Interference

Proactive interference

Forgetting occurs when older memories, already stored, disrupt the recall of newer memories.

The degree of forgetting is greater when the memories are similar.

Retroactive interference

Forgetting occurs when newer memories disrupt the recall of older memories already stored. The degree of forgetting is again greater when the memorics are similar.

Procedure

Procedure McGeoch and McDonald studied retroactive interference by changing the amount of similarity between two sets of materials. Participants had to learn a list of 10 words until they could remember them with 100% accuracy. They then learned a new list. There were six groups of participants who had to learn different types of lists:

• Group synonyms synonyms- words with the same meanings as the originals.

• Group 2: antonyms- words with the opposite meanings to the originals.

• Group 3: words unrelated to the original ones.

• Group 4: consonant syllables,

• Group 5: three-digit numbers.

• Group 6: no new list - these participants just rested.

Findings

When the participants then recalled the original list of words, their pertormance depended on the nature of the second list. The most similar material (synonyms) produced the worst recall. This shows that interference is strongest when the memories are similar. The results are shown in the graph on the left.