Proactive Interference: Why Old Learning Blocks New
Proactive interference explained: how prior knowledge can block new learning, with classroom strategies to reduce confusion. Includes examples from maths, science and languages.
Proactive interference is when older memories or habits make it harder to learn or remember something new. It often shows up when you keep typing an old password, mix up a new learner’s name with last year’s class, or struggle to remember a recently changed phone number. Unlike retroactive interference, where new learning disrupts older memories, proactive interference works the other way round. Once you spot it in everyday life, it becomes much easier to see why memory can be so surprisingly stubborn.
What is proactive Interference?
Proactive interference is the disruption of new learning by previously stored information that competes for recall and attention. Teachers can help learners by showing differences clearly. Use spaced practice and contrastive examples (Underwood, 1957). This helps learners separate new information from old knowledge (Baddeley, 1999).
Proactive interference means old learning blocks new learning. Older memories stop us forming or recalling recent ones. For example, you might only recall an old phone number (Underwood, 1957). Knowing this helps explain learning difficulties (Anderson & Neely, 1996).
For a practical overview of how these ideas apply in lessons, see our guide to working memory in the classroom. The basic definition matches A level psychology explainers such as Tutor2u, Seneca Learning, Save My Exams and The Decision Lab. This article adds lesson sequencing, research caveats and university-facing citations.
| Aspect | Proactive Interference | Retroactive Interference |
|---|---|---|
| Definition | Old information interferes with new information | New information interferes with recalling old information |
| Direction | Past → Present (old blocks new) | Present → Past (new blocks old) |
| Classroom Example | Previous Spanish vocabulary makes it harder to learn French words | Learning French words makes it harder to recall previously learned Spanish |
| Common Scenario | Difficulty remembering new phone number because old one keeps coming to mind | Can't remember old phone number after learning new one |
| Teaching Strategy | Acknowledge prior knowledge, explicitly compare old vs. New concepts, spacing practise | Regular review of previously learned material, interleaved practise, retrieval practice |
Key Takeaways
- Proactive interference is a pervasive obstacle to learning new information effectively: This phenomenon, where prior learning systematically impedes the acquisition and recall of new, often similar, material, makes it harder for learners to master new concepts (Underwood, 1957). Understanding its impact is crucial for teachers when designing curriculum and instructional sequences.
- Teachers can actively employ strategies to minimise proactive interference in the classroom: Introducing distinct categories, varying the context of learning, and spacing out instruction can help learners differentiate new knowledge from previously learned, similar material (Wickens, 1970). These pedagogical approaches enhance the distinctiveness of new information, reducing the likelihood of older memories interfering.
- The degree of similarity between old and new information is a critical determinant of proactive interference: When new material closely resembles existing knowledge, the older memories are more likely to intrude, causing confusion and hindering the retrieval of the newer information for learners (McGeoch & McDonald, 1931). This shows why teachers need to make new concepts clearly distinguishable from previously taught, related topics.
- Proactive interference can contribute to the formation of inaccurate or false memories: Older, similar memories can be mistakenly recalled or blended with new experiences, leading learners to believe they remember something that did not actually occur, due to source monitoring errors (Johnson, Hashtroudi, & Lindsay, 1993). This has implications for how learners reconstruct events or information over time.
Interference theory explains why learners forget (Baddeley, 1986). Old and new facts compete and get in the way of memory (Atkinson & Shiffrin, 1968). This limits working memory and makes learning much harder.
This process of proactive interference can have a strong effect on learners (Underwood, 1957). Teachers should note that old and new information can be too similar. When this happens, learners are more likely to forget the new material (Baddeley, 1999; Ebbinghaus, 1885).
Previous learning can block new knowledge (Anderson, 2000). Baddeley (1986) said the limits of short-term memory cause this interference. This makes it much harder for learners to recall new facts.
In cognitive load theory, proactive interference often becomes extraneous load. This means the learner uses working memory to hold back the wrong earlier rule. As a result, they have less space to think about the new task (Sweller, 1988; Paas et al., 2003).
This matters for learners with ADHD, dyslexia, dyscalculia or known working-memory difficulties. Their executive-control or phonological-loop demands may already be high (Maehler & Schuchardt, 2016; Orban et al., 2022; Wang et al., 2022).
Working memory and attention rely on the prefrontal cortex. Too much information can overwhelm this area. This overload can create proactive interference, where old learning gets in the way. Research shows that neural mechanisms are key (Lee, 2022).
