explained the results of the experiment by considering the role of schema. Schemas are a mental representation of knowledge.

These schemas led the individual to assemble the knowledge in a meaningful way. 

Using the above -mentioned paradigm and experiments supporting it, it can be inferred that previously learned knowledge has major impacts on newly learned information.

It can either distort it or can inhibit it from being learned completely.

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Psychologists have proposed two theories to conceptualize proactive interference theory and decay theory.

According to interference theory, some information competes with other information inhibiting it from being memorized or retrieved.

There can either be proactive interference or retroactive interference.

In proactive interference previously learned information interferes with newly learned information and renders it difficult to learn and retrieve it.

In short term memory, proactive interference can be understood through the Brown-Peterson paradigm while in different modules of long term memory, it has been observed through different experiments. 

FAQs about Proactive Interference 

What is proactive interference in memory?

It is a process where previously learned information holds an individual back from learning or retrieving new information.

It can occur both in short term and long term memory. 

Why is proactive interference important?

Proactive interference is important to understand because it plays a major role in forgetting especially in older adults who can very efficiently retrieve previous information while having difficulty in retaining new information. 

What is recency effect in psychology?

Recency effect is associated with the order of representation of stimuli.

According to recency effect, most recently earned information is better remembered and plays a major role in judgment formation than previously received information. 


Neath, I., & Surprenant, A. M. (2015). Proactive interference.

McLeod, S. A. (2018). Proactive and retroactive interference. Simply Psychology.

Teague E.B., Langer K.G., Borod J.C., Bender H.A. (2011) Proactive Interference. In: Kreutzer J.S., DeLuca J., Caplan B. (eds) Encyclopedia of Clinical Neuropsychology. Springer, New York, NY

Sternberg, R. J., & Sternberg, K. (2016). Cognitive psychology. Nelson Education.

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