Perry et al.
(Personal space)
Psychology being investigated
What is interpersonal space?
Interpersonal distance (personal space): The relative distance between people. It is the area
of space around a person in which they prefer not to have others enter.
Who introduced the idea of personal space?
Edward T. Hall introduced the idea of interpersonal distance in 1966.
What are the preferences for middle class Americans of interpersonal
distance?
Intimate: used between romantic partners or very close family members and involves all
senses.
Personal: used with other people in most everyday interactions, in which we can see, touch
and hear the other person.
Social: used in formal interactions with others, in which we may use louder voices, body
movements and eye contact.
Public: used to keep distance from public figures, in which a loud voice and body
movements usually feature.
Give examples of requirements using studies of interpersonal space:
There are several factors that have been found to influence personal space requirements
apart from how well we know the other person, for example, situational variables such as
culture (Beaulieu, 2004).
What is the relationship between oxytocin and empathy?
Oxytocin is a social hormone that heightens the importance of social cues and is linked to
positive social behaviours such as empathy. Empathy is linked to personal space.
Background
Perry et al. were interested in investigating how people’s personal space preferences are
affected by a few different factors. One of these is interpersonal distance, so they measured
people’s preferences for different social figures so they could compare how close people
want to be to strangers or friends. Perry et al. believed this preference could be influenced
by the action of social hormones on individuals’ preferences, so they also looked at the
effect of the OT.
Perry et al. tested whether people with different empathy abilities were influenced by OT in
the same or different ways when asked about their personal space preferences. In
psychology this is an interaction effect, meaning the effect of 2 or more independent
variables on at least one dependent variable in which the combined effect of the IVs is
greater or less than each variable on their own. This is represented by an x.
Aim
The aim of the study was to test the differential effect of the social hormone oxytocin (OT) on
personal space preference in relation to a person’s empathy ability.
The researchers believed that controlling for empathetic traits in individual participants would
reveal the effect of OT on interpersonal distance choices.
Nature vs Nurture in relation to empathy
Research suggests that empathy is an innate capacity, meaning that individuals are born
with it. This relates to the nature side of the debate. However, this capacity is developed over
time through interactions with others. Through nurture, individuals develop empathy as they
learn to identify and regulate emotions.
Research method and design
This study was a laboratory experiment conducted at the University of Haifa. This means it
took place in an artificial environment. It used a mixed experimental design to allocate
participants.
In both Experiments 1 and 2, the study used an independent groups design for the IV of
“empathy”. This IV was operationalised as 2 levels: “high” or “low”. Participants were
categorised into different groups and could only be either a “high” empathiser or “low”
empathiser. This IV was naturally occurring and was not manipulated by the researchers.
In both Experiments 1 and 2, the study used a repeated measures design, as all of the
participants took part in both levels of the second IV of “treatment”. The IV of “treatment” was
operationalised in the experiment as: OT administered and placebo administered. This IV
was manipulated by the researchers.
In Experiment 1 only there was a third IV known as “condition”. This was also a repeated
measures design and included the levels stranger, authority, friend and ball. There was no
third IV in Experiment 2 as the participant was always asked to imagine their personal space
in relation to the same person. This means there was no manipulation of this part of
Experiment 2.
The dependent variable (DV) was the personal space requirements of each participant. In
Experiment 1, the DV was operationalised as the preferred distance measured between
participant and approaching person/object. In Experiment 2 the DV was operationalised as
the preferred distance and angle between two chairs in a room.
Sample
54 male undergraduates from the University of Haifa, aged 19-32 years (mean age 25),
participated in this experiment for course credit or payment. All participants had normal
vision and no history of psychiatric or neurological disorders. Five participants were
left-handed. Participants were divided into two groups based on their scores on the
Interpersonal Reactivity Index (IRI), a 28-item self-report measure with four 7-item subscales
all relating to empathy.
The High Interpersonal Reactivity group contained 20 participants with empathy scores
greater than or equal to 40 and a mean age of 23.9 years. The Low Interpersonal Reactivity
group contained 20 participants with empathy scores below 33 and a mean age of 25.9
years.
