[Pophealth] Trust and oxytocin administration

[Stephen Bezruchka]

I've previously pointed out the relationship between oxytocin and trust, 
and its relationship with income inequality (Uslaner's The Moral 
Foundations of Trust and others).  Today's premier journal, Nature, 
carried the results of an experiment as well as an editorial (below) which 
was rather typical for being written by an American and fearing politicans 
would spray the stuff around during elections!  The New York Times also 
suggested the expected individual response.  As DAvid Levitt pointed out, 
NPR picked it up too.  So we should mention the relationbship with income 
inequality within the US and among countries (graphs on pg 41-2 of 
WIlkinson's The Impact of Inequality).

Someday, perhaps in addition to nasal sprays for allergies and wheezing, 
we'll carry a canister of oxytocin there with our iPod.  But the basics 
suggest that with our declining levels of trust in the US, our oxytocin 
titers must be dropping.  I don't think nasal sprays are the answer.

Stephen
***

Trust, and  Oxytocin administration
Damasio, A. (2005). ÒHuman behaviour Brain trust.Ó Nature 435(7042): 
571-572.
Kosfeld, M., M. Heinrichs, et al. (2005). ÒOxytocin increases trust in 
humans.Ó Nature 435(7042): 673-676.

Nature June 2, 2005, 435 pg 571-2 HUMAN BEHAVIOUR Brain trust Antonio 
Damasio
As is the case with other social interactions, financial transactions 
depend on trust. That fact is behind ingenious experiments that explore 
the neurobiological underpinnings of human behaviour.

