perry study (ID, oxytocin)

Anat Perry,1 David Mankuta,2 and Simone G. Shamay-Tsoory1
1. Psychology Department, University of Haifa, Mount Carmel, Haifa, 3498838, Israel
2. Obstetrics and Gynecology Department, Hadassah Hebrew University Hospital, Jerusalem, 91120, Israel

Definition of Interpersonal Distance: The space between individuals during social interactions, which influences dynamics and comfort levels.
- Analogy to emotional and motivational factors: When someone's distance is encroached, it may invoke feelings of threat.
Cultural Aspects: Interpersonal distance varies across cultures but is felt explicitly when someone stands outside expected norms.
Empirical Measurement: Interpersonal distance can be mapped through measures of proximity and observational studies.

Introduced by Hall (1966): Four zones of spatial distance:
1. Intimate Distance: Used between lovers or family, involves all senses except vision.
2. Personal Distance: Everyday interactions where touch and vision are present, but not smell.
3. Social Distance: Formal interactions with external cues (body language, voice volume).
4. Public Distance: Used around public figures, associated with loud voice and body movements.

Personality Traits and Interpersonal Differences: Individual differences, like personality traits and social anxiety levels, influence distance preferences.
- Research Findings: Individuals with higher social anxiety prefer greater distances (Scheele et al., 2012; Perry et al., 2013).
Friendship and Attraction: Correlate with preferred interpersonal distances (Sundstrom and Altman, 1976).
Amygdala's Role: Lesions in the amygdala reduce need for distance; amygdala activity relates to discomfort at close distances (Kennedy et al., 2009).

Definition: Oxytocin is a neuromodulator often referred to as a 'social hormone.'
Function: Modulates social behavior and cognition across species.
Behavioral Implications: OT generally encourages pro-social behaviors but can suppress them based on the context (e.g., risk aversion, cooperation levels).
- Contexts include relationships, gender dynamics, and individual empathy levels.
Social Salience Hypothesis: Suggests OT influences attention to social signals, leading to varying effects based on the social context and individual traits.
- Neuroimaging studies reveal differential amygdala activation with OT during social task performance (Kirsch et al., 2005; Domes et al., 2007).

Definition of Empathy: The capacity to respond to the experiences of others (Davis, 1983).
Four Measures of Empathy:
1. Perspective Taking: Understanding another's viewpoint.
2. Empathic Concern: Feeling care and concern for others.
3. Personal Distress: Feeling discomfort in response to others' distress.
4. Fantasy Abilities: The ability to imagine oneself in others' positions.

Hypothesis: OT would affect preferred interpersonal distance, varying according to individual empathy levels.
- Highly empathic individuals would prefer closer distances after OT administration, while those with low empathy would prefer greater distances.
Experimental Paradigms: Two experiments were conducted:
1. Comfortable Interpersonal Distance (CID) Paradigm: Participants indicated comfort distances from approaching figures.
2. Choosing Rooms Paradigm: Participants selected rooms for discussing intimate topics based on their preferences.

Demographics: 54 male undergraduate students, aged 19 to 32 (mean age 25.29, s.d. 2.74). All participants reported normal visual acuity and no psychiatric or neurological history.
Empathy Assessment: Grouped into high and low empathy based on Interpersonal Reactivity Index (IRI) scores.
Ethics Approval: Obtained from the relevant ethics committees prior to the study.

Conducted over two sessions, 1 week apart. Participants administered either intranasal OT or placebo.
Informed Consent: All participants signed consent forms before beginning the study.

Participants completed the IRI scale, containing 28 self-report items across four dimensions of empathy.
A 45-minute waiting period followed the administration of OT to ensure hormone levels plateaued before beginning experimental tasks.

Participants indicated stopping distances of approaching protagonists (friend, stranger, authority figure, or a ball).
Modified version obtained strong correlation with physical distances in real life (Duke and Kiebach, 1974).
Predictions: OT would promote closer distances among empathic individuals but farther distances among those lower in empathy.

Participants chose between pairs of similar rooms for discussing personal topics in the future.
Room parameters included distances and angles between chairs and objects within.
A total of 168 pairs were shown over the course of the experiment.

ANOVA indicated significant effects based on condition:
- Distances preferred (mean %): Stranger: 39.82, Authority: 34.12, Friend: 12.46, Ball: 20.20.
Interaction of treatment and empathy revealed:
- High empathy group preferred closer distances with OT (PL: 26.11 → OT: 23.29).
- Low empathy group showed opposite effects (PL: 26.98 → OT: 30.20).

ANOVA revealed that preference differences were only significant in chair distances:
- High empathy group chosen chair distances (PL: 80.58 → OT: 78.07). In contrast, low empathy group (PL: 78.33 → OT: 80.14).
Third-order interaction condition × treatment × empathy: indicated specific influence due to OT on interpersonal contexts over non-interpersonal contexts.

Confirmed OT's role in influencing interpersonal distance preferences contingent upon empathy traits.
- High empathy tended towards closeness, while low empathy exhibited distance preference.
Caution Recommended: Modulating factors in OT administration need to consider different individual contexts and personality traits significantly impact response.

Sample Diversity: Focused only on males, precluding generalizability to females.
Contextual Validity: Computer-based stimuli may lack ecological validity compared to real-life interactions.

Results underscore caution about the use of OT with individuals with social deficits, highlighting that it may exacerbate pre-existing biases rather than generalize pro-social effects.

A comprehensive list of studies, offering supporting literature for the findings and proposed hypotheses, including those by Bartz et al. (2011), Davis (1983), Scheele et al. (2012), and others.