title: Transcranial Stimulation Over the Dorsolateral Prefrontal Cortex Increases the Impact of Past Expenses on Decision-Making.
abstract: Goal-directed choices should be guided by the expected value of the available options. However, people are often influenced by past costs in their decisions, thus succumbing to a bias known as the "sunk-cost effect." Recent functional magnetic resonance imaging data show that the sunk-cost effect is associated with increased activity in dorsolateral prefrontal cortex (dlPFC) and altered crosstalk of the dlPFC with other prefrontal areas. Are these correlated neural processes causally involved in the sunk-cost effect? Here, we employed transcranial direct current stimulation (tDCS) to examine the role of the dlPFC for biasing choices in line with the cost of past expenses. Specifically, we applied different types of tDCS over the right dlPFC while participants performed an investment task designed to assess the impact of past investments on current choices. Our results show a pronounced sunk-cost effect that was significantly increased by anodal tDCS, but left unaltered by cathodal or sham stimulation. Importantly, choices were not affected by stimulation when no prior investments had been made, underlining the specificity of the obtained effect. Our findings suggest a critical role of the dlPFC in the sunk-cost effect and thus elucidate neural mechanisms by which past investments may influence current decision-making.
authors.affiliation: Department of Cognitive Psychology, Institute for Psychology, University of Hamburg, Hamburg, Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Bogdanov
authors.affiliation: Laboratory for Social and Neural Systems Research (SNS-Lab), Department of Economics, University of Zurich, Zurich, Switzerland.
authors.forename: Christian C
authors.initials: CC
authors.lastname: Ruff
authors.affiliation: Department of Cognitive Psychology, Institute for Psychology, University of Hamburg, Hamburg, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Schwabe
mesh_terms: D000293:Adolescent; D000328:Adult; D002755:Choice Behavior; D003657:Decision Making / Q000502:physiology*; D004311:Double-Blind Method; D004467:Economics; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D017397:Prefrontal Cortex / Q000502:physiology*; D011597:Psychomotor Performance; D012309:Risk-Taking; D065908:Transcranial Direct Current Stimulation; D055815:Young Adult
keywords: brain stimulation; dlPFC; sunk-cost effect; tDCS; value-based decision-making