Dement and Kleitman (1957) Sleep Study

• Dement and Kleitman's 1957 study investigated the relationship between eye movements and dreaming during sleep

Participants

• Nine adult participants were studied, but results from only seven were widely reported
• Some participants were identified by their initials (WD, KC, DN, IR, DE, PM, and BB)

Procedure

• Participants arrived at the lab before their normal bedtime and slept in a dark, quiet room
• EEG electrodes were attached to the participants' scalp and around the eyes to record brain activity and eye movements
• Participants were awakened at various times during the night and asked to report their dream content

EEG Measurement

• EEG was used to objectively measure brain activity and identify different sleep stages, particularly REM sleep
• EEG recordings helped determine when dreaming was most likely to occur

Eye Movement Measurement

• EOG (electro-oculogram) recorded horizontal and vertical eye movements during sleep
• Researchers observed correlations between eye movement patterns and the content of dreams

Aims

• To investigate the relationship between eye movements and dream content.
• To test whether dream recall differs between REM and NREM sleep stages
• To investigate whether the duration of REM sleep correlates with the duration of dreams

Hypotheses

• Hypothesis 1: There is a relationship between REM sleep and dreaming
• Hypothesis 2: There is a relationship between the type of eye movement and the image in the dream
• Hypothesis 3: There is a relationship between the duration of REM sleep and the participant's estimate of dream duration

Findings: Dream Recall

• Dreams were more frequently reported during REM sleep than during NREM sleep
• 79.6% of awakenings during REM sleep produced dream reports, compared to 7% during NREM
• Participants could often accurately recall the dream content when awakened during REM sleep

Findings: Eye Movements

• Patterns of eye movements during REM sleep were related to the visual content of dreams
• Vertical eye movements were associated with dreams involving vertical movements (e.g., climbing a ladder)
• Horizontal eye movements were associated with dreams involving horizontal movements (e.g., watching a tennis match)
• Little to no eye movement was associated with dreams involving fixed objects or distant vision

Findings: Dream Duration

• Participants were able to estimate the length of their dreams accurately
• The duration of REM sleep was significantly correlated with the participant's estimate of dream duration
• Participants who were awakened after 5 minutes of REM sleep estimated their dream duration to be shorter than those awakened after 15 minutes

Conclusions

• REM sleep is a distinct sleep stage associated with dreaming
• Eye movements during REM sleep are related to the content of dreams
• The duration of REM sleep correlates with the subjective duration of dreams

Methodological Considerations

• The study used a laboratory experiment, allowing for controlled observation of sleep patterns
• EEG and EOG provided objective measures of brain activity and eye movements
• The sample size was small, which limits the generalizability of the findings
• Participants had to sleep in an unusual environment, which might have affected their sleep patterns

Strengths

• Use of objective measures (EEG, EOG) increased the validity of the findings
• High level of control in the laboratory setting
• Findings provided valuable insights into the nature of dreaming and its relationship to sleep stages

Weaknesses

• Small sample size limits generalizability
• Artificial laboratory environment might have affected sleep patterns
• Reliance on self-report for dream content introduces potential bias
• Intrusive awakenings may have impacted dream recall