Motivation and emotion/Book/2017/Oxytocin and trust

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Oxytocin and trust:
What is the effect of oxytocin on trust?
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  • What is the effect of oxytocin on trust?
  • How can specific motivation and/or emotion theories and research help
Key questions

What is oxytocin, and what functions does it have?

What is trust? How is it defined, and how can it be measured?

Based on research findings, what effect does oxytocin have on trust?

How do theoretical frameworks explain the effect of oxytocin on trust?

How has the effect of oxytocin on trust been applied?


What is oxytocin?[edit]

Oxytocin is a peptide hormone stored in the hypothalamus and secreted by the posterior pituitary gland to influence central and peripheral functions within the body. Traditionally, oxytocin was understood as the primary hormone involved with female reproduction, due to its crucial role during childbirth and breastfeeding. This is because oxytocin is naturally released to facilitate contractions during labour, and lactation during nursing (Assad, Pandey & Sharma, 2016; Gimpl & Farenhol, 2001). However, oxytocin is not limited to these functions. More recently, researchers have found that oxytocin also plays a key role in prosocial behaviour. 

Figure 1. Oxytocin is released during intimate behaviours with partners, such as hugging, which is linked to attachment bonding in relationships.

Social functions of oxytocin[edit]

The release of oxytocin has also shown to be important in a range of social behaviours. A number of animal studies have observed the effect of oxytocin on maternal and nurturing behaviours. In rodents, injective administration of oxytocin into the mothers’ brain has led to the onset of behaviours such as grooming, licking, and nest building towards its pup. This suggests oxytocin may facilitate nurturing behaviours (Ross & Young, 2009). 

Oxytocin has also been linked to the formation of mother-infant bonding and attachment through facilitation of memories attached to smells. These memories allow the mother to discriminate between their own child and others, and becomes in favour of their own infant. Oxytocin may also play a role in animal pair bonding, as it has appeared to stimulate formation of partner preferences (Ross & Young, 2009).

These fascinating findings from animal research has generated interest into human studies. Although there have been some inconsistencies in research, these effects of oxytocin on social behaviours may also be observed in humans (Bartz, Zaki, Bolger, & Ochsner, 2011; Lim & Young, 2006). Increased oxytocin levels have been correlated with emotional behavioural responses from mothers to their infants, such as frequent checking, focused eye gaze on infant, and affectionate touch. This proposes that oxytocin is involved with human maternal nurturing behaviour (Ross & Young, 2009).

Oxytocin is also released during sexual and intimate behaviours between romantic partners, leading to an enhancement in pair bonding (Ross & Young, 2009). For example, when we cuddle or kiss our partners, oxytocin is released into the body, which influences our feelings of attachment and caring for that person. Given its role in relationship attachment and bonding, oxytocin is often referred to in popular news as the 'love hormone' (Bartz et al., 2011).

In addition to this, oxytocin has been shown to have a significant role in social cognition. Administration of oxytocin through a nasal spray (a common method in research) has led to improvements in recognition of familiar human faces, judgement of others' emotions, and trust (Ross & Young, 2009). Oxytocin’s influence on trust has been one of the most prevalent findings in current literature. Research examining the relationship between oxytocin and trust will be the primary topic of discussion for the remainder of this book chapter. Firstly, the definition of trust and how it may be measured will be explored. 

Table 1. Social Functions of Oxytocin

Function Behaviour
Maternal nurturing Grooming, licking, nest building in rodents, and frequent checking, focused eye gaze, and affectionate touch in humans
Mother-infant attachment Memories of smells facilitate preference for own child rather than others
Relationship attachment Stimulates partner preferences, and released during sexual behaviour and intimacy with partner
Social cognition Recognition of familiar faces, judgement of others' emotions, and trust


What is trust?[edit]

- What is trust/how do everyday people perceive trust? - Provides basis of social relationships

- Types of trust relationships eg. friendships, business partnerships

- Definition of trust/components of trust:

  • Interdependence, Vulnerability/risk, Intentionality (Weber, Malhotra & Murnighan, 2004)

Measures of trust[edit]

- Self-report

- Trust game (Camerer & Weigelt, 1988; Kosfeld, Heinrichs, Zak, Fischbacher & Fehr, 2005)

What is the effect of oxytocin on trust?[edit]

Relationship between oxytocin and trust[edit]

- Trust has been shown to increase with oxytocin intranasal administration during the trust game (Kosfeld et al., 2005).

- Oxytocin levels through peripheral measures are higher when showing trustworthiness during the trust game (Zak, Kurzban & Matzner, 2005). 

Oxytocin's effect on betrayal of trust[edit]

- Trust is maintained with oxytocin administration even after being betrayed - indicated by brain regions (Baumgartner et al, 2008).

Context dependent effects of oxytocin[edit]

- Oxytocin may only influence trust behaviour in the trust game if players are seen as reliable (Mikolajczak et al., 2010a).

- Oxytocin may also influence trust in contexts other than the trust game - when sharing confidential information and sharing emotions with others (Lane et al., 2013; Mikolajczak et al., 2010b).