The hippocampus helps link new events in memory. But proactive interference is managed by a wider memory-control system. This system separates the current cue from familiar but irrelevant memory traces (Anderson & Neely, 1996; Jonides et al., 1998).
For teachers, the useful step is to mark old and new contexts clearly. Yesterday's equivalent-fraction routine is useful background knowledge, but today's ratio task needs a different retrieval cue.
How Does Proactive Interference Affect Memory?
Proactive interference is a memory effect. It happens when earlier learning disrupts how we store and recall new facts. Older facts compete with current learning for space in working memory.
This makes it much harder to process new facts (Anderson, 2000). Interference increases when old and new facts are similar (Underwood, 1957).
Researchers have studied this effect. Proactive interference happens when old information blocks new learning (Underwood, 1957). Waugh and Norman (1965) found that prior knowledge can make it harder for a learner to recall fresh data.
Learners often revisit older information, so it becomes strong in long-term memory. Rehearsal makes these older memories stronger (Anderson & Schooler, 1991; Wixted & Ebbesen, 1991). Recent work by Murayama et al (2014) supports this.
Older facts are often easier to recall than recent memories. Karpicke (2008) showed that retrieval practice strengthens learning through active recall, not repeated review. Forward-testing studies add the interference point: brief tests between learning episodes reduce intrusions from earlier material and make the next set easier to learn (Szpunar et al., 2008).
Older learners show more proactive interference (Hasher et al., 1999). They have stored more memories, said Naveh-Benjamin (2000). This increases differences in proactive interference chances.
Older learners may have slower motor skills and encoding (Salthouse, 1996). Recognition memory also declines as age differences grow (Park, Smith, & Cavanaugh, 1990; Verhaeghen & Marcoen, 1993). These changes impact how learners process information in the classroom.
These mechanisms are crucial for cognitive control (Jonides et al., 1998). FMRI and probe tasks assess how the brain handles proactive interference. They focus on the left anterior and ventrolateral prefrontal cortex. These areas support learners' cognitive control (Jonides et al., 1998).
Everyday Examples of Memory Interference
Memory interference happens every day when old learning disrupts accurate recall. Learners struggle when past vocabulary gets in the way of new words (Underwood, 1957). Spanish speakers mixing up similar English words illustrates this pattern. Old habits can also stop athletes from learning new skills (Anderson, 2000).
Proactive interference happens when old habits block new learning. (Anderson, 2000) Past knowledge hinders a learner's ability to grasp fresh concepts. (Underwood, 1957; Baddeley, 1999) This creates challenges for retaining new information. (Crowder, 1976)
In everyday memory and cognition, proactive interference explains why an old password can appear when a site asks for the new one. It also explains why a driver who moves country may reach for the windscreen wipers instead of the indicator. In school, the same process appears when a learner brings Spanish vocabulary into French or keeps using a familiar arithmetic routine after the rule has changed.
This happens because the old memory of driving a manual car blocks the new automatic memory. By understanding proactive interference, you can take steps to reduce its impact. This will improve your ability to learn and keep new facts.
Another example of proactive interference can be seen in short-term memory. When trying to remember a new phone number, a person may struggle if they have previously memorised a different phone number that is similar in sequence.
Anderson (2003) found that older memories can block new learning. Learners actively forget old facts. Shapiro and Leopold (2012) showed that mnemonics help to separate memories. These tricks help learners to recall facts.
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Proactive interference examples
Example 1: Writing Dates of a New Year
One of the most common examples of proactive interference is seen during the first few weeks or even months of a new year.
During this time, people tend to write the dates of the previous year because they have frequently rehearsed the past year and for them, it is easier to recall the previous year than the new year. Hence, their memories of the previous year interfere with their ability to remember that they have to write the date according to new the year.
Example 2: Remembering rules of a New Language
If a person is trying to learn French, but has already learned German, he may frequently find themself using German words instead of French words. Or, if a native English speaker tries to learn Italian in control conditions he may confuse English language rules with that of Italian. Their old memories of English words in their mind interfere with the new learning, making it more difficult to remember the rules of Italian.
Example 3: Recalling the names of Learners
Teachers frequently face problems in remembering the new learners' names and confuse new learners names with the names of learners they had in past years. Even teachers with many years of teaching experience may confuse the names of learners with names of their parents or siblings!
