More evidence that less is better: Sub-optimal choice in dogs.

Rebecca J Chase,David N George

doi:10.3758/s13420-018-0326-1

Abstract

The less-is-better effect is a preference for the lesser of two alternatives sometimes observed when they are evaluated separately. For example, a dinner service of 24 intact pieces might be judged to be more valuable than a 40-piece dinner service containing nine broken pieces. Pattison and Zentall (Animal Cognition, 17: 1019-1022, 2014) reported similar sub-optimal choice behavior in dogs using a simultaneous choice procedure. Given a choice between a single high-value food item (cheese) or an equivalent high-value item plus a lower-value food item (carrot), their dogs chose the individual item. In a subsequent test, the dogs preferred two high-value items to a single high-value item, suggesting that avoidance of multiple items did not cause the sub-optimal choice behavior. In two experiments, we replicated Pattison and Zentall's procedure while including additional controls. In Experiment 1, habituation of neophobia for multiple items was controlled for by intermixing the two types of test trial within a single experimental session. In Experiment 2, we controlled for avoidance of heterogeneous rewards by including test trials in which a choice was offered between the combination of items and a single low-value item. In both experiments we observed sub-optimal choice behavior which could not be explained by either of these putative mechanisms. Our results, as well as those of Pattison and Zentall, are consistent with the suggestion that dogs' assessment of the total value of multiple items is based, at least partly, on their average quality.

Highlights

In a variety of situations, people make decisions that are suboptimal and are based on heuristics rather than a rational and objective consideration of all available information (Kahneman & Tversky, 1979)
The three dogs who chose one side 24 times (Barney, Benson, and Poppy) were included in the analyses reported below, but additional tests were performed from which their data were excluded
On probe test trials where they were given a choice between a single highvalue item and an identical high-value item plus a piece of carrot, the dogs chose the alternative with the lower total value – the single high-value item

Summary

Introduction

In a variety of situations, people make decisions that are suboptimal and are based on heuristics rather than a rational and objective consideration of all available information (Kahneman & Tversky, 1979). Six out of nine dogs showed a less-is-better effect: A preference for a single high-value item over the combination of a high-value item plus a low-value item. This session was the same as the test session of Experiment 1 with the exception that the dogs were offered a choice between a single low-value item and a combination of a low-value item and a high-value item on the six control trials.

Results

Conclusion