PDF (PhD Thesis Susan Chipchase) - Nottingham eTheses ...

depend on nonanalytic processing. The use of analytic processing at retrieval
seems to remove or reduce this effect of increased memory for positive stimuli.
Despite the identical presentation of stimuli we only found evidence of
an overall emotional enhancement bias in some conditions. This would suggest
that whether an emotional enhancement of memory will be observed depends
on the retrieval processing strategy encouraged by the retrieval task. These
findings are consistent with the idea that the process of retrieving memories is
different for emotional than non-emotional stimuli (e.g. Maratos & Rugg,
2001; Smith et al., 2004).
We found an emotional enhancement for positive, but not negative,
stimuli in comparison to neutral stimuli. This is in contrast to findings of some
previous studies which have found an advantage for negative stimuli, but not
positive (Ochsner, 2000) and in contrast to other studies which have found an
advantage for both pleasant and unpleasant stimuli (Dewhurst & Parry, 2000;
Dolcos et al., 2005). Some of the differences in patterns of emotional
enhancement of memory may be due to the different time frames involved. We
tested recognition immediately after exposure to the photographs, Ochsner
(2000) tested recognition after 2 weeks, and Dolcos et al. (2005) tested
recognition after 1 year. However, Dewhurst & Parry (2000) found an
emotional enhancement of memory after only a 10 minute delay. The length of
time for which our stimuli were presented at encoding may explain our lack of
an enhancement of memory for negative stimuli. Kensinger, et al (2006) found
an enhancement of memory for negative, over neutral, stimuli at 1000 ms and
500 ms but not at 250 ms.
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