BACKGROUND
1. Amygdala
- Plays a role in preferred interpersonal distances.
- The more discomfort people feel with an interpersonal distance that is too close,
the higher their levels of amygdala activity.
- Amygdala activity is known to be affected by the hormone oxytocin.
AIM
To investigate how oxytocin affects preferred interpersonal distance for those scoring high or low
in empathy traits.
IV & DV
PROCEDURE
- Participants visited the laboratory twice, a week apart, at the same time.
- On their first visit, they were randomly given either oxytocin (24 units in 250 ml of saline)
or a placebo (250 ml of saline without oxytocin).
- Three droplets were self-administered to each nostril.
- The following week, they administered the alternative solution.
EXPERIMENT 1
- Eighty-four pairs of rooms were each shown twice, giving a total of 168 pairs.
- During the task, participants sat 60 cm from the computer screen and were shown each
pair of rooms for two seconds.
- They had to fixate on a point on a blank screen for 0.5 seconds between each pair.
RESULTS
Experiment 1
- Oxytocin decreased the preferred mean distance from a protagonist in the high empathy
group (placebo: 26.11 per cent vs oxytocin: 23.29 per cent) and increased it in the low
empathy group (placebo: 26.98 per cent vs oxytocin: 30.20 per cent). This difference,
however, was very small.
- In the high empathy group, placebo condition, there were significant differences between
the preferred distances for friend and authority, as well as friend and stranger, as
expected. However, not between the ball and all other conditions. When oxytocin was
administered, participants were willing to be significantly closer to the ball than the
stranger or authority figure.
Experiment 2
- Those in the high empathy group chose closer chair distances in the oxytocin condition
compared to the placebo condition (80.58 cm versus 78.07 cm), while the opposite effect
was found for the low empathy group (78.33 cm in the oxytocin condition versus 80.14
cm in the placebo condition). The effect of oxytocin on preferred chair distance was only
approaching significance for the high empathy group, however.
- Oxytocin did not have an effect on preferred chair angle for either the high or the low
empathy groups.
METHODOLOGICAL ISSUES
Reliability
- Standardization- A strength of this research is its high level of standardization. Using a
computer allowed researchers to control timings, speeds and visuals to ensure they
were the same between participants. For example, in Experiment 2, each pair of rooms
was presented for two seconds and all the furniture items in the room were kept the
same. This means that the procedure can be replicated to see if the findings about the
effects of oxytocin and empathy on interpersonal distance are reliable.\
Validity
- Validated paradigm- A strength of this research was its use of a widely validated
paradigm to investigate preferred interpersonal distance. The CID paradigm, involving a
protagonist approaching the participant in a computerized room, has been tested
previously on a variety of different sex and age groups in a pen and paper format. It was
found to be a valid measure of preferred interpersonal distance, which increases the
validity of Perry et al.’s findings relating to the effects of oxytocin and empathy on
interpersonal distance.
- Double-blind procedure- The use of a double-blind procedure in the administration of
either oxytocin or the placebo was also a strength. Neither the participant nor the
experimenter knew which solution was being administered in weeks one and two. This
avoided any experimenter effects or demand characteristics, whereby either the
experimenter or the participant consciously or unconsciously influenced the study’s
findings as a result of any prior expectations about the effects of oxytocin, thus making
the findings more valid.
- Self-report- One weakness of the design was that participants were categorized as
being high or low in empathy on the basis of their own self-report, which may be biased.
Participants were required to complete the IRI themselves, which may have led some
participants to demonstrate social desirability bias. Participants may have preferred to be
seen as higher in empathy because it is seen as a desirable trait in society and they did
not want to be evaluated negatively by the experimenter. This raises validity issues, as
some people low in empathy may have ended up in the high empathy category.
Objectivity and subjectivity
- A strength of this research was the use of quantitative data, which did not require
subjective interpretation from the researchers. For example, Experiment 1 recorded the
percentage distance remaining between the door through which a protagonist entered
and the participant in the center. This data allowed the researchers to objectively
compare participants’ scores in each of the different conditions in an unbiased way,
which increased the validity of the results and allowed for a statistical analysis of the
findings to be undertaken to determine the strength of any differences.
Generalisations and ecological validity
- Generalising beyond the sample- One weakness of this study is that it only used male
participants. Previous research has shown that males and females respond differently to
oxytocin. For example, oxytocin may induce positive social judgments and altruism in
females, while promoting the opposite effect in males. Therefore, it is not possible to
apply the findings of this study relating to oxytocin’s effects on personal space to
females.
- Generalising to everyday life- One issue with this research is the fact that it used
computer-based tasks in a laboratory setting, which lacks ecological validity. Asking
participants to respond to computer animations would not have recreated the intense
feelings of discomfort that a person may feel in a real-life social situation of someone
invading their personal space. Therefore, differences between the control and oxytocin
conditions may have been minimised due to the lack of genuine feelings of discomfort,
and not reflect real-life preferences.
