List-method directed forgetting of
neutral and emotional words
Simon Nørby, PhD
Department of Learning
Aarhus University
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)
The directed forgetting paradigm: Explanation

Inhibition: What?

Attempting inhibition of a bad memory
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
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.
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).
Results (1st session)
Recall of neutral list 1 words inferior to
recall of neutral list 2 words.
Recall
50
Recall %
40
30
List 1
Recall of negative list 1 words slightly
superior to recall of negative list 2 words.
List 2
20
10
Recall of positive list 1 words inferior to
recall of positive list 2 words.
0
Neutral
Negative
Positive
Results (2nd session)
Recall
Increased difference in recall of list 1 and
list 2 neutral words.
50
Recall %
40
30
List 1
List 2
Increased difference in recall of list 1 and
list 2 negative words.
20
10
0
Neutral
Negative
Positive
Still a minor difference in recall of list 1
and list 2 positive words.
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.
30
Baseline corrected recall (%)

NoThink: Emotional
NoThink: Neutral
Think: Emotional
Think: Neutral
20
10
0
-10
0 (Baseline)
8
16
Repetitions
(from Nørby, Lange & Larsen,
2010)
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.
That was it…
Thanks to:
Axel Larsen
Christian Gerlach
Learning Lab Denmark (DPU)
Center for Visual Cognition (KU)