title: Rats exhibit reference-dependent choice behavior.
abstract: Human preferences depend on whether a chosen outcome appears to be a loss or a gain compared with what had been expected, i.e., in comparison to a reference point. Because reference dependence has such a strong influence on human decision-making, it is important to uncover its origins, which will in turn help delineate the underlying mechanisms. It remains unknown whether rats use reference points in decision-making, and yet, the study of rats could help address the question of whether reference dependence is evolutionarily conserved among mammals and could provide a nonhuman animal model to investigate the neural mechanisms underlying this important cognitive process. The aim of the current study was to determine whether rats show reference-dependent choice behavior. We developed a novel paradigm by modifying the "T" maze by installing "pockets" to the left and right of the "T" stem that held reward pellets so rats would potentially develop reference values for each option prior to choice. We found that the rats were indeed sensitive to the way alternatives were presented. That is, they exhibited reference-dependent choice behavior by avoiding the choice option framed as a loss (e.g., having four reward pellets in the pocket, but receiving only one), at least under conditions with certain outcomes and clear differences between the reference and outcome quantities. Despite the small number of rats in this study, this species-level capacity suggests that reference dependence in general and loss aversion in particular may be conserved traits that evolved at or before the emergence of mammals.
authors.affiliation: Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea.
authors.forename: Mehwish
authors.initials: M
authors.lastname: Bhatti
authors.affiliation: Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea.
authors.forename: Hyeran
authors.initials: H
authors.lastname: Jang
authors.affiliation: Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH 03755, USA.
authors.forename: Jerald D
authors.initials: JD
authors.lastname: Kralik
authors.affiliation: Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea. Electronic address: jsjeong@kaist.ac.kr.
authors.forename: Jaeseung
authors.initials: J
authors.lastname: Jeong
mesh_terms: D000818:Animals; D002755:Choice Behavior; D005715:Gambling; D008297:Male; D018782:Maze Learning; D011581:Psychological Tests; D017207:Rats, Sprague-Dawley / Q000523:psychology*; D012201:Reward; D012309:Risk-Taking; D013647:Task Performance and Analysis
keywords: Framed; Gain; Loss; Loss aversive behavior; Rats; Reference dependence