Dement and Kleitman (1957)

• The study of dream activity and its relation to physiological variables during sleep necessitates a reliable method of determining with precision when dreaming occurs
• Such a relationship was reported by Aserinsky and Kleitman who observed periods of rapid, conjugate eye movements during sleep and found a high incidence of dream recall in Ss awakened during these periods and a low incidence when awakened at other times
• Enzymes


  • They increase the rate of chemical reactions without themselves being consumed or permanently altered by the reaction
  • They increase reaction rates without altering the chemical equilibrium between reactants and products
• As temperature increases


  The rate of reaction increases
• The occurrence of these characteristic eye movements and their relation to dreaming were confirmed in both normal Ss and schizophrenics, and they were shown to appear at regular intervals in relation to a cyclic change in the depth of sleep during the night as measured by the EEG
• Three approaches were used to rigorously test the relation between eye movements and dreaming: (a) Dream recall during rapid eye movement or quiescent periods was elicited without direct contact between E and S, (b) The subjective estimate of the duration of dreams was compared with the length of eye movement periods before awakening, (c) The pattern of the eye movements was related to the dream content
• Rapid eye movements (REM)


  Discrete periods during which the eyes exhibited rapid movements
• No rapid eye movements (NREM)

  Interspersed periods in which rapid eye movements were absent
• Rapid eye movement periods occurred at fairly regular intervals throughout the night, with an average of one REM period every 92 minutes
• Awakenings during REM periods generally terminated the REM's until the next period, and the sequence of EEG changes, excluding the brief period of wakefulness, was the same as that following a REM period that ended spontaneously
• Subjects uniformly showed a high incidence of dream recall following REM awakenings and a very low incidence of recall following awakenings during periods of NREM
• The incidence of dream recall dropped precipitously almost immediately upon cessation of REM's
• Most instances of inability to recall dreaming after awakenings during REM periods occurred in the early part of the night
• Length of rapid eye movement periods

  Subjectively estimated duration of dreams
• Subjects were able to accurately choose whether the duration of their dream was 5 or 15 minutes based on their recall, except for one subject who tended to underestimate the duration
• Regularly occurring periods of REM's were observed during every night of experimental sleep in nine adult Ss
• A high incidence of dream recall was obtained from Ss when awakened during REM periods and a very low incidence when they were awakened at other times
• Series of awakenings either 5 or 15 min. after the REM's (dreaming) had begun


  Ss judged the correct dream duration with high accuracy
• The pattern of the REM's


  Was related to the visual imagery of the dream
• The eye movements recorded in analogous situations while awake corresponded closely in amplitude and pattern to those observed during dreaming
• It seems reasonable to conclude that an objective measurement of dreaming may be accomplished by recording REM's during sleep
• This stands in marked contrast to the forgetting, distortion, and other factors that are involved in the reliance on the subjective recall of dreams
• It thus becomes possible to objectively study the effect on dreaming of environmental changes, psychological stress, drug administration, and a variety of other factors and influences
• Specifically, they wanted to investigate:

  1. Does dream recall differ between REM and nREM stages of sleep
  2. Is there a positive correlation between subjective estimates of dream duration and the length of the REM period before waking?
  3. Are eye movement patterns related to dream content?
• Electroencephalograph (EEG)


  Machine that can detect and record minute changes in voltage associated with electrical activity in nerve and muscle cells
• Electro-occulograph (EOG)


  EEG used to record the frequency of eye movements
• Independent Variables


  1. Occurrence of Sleep Stage (REM or nREM)

  2. Duration of REM Sleep (5 or 15 minutes)

  3. Pattern of Eye Movement during REM Sleep (mainly vertical, mainly horizontal, both vertical and horizontal, very little or no movement)
• Dement and Kleitman (1957)

  Researchers who studied the relationship of eye movements during sleep to dream activity

  
• Independent Variable (IV)


  The variable that is manipulated or changed by the researcher
• Dependent Variable (DV)


  The variable that is measured or observed for change by the researcher
• The independent and dependent variables for each aim were:
• This study was a laboratory experiment

  • High levels of control over variables but may lack ecological validity
• The data collected was mostly quantitative


  • Relatively easy to collect and analyze statistically, but reduces complex qualitative phenomena to numbers
• The data collected about dream content was more qualitative


  • Gives richer and more interesting data but difficult to use for comparisons and hard to analyze statistically
• The sample was very small (9 participants, 5 studied intensively)
• It is possible that sleep patterns and relationships between eye movements and dreaming vary from person to person, so the conclusions may not generalize well
• The research studied participants who went to sleep in a laboratory with electrodes stuck to their heads, which is unlikely to bear much relation to normal sleep
• Participants were woken up several times during the night and asked about their dreams, which is unlikely to happen normally and may have affected their sleep
• Dement and Kleitman's research generated very many other studies into sleep and dreaming and there have been many useful findings
• This study supports both nature and nurture perspectives