The nature of dreams
Psychological theory: Freud's psychoanalytic theory
Sigmund Freud (1900) proposed that the unconscious mind expresses itself through dreams and, therefore, the content of a person's dreams can reveal what is in their unconscious.
Dreams as primary-process thought (repression) The id is associated with irrational, instinct-driven unconscious thought called primary-process thought. This form of thought is unacceptable to the adult conscious mind so is relegated to our dreams, i.e. repressed. If we do not dream, the energy invested in these desires would build uo to intolerable levels and so threaten our sanity.
Dreams as wish fulfilment Freud believed that all dreams were the unconscious fulfilment of wishes that could not be satisfied in the conscious mind. Dreams, therefore, protect the sleeper (primary-process thought) but also allow some expression to these buried urges (wish fulfilment).
The symbolic nature of dreams According to Freud, the contents of dreams are expressed symbolically. The real meaning of a dream (latent content), is transformed into a more innocuous form (mainfest content), through the process of dreamwork. Dreamwork consists of various processes such as condensation (rich,complex dream thoughts are condensed to the brief images) and symbolism (a symbol replaces an action, person, or idea).
Neurobiological theory: The activation-synthesis hypothesis
Most dreams occur in conjunction with rapid eye movements; hence, they are said to occur during REM sleep, a period typically taking up 20-25% of sleep time. Allan Hobson and Robert McCarley (1977) suggested that the chararcteristsic neurobiological activity associated with REM sleep can explain what we experience as dreams.
There is clear evidence from EEG measurements that the cerebral cortex is highly active during REM sleep, although few external stimuli are being received. Likewise, although the motor cortex (the part of the brain that initiates impluses to promote movement) is active, impulses do not reach the muscles that control the limbs - we are effectively paralysed during REM sleep. The only muscles that are allowed to express themselves are those that control the eyes. This is why REM sleep is accompanied by rapid eye movement. Hobson and McCarley (1977) suggested that during REM sleep, the brainstem generates random signals that are essentially indistinguishable from external stimuli.
It is during the synthesis part of this process that dreams are created. When the activation (random electrical signals from the brainstem) reaches the areas of the brain that normally process internal and external sensations (e.g. the prefrontal cortex), these areas of the brain essentially do the same job that they do when we are awake - they try to make sense of the stimuli being received.
The synthesis portion of the model proposes that the often bizarre nature of dreams is due to the…