Biological Explanations of Interpersonal Relationships
Chemical Messengers
- Oxytocin, Vasopressin, and Dopamine are key neurotransmitters that play a significant role in bonding, trust, and love.
- They are all part of the endocrine system, where hormones are secreted by glands and transported by blood.
- They bind to target cells to either increase or decrease their function.

Oxytocin
- Often called the "love hormone," oxytocin is released during physical touch, childbirth, and sexual activity.
- It promotes feelings of trust and attachment.
Baumgartner et al. (2008): Participants who received oxytocin were more likely to trust others, even after experiencing betrayal.
Vasopressin
- Vasopressin is linked to long-term commitment and monogamous behaviors, especially in males.
- It influences social bonding and pair formation.
Winslow et al. (1993): Prairie voles with higher vasopressin levels exhibited stronger pair-bonding behaviors.
Dopamine
- Dopamine is associated with the reward system in the brain, creating feelings of pleasure and motivation.
- It reinforces behaviors that are pleasurable, such as spending time with a loved one.
Fisher et al. (2005): Brain scans of individuals in love showed increased dopamine activity in areas related to reward and motivation.
NoteCritical Thinking
- Bidirectional ambiguity: do hormones cause us to feel love or does love cause the release of hormones?
- Studies typically show a strong correlation between hormones and behaviour.
Cognitive Explanations
Equity Theory
- Equity Theory suggests that relationships are maintained when both partners perceive fairness in the distribution of resources (e.g., time, effort, affection).
- Imbalances can lead to dissatisfaction and conflict.


