- seCtIon FIVe: BoRDeRLAnDs
belief – something we have to do in many social negotiations about entitlements
and obligations (Mahr and Csibra, 2017).
Even the concepts we often use to think about memory can lead us astray: we
tend to use the word ‘vivid’ to describe powerful memories, but when we talk
about vividness, are we referring to the level of detail or accuracy of the memory
or its intensity (Jajdelska et al., 2011)? There is evidence that a strongly emotional
sense of being ‘brought back’ to a past time can make people assume there is
more detail in their memories than is actually the case (Herz and Schooler, 2002).
Language plays many other roles in the fluidities of human memory. False mem-
ories can be created by presenting people with short narratives of plausible but
false childhood events mixed in with a few real ones; during interviews, people
need little encouragement to search for relevant thoughts, images, and feelings
and so create the ‘memory’. Doctored photographs can have the same effect: in
a study which asked participants to describe all they could remember about the
family events pictured, half of the twenty participants had talked themselves
into believing the memory was real, with their emotional involvement increasing
across the three interviews (Wade et al., 2002).
The dividing line between real and unreal is obviously blurred in the context of
memory. The division is particularly interesting when it concerns experiences
for which there can be no public corroboration, including dreams, fantasies,
and hallucinations. Did I really feel moved by a woman’s death? What does this
question mean?HALLUCINATIONS
DeFInInG HALLUCInAtIons
The term ‘hallucination’ is not easy to define, although some rough distinctions
can be helpful if not applied too rigidly. Hallucinations were distinguished from
illusions early in the nineteenth century, on the basis that hallucinations are
entirely ‘internal’ whereas illusions are misperceptions of ‘external’ things. Illu-
sions include familiar visual illusions such as the Müller-Lyer, Ponzo, or Café Wall
illusions (see Chapter 3), as well as misperceptions like seeing a pullover as a cat.
By contrast, hallucinations are perceptual experiences not elicited by an external
stimulus. This distinction is still used (e.g. Waters et al., 2014), but there is no clean
dividing line. For example, imagine that someone sees the ghost of a headless
monk float across the altar in church. We might say that there was nothing there
and that the monk was a hallucination, or alternatively that a faint swirl of candle
smoke or incense was misperceived and that the monk was an illusion.
True hallucinations are sometimes distinguished from pseudo-hallucinations, in
which the person knows that what is seen or heard is not real. For example, if you
heard a voice telling you that the thought-police were coming to get you, and you
believed they were, you would be suffering a true hallucination, but if you heard
the same voice as you were nodding off over your computer, and realised you
were working too late, that would be a pseudo-hallucination. One problem with
this distinction is that if taken too literally there must be very few true hallucina-
tions. Even with a double dose of LSD, most people still know that the arms of the
enormous monster threatening to engulf them are really the branches of a tree,