Perry et al. · personal space
Study how oxytocin and measured empathy relate to preferred interpersonal distance across two computer-based tasks. Interpret the interaction carefully: a small, all-male sample and mixed statistical strength do not support a universal ‘closeness hormone’ claim.
Section Paper 1 · Approaches, Issues and Debates
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
How was empathy used in the study?
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
Social approach. The study investigates whether oxytocin changes the personal space people prefer and whether the pattern differs with participants’ empathy scores and the social meaning of the other person or object.
Background: Interpersonal distance helps regulate comfort in social interaction. Oxytocin has been linked to social processing, but its effects may depend on context and individual differences rather than making everyone more trusting or close. Perry and colleagues tested empathy as a moderator.
Aim and procedure
Fifty-four male University of Haifa students aged 19–32 took part. Each attended two sessions a week apart in a double-blind, placebo-controlled crossover design and received 24 IU intranasal oxytocin in one session and saline placebo in the other. A 28-item Interpersonal Reactivity Index grouped 20 participants as high empathy and 20 as low empathy; the middle scores were not in those comparisons. In Experiment 1, participants used a computerised Comfortable Interpersonal Distance task to stop an approaching friend, stranger, authority figure or ball. In Experiment 2, they chose between computer images of rooms that varied in chair spacing and non-social table–plant spacing. Task order was counterbalanced.
Results and conclusion
Both tasks showed a pattern in which the oxytocin–placebo difference depended on empathy and social distance. In Experiment 1, high-empathy participants chose closer distances with oxytocin for some figures; the overall empathy-by-treatment effect was only marginal, while the interaction with figure type was significant for the high-empathy group. In Experiment 2, the treatment-by-empathy interaction was significant for chair spacing but not for table–plant spacing; separate within-group changes were not significant. Lower-empathy participants showed an opposite directional pattern, which should not be described as a proven effect for that group.
The findings are consistent with oxytocin changing the salience of social cues in ways that depend on individual differences, rather than uniformly increasing closeness. Because some comparisons were marginal or non-significant and only men were studied, the result is not a general claim about all people or a treatment effect.
Evaluate the evidence
The double-blind placebo crossover lets each participant experience both treatments, reducing between-person differences. Two different distance tasks provide a limited conceptual replication.
Only 54 male students from one university took part, and empathy analyses used selected high and low scorers; the sample cannot represent women or all empathy levels.
Computerised approaches and room choices standardise stimuli but are not actual interpersonal encounters. The tasks may capture different aspects of personal space.
The design has multiple factors and small groups. Some key interactions were marginal or not significant within each group, so interpretation should reflect statistical uncertainty rather than the abstract’s broadest wording.
Ethics and issues/debates
The paper reports written consent, screening and ethics committee approval. Intranasal oxytocin is a pharmacological manipulation, so medical screening, qualified oversight and explicit consent are central safeguards.
The room-choice task used a cover story about a later personal conversation that did not occur; participants were told the study’s purpose at the end. Deception and debriefing should be evaluated alongside the reported consent process.
Empathy was measured by self-report and used to create groups; it was not randomly assigned, so the study tests moderation by measured traits rather than causing high or low empathy.
Oxytocin’s effect appears context-dependent in these tasks; avoid describing it as a simple ‘love’ or ‘trust’ hormone.
The findings concern preferred distance in computer tasks and do not establish how people will behave in every real social setting.
Sources for this lesson
Pause and explain
Why should the low-empathy result be described cautiously?
Worked example
A headline says, ‘Oxytocin makes people want everyone closer.’ Correct it using the study design and results.
Show the worked solution
- The study compared oxytocin with placebo in 54 male students and analysed high- and low-empathy groups.
- Closer preferred distances were mainly found in the high-empathy group and depended on the task or figure.
- Some contrasts were not significant, so the findings do not show a universal effect.
Answer The results suggest an empathy- and context-dependent pattern in two computer tasks. They do not show that oxytocin makes everyone prefer closer social distance.
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.
In the room-choice task, the treatment-by-empathy interaction appeared for chair spacing but not table–plant spacing. What does that pattern suggest?
Give me a hint
Compare a social distance with a non-social distance and avoid claiming a broad effect.
Compare my reasoning
- Chair spacing represented imagined interpersonal distance; table–plant spacing was a non-social control measure.
- The interaction was reported for chair distance, not the table–plant control.
- This suggests the pattern was tied to social spacing in this task, not every distance preference.
The result is consistent with an empathy-dependent oxytocin pattern for interpersonal spacing, rather than a general preference for changing all distances.
Look for these in your work
- Social and non-social measures distinguished
- Result tied to the measured task
- No universal claim
Evaluate the strength of the double-blind crossover and one limitation of the empathy comparison.
Give me a hint
Separate control of drug condition from the way empathy groups were formed.
Compare my reasoning
- Each participant completed oxytocin and placebo sessions, so stable individual differences are partly controlled.
- Neither the participant nor experimenter knew the session condition, reducing expectancy effects.
- Empathy was measured and participants with middle scores were not in the high/low group comparison; it was not randomly assigned and the analysis does not represent a continuous range.
The crossover and blinding strengthen the treatment comparison, but empathy remains a measured individual difference and selecting score extremes limits generalisation.
Look for these in your work
- Design strength explained
- Bias control identified
- Measured moderator limitation stated
Plan a replication that tests whether the pattern generalises beyond this sample without giving oxytocin to participants yourself.
Give me a hint
Use a safe non-drug design and define a social-distance outcome and comparison group.
Compare my reasoning
- Recruit a more varied adult sample, including genders and a wider age range, with ethics review and informed consent.
- Measure empathy continuously with a validated questionnaire and use a computer task with social and non-social distance conditions.
- Randomise or counterbalance task order, report uncertainty and avoid interpreting correlation with empathy as causal.
A broader, non-drug replication can test whether empathy relates to distance preferences across contexts, but it cannot reproduce the oxytocin manipulation without appropriate medical research oversight.
Look for these in your work
- Population broadened
- Outcome and comparator defined
- Causal and medical limits respected
Common mistakes
- Calling the low-empathy directional trend a proven significant effect
- Treating empathy group membership as an experimentally manipulated variable
- Describing the study as a treatment for social difficulty
- Ignoring that only male university students were included
What can you explain now?
What is the safest summary of the oxytocin result?
Compare with the explanation
Its association with preferred distance varied by empathy and social context in these tasks
Some effects were marginal or not significant, so a universal closeness claim goes beyond the evidence.
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Make it stick
Name the aim, the best-evidenced result and one methodological limitation of Perry et al..
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