'Activation Synthesis Theory' is a
neurobiological theory of
dreams, put forward by
James Allan Hobson and
Robert McCarley in
1977, which states that dreams are a
random event caused by firing of
neurons in the
brain. This random firing sends signals to the body's
motor systems, but because of a
paralysis that occurs during
REM sleep, the
brain is faced with a
paradox. It synthesizes a narrative by drawing on
memory systems in an attempt to make sense of what it has experienced.
The original 1977 theory denied that dreams have meaning or are related to our real world environments. But this point drew criticism from other
dream experts. In response, in
1988, Hobson published a revised theory acknowledging that dreams do reflect past memories, fears, hopes, and desires.
To put it simply, Hobson and McCarley suggest that during REM sleep the
cortex is highly active and activity in the brain triggers certain neurons at random (activation). The brain then tries to make sense of this by synthesizing the random impulses into what we experience as dreams, for example a cell triggering the area of the brain that controls balance may lead to a dream of falling. When we sleep, all sensory and motor input is blocked and neurons in the cerebral cortex are activated by random impulses; the forebrain then interprets this activity and produces the dream.
However, Hobson and McCarley rule out the idea that dreams may be caused by real events and are sometimes repeated over the period of a few nights and therefore cannot be completely random. Additionally, it has been argued by some that Hobson and McCarley's account of dreaming is incompatible with the phenomenon of
lucid dreaming, though
neuroimaging studies on the relationship of lucid dreaming to normal dreaming are still ongoing.
References
#Hobson, J. A., & McCarley, R. (1977). The brain as a dream state generator: An activation-synthesis hypothesis of the dream process. American Journal of Psychiatry, 134, 1335-1348.
#Hobson, J. (1988). The Dreaming Brain. New York: Basic Books.