Procedure
Participants attended the university in order to complete Experiment 1 and then again, a
week later on the same day and time to complete Experiment 2.
OT administration
Participants were randomly administered a treatment of either a solution of 24 international
units in 250 ml of intranasal OT or a placebo saline solution which did not contain the
hormone. The nasal drops were self-administered by participants using a nasal dropper,
under the supervision of the experimenter. This procedure used a double-blind technique;
neither the participant nor experimenter knew whether the participant had received the OT or
saline solution.
Assessment of empathy
After the solution was administered, participants completed the IRI online questionnaire.
After completing this, participants were given nature magazines and waited in a quiet room
for 45 minutes. The order of the experiments was counterbalanced, meaning that half the
participants undertook OT one week then saline the next week, and the other half first took
saline on their first week and OT on their second.
Experiment 1: The Comfortable Interpersonal Distance (CID) paradigm
This experiment used a modified version of an older, paper-based interpersonal space test
known as the Comfortable Interpersonal Distance (CID) paradigm. A circle was presented on
a computer screen and participants were instructed to imagine themselves in the centre of
the room with another person approaching them along a radius. The participant had to
indicate by pressing the keyboard space bar at the point along the radius where they would
want the person to stop their approach. The computer animation had options for the
imagined other to be one of the following conditions: a close friend, stranger, authority figure
or a rolling ball.
The animation stopped when the figures collided or the participant pressed the spacebar.
There were 24 trials for each figure and 96 trials in total. The researchers recorded the
percentage of remaining distance from the total distance.
Experiment 2: choosing rooms
Participants were told that after doing two runs of the experiment (placebo and OT) that they
would be asked to sit in a room with another participant to discuss personal topics.
Participants were informed they were going to be shown pairs of similar rooms and for each
trial choose the one room they preferred. They were told that this information would be used
to design a room according to their preferences.
The computerised stimuli were coloured pictures with two identical chairs in the middle, a
table on one side, a cupboard, a plant, a lamp and a clock. The experimental condition was
the preferred distance between chairs and consisted of the following stimuli:
- Distance between the chairs
- Angle of the chairs positions
The control condition was preferred distance between table and plant and consisted of the
following stimuli:
- Distance between the table and the plant
- Angle of the table and plant positions
The experiment included 21 different pairs of chair distances, 21 different pairs of table-plant
differences and three options for each pair of angles, repeated seven times to equal 21 pairs
of comparative angles. Each participant was shown a total of 84 pairs, each repeated twice
to equal 168 pairs overall.
The two picture sets were shown on a computer screen for 2 s and the participant had to
select their preference. The mean preferred distance between chairs, between table and
plant and the preferred angle for these furniture pairs was calculated.
Results
Experiment 1: CID
There were three IVs manipulated in Experiment 1: condition, treatment and empathy. The
dependent variable of preferred distance was presented as a mean percentage distance
from the centre of the circle. A higher percentage means participants preferred a greater
personal distance.
IV: condition
For Experiment 1 there were differences found between preferred distances between
stranger, authority, ball and friend across all trials. This findings supports the idea that
participants’ need for personal distance increases the less well the approaching figure is
known to them.
Stranger Authority Ball Friend
Mean distance 39.82% 34.12% 20.20% 12.46%
Interaction effect of IVs: treatment x empathy
OT was found to decrease the mean preferred distance from participant to other in the high
empathy group but had the opposite effect in the low empathy group. The effect of OT on the
low empathy group was to increase the preferred distance between self and other. This
finding suggests that the administration of OT has a differential effect rather than the same
effect on high and low empathizers.
