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C. Sleeping

Why do we sleep? We don't know, but....      [Not in book]

1. Energy Conservation & Body Healing (Krueger et al, 2016)

Sleep Cycles & Memory
                Consolidation2. Memory Consolidation !!!!

Glymphatic system3. Toxic Waste Removal (New, 2013)

Some Additional Comments

D. Dreams

The Phenomenon of Dreaming

Content of Dreams (Domhoff, 2001)

From the work of Calvin Hall and others in the middle-late 20th century, the following four (4) themes appear about dream content:

(1) Changed relatively little in American college students during the 20th century despite broad cultural changes & shifts.

(2) Little change in content once adulthood is reached: older adults dream about the same things as college students do. Confirmed in both cross-sectional and longitudinal (dream journal) research. (Repetition Principle)

(3) Stable cross-cultural similarities & differences
  • Males dream twice as often of males as females; females dream equally about males & females 
  • M & F: aggression > friendliness; misfortune > good fortunes; negative > positive emotions
  • Animals: small traditional societies > industrialized societies 
  • Aggression: M > F
(4) Continuity between concerns of waking life and dream content (Continuity Principle)

Explanations: Why Do We Dream?

Short Answer = We Actually Don't Know, but....

Freud   Cartwright   Hobson Domhoff

Wish Fulfillment (Sigmund Freud): Ungratified needs (sexual & aggressive) are expressed symbolically in dreams.

Problem-Solving (Rosalind Cartwright): Creative thinking applied to problems. There is a continuity between awake & dream content.

Activation-Synthesis (J. Allan Hobson): Subcortical area of brain activates for various purposes (perhaps cataloguing or erasing daytime experiences) and brain has to make sense of the activation. Thus, dreams are the ways it accounts for the activation.

No Adaptive Purpose (G. William Domhoff). Since we remember few of our dreams, it is hard to see that there is any adaptive purpose per se for dreaming itself. But, they DO make a kind of sense. "75 to 100 dreams from a person give us a very good psychological portrait of that individual." They reflect something of the individual's underlying personality in a general sort of way.

E. Hypnosis


 Franz Anton Mesmer & Mesmerism

  • The late 18th century Viennese physician, Franz Mesmer, "borrowed" (stole) an idea from the Jesuit, Fr. Maximillian Hell, who used magnets to "cure" people of illnesses.
  • Mesmer argued that there was an interior "animal magnetism" which he could manipulate for the health of people by laying on his hands.
  • Actually, Mesmer had discovered the power of suggestion (also called "the placebo effect").
  • A Scottish physician, James Braid, later coined the term hypnotism to identify the trance-like state induced in subjects by later followers of Mesmer, the "mesmerists".


F. Mesmer (L)    J. Braid (R)


Fr. Maximillian Hell, S.J.

What is hypnosis?

Hypnosis is defined by the American Society of Clinical Hypnosis as "a state of inner absorption, concentration and focused attention."

  • Anesthesia (pain relief)
  • Sensory distortion & hallucinations
  • Disinhibition (see below Myth #1)
  • Posthypnotic Suggestion & Amnesia (see below Myth #2)


  • Myth #1: Fear that hypnosis will cause a loss of control or a surrender of will to the hypnotist
  • Myth #2: Fear that hypnosis will cause a loss of memory or amnesia for what happened during hypnosis. This is true for only a small percentage of subjects and, usually, only if suggested by hypnotist.

What explains hypnosis?

[Sarbin @ 2004 APA] Two rival theories continue to dominate the debate

Role Playing (Nick Spanos, Ted Barber, Ted Sarbin) = Minority view

  • Suggestible people fill the role expected of a hypnotized subject
  • EEG of hypnotized subject is no different from non-hypnotized
  • Many phenomena of hypnosis (e.g., body becomes a "human plank") can be duplicated without hypnosis
  • Hypnotized subjects provide incorrect or inaccurate memories in age-regression hypnosis.

Altered State of Consciousness (Ernest "Jack" Hilgard, Martin Orne) = Majority view

  • Hypnosis creates a dissociated state of consciousness, i.e., mental processes are split into two separate streams of awareness. 
    • Consider the everyday experience of "highway hypnosis" -- driving for long distances without any consciousness while thinking about many other issues.


Carey, B. (2009, Nov. 9). A dream interpretation: Tuneups for the brain. New York Times (Online).

Domhoff, G. W. (n.d.). Dreams have psychological meaning and cultural uses, but no known adaptive function. Quantitative Study of Dreams (Adam Schneider & G. William Domhoff), University of California, Santa Cruz.  http://www2.ucsc.edu/dreams/Library/purpose.html

Giambetti, P. (2015). Fatal insomnia (Fatal Familial Insomnia). Merck Manual (Professional version). http://www.merckmanuals.com/professional/neurologic-disorders/prion-diseases/fatal-insomnia

Krueger, J. M., Frank, M. G., Wisor, J. P., & Roy, S. (2016). Sleep function: Toward elucidating an enigma. Sleep Medicine Reviews. http://dx.doi.org/10.1016/j.smrv.2015.08.005

Rechtscheffen, A., & Bergman, B. M. (2002). Sleep deprivation in the rat: An update of the 1989 paper. Sleep, 2591), 18-24. Retrieved from www.journalsleep.org/Articles/250104.pdf

Stickgold, R. (2015, October). Sleep on it! Scientific American, 52-57.

This page was originally posted on 11/14/03 and last updated on November 24, 2016