Learn in your language
Skip to content
A Level · Cambridge (CIE) · 9990

Dement and Kleitman · sleep and dreams

Read the sleep-laboratory study as evidence about dream reports and REM: distinguish recorded physiology from participants’ accounts, then evaluate what the relationship can and cannot show.

Cambridge International AS & A Level Psychology 9990 · 2028–2030 · Version 1 · CORE-01
Exam scope and assessment notes

Original StudyForA teaching mapped to the Cambridge 2028–2030 syllabus. These lessons are independent study support, not Cambridge material, official mark schemes or awarded grades. No lesson reproduces a research article or Cambridge question. Human subject-expert review and full timed-paper grading remain pending. This lesson synthesises the named study from its original article and Cambridge's study outline; it is an original summary, not a reproduction of the paper.

Before you begin

  • This is one of the 12 compulsory AS core studies in the 2028–2030 Version 1 syllabus. Check that your exam entry uses this syllabus year.

Work on paper. Try each question before revealing help, and explain why your method works.

Quick readiness check

Which part of the study was measured physiologically?

What you will learn

  • Explain the study aim, sample, procedure and findings
  • Evaluate the method, ethics and evidence
  • Apply the relevant approach and issues/debates without overclaiming

Approach and research focus

Biological approach. The study asks how rapid eye movements and sleep stage relate to dream activity. It treats sleep as a measurable biological state while using participants’ reports to describe private experience.

Background: Earlier sleep research had identified recurring sleep stages and rapid eye movements. Dement and Kleitman tested whether REM recordings could be related systematically to reported dreaming, rather than treating every dream account as an isolated anecdote.

Aim and procedure

Nine adult volunteers (seven men and two women) slept in a laboratory while EEG and eye-movement recordings identified sleep states. Researchers woke participants during REM or non-REM periods and asked whether they had been dreaming, what the dream was about, and how long it seemed to last. The study combined repeated controlled awakenings with correlational comparisons between recorded sleep and recalled dream content; reported dream content remained self-report.

Results and conclusion

Across 351 awakenings, participants reported dreams after 152 of 191 REM awakenings and after 11 of 160 non-REM awakenings. The researchers also compared the duration of REM periods with participants’ estimates of dream duration and examined whether patterns of eye movement corresponded with reported dream scenes.

Dream reports were much more common after REM awakenings in this sample, supporting an association between REM sleep and reported dreaming. The findings do not show that every REM period contains a remembered dream or that eye movement alone reveals a dream’s exact content.

Evaluate the evidence

Repeated recordings and controlled awakenings allow comparison within a sleep laboratory, and EEG/eye movement measures do not depend only on a participant’s memory.

The sample was very small and demographically narrow; one person also contributed repeated observations, so awakenings are not equivalent to independent participants.

Waking interrupts sleep, while dream presence, duration and content depend on recall and verbal report. The laboratory procedure may not represent ordinary sleep.

Ethics and issues/debates

Awakening people repeatedly may cause fatigue or discomfort; informed agreement, a safe stopping point and consideration of sleep disruption are important.

The syllabus summary does not establish every consent or risk-management detail. Describe ethical implications without inventing procedures not documented in the paper.

Biological measurement makes sleep stages observable, but participants’ accounts are needed to infer subjective dream experience.

The study supports an association; avoid claiming that REM is the sole cause of dreaming or that the results establish dream meaning.

Generalisation is limited by the small adult volunteer sample and laboratory setting.

Sources for this lesson

Pause and explain

Why should 351 awakenings not be described as 351 independent people?

Put the idea to work

Worked example

A learner says, ‘The study proves that people only dream in REM sleep.’ Assess this claim using the reported awakenings.

Show the worked solution
  1. Compare the reports after REM and non-REM awakenings.
  2. REM awakenings were followed by 152 dream reports out of 191; non-REM awakenings by 11 out of 160.
  3. The non-REM reports show that the result is not ‘only REM’, and reports measure recall rather than all dream activity.

Answer The evidence supports a strong association between REM and reported dreaming, not the absolute claim that dreaming occurs only in REM. Some non-REM awakenings produced dream reports, and an unreported dream may have been forgotten.

Try a topic test

Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.

Test this topic →

From guided practice to a new situation

Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.

1 · Guided

The paper reports dream recall after 152/191 REM awakenings and 11/160 non-REM awakenings. State the pattern and one limit.

Give me a hint

Compare how often reports followed the two types of awakening, then distinguish report from experience.

Compare my reasoning
  1. Dream reports followed many more REM than non-REM awakenings.
  2. The difference supports a relationship between recorded sleep stage and reported dreaming.
  3. A person might dream but not recall it, so the figures measure reports rather than every dream.

Dream reports were substantially more frequent after REM awakenings, but recall counts cannot establish that no dreams occurred in non-REM sleep.

Look for these in your work

  • Both sleep conditions compared
  • Association stated
  • Recall limitation explained
2 · Independent

Explain why repeated laboratory recordings strengthen the method, then identify a sampling limitation.

Give me a hint

Separate control of measurement from representativeness of participants.

