List-method directed forgetting of neutral and emotional words

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 Attempting inhibition of a bad memory • 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) From MacLeod, 2003

4. Design • Aims • 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 • 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)