Example 4: Travelling to another country
Currency use can be hard in new countries. Prior experience interferes with using unfamiliar money. This impacts a learner's ability to handle the new system fluently.
Example 5: Shopping of Grocery
A person may face difficulty, in case of changing his diet, and learning a new list of things to purchase at the store. During grocery shopping, old purchases memory may interfere with remembering the new things in the shopping list, making it hard to remember new names while grocery shopping in the store.
How to Reduce Interference in Class
You can reduce class interference by helping learners spot new ideas. Show how these ideas differ from older knowledge. Use comparison, spacing, and retrieval practice. Use it as a starting point for professional discussion: identify the learner's current need, record evidence from more than one lesson, and agree the next classroom adjustment with the SENCO or family.
Group facts by type. Use spaced repetition to build recall. Active recall and quick feedback build strong knowledge. They also cut interference from old facts (Anderson, 2000; Bjork, 1992).
Use the next steps as a planning check: make the new cue distinct, test it briefly, then leave enough time for consolidation before teaching another highly similar idea.
- Pay attention to new information
Reduce proactive interference by asking learners to retrieve the new information without notes. Then ask them to explain how it differs from the old information. Correct the specific intrusion, as this is more useful than asking for more practice without naming the competing memory.
Research shows that active learning gets learners more engaged. Discussions, problem-solving, and case studies help learners to grasp new facts (Prince, 2004). Looking at real-world uses also keeps learners involved (Freeman et al., 2014). Overall, active learning helps to deepen their understanding.
Practising concepts helps learners link old and new knowledge, building durable retrieval pathways. Repeat the topic until learners master the skill (Wickens, 1970; Underwood, 1957).
To reduce proactive interference, make the new information distinctive. A mnemonic, song or rhyme can help, but the stronger classroom move is contrast: show the old example and new example side by side, then ask learners to say what changed.
You can remember new facts more easily by making them stand out from past memories.
Past memories can make it harder to recall new information when the new content is very close to prior learning (Underwood, 1957; Wickens, 1970). Teachers can make new content stand out, so learners find recall easier. This reduces interference with older memories.
In class, use one clear visual contrast, one worked non-example and one short comparison prompt. For example, ask learners to label which features belong to equivalent fractions and which belong to ratio before they practise mixed questions.
- Overlearning
Krug (1961) found that overlearning means learners practise after they grasp a topic. This practice helps learners remember facts and reduces mix-ups. Frequent practice supports overlearning and strengthens memory.
Practice helps information stay in long-term memory. It also improves recollection and learning performance.
Visual memory is a key capacity for processing visual data in tasks like reading or problem-solving (Luu et al., 2019). Overlearning may hinder a learner's visual memory (Luu et al., 2019). This could make it harder for them to process information.
Overlearning helps learners remember information, but it needs balance. Short breaks can reduce the clash between old and new learning. Sleep can also reduce proactive interference, as it helps the brain secure learning after competing paired-associate tasks (Bjork, 1994; Abel & Bäuml, 2014).
What is Retroactive Interference?
Retroactive interference is a memory problem. It happens when newer learning disrupts the recall of older facts. Proactive interference happens when old knowledge blocks new learning. In short, retroactive interference means new learning makes older facts harder to recall.
Retroactive interference can hinder learning because it affects inhibitory control (Shimamura, 1995). Learners studied Japanese and German word pairs. Then, Anderson & Neely (1996) gave learners interfering word pairs. Barnes & Underwood (1959) researched this topic too.
The trial participants were provided with the interference task after a few minutes of the learning task. According to the findings of experiments, the interference task led to a decrease in learning up to 20% irrespective of how long the practise trial group waited between being presented with both tasks.
These tests show that interference can make it hard to form new memories.
Here are some everyday examples of retroactive interference:
- A professional actor learns a new monologue for each play. They may forget the monologue they learned for an old play.
- A university learner learns a lot of theories of his relevant field in each semester. But, as he learns new theories in his current semester, he has trouble recalling the theories he had learned in previous semesters.
- An employee learns names of his new colleagues after joining a new company. Then a time comes when he finds it difficult to recall names of his co-workers from his previous job and incorrectly call old colleagues with the names of his colleagues at his new company.
- Learners retrieve, connect and explain key ideas.
- Complex content is chunked without lowering challenge.
- Working-memory supports are built into the plan.
What is Hermann Ebbinghaus's forgetting curve?
