Evidence against simple distinction between LTM and STM

Question 1

Asked participants to do arithmetic for 12s after each item in the list was presented. A & S’s model would predict displacement from STM (supported by data from Glanzer & Cunitz 1966), BUT a recency effect was still observed

• Argued that recency effect may not be due to STM, but occurs because recall is a backwards-looking process, resulting in preferential access to recent events

Answer 1

Bjork and Whitten 1974

Question 2

• Asked participants to recall a list of unrelated words while simultaneously performing a digit span task.
• Normal recency effect was observed, even with long sequences of digits
• Suggests that recency may be due to some other system than a limited-capacity short-term store.

Answer 2

Baddeley and Hitch 1977

Question 3

Argues that the distinction between STM and LTM is unneccssary. Proposed a ‘telephone pole’ analogy to explain both short-term and long-term recency effects

“The items in a memory list, being presented at a constant rate, pass by with the same regularity as do telephone poles when one is on a moving train. The crucial assumption is that just as each telephone pole in the receding distance becomes less and less distinctive from its neighbors, likewise each item in the memory list becomes less distinctive from the other list items as the presentation episode recedes into the past.”

Answer 3

Crowder 1976

Question 4

Review

• When memory of patients with medial lobe temporal damage was tested using novel visual objects, impairment was observed after only a seconds- suggesting that patients exhibited a short-term as well as long-term memory deficit
• When patients with supposedly selective STM deficits were tested using novel words, their short-term recall impairment was found to extend to LTM
• Argue that the selective memory preservation seen in previous studies may have occurred because simple, over-learned stimuli were used (e.g digits, words). Perhaps these types of v familiar stimuli become represented in other areas of the brain, resulting in “selective” memory impairments that are more apparent than real [still controversial]

Answer 4

Ranganath and Blumenfeld 2005 (Review)

Question 5

Asked participants to actively maintain a novel face in memory for 7s, then decide whether a second presented face was the same or different

• Activation was observed in the medial temporal lobe during the short-term active maintenance period- suggesting that this region may be involved in both STM and LTM

Answer 5

Ranganath and D’Esposito 2001