Compare my reasoning
  1. EEG and eye-movement recordings identify sleep periods consistently.
  2. Controlled awakenings let the researchers ask about reports at selected stages.
  3. Nine volunteers, including only two women, provide a narrow basis for generalising to all sleepers.

Repeated physiological records and controlled awakenings support a systematic comparison, while the small, narrow volunteer sample limits generalisation.

Look for these in your work

  • A procedural strength stated
  • Measures linked to the aim
  • Sample limitation tied to generalisation
3 · Transfer

Plan an ethical follow-up that tests whether sleep stage predicts later dream recall in a more varied adult sample.

Give me a hint

State a sleep-stage measure, a recall measure and a safeguard for participants.

Compare my reasoning
  1. Recruit a larger, more varied adult volunteer sample and obtain informed agreement.
  2. Record sleep stage and use a standardised, brief dream-recall prompt after planned awakenings.
  3. Limit awakenings, monitor fatigue and allow participants to stop; report that recall is not identical to dream occurrence.

Use a varied volunteer sample, standardised sleep and recall measures, and minimise waking burden with a clear stop option. Interpret the result as an association with recalled dreams.

Look for these in your work

  • Sample and measures fit the question
  • Procedure can be repeated
  • Sleep disruption and inference limits addressed

Common mistakes

  • Calling all awakenings independent participants
  • Treating dream reports as direct recordings of private experience
  • Saying non-REM dreams never occurred
  • Inferring dream content from eye movement without the participant’s report
Recall without your notes

What can you explain now?

What is the safest conclusion from the REM and non-REM recall counts?

Compare with the explanation

Dream reports were more common after REM awakenings in this sample

The non-REM reports and self-report measure rule out an absolute claim about all dreaming.

After trying it yourself, choose your next review. This is your self-assessment.

Your review choice appears on Today. Sign in to sync it across devices.

Make it stick

Name the aim, the best-evidenced result and one methodological limitation of Dement and Kleitman.

If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.

Keep learning Psychology

Course scope and assessment

Seven original lessons map all 15 AS research-method and methodological-concept sections to explained Guided, Independent and Transfer practice. All 12 compulsory AS core studies have original study-specific teaching and staged practice; five additional A Level methodology lessons cover research design and validity. All 15 Clinical, all 15 Consumer (2.1.1–2.5.3) and all 15 Health (3.1.1–3.5.3) Psychology sections link to original teaching and staged practice. All 15 Organisational Psychology sections 4.1–4.5 now have original teaching and explained staged practice; the six new 4.4–4.5 lessons bring the planning map to 92 of 92 indexed sections. Consumer lessons cover physical and psychological environments; decision models, heuristics and mistakes; packaging, selling and buying; advertising, self-monitoring, product placement, brand recognition and slogans. Evaluation boundaries are explicit: studies use particular products, samples, tasks and settings; gaze, recall, self-report, EEG indices, ratings, choices and purchases are different outcomes. Health evidence is bounded: Laba et al. measured hypothetical preferences; Riekert and Drotar raise a non-response concern; Chung and Naya's cap tracked openings, not swallowing; Chaney et al. was a short caregiver-reported pilot; Yokley and Glenwick examined immunisation attendance in one public-health setting. MacLachlan et al. report one patient, not a controlled treatment effect; Brudvik et al. compared separate child, parent and physician ratings in one emergency department. Chandola et al. found a cohort association; Wang et al. measured responses during a monitored arithmetic task; Evans and Wener observed commuters; Bridge et al. found mixed self-rated outcomes in radiotherapy. Janis and Feshbach measured short-term self-reports in one school; Lewin et al. tested a rehabilitation package, not information alone. Tapper et al. and Fox et al. studied bounded school and worksite programmes; incentive effects do not establish transfer or rule out reporting effects. Weinstein measured comparative expectations, while Seligman’s framework is conceptual and Shoshani and Steinmetz used a school-level comparison. These findings do not establish universal health effects or diagnose individuals. Need-theory examples use a child measurement study, not a workplace test; SMART is a practical checklist, not a motivational theory. Landry et al. compared reward framing with student volunteers in a lab; this does not establish universal effects in workplaces. Cuadrado et al. (2008) measured undergraduate evaluations of presented leaders, not workplace performance or hiring; this does not establish a universal gender effect. The historical 1995 Munchausen criteria are not a current diagnostic checklist. Cambridge’s 2028–2030 Reference List treats Oruč et al. (1997) as an example of genetic explanation although its participants had bipolar I; gambling disorder is listed in Cambridge’s Clinical topic but classified under addictive behaviours in ICD-11. Candidates choose two options, but all four remain listed so schools can select a route. The 92-section count is a planning index, not a Cambridge score. Remaining work is deeper coverage review, separate-year syllabus reconciliation, timed-paper practice and human subject-expert review. The separate 2027 and 2024–2026 syllabuses are not reconciled into this route. Practice is not official grading, a timed-paper simulation or human subject-expert review.

StudyForA · Learn with understanding

Original teaching content and links to official sources. Check your exam year and qualification before using a resource.