Emergence of group rationality from irrational individuals

Takao Sasaki, Stephen Pratt

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

Evolutionary theory predicts that animal decision makers should be rational, meaning that they consistently choose fitness-maximizing options. Despite this, violations of rationality have been found repeatedly in humans and other animals. The significance of these violations remains controversial, but many explanations point to cognitive limitations that prevent animals from adequately processing the information needed for fully rational choice. Instead, they rely on heuristics that usually work well but yield systematic errors in specific contexts. Although past research on rationality has focused on individuals, many highly integrated groups, such as ant colonies, regularly make consensus choices among food sources, nest sites, or other options. These collective choices emerge from local interactions among many group members, none of whom take on the whole burden of decision making. We hypothesized that groups may evade the irrational consequences of individual limitations by distributing their decision making across many group members. We tested this in the well-studied case of collective nest-site selection by Temnothorax ants. We found that individual ants, but not colonies, strongly violated rationality when presented with a challenging nest-site choice. Specifically, isolated individuals irrationally switched their preference between 2 alternative nest sites based on their experience of an unattractive decoy. Given the same choice, intact colonies maintained consistent preferences regardless of the decoy's presence. Previous studies have stressed how distributed decision making can filter out random errors made by group members. Our results show that collectives can also suppress systematic errors that emerge from the decision heuristics of cognitively limited individuals.

Original languageEnglish (US)
Pages (from-to)276-281
Number of pages6
JournalBehavioral Ecology
Volume22
Issue number2
DOIs
StatePublished - Mar 2011

Fingerprint

nest site
nesting sites
eclosion
ant
decision making
heuristics
animal
Formicidae
Temnothorax
animals
evolutionary theory
site selection
food choices
fitness
filter
food
decision

Keywords

  • collective cognition
  • decision-making
  • dynamic systems
  • rationality

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Ecology, Evolution, Behavior and Systematics

Cite this

Emergence of group rationality from irrational individuals. / Sasaki, Takao; Pratt, Stephen.

In: Behavioral Ecology, Vol. 22, No. 2, 03.2011, p. 276-281.

Research output: Contribution to journalArticle

@article{2dc3ad399c054ca6a630b8fdda58c0d0,
title = "Emergence of group rationality from irrational individuals",
abstract = "Evolutionary theory