Randolph M. Nesse

Current Research

My primary specific research goal is to discover how natural selection shaped the capacity for mood in order to better understand how natural selection shaped capacaties for high and low mood and the mechanisms that regulate them. This involves trying to understand in what situations are high and low mood give a selective advantage, and how. The methods include both comprative studies of motivation regulation in different species, and also studies of mood variation in individuals, especially as a funciton of goal pursuit. My current thesis is that some pathological depression is an extreme of systems that normally disengage motivation when an organism is engaging in efforts that will not pay off. Such situations may well be much more prevalent now for humans than they were in ancestral times because so many of us pursue large goals with uncertain payoffs.

This is an excellent specific challenge that may help to show the utility of Darwinian medicine.

Closely related is my work on how best to gather and analyze data on people’s primary life projects in order to find out if and why they are unable to give up the pursuit of an unreachable goal.  This should illuminate the psychology of depression and give insight into subtypes of depression defined in terms of their etiology instead of their symptoms.    

I am also working to understand the role of subjective commitment in modulating human relationships.  If natural selection has shaped capacities for subjective commitment, study of these mechanisms could help to bridge the gap between evolutionary approaches to human behavior based on kin selection/reciprocity and the complexity, emotionality, and morality that we observe in human relationships.  This turns out to be related to the work on depression, because it may help to explain why people often remain committed to unsatisfying personal relationships. 

Current projects include:

Depression and Anxiety

Darwinian medicine

The Evolution of Subjective Commitment
This recently published book addreses the possibility that natural selection may have shaped a capacity for subjective commitment because of the advantages it gives in many social situations.  In this context, a subjective commitment is a signal that one will, in the future, act in ways that would not be in his or her self-interest.  The benefits come by influencing others, either by promises of aid or threats of harm.