PhD students Rachel Bedder, Benjamin Chew, and Akshay Nair all presented their research at the Society of Biological Psychiatry conference in New York. Rachel presented her results showing that happiness is higher when subjects know future blocks contain trials with potential rewards, and the people for whom mood is most affected by future prospects take more risks when they are in a good mood. Benjamin presented his real-time fMRI study showing that subjects take more risks when BOLD activity in the dopaminergic midbrain is low at the time that options are presented, suggesting that endogenous fluctuations in dopamine-related activity are a major factor in determining choice variability, possibly including irrational behaviour. Akshay presented his results showing that people respond more quickly when the amount of reward they lose by not acting is high. People with greater apathy were less sensitive to changes in this opportunity cost and also to changes in the overall reward rate of the environment.
- Rachel Bedder, Bastien Blain, Emily Lowther & Robb Rutledge. A computational model of mood and future prospects.
- Benjamin Chew*, Tobias Hauser*, Marina Papoutsi, Raymond Dolan & Robb Rutledge. Endogenous fluctuations in the dopaminergic midbrain modulate choice behavior.
- Akshay Nair, Geraint Rees, Sarah Tabrizi & Robb Rutledge. How fast should I go? Sensitivity of action initiation to opportunity cost predicts apathy.