YOUR MEMORIESof familiarity. It’s possible that the déjà vu experienced in this scenario
stems from that original, unnoticed glimpse of the scene, stored away
as an implicit memory.
Brown and Marsh created a pared-down version of this situation in
the lab. They presented participants with a range of symbols, some well-
known, others completely new. The key finding was that flashing a novel
symbol for just a few milliseconds (too quickly to be consciously seen)
before presenting it again for a longer period led the participants to
mistakenly claim to have seen the symbol before. Indeed, novel symbols
not preceded by a subliminal flash were judged to be familiar just three
percent of the time, compared with fifteen percent of the time when
preceded by a subliminal flash. Moreover, after the experiment, half
the participants said they’d experienced déjà vu during the study. The
researchers concluded that their findings provided a possible mechanism
for how false recognition – in other words, déjà vu – occurs in real life.
Nostalgia
An important mental activity made possible by memory is nostalgia –
reminiscing sentimentally about “the good old days”. The term was first
coined in the seventeenth century by a Swiss doctor, Johannes Hofer,
with reference to the homesickness experienced by Swiss mercenaries
fighting in other countries. Possible causes cited at the time included
the effect of changing atmospheric pressure on the brain and the noise
of cow bells! For much of the twentieth century, nostalgia continued to
be viewed as a negative emotion, synonymous with homesickness. Over
the last decade or so, however, there has been something of a revolution
in the way nostalgia is construed by psychologists. This is thanks largely
to the research efforts of Constantine Sedikides, Tim Wildshut, Clay
Routledge and their colleagues, who have shown that nostalgia actually
plays a positive role in our mental lives.
One of nostalgia’s key functions appears to be as a means of protecting
against the effects of loneliness. In one study, Wildshut and his team
triggered loneliness in university students by falsely telling them that
they had achieved a high score on a loneliness questionnaire and were,
indeed, lonely. Compared with the control group, the tricked students
subsequently scored particularly highly on a measure of nostalgia that
tapped how much they were missing things from their past (such as
holidays they’d had or pets they’d owned). Of course, this only shows that
feelings of loneliness trigger nostalgic thoughts, not that those nostalgic