title: Monetary, Food, and Social Rewards Induce Similar Pavlovian-to-Instrumental Transfer Effects.
abstract: Multiple types of reward, such as money, food or social approval, are capable of driving behavior. However, most previous investigations have only focused on one of these reward classes in isolation, as such it is not clear whether different reward classes have a unique influence on instrumental responding or whether the subjective value of the reward, rather than the reward typeper se, is most important in driving behavior. Here, we investigate behavior using a well-established reward paradigm, Pavlovian-to-instrumental transfer (PIT), and three different reward types: monetary, food and social rewards. The subjective value of each reward type was matched using a modified Becker-DeGroot-Marschak (BDM) auction where subjective reward value was expressed through physical effort using a bimanual grip force task. We measured the influence of reward-associated stimuli on how participants distributed forces between hands when reaching a target effort range on the screen bimanually and on how much time participants spent in this target range. Participants spent significantly more time in the target range (15% ± 2% maximal voluntary contraction) when a stimulus was presented that was associated with a reward used during instrumental conditioning or Pavlovian conditioning compared to a stimulus associated with a neutral outcome (i.e., general PIT). The strength of the PIT effect was modulated by subjective value (i.e., individuals who showed a stronger PIT effect rated the value of rewards more highly), but not by reward type, demonstrating that stimuli of all reward types were able to act as appetitive reinforcers and influenced instrumental responding, when matched to the same subjective reward value. This is the first demonstration that individually matched monetary, food and social rewards are equally effective as appetitive reinforcers in PIT. These findings strengthen the hypotheses that the subjective value is crucial for how much reward-associated stimuli influence behavior.
authors.affiliation: Neural Control of Movement Lab, Department of Health Science and Technology, Federal Institute of Technology ZurichZurich, Switzerland; Neuroscience Center Zurich, Federal Institute of Technology Zurich, University and Balgrist Hospital Zurich, University of ZurichZurich, Switzerland.
authors.forename: Rea
authors.initials: R
authors.lastname: Lehner
authors.affiliation: Neural Control of Movement Lab, Department of Health Science and Technology, Federal Institute of Technology Zurich Zurich, Switzerland.
authors.forename: Joshua H
authors.initials: JH
authors.lastname: Balsters
authors.affiliation: Neural Control of Movement Lab, Department of Health Science and Technology, Federal Institute of Technology Zurich Zurich, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Herger
authors.affiliation: Neuroscience Center Zurich, Federal Institute of Technology Zurich, University and Balgrist Hospital Zurich, University of ZurichZurich, Switzerland; Laboratory for Social and Neural Systems Research, Department of Economics, University of ZurichZurich, Switzerland.
authors.forename: Todd A
authors.initials: TA
authors.lastname: Hare
authors.affiliation: Neural Control of Movement Lab, Department of Health Science and Technology, Federal Institute of Technology ZurichZurich, Switzerland; Neuroscience Center Zurich, Federal Institute of Technology Zurich, University and Balgrist Hospital Zurich, University of ZurichZurich, Switzerland; Movement Control and Neuroplasticity Research Group, Department of Kinesiology, Biomedical Sciences Group, KU LeuvenLeuven, Belgium.
authors.forename: Nicole
authors.initials: N
authors.lastname: Wenderoth
keywords: Becker-DeGroot-Marschak auction; Pavlovian-to-instrumental transfer; cue-controlled behavior; effort; reward type; subjective reward value