Dement and Kleitman, 1957

• Assumptions

   Behavior and emotions is explained in terms of hormones,genetics , the brain and evolution
• Assumption

  Similarities and differences between people can be due to biological factors and interaction with other
• EOG

  Electro-oculo-graphy” 

  • is a technique used to measure the resting potential of the retina. (eyes)
  • It involves placing electrodes near the eyes to record the electrical activity generated by eye movements.
• "Electro-encephalography."

   It is a non-invasive technique used to record the electrical activity of the brain.
• Dream narrative

  Refers to a story or account of a dream experienced by an individual. It is a recounting of the events, characters, emotions, and experiences that occurred within the dream state.
• In Brief

  • Participants were invited to a sleep laboratory , where an EEG machine to monitor their brain waves during sleep .
  • They were woken up multiple times during the night to be asked if they remember any dream content 
  • Participants were woken up during nREM and REM .
  • Researchers used the EEG to determine any waves patter on the EEG
• Study 1 

  • Whether dream recall is more common in REM than nREM

  Study  2

  • Whether participants can accurately estimate the duration of their dreams
  • To  investigate if there is a positive correlation between the length of REM and ppts estimate of dream length

  Study 3

  • Do the eye movements relate to the dream  content?
  • whether the pattern of eye movements during REM sleep is related to the content of the dreams. This would help determine if eye movements are expressions of visual experiences within the dream, or merely random motor discharge
• Independent Variables: Depth of sleep (through brain waves), eye-movement potentials, and dream recall upon awakening.
• Dependent Variables: None explicitly stated, but one could argue that the act of waking up the subject to test dream recall could be considered a manipulated variable
• Study 1

  Natural experiment in a laboratory setting

  Whether people was woken up in REM or nREM sleep

  Whether a dream was reported and if so , the detail
• Study 2

  (True) Lab experiment - Repeated measures and correlation

  waking up after 5 or 15 minutes in REM

  Ppts estimate of dream length 

  (5 or 15 mins)
•  participants in the study

  • 9 adults (initially)
  • 7 male and 2 female 
  • Five studied in detail - spent between 6 and 17 nights
• Longitudinal Study : it involves collecting and comparing data from the same group of people , on at least 3 occasions over an extended period  
• Strengths

  • Allow researchers to follow their subjects in real time. This means you can better establish the real sequence of events, allowing you insight into cause-and-effect relationships.
  • Prospective longitudinal studies eliminate the risk of recall bias, or the inability to correctly recall past events.
• Weaknesses

  • Time-consuming and often more expensive than other types of studies, so they require significant commitment and resources to be effective.
  • Attrition (withdrawal), which occurs when participants drop out of a study, is common in longitudinal studies and may result in invalid conclusions.
• Longitudinal studies are better to establish the correct sequence of events, identify changes over time, and provide insight into cause-and-effect relationships, but they also tend to be more expensive and time-consuming than other types of studies.
• Procedure

  First Part 

  1. Participants ts were asked to live normally except no alcohol or caffeine
  2. Arrived at the sleep lab at the University of Chicago
  3. Normal bedtime (it will dependent on each participants )
  4. Sensors connected to their face (EEG and EOG)
  5. Slept in a small dark room 

  Second Part 

  1. Participants woke up with a loud ‘doorbell’ at different times in the night or sleep stage
  2. If the Participants had been dreaming, they were asked to record their dream in a recorder next to the bed
  3. Occasionally, the researcher entered the room to ask a question
• Aim 2

  Whether participants can accurately estimate the duration of their dreams

  Results

  REM when woken - 80%  dream report (dreams)

  • nREM when awoken - 7% dream report  (very few dreams)

  Duration of REM before waking

  • 5 minutes - accuracy of dream duration - 88% (short dreams)
  • 15 minutes - accuracy of dream duration - 78% (long dreams)

  At the beginning it was an open question and it was challenging for participants so the gave them guidance
• Aim 3

  Linking Eye Movements to Dream Content

  Result

  Mainly  Vertical movement at the bottom of a cliff looking up  throwing basketballs at a net

  Mainly Horizontal Movement 

  watching two people throwing tomatoes at each other

  Mixed 

  talking in a group of people, searching for something

  Limited

  looking into the distance whilst driving a car
• Conclusion

  1. Dreams almost certainly occur during REM
  2. Dreams happen in real time
  3. Eye movement correspond to what the content of the dream
  4. Dreams can be measured objectively using a EEG to identify REM sleep
• Applications to real life

  Treating sleep issues

  And EEG can be used to determine when a person is in REM or non-REM sleep and can be  used to support a analysis of sleep issues, as some sleep disorders occur in certain stages of sleep only..
• strengths

  Quantitative data

  A strength of this study was its use of quantitative data which can be objectively analysed.