Michael Kosfeld and his colleagues got students in Zurich to play a 
serious game. The game involved real monetary exchanges between two people 
playing the anonymous roles of ÔinvestorÕ and ÔtrusteeÕ; beforehand, each 
subject had received either the neuropeptide oxytocin or an inert placebo, 
via nasal spray.
As a group, the investors who received oxytocin exhibited more trust in 
the anonymous trustee than did the investors who received the placebo. 
Because intranasally administered oxytocin crosses the blood-brain barrier 
into the central nervous system, Kosfeld et al. (page 673 of this issue)1 
conclude that the central action of oxytocin increases trusting behaviour; 
and because the oxytocin spray did not change the behaviour of the 
trustees, it seems that oxytocin only increases trust, not the reliability 
of the trustee. This is a remarkable finding, and to explain its 
significance we must first say a word about trust and about oxytocin 
itself.
Given the polarities of reward and punishment that pervade biology at 
various levels, trust is essential for the normal operation of human 
societies. Remove trust and you compromise love, friendship, trade and 
leadership. Little is known about the neurobiology of trust, although the 
phenomenon is beginning to attract attention2.
As for oxytocin, it is a small peptide, consisting of nine amino acids, 
that is produced mostly in the hypothalamus, the brainÕs master controller 
of biological regulation, including emotion. Oxytocin acts both on certain 
targets of the body (it is best known for inducing labour and lactation) 
and on brain regions whose function is associated with emotional and 
social behaviours (the amygdala and nucleus accumbens, for example) -- 
that is, it works both as a hormone and as a neuromodulator, a kind of 
neurotransmitter. In animals, oxytocin contributes to social attachments, 
including male and female bonding after mating, mother and infant bonding 
after childbirth, and assorted sexual behaviours3,4. Besides triggering 
complex and specific action-programmes, oxytocin may well work part of its 
charm by selectively lowering the natural resistance that animals have to 
the proximity of others, thus facilitating what is known as Ôapproach 
behaviourÕ.
Given this background, Kosfeld et al.1 hypothesized, reasonably and 
perceptively, that oxytocin might be involved in trusting behaviour in 
humans. After all, trust and approach behaviour are indelibly linked. We 
commonly describe the child who approaches others with ease as ÔtrustingÕ, 
and we use comparable descriptions for animals in similar situations. 
Kosfeld and colleaguesÕ finding supports their hypothesis and opens the 
way to a richer understanding of perhaps the most complex tier of human 
social interactions. I once likened5 oxytocin to a love potion, the magic 
elixir that makes Tristan fall for Isolde: add trust to the mix, for there 
is no love without trust.
Kosfeld et al. provide an engaging discussion of the possible mechanisms 
behind their finding. They reject the possibility that oxytocin has a 
nonspecific positive effect on social behaviour, because of its different 
influence on investors and trustees. Approach and trust possibly dominate 
the behaviour of investors, and that is where oxytocin works, whereas 
trustee behaviour is dominated by a principle of reciprocity, for which 
oxytocin seems irrelevant. Kosfeld et al. also reject the possibility that 
oxytocin merely reduces the sensitivity to risk, because in a control 
experiment in which the investors knew the trustee was a computer, they 
did not take any extra risks. The authors finally settle for an attractive 
pair of factors: that oxytocin overcomes the aversion to betrayal (which 
applies only to the investors), and that this is combined with the effects 
of reward that result from enhanced approach behaviour.
The significance of the study lies in what it can tell us about 
non-experimental circumstances, when the equivalent of an investor is not 
sniffing oxytocin. What might be happening then? First, perceiving certain 
social configurations probably leads to oxytocin release in selected brain 
regions -- that is, the cognitive appraisal of a situation, based on an 
individualÕs genetic make-up and past experience, triggers a chain of 
neural events that includes (but is not limited to) the release of 
oxytocin. Second, oxytocin modulates the activity of cognitive neural 
networks, resulting in enhanced trusting behaviour. Whether this result is 
achieved via a mostly unconscious bias (by altering the competition among 
ensembles of neurons that represent varied choice options), or a conscious 
deliberative process, remains to be established -- although the evidence 
seems to favour the former possibility in the current experiment. However, 
the input, along the cognitive chain, of neural events arising in brain 
areas associated with social and emotional responses is a requisite part 
of the explanation. The finding points to the crucial involvement of 
emotional phenomena in the processes leading from cognition to behaviour.
The authorsÕ results open up possibilities for investigating conditions in 
which trust is either diminished, as in autism, or augmented. For example, 
patients with bilateral damage to the amygdala approach strangers with 
unusual ease, and fail to recognize untrustworthy individuals whom normal 
people would resolutely avoid6. In this case, damage to the amygdala may 
prevent the detection of the potential threat evoked by certain stimuli. 
And children with Williams syndrome, a rare genetic disorder, approach 
strangers fearlessly and indiscriminately7. Might their high level of 
trust be due to excessive oxytocin release?
Some may worry about the prospect that political operators will generously 
spray the crowd with oxytocin at rallies of their candidates. The scenario 
may be rather too close to reality for comfort, but those with such fears 
should note that current marketing techniques -- for political and other 
products -- may well exert their effects through the natural release of 
molecules such as oxytocin in response to well-crafted stimuli. Civic 
alarm at the prospect of such abuses should have started long before this 
study, and the authors cannot be blamed for raising it. Whatever the 
beneficial biomedical applications, or the abuses, may turn out to be, 
Kosfeld et al. have made a valuable contribution to our understanding of 
the role of neuromodulators in human behaviour that involves choice.
¥ Antonio Damasio is in the Department of Neurology, University of Iowa 
College of Medicine, 200 Hawkins Drive, Iowa City, Iowa 52242, USA.
e-mail: antonio-damasio at uiowa.edu
1. Kosfeld, M., Heinrichs, M., Zak, P. J., Fischbacher, U. & Fehr, E. 
Nature 435, 673-676 (2005).
2. King-Casas, B. et al. Science 308, 78-83 (2005).
3. Carter, C. S. Psychoneuroendocrinology 23, 779-818 (1998).
4. Insel, T. R. & Shapiro, L. E. Proc. Natl Acad. Sci. USA 89, 5981-5985 
(1992).
5. Damasio, A. R. DescartesÕ Error: Emotion, Reason, and the Human Brain 
(Penguin, New York, 1994).
6. Adolphs, R. & Damasio, A. R. Nature 393, 470-474 (1998).
7. Doyle, T. F. et al. Am. J. Med. Genet. 124A, 263-273 (2004).