Suboptimal choice by dogs: when less is better than more.

Area of Science:

• Behavioral Economics
• Comparative Psychology
• Animal Cognition

Background:

• The "less is more" effect, a form of affect heuristic, is documented in humans and non-human primates.
• This effect describes the tendency to devalue a set of items when a less desirable item is added, even if the total value should increase.

Purpose of the Study:

• To investigate the presence of the "less is more" effect in a social, non-primate species: domestic dogs.
• To determine if dogs exhibit similar valuation biases as observed in humans and monkeys.

Main Methods:

• Dogs were presented with choices between food items.
• The primary experiment involved offering dogs a choice between a slice of cheese and a combination of cheese plus a slice of carrot.
• Dogs' preferences were recorded based on their selections.

Main Results:

• Dogs readily consumed both cheese and carrots.
• When given a choice, the majority of dogs preferred a single slice of cheese over a slice of cheese accompanied by a slice of carrot.
• This indicates a preference for the simpler, more valuable option.

Conclusions:

• The "less is more" effect was demonstrated in domestic dogs.
• This finding suggests that this cognitive bias may be more widespread across species than previously understood.
• The study contributes to understanding the evolution of decision-making and valuation processes.