  This would help to reduce the effects of subjectivity on interpretation of dream content. For example, the number of words in the dream narrative was calculated and correlated against the amount of time spent in REM sleep. This avoided researcher bias in the interpretation of data about dreaming and REM sleep, which increases the validity of the findings.
• Strengths

  Protection of Participant 

  Maintaining confidentiality was a strength of this research. The researchers used participants' initials when discussing their results, which kept their identity hidden.

  Furthermore, no other personal details about the participants were shared. This prevented any embarrassment due to the participants' personal dream content being revealed publicly.
• weaknesses

  Individual differences

  One weakness of the operational definition of dream length (number of words used in narrative) is that there may have been significant individual differences in how verbal each participant was. For example, some participants may have a broader vocabulary and thus describe a short dream in much more detail than others. This would affect the validity of the data when correlating the number of words in a dream narrative and the length of REM sleep.
• weakness

  Some results discarded

  In the study, one issue is that the loss of some dream recordings might have affected the validity of the data. Of the 152 dreams recalled, the recordings for six had to be discarded as they could not be understood from the tape. This may have affected the validity of the data, as these poor recordings might have been genuine dream reports during non-REM sleep, with participants simply feeling more tired after waking from deep sleep and giving a mumbled recording; there is no way to know.
• Generalisability

  Weakness

  Very small group of people 

  Generalising beyond the sample

  One weakness of the sample is that there was a significant variation in the duration of sleep cycles even between the small number of five main participants. One participant averaged one period of eye movement every 70 minutes, while another only had a period of eye movement every 104 minutes. The researchers should, therefore, be cautious when generalising any findings to others, as the study demonstrated individual differences in sleep patterns.
• Generalising to everyday life

  A weakness is that the study 

  On the other hand, Dement and Kleitman believed that their results were generalisable for two reasons - firstly, because their results were similar to other studies of uninterrupted sleep and, secondly, because the physiological process of going through cycles of REM and non-REM is the same for everyone (although with individual differences in length). This would suggest that the results relating to REM sleep and dreaming could, therefore, be applied to all people.
• Reliability

  Reliability

  A strength of this research was the high level of standardisation in the procedure. All participants were fitted with the same equipment, including electrodes near their eyes and scalp, with the wires tied together behind their head. They all slept in a bed in a quiet, dark room, were woken by a doorbell and were required to narrate their dream into a tape recorder. Ensuring such a consistent procedure meant that the study could be replicated to test whether the association between dreaming and REM sleep was reliable.
• Weakness of the study:

  • Ecological Validity: the study lacks ecological validity as participants were sleeping in a laboratory attached to an EEG with electrodes on their heads, affecting their normal sleep patterns and ability to fully relax and sleep as they would normally, especially with multiple awakenings
  • Mundane realism: participants were asked to avoid drinking caffeine and alcohol before bed, which might not be a normal occurrence for them in real life, reducing the researchers' ability to confidently apply the findings to regular sleep conditions in a person's own home
• Strength 

  A strength of this study is that the researchers ensured nobody else was present when the participants recalled their dreams. This was to avoid the possibility of the experimenter influencing a person's dream narrative through prompting or expectation. Although an experimenter did enter the room occasionally to question the participant further about their dream content, this was after the participant had given their full recording. This made the research more valid and the dream reports free from experimenter effects.
• Issues and debates

  Nature: all participants recorded a greater recall better during the REM sleep than nREM meaning that people drea as a innate biological mechanism

  Nurture: The content is different because every individual has different .Meaning peoples live experiences are different which will impact the content.
• Issues and debates

  Individual : Everybody dreams (different types) (not much)

  Situational : The content of the dream differs from one person to another . The length of the rem and time in stages changes