Memory and Altered States

A variety of studies and experiments have explored the effects of certain
variables on consciousness. For instance, it is important to ascertain the way
in which variables that increase memorability in turn influence metamemory.
Results have been inconsistent. However, it was found that when experimenters
directed subjects to remember some items and forget others, there
was an increase in recalling those items that experimenters were directed to
remember. There was, nevertheless, no effect on the accuracy of what was
remembered.

Sleep and dreams, hypnosis, and other altered states have provided another
intriguing area of study for those interested in consciousness. The relationship
of naps to alertness later in the day has proved of great interest to
psychologists. In one study, nine healthy senior citizens, seventy-four to
eighty-seven years of age, experienced nap and no-nap conditions in two
studies each. Napping was for one and one-half hours, from 1:30 to 3:00 p.m.
daily. The no-nap condition prohibited naps and encouraged activity in that
period. Various tests were used to measure evening activity as well as record
sleep. Aside from greater sleep in the twenty-four-hour period for those who
had the ninety-minute nap, there was no difference on any other measure.
The threat simulation theory of dreaming holds that dreams have a biological
function to protect the dream self. This dream self behaves in a defensive
fashion. An empirical test of this theory confirmed the predictions
and suggests that the theory has wide implications regarding the functions
of consciousness.

The study of consciousness, then, has elucidated understanding of perception,
memory, and action, created advances in artificial intelligence, and
illustrated the philosophical basis of dissatisfaction with the dualistic separation
of mind and body. Electrical correlates of states of consciousness have
been discovered as well as structures in the brain stem that regulate the
sleep cycle. Other studies have looked at neural correlates in various states
such as wakefulness, coma, the persistent vegetative state, the “locked-in”
syndrome, akinetic mutism, and brain death. There are many other areas of
consciousness in which neuroscience has made major advances.

An important problem neglected by neuroscientists is the problem of
meaning. Neuroscientists are apt to assume that if they can see that a neuron’s
firing is roughly correlated with some aspect of the visual scene, such
as an oriented line, then that firing must be part of the neural correlate of
the seen line. However, it is necessary to explain how meaning can be expressed in neural terms as well as how the firing of neurons is connected to
the perception of a face or person.