Oxytocin (OT) group Control group placebo
High empathy group 23.29% 26.11%
Low empathy group 30.20% 26.98%
Interaction effect of IVs: treatment x condition x empathy
There was also an interaction between the IVs of treatment, condition and empathy. With the
placebo, high empathisers showed statistically significant differences between preferred
distances from friend and authority, as well as friend and stranger. With OT, the same
differences appeared, but there were also significant differences between ball and stranger
and ball and authority. This finding could indicate that the ball is an invitation to social
interaction, a cue which is enhanced with the treatment of OT for high empathizers.
Oxytocin (OT) group Control group placebo
Stranger 39.73% 38.55%
Authority 30.55% 33.92%
Ball 14.42% 20.96%
Friend 8.49% 11.02%
Experiment 2: choosing rooms
For Experiment 2, there were differences in preferences for chair distance but not for
preferred angles. Participants in the high empathy group chose closer chair distances
following OT administration than placebo administration. OT administration had the opposite
effect for those participants in the low empathy group.
Oxytocin (OT) group Control group placebo
High empathy group 78.07 cm 80.58 cm
Low empathy group 80.14 cm 78.33 cm
Interaction between treatment and empathy was only present in the experimental condition
(distance between chairs) meaning OT and empathy had no effect on choices of distance
between the plant and table. This finding supports the social salience hypothesis, as OT did
not affect participants’ general preferences, only the preferences that have social context.
Finally the results of both experiments were compared to establish a relationship. This
comparison showed a moderate correlation between average distance chosen in Experiment
1 under placebo treatment and average chair distance chosen in Experiment 2 under
placebo treatment.
Conclusion
The administration of OT enhances social cues in opposite ways for individuals with different
empathetic abilities, supporting the idea of social salience. People with low empathetic ability
respond to OT with a preference for increased personal distance and those with high
empathetic ability respond to OT with a preference for decreased personal distance.
The results also confirmed the findings of previous personal space research that people
need less distance between themselves and their close friends than they need with
strangers.
Evaluation
Because this study took place in an artificial environment of a university, it lacks ecological
validity. Participants’ experience of personal space with individuals who are actually known
to them might not be the same as the decisions they made about personal distance in the
study. Furthermore, participants were asked to judge their preferred distances using
computer generated images and to respond using keyboards. This meant that the tasks in
Experiments 1 and 2 lacked mundane realism.
However, the study had good internal validity. The order of experiments was
counterbalanced and this was used to prevent order effects. Extraneous variables were also
controlled, as social interaction after OT or saline administration was minimised through the
use of the waiting room. Researchers overseeing the saline or OT administration were taking
part in a double blind design procedure, therefore, participants should have been less
subject to demand characteristics and free of researcher bias.
This study was a laboratory experiment with a highly standardised procedure. For example,
the computer program projected the images of the room in Experiment for a consistent 2
seconds each time. Likewise, the images were computer generated for maximum accuracy
and consistency. This meant that the results were reliable.
Ethics
The study was ethically strong as written, informed consent was obtained from participants.
The study was approved by the University of Hafia’s ethics committee and The Hadassah
Medical Centre, which was important for safeguarding the well-being of participants,
researchers and the reputation of psychology. Participants reported no side effects from the
OT or placebo that was administered in a painless manner meaning they were protected
from physical harm. The participants were deceived about the purpose of the task in
Experiment 2, as no personal discussion ever took place. However, this deception was
unlikely to cause them psychological distress. Participants were fully debriefed after the
study and informed and told of the aim of the study.
Issues and Debates
Application to everyday life
The findings from Perry et al. have important implications for those with social difficulties, for
example, people with autism spectrum disorder or social anxiety disorder. Many people
expect OT as a social hormone to have a universally positive effect. However, this research
shows the effect of OT to be more complex as it was found to differentially enhance the
importance of existing social cues. This means that administering OT as a treatment could
actually cause further social difficulty.
Individual vs situational
Perry et al. study shows us that situational factors matter in our preferences for personal
space, for example need for space depends on our relationship to the person we are
interacting with. As well as interpersonal context, individual factors could also explain some
differences in personal space requirements. Individual traits such as empathetic ability can
explain why, even when people are exposed to the same levels of social hormone, their
personal space needs differ.
