title: Biases in preferences for sequences of outcomes in monkeys.
abstract: Movies, vacations, and meals are all examples of events composed of a sequence of smaller events. How do we go from our evaluations of each scene in a movie to an evaluation of the sequence as a whole? In theory, we should simply average the values of the individual events. In practice, however, we are biased towards sequences where each element tends to be better than the previous, where the last value is large, and we overweight the best (or worst) part of the sequence. To study how general these biases are we examined monkeys' preferences for sequences of rewards in a novel reward repeat task. Monkeys were first given a sequence of rewards and then chose between repeating the sequence or receiving a standard comparator sequence. We found that, like humans, monkeys overweight events that happen later in a sequence, so much so that adding a small reward to the end of a sequence can paradoxically reduce its value. Monkeys were also biased towards sequences with large peak values (the highest value in the sequence), but only following a working memory challenge, suggesting that this preference may be driven by memory limitations. These results demonstrate the cross-species nature of biases in preferences for sequences of outcomes. In addition, monkeys' consistent preference for sequences in which large values occur later challenges the generality of discounting models of intertemporal choice in animals.
authors.affiliation: Department of Brain and Cognitive Sciences, University of Rochester, Meliora Hall, Rochester, NY 14627, United States; Center for Visual Science, University of Rochester, Meliora Hall, Rochester, NY 14627, United States. Electronic address: blanchard.tommy@gmail.com.
authors.forename: Tommy C
authors.initials: TC
authors.lastname: Blanchard
authors.affiliation: Department of Brain and Cognitive Sciences, University of Rochester, Meliora Hall, Rochester, NY 14627, United States.
authors.forename: Lauren S
authors.initials: LS
authors.lastname: Wolfe
authors.affiliation: Centre for Health Policy, South Kensington Campus, London SW7 2AZ, United Kingdom; Department of Surgery and Cancer Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.
authors.forename: Ivo
authors.initials: I
authors.lastname: Vlaev
authors.affiliation: UCL Institute of Cognitive Neuroscience, University College London, 12 Queen Square, London WC1N 3BG, United Kingdom; Wellcome Trust Centre for Neuroimaging, University College London, 12 Queen Square, London WC1N 3BG, United Kingdom; Department of Neurology, Northwestern University, 303 East Chicago Avenue, Ward 10-185, Chicago, IL 60611, United States.
authors.forename: Joel S
authors.initials: JS
authors.lastname: Winston
authors.affiliation: Department of Brain and Cognitive Sciences, University of Rochester, Meliora Hall, Rochester, NY 14627, United States; Center for Visual Science, University of Rochester, Meliora Hall, Rochester, NY 14627, United States.
authors.forename: Benjamin Y
authors.initials: BY
authors.lastname: Hayden
mesh_terms: D000818:Animals; D002755:Choice Behavior / Q000502:physiology*; D003463:Cues; D008253:Macaca mulatta; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology
keywords: Biases; Heuristics; Intertemporal choice; Macaque; Peak-end