Hermann Ebbinghaus's forgetting curve describes how newly learned information is lost over time when it is not reviewed. The decay theory states that a memory trace is developed at the time of the formation of a new theory.
Ebbinghaus (no date) showed that memory fades without effort to keep it. Learners forget new facts quickly within the first few hours. After this fast drop, the rate of forgetting slows down over time. Ebbinghaus noted this pattern in his memory research.
This curve suggests that without any effort to retain information, we forget most of what we learn within a short period of time. However, the study mentioned in the context suggests that proactive interference can slow down the decay of memory traces and potentially improve memory retention over time.
Short-term memory has a key role in proactive interference. The forgetting curve shows that we soon forget new information if we make no effort to keep it. When we actively try to remember it, it can stay in short-term memory.
Anderson (2000) found that retroactive interference harms memory. This happens when new learning blocks older facts. Learners remember better when they actively review facts (Rohrer & Pashler, 2007). Cepeda and colleagues (2008) showed spaced practice also helps.
Previous experiments suggest that with the passage of time, these memory traces fade out and finally disappear. If a person does not retrieve and rehearse information, it will eventually be discarded.
The Decay Theory has been a topic of debate among researchers for years. Some trials have supported the theory, while others have found evidence to contradict it.
According to a study (Journal of Memory and Language), proactive interference slows memory trace decay. This means the memory trace fades more slowly. Rehearsing information also stops it from fading quickly. The study supports this, as suggested by researchers.
What Is Dual Task Interference in Learning?
Dual task interference in learning is the drop in performance that occurs when learners do two activities at once. Performance drops because working memory has limits (Baddeley, 2000). Teachers see learners struggle taking notes while listening. Both activities need the same brain power (Gathercole & Baddeley, 1993).
People struggle to do two simple tasks at once. Dual-task situations are very common today. For example, people use mobile phones while driving, cooking, or writing.
Doing a physical task and a mental task at once harms learner performance. Cross-talk and capacity-sharing are key dual-task theories. Researchers explore this concept in many studies.
Dual-task interference might stem from short-term memory demands. Attending to two tasks at once uses up these memory resources. This split attention can hinder performance (Pashler, 1994).
Baddeley (1986) showed dual tasks hurt learner retention. Interference can lower performance levels. Wickens (1984) found task difficulty and thinking skills change interference.
What Is Output Interference in Memory Retrieval?
Output interference happens when recalling one memory blocks related facts right after. Accessing one fact can stop you finding similar memories. Learners might forget a test answer because they just recalled a different one (Smith, 1971).
Output interference harms memory accuracy. Anderson and Schooler (1991) showed learners recalled fewer correct answers in sequence. Baddeley (2009) and Raaijmakers & Shiffrin (1980) found that learners made more errors. They gave fewer right answers.
To better understand output interference, researchers have used studies with positive trials. In these trials, participants see a list of items to remember. Researchers then test their memory by asking them to recall the items in order.
Nairne (2002) showed that output interference affects all answers from learners. Baddeley (1986) and Anderson (2000) found it lowers memory test scores. Researchers suggest reducing interference to boost memory.
How Does Proactive Interference Create False Memories?
Proactive interference means that earlier learning can distort new recall. It can create false memories that mix past details with current events. Learners might remember events that did not occur. The brain fills memory gaps with past details (Bartlett, 1932).
Classrooms are prone to this. Learners may blend different lessons into one memory. (Anderson, 1983).
A false memory differs from proactive or retroactive interference because it is a recollection that feels real but is partly or wholly inaccurate. In class, this might look like a learner confidently recalling that a diagram appeared in yesterday's lesson when it came from a different topic.
Research shows that mixing up where facts come from creates false memories. Old knowledge can also get in the way. This mix-up leads to learners remembering events wrongly (Loftus, 2005; Schacter, 1999).
Short-term memory can affect false memories. New information stays there for a short time before it moves into long-term storage. If similar information arrives soon after, it can muddle the first memory (Loftus, 2005). This interference leads to mistakes in what learners remember (Schacter, 1999).
To reduce this risk, ask learners to attach each new idea to its source, lesson context and worked example, not just to the topic label.
Limitations of Proactive Interference Theory
Proactive interference theory is limited because it explains memory competition better than the ways prior knowledge supports learning. It stresses memory competition, but not how memories help the learner. Some doubt if lab studies reflect classrooms (Anderson, 2000). The theory struggles when prior knowledge aids learners (Underwood, 1957).
A lot of psychological review research has been carried out to study the impacts of proactive and retroactive interference. But, there are some problems with these theories.
Most trials on interference theory occur in a lab involving word memory tasks. In the real world, people do not perform word memory tasks frequently. Due to this, most psychological review research on proactive interference & retroactive interference may not be applicable to the real world.
Anderson and Neely (1996) found proactive interference occurs outside labs. Learners struggle with new language words, because old language knowledge gets in the way. Baddeley (1999) also supports this interference in real-world settings.
Job changes may cause proactive interference, impacting a learner's recall of new duties. Despite critiques, research by Underwood (1957) and Anderson (2000) shows this interference affects real situations. Keppel and Underwood (1962) investigated forgetting rates as well.
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Frequently Asked Questions
Why Proactive Interference Matters in Teaching
Proactive interference happens when old memories block new ones. This explains why learners write last year's date or mix languages. Understanding this helps teachers spot memory issues, not just lack of effort. Knowing memory processes allows you to use helpful strategies. (Anderson, 2000)
How Teachers Can Spot Interference
Learners may show proactive interference when they use old methods after new teaching. Watch for language learners mixing vocab (Underwood, 1957). Learners might also apply old maths to new problems (Anderson, 1983).
Difficulty with updated ICT or science shows this too (Baddeley, 1990). Interference is strong when old and new information seem similar (Crowder, 1976).
Classroom Strategies That Reduce Interference
Comparing new information with old information helps learners spot key differences. Teachers can organise material into clear categories and use spaced practice (Bjork, 1992). Active recall, such as testing, helps new memories become strong enough to compete (Roediger & Butler, 2011). Regular review helps too (Karpicke & Roediger, 2008).
Why Older Learners Show More Interference
Learners build memories, which can cause learning interference. Underwood (1957) found more stored information increases proactive interference with age. Anderson & Neely (1996) suggest older learners might need more support with prior knowledge.
How Interference Affects Language Teaching
Proactive interference happens when old language knowledge blocks new language learning. Teachers can point out language differences. Ellis (1995) suggests this approach.
Contrastive analysis helps to show rule changes, according to Lado (1957). Extra practice strengthens new patterns, as DeKeyser (2007) recommends. Creating clear language contexts helps learners too (Baddeley, 1990).
Interference vs Simple Forgetting
Underwood (1957) showed old learning blocks new information access. Prior knowledge becomes strong and dominates retrieval. Anderson (1983) and Baddeley (1999) found learners revert to old knowledge, impacting new material. This may make learners seem forgetful.
Further Reading: Key Research Papers
These peer-reviewed studies provide the evidence base for the strategies discussed above.
Buildup and release from proactive interference: The forward testing effect in children's spatial memory View study ↗
Aslan et al. (2024)
Regular testing can enhance children's spatial memory by reducing proactive interference from prior learning. Teachers should integrate frequent, low-stakes tests not only for assessment but also to help pupils consolidate new information and prevent older knowledge from impeding the learning of new concepts.
Elementary math in elementary school: the effect of interference on learning the multiplication table View study ↗
Dotan et al. (2021)
This study indicates that the sequential teaching of multiplication tables can cause interference, making memorisation challenging for some children. Educators should explore varied teaching methods that minimise proactive interference, aiding pupils in distinguishing between similar mathematical facts and improving recall.
Differential effects of proactive and retroactive interference in value-directed remembering View study ↗
Murphy et al. (2022)
This paper examines how prior and subsequent learning impact memory for valued information. Teachers should be aware that presenting too much information, especially similar concepts, can lead to interference, affecting what pupils remember. Structuring lessons to highlight key information and reduce cognitive load can support better recall.
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References
Anderson (2000).
Anderson (1983).
Ausubel (1958).
Baddeley (1999).
Baddeley (1986).
Baddeley (2000).
Baddeley (1990).
Bartlett (1932).
Crowder (1976).
Freeman et al. (2014).
Hasher et al. (1999).
Jonides et al. (1998).
Lee (2022).
Loftus (2005).
Luu et al. (2019).
Pashler (1994).
Prince (2004).
Salthouse (1996).
Schacter (1999).
Shimamura (1995).
Smith (1971).
Szpunar et al. (2008).
Underwood (1957).
Wickens (1970).
