Perry et al. (2015)

Mehar -

Ps = Participants. Pp = Participant. IV = Independent Variable. DV = Dependent Variable.

Aim
To investigate the effect of oxytocin on preferred interpersonal distance for those scoring high or low in empathy traits.

Research Hypotheses

  1. Administering oxytocin will affect preferred interpersonal distance depending on the persons’ level of empathy.
  2. People with high empathy would prefer closer distance and those with low empathy would prefer great distance.

Background
Dr. Anat Perry is a professor at the Hebrew University of Jerusalem who studies empathy and social processes from a social cognitive neuroscience perspective.
Perry et al. wanted to find the effects of oxytocin on people’s preferred interpersonal distances, depending on their level of empathy. They also wanted to test the Social Salience Hypothesis (SSH) and see if giving oxytocin would cause people to process social situations deeply, hence affecting their subsequent behaviour.

The amygdala affects the preferred interpersonal distances, and lesions to this area reduce the need for interpersonal distance from others. There’s high amygdala activity when personal spaces are invaded. The hormone oxytocin affects the amygdala.

The Social Salience Hypothesis (SSH) states that oxytocin increases attention to social cues, leading people to interpret and respond differently based on the situation. A person may feel comfortable in certain situations while another may not.

Psychology Being Investigated
Interpersonal distance = The distance between 2 people, which varies depending on the relationship with the other person, cultural norms, or personal factors.

Personal Space = Every person has a personal space which is an invisible boundary around them. If another enters this personal space, the person may feel uncomfortable or threatened.

Hall's (1966) 4 Zones of Interpersonal Distance:
1) Intimate distance for close relationships
2) Personal distance for everyday interactions
3) Social distance for formal interactions
4) Public distance for public figures.

Empathy = A person’s ability to understand the thoughts, feelings, and experiences of another. The level of empathy a person affects the way they process social cues. Empathy has 2 dimensions: cognitive & affective empathy.

  1. Cognitive empathy = The ability to determine another’s emotional state.
  2. Affective empathy = The ability to ‘feel’ another’s emotional state.

Oxytocin = A social hormone which helps in social bonding and promotes prosocial behaviour.
Scheele et al. (2012) found that giving oxytocin to males in monogamous relationships increased their preferred interpersonal distance with attractive females when in the presence of a female researcher, compared to a control condition.

Sample: 56 male undergraduates from the University of Haifa in Israel, aged 19-32 years. They received course credit or payment for their participation. 5 were left-handed; all had normal vision and were mentally well (confirmed by a screening interview).

Sampling Technique: Volunteer (self-selecting).

Research Method = 2 Laboratory experiments.
Research Design = Repeated measures design with randomisation.

Independent Variables:

  1. Ps’ level of empathy: high or low.
  2. Whether Ps received the nasal drops with oxytocin or placebo (saline solution). Ps took part in both conditions but alternatively over the 2 weeks.

Dependent variable = Whether oxytocin affected Ps' preferred interpersonal distance depending on their level of empathy.

Procedure
Ps were divided into 2 groups: high or low empathy – this part of the design was independent measures since their classification was dependent on their level of empathy. High or low empathy was operationalised using a 28-item online questionnaire called the Interpersonal Reactivity Index (IRI).
The IRI has 4 seven-item sub-sections, each assessing a different part of empathy. Ps in the high empathy group (n=20) had scores of 40 and over, whereas people in the low empathy group (n=20) had scores of 33 or under.

Ps were given the oxytocin and placebo in a randomised order to avoid order effects. The order in which they received each solution was counterbalanced. During week 1 half of the sample were given nasal drops, and the other group, the placebo. During week 2, Ps were given the alternative treatment. The double-blind technique was implemented, so the Ps and the experimenter didn’t know which solutions were administered.

Experiment 1 – The Comfortable Interpersonal Distance paradigm
A computer animation was used to measure all Ps’ preferred interpersonal distance (DV) from different people (a stranger, an authority figure, and a friend) and an object (a ball) (IV).

Ps indicated when they wanted the person/object to stop. A percentage (%) score was given to indicate the distance left. 0 = figures touching; 100 = furthest distance. Ps sat at a computer while 3-second animations were shown with a figure approaching the centre of the room from one of 8 entrances. Ps imagines they were at the centre of the room. Name of figure was shown for a second, and a fixation pooint for 0.5 seconds. Ps pressed the spacebar on the computer when they wanted the figure to stop. There were 96 trials in total.

Experiment 2 – ‘Choosing Rooms’ (computer-based task)
Ps were told the task was to help plan the layout of a room where they’d have a conversation with another Ps about a personal topic. Researchers could compare preferences for the spatial arrangement of the chairs (IV), table and plant (a control condition) to then measure Ps preferred interpersonal distance (DV).

Experimental Conditions:
1) Distance between chairs
2) Angle of the chairs' positions.
Control Conditions:
1) Distance between table and plant
2) Angle of positions of table and plant.

Researchers calculated the following values:
1) Mean preferred distance
2) Mean preferred angle between different items of furniture in a room.

Controls

  • Double-Blind Technique - The Pp & researcher administering the saline or oxytocin didn't know which was being given.
  • Order of experiments were counterbalanced.
  • All Ps waited 45 minutes before starting the experiment after getting administered a solution. This was to ensure their oxytocin levels stabilised.
  • Standardised Procedures - The same 3-second animations were used for all Ps.
  • Fixation points were used to ensure attention.

Results - Experiment 1

  • Oxytocin decreased the preferred mean distance from a protagonist in the high-empathy group (placebo - 26.11% vs oxytocin - 23.29) and increased it in the low empathy group (placebo - 26.98% vs oxytocin 30.20%).
  • Significant differences were found for the preferred distance between a friend and an authority figure, and a friend and a stranger in the high empathy placebo group.
  • Ps were willing to be closer to the ball than the stranger or authority figure in the oxytocin condition.

Results - Experiment 2

  • The high empathy group chose closer chair distances in the oxytocin condition (80.58) compared to the placebo (78.07). The opposite effect was found in the low empathy group (oxytocin - 78.33 vs placebo - 80.14).
  • Oxytocin did not significantly affect preffered chair angle.

Conclusions

  1. Oxytocin affects preferred interpersonal distance dependent on empathy level. High empathy individuals prefer closer distances after oxytocin compared to the placebo.
  2. Preferred interpersonal distance increased with the use of oxytocin for individuals with low empathy scores compared to the placebo.

Ethics

  • Informed consent was taken before administering Ps the nasal solution.
  • Ps were debriefed on the purpose of the study at the end.

Strengths and Weaknesses

  • The double-blind technique used when administering the solution helps reduce experimenter bias and demand characteristics since neither the Pp nor the experiementer knew whether oxytocin or saline was being given. This ensures that responses from Ps weren't exaggerated in terms of acting more or less sensitive to changes in personal space, leading to increased validity of resuts.
  • Quantitative data collected can be easily analysed and allows scores across experiments to be compared. The percentage distance remaining was measured without subjective interpretation, thus increasing the objectivity of data.
  • The validity of results collected from the self-report measure may be questionable due to social desirability effects as Ps filled them out. Ps may have over-reported their empathy to appear more socially desirable.
  • The sample only consisted of males, hence findings aren't generalisable to explain the behaviour of women and children in the same situation. Generalisability