Consciousness 155Seems like quite a stretch. Wouldn’t there be lots of other possible
interpretations?Yes, and today many professionals are no longer as fond of Freud’s dream analysis as
they once were. But there are still some people who insist that dreams have symbolic mean-
ing. For example, dreaming about being naked in a public place is very common, and most
dream analyzers interpret that to mean feeling open and exposed, an expression of child-
hood innocence, or even a desire for sex. Exactly how the dream is interpreted depends on
the other features of the dream and what is happening in the person’s waking life.
The development of techniques for looking at the structure and activity of the brain
(see to Learning Objective 2.9) has led to an explanation of why people dream
that is more concrete than that of Freud.
THE ACTIVATION-SYNTHESIS HYPOTHESIS Using brain-imaging techniques such as a
PET scan (see Chapter Two), researchers have found evidence that dreams are products
of activity in the pons (Hobson, 1988; Hobson & McCarley, 1977; Hobson et al., 2000;
Weber et al., 2015). This lower area inhibits the neurotransmitters that would allow
movement of the voluntary muscles while sending random signals to the areas of the
cortex that interpret vision, hearing, and so on (see Figure 4. 4 ).
When signals from the pons bombard* the cortex during waking consciousness,
the association areas of the cortex interpret those signals as seeing, hearing, and so on.
Because those signals come from the real world, this process results in an experience
of reality. But when people are asleep, the signals from the brain stem are random and
not necessarily attached to actual external stimuli, yet the brain must somehow interpret
these random signals. It synthesizes (puts together) an explanation of the cortex’s activa-
tion from memories and other stored information.
*bombard: to attack or press.
Figure 4.4 The Brain and Activation-Synthesis Theory
According to the activation-synthesis theory of dreaming, the pons in the brainstem sends random signals
to the upper part of the brain during REM sleep. These random signals pass through the thalamus, which
sends the signals to the proper sensory areas of the cortex. Once in the cortex, the association areas of the
cortex respond to the random activation of these cortical cells by synthesizing (making up) a story, or dream,
using bits and pieces of life experiences and memories.
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