- There may have been a lack of replication in these findings (Nave, Camerer, & McCullough, 2015). 

Theoretical explanations[edit]

Social salience hypothesis[edit]

- Oxytocin increases attention to external social cues (Shamay-Tsoory & Abu-Akel, 2016).

Approach-avoidance hypothesis[edit]

- Oxytocin increases approach behaviours and reduces avoidance behaviours in social contexts (Kemp & Guastella, 2010).

Can we improve trust?[edit]

Applications of oxytocin and trust[edit]

Couples therapy[edit]

- Researchers have investigated the effect of intranasal administration of oxytocin to potentially increase trust among couples in conflict (Ditzen et al., 2009).

Mental health[edit]

- Oxytocin may help increase social learning capabilities and trust in adults with autism (Andari et al., 2010).

- Social phobia

- Schizophrenia

Quiz questions[edit]

Here are some example quiz questions - choose the correct answers and click "Submit":


Approximately how many neurons are in the human brain?

1,000,000 (1 million)
10,000,000 (10 million)
100,000,000 (100 million)
1,000,000,000 (1 billion)
10,000,000,000 (10 billion)


A typical neuron fires ________ per second.

1 to 4
5 to 49
50 to 99
100 to 199
200 to 499

For more information, see Help:Quiz.


  • Brief overview of chapter
  • Take home messages

See also[edit]


Andari, E., Duhamel, J., Zalla, T., Herbrecht, E., Leboyer, M., & Sirigu, A. (2010). Promoting social behavior with oxytocin in high-functioning autism spectrum disorders. Proceedings Of The National Academy Of Sciences, 107(9), 4389-4394.

Assad, N., Pandey, A., & Sharma, L. (2016). Oxytocin, functions, uses and abuses: a brief review. Theriogenology Insight - An International Journal Of Reproduction In All Animals, 6(1), 1.

Bartz, J., Zaki, J., Bolger, N., & Ochsner, K. (2011). Social effects of oxytocin in humans: context and person matter. Trends In Cognitive Sciences.

Baumgartner, T., Heinrichs, M., Vonlanthen, A., Fischbacher, U., & Fehr, E. (2008). Oxytocin shapes the neural circuitry of trust and trust adaptation in humans. Neuron, 58(4), 639-650.

Camerer, C., & Weigelt, K. (1988). Experimental tests of a sequential equilibrium reputation model. Econometrica, 56(1), 1.

Ditzen, B., Schaer, M., Gabriel, B., Bodenmann, G., Ehlert, U., & Heinrichs, M. (2009). Intranasal oxytocin increases positive communication and reduces cortisol levels during couple conflict. Biological Psychiatry, 65(9), 728-731.

Gimpl, G., Fahrenhol, F. (2001). The oxytocin receptor system: structure, function, and regulation. Physiological Reviews. 81 (2) 629-683 

Kemp, A., & Guastella, A. (2010). Oxytocin: prosocial behavior, social salience, or approach-related behavior?. Biological Psychiatry, 67(6), e33-e34.

Kosfeld, M., Heinrichs, M., Zak, P., Fischbacher, U., & Fehr, E. (2005). Oxytocin increases trust in humans. Nature, 435(7042), 673-676.

Lane, A., Luminet, O., Rimé, B., Gross, J., de Timary, P., & Mikolajczak, M. (2013). Oxytocin increases willingness to socially share one's emotions. International Journal Of Psychology, 48(4), 676-681.

Lim, M., & Young, L. (2006). Neuropeptidergic regulation of affiliative behavior and social bonding in animals. Hormones And Behavior, 50(4), 506-517.

Mikolajczak, M., Gross, J., Lane, A., Corneille, O., de Timary, P., & Luminet, O. (2010a). Oxytocin makes people trusting, not gullible. Psychological Science, 21(8), 1072-1074.

Mikolajczak, M., Pinon, N., Lane, A., de Timary, P., & Luminet, O. (2010b). Oxytocin not only increases trust when money is at stake, but also when confidential information is in the balance. Biological Psychology, 85(1), 182-184.

Nave, G., Camerer, C., & McCullough, M. (2015). Does oxytocin increase trust in humans? A critical review of research. Perspectives On Psychological Science, 10(6), 772-789.

Ross, H., & Young, L. (2009). Oxytocin and the neural mechanisms regulating social cognition and affiliative behavior. Frontiers In Neuroendocrinology, 30(4), 534-547.

Shamay-Tsoory, S., & Abu-Akel, A. (2016). The social salience hypothesis of oxytocin. Biological Psychiatry, 79(3), 194-202.

Weber, J., Malhotra, D., & Murnighan, J. (2004). Normal acts of irrational trust: motivated attributions and the trust development process. Research In Organizational Behavior, 26, 75-101.

Zak, P., Kurzban, R., & Matzner, W. (2005). Oxytocin is associated with human trustworthiness. Hormones And Behavior, 48(5), 522-527.

External links[edit]