Peterson and peterson

• 24 undergraduates (1959)
• Each student took part in 8 trials
• Conducted in a lab, highly controlled setting- lack of extraneous variables coming into play however means it lacks ecological validity
• Longer the retention interval- the worse the recall
• worse recall as retention level increases- suggests STM is very short, unless something is repeated over and over
• Artificial- trigrams- not representative of everyday life
• Lack of external validity
• memory trace dissapears if not rehearsed,
• the info may be displayes in STM- new info pushes out the current info