Little American Brown Weasel

The Top Two Inches has an interesting blog post about dating, called, “Dating — Don’t Do It“. Interesting read, and it got me thinking about trust.

Trust is first built in one part of the brain, and then your brain comes to a fork in the road: the “unconditional” trust brain area or the “conditional” trust brain area.

I’ll post more later, but think about it: if those areas of the brain are damaged, then your whole world view is skewed.

Let’s say you have “negative attributional bias” — meaning you always assume the negative about other people. This is another way of saying that you don’t trust anyone who is loaded into your “conditional” trust brain areas. Psychopaths, in fact, have pro-active aggression sometimes precisely because they have this “negative attributional bias” (I don’t have time to put up links to papers right now, but this is interesting. . . )

Or, let’s say you are too trusting. Maybe you put all your retirement in an annuity sold by a door to door salesman with no license to sell insurance products. Could that be an organic defect in the “unconditional” trust brain areas, leading to inappropriately trusting when anyone would know not to?

Here’s from Krueger et al, December 11 PNAS

“. . .the paracingulate cortex is critically involved in building a trust relationship by inferring another person’s intentions to predict subsequent behavior. This more recently evolved brain region can be differently engaged to interact with more primitive neural systems in maintaining conditional and unconditional trust in a partnership. Conditional trust selectively activated the ventral tegmental area, a region linked to the evaluation of expected and realized reward, whereas unconditional trust selectively activated the septal area, a region linked to social attachment behavior”

Full abstract from PNAS after the jump

Published online before print December 4, 2007, 10.1073/pnas.0710103104
PNAS | December 11, 2007 | vol. 104 | no. 50 | 20084-20089

Neural correlates of trust

Frank Krueger^*, Kevin McCabe, Jorge Moll, Nikolaus Kriegeskorte, Roland Zahn^¶, Maren Strenziok^*, Armin Heinecke^||, and Jordan Grafman^*,**

*Cognitive Neuroscience Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1440; The Center for the Study of Neuroeconomics, George Mason University, Fairfax, VA 22030; Cognitive and Behavioral Neuroscience Unit, LABS-D’Or Hospital Network, 2228-080, Rio de Janeiro, Brazil; Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1148; ^¶Neuroscience and Aphasia Research Unit, School of Psychological Sciences, University of Manchester, Manchester M13 9PL, United Kingdom; and ^||Brain Innovation B.V., Universiteitssingel 40, 6201 BC Maastricht, The Netherlands

Communicated by Vernon L. Smith, George Mason University, Fairfax, VA, October 25, 2007 (received for review July 12, 2007)

Trust is a critical social process that helps us to cooperate with others and is present to some degree in all human interaction. However, the underlying brain mechanisms of conditional and unconditional trust in social reciprocal exchange are still obscure. Here, we used hyperfunctional magnetic resonance imaging, in which two strangers interacted online with one another in a sequential reciprocal trust game while their brains were simultaneously scanned. By designing a nonanonymous, alternating multiround game, trust became bidirectional, and we were able to quantify partnership building and maintenance. Using within- and between-brain analyses, an examination of functional brain activity supports the hypothesis that the preferential activation of different neuronal systems implements these two trust strategies. We show that the paracingulate cortex is critically involved in building a trust relationship by inferring another person’s intentions to predict subsequent behavior. This more recently evolved brain region can be differently engaged to interact with more primitive neural systems in maintaining conditional and unconditional trust in a partnership. Conditional trust selectively activated the ventral tegmental area, a region linked to the evaluation of expected and realized reward, whereas unconditional trust selectively activated the septal area, a region linked to social attachment behavior. The interplay of these neural systems supports reciprocal exchange that operates beyond the immediate spheres of kinship, one of the distinguishing features of the human species.