1. List-method directed forgetting of neutral and emotional words
Simon Nørby, PhD
Department of Learning
Aarhus University

2. The directed forgetting paradigm: Description
Subjects are lead to believe that they should forget about a previously shown list of items.
(see MacLeod, 1998)
Four phases (always two lists)
Presentation of list 1
An unexpected instruction to forget list 1 items
Presentation of list 2
Free recall and maybe other memory tests
Inferior recall of List 1 compared to list 2 items (or in relation to a control group).
(see Bjork et al., 2006; MacLeod, 1998)

3. The directed forgetting paradigm: Explanation
Inhibition: What?
Some mechanism lowers the state of activation of a memory.
(see Bjork, 1989)
Inhibition: How?
Active forgetting in contrast to other theories (e.g. decay; interference).
(see Anderson, 2005)
Inhibition: Why?
Forgetting in tests of recall but not recognition.
(e.g. Basden, Basden & Gargano, 1993)
Attempting inhibition of a bad memory
From MacLeod, 2003

4. Design Aims Background
To investigate forgetting of emotional and neutral stimuli. To test the “long-term” effect of volitional forgetting.
Background
Most studies on violational forgetting use neutral stimuli, but there are reasons that forgetting of emotional material may be especially difficult.
People often want to retain positive and forget negative memories. The question about whether or not this is possible has clinical relevance.
Most studies on violational forgetting apply immidiate tests. Important to investigate whether violational forgetting has prolonged effects.

5. Design Subjects Materials Procedure
Danish students and recent graduates between 18 and 35 years of age.
Materials
48 Danish nouns (controlled for word-length, frequency, semantics, concreteness, emotionality).
16 negative, 16 positive and 16 neutral nouns.
Distributed evenly among conditions.
E.g.: “tumor”, “gift”, “handle”.
Procedure
A standard list-method DF paradigm. The “whoops method”. A re-test after one week (+/- 4 timer).

6. Results (1st session)
Recall of neutral list 1 words inferior to recall of neutral list 2 words.
Recall of negative list 1 words slightly superior to recall of negative list 2 words.
Recall of positive list 1 words inferior to recall of positive list 2 words.

7. Results (2nd session)
Increased difference in recall of list 1 and list 2 neutral words.
Increased difference in recall of list 1 and list 2 negative words.
Still a minor difference in recall of list 1 and list 2 positive words.

8. Interpretation
It is hard to forget negative memories, and attempts to do so may increase recall of such memories, especially over time.
Bad is strong (and stronger than good).
Ironic processing of negative material
(see Baumeister et al., 2001; Wenzlaff & Wegner, 2000)
The result is consistent with the outcome of a study that employed the Think/no-think paradigm.
Indicate that it is hard to forget the most unwanted memories, i.e., unpleasant memories.
(from Nørby, Lange & Larsen, 2010)

9. Interpretation
The increased forgetting effect on the neutral items over time could be due to:
Inhibition not taking immediate effect.
Emotional list 1 items having processing priority
A remember-remember control group should be engaged.
A new experiment should investigate the temporal aspect further.

10. That was it… Thanks to: Axel Larsen Christian Gerlach
Learning Lab Denmark (DPU)
Center for Visual Cognition (KU)