Memory- forgetting incl. interference theory, retriveal failure, cue dependent forgetting

What are the two main theories of forgetting in LTM?

Interference theory - memories disrupt each other.

Retrieval failure - memory is stored but cannot be accessed due to missing cues.

What is interference theory?

Forgetting occurs when one memory blocks another, causing distortion or forgetting.

Proactive interference: old memories block new memories

Retroactive interference: new memories block old memories

What is proactive interference?

When an older memory interferes with the ability to recall a newer memory.

Example: Struggling to remember your new phone number because you keep recalling your old one.

What is retroactive interference?

When a newer memory interferes with the ability to recall an older memory.

Example: Struggling to remember your old home address after moving to a new one.

McGeoch and McDonald (1931) - Retroactive Interference Study

Procedure: Participants learned a list of words, then a second list (synonyms, antonyms, unrelated words, etc.).

Findings: The more similar the second list was, the more forgetting occurred.

📊 Synonym group recalled 3.1 fewer items.

✅ Conclusion: Greater similarity = more interference.

Underwood (1957) - Proactive Interference

Aim: Does learning earlier word lists interfere with learning new ones?

Findings: Participants who learned more word lists recalled fewer items from the most recent list.

✅ Conclusion: Evidence for proactive interference.

Underwood & Postman - Retroactive Interference

Procedure:

Experimental group learned two word lists

Control group learned one

Findings: Experimental group's recall of first list was worse.

✅ Conclusion: New learning interfered with previous learning.

Evaluation of Interference Theory

❌ Artificial stimuli - word lists lack personal meaning → low ecological validity

❌ Short time frames - unlike real-life memory recall over days/weeks

✅ Replicable and controlled experiments

✅ Explains why forgetting occurs when memories are similar

What is retrieval failure?

Definition: Memory is available in LTM but cannot be accessed because cues are missing.

➡️ Known as cue-dependent forgetting.

What are retrieval cues?

Triggers that help us access memories.

External cues = context (e.g. environment)

Internal cues = mood or state (e.g. emotion, drugs)

Context-dependent forgetting - Godden & Baddeley (1975)

Procedure: Divers learned and recalled word lists in four combinations (land/underwater).

Findings: Recall was better when context at learning and recall matched.

✅ Supports external cue role in retrieval.

State-dependent forgetting - Carter & Cassaday (1998)

Procedure: Participants took antihistamines (drowsy state) when learning/recalling.

Findings: Matching internal states → 40% better recall

✅ Supports internal cues in memory retrieval.

Cue Overloading

A retrieval cue becomes less effective when it is associated with too many memories.

🔁 Makes recall harder, even if the cue is present.

Tulving & Psotka - Interference vs Cue-Dependent Forgetting

Procedure: Participants learned 1-3 word lists with category cues, then did free recall or cued recall.

Findings:

In free recall, more lists = worse recall → retroactive interference

In cued recall, performance improved, even with many lists → supports retrieval failure

✅ Shows that forgetting can be reversed if the right cue is provided.

Strengths of Cue-Dependent Forgetting

✅ Real-world application - e.g. eyewitness memory, revision techniques

✅ Supported by well-controlled lab studies (e.g. Godden & Baddeley)

✅ Explains tip-of-the-tongue phenomenon

Limitations of Cue-Dependent Forgetting

❌ May not apply to complex or emotional memories

❌ Context effects are often weak in real life (Smith, 1979)

❌ Lab studies = low ecological validity