to catch up with theory before they could investigate this aspect of Freud’ s
theory.
In the 1950s researchers discovered that mammals experience two dis-
tinctly different kinds of sleep (Aserinsky & Kleitman, 1953). Each night we al-
ternate between periods of REM and non-REM sleep. The acronym REM
derives from the phrase “rapid eye movement ”; this period is usually accompa-
nied by rapidly moving eyes underneath closed lids. REM sleep is sometimes
called paradoxical sleep because, although our muscles are especially relaxed
during this time, our brain activity, as measured by an instrument called an
electroencephalograph, is similar to that of the waking state. Most adults spend
1 1/2 to 2 hours a night in REM sleep, spread over several periods.
The significance of this discovery for personality researchers is that REM
sleep is filled with dreams, whereas non-REM sleep has significantly fewer
dreams. Thus the discovery of REM sleep created new opportunities fordream researchers. Researchers could look at the effects of depriving people
of REM sleep, they could correlate psychological variables with the length
and amount of REM sleep, and they could wake people during REM sleepto capture dreams that might be lost by morning (Arkin, Antrobus, & Ellman,
1978; Cohen, 1979).
What did REM sleep research reveal about the relationship between
dreaming and mental health? Early researchers maintained that REM sleep,and therefore dreaming, was necessary for psychological health and that de-
priving someone of REM sleep might create serious psychological distur-
bances. Subsequent research has challenged this conclusion (Hoyt & Singer,
1978; Vogel, 1975). But dreaming does seem to have some psychological ben-
efits. Individuals deprived of REM sleep have more difficulty with stressful
tasks (McGrath & Cohen, 1978). Participants in one study were shown a
film about autopsy procedures before and after a night ’s sleep (Greenberg,
Pillard, & Pearlman, 1978). The film, depicting a physician performing an
autopsy in gruesome detail, was selected for the study because it invariably
created high levels of anxiety in viewers. Participants deprived of REM sleep
had a difficult time coping with their anxiety. Participants allowed to dreambetween showings of the film were significantly less disturbed by the film the
second time they saw it. Finally, researchers find that individuals deprived of
REM sleep one night typically respond by increasing their amount of REMsleep the next night (Bulkeley, 1997). This rebound effect also suggests that
REM sleep serves some important function.
Other research finds at least partial support for Freud’ s notion that
dreams provide an outlet for suppressed thoughts. Trauma victims who avoid
thinking about their experience during the day often have dreams about the
traumatic event at night (Mellman, David, Bustamante, Torres, & Fins,2001). Participants in one study were asked before sleep to deliberately re-
press thoughts about someone they knew while engaging in a stream-
of-consciousness writing exercise (Wegner, Wenslaff, & Kozak, 2004). Thatnight, those participants had more dreams about the person they had tried
not to think about than did participants allowed to write about the person
they knew.74 CHAPTER 4 The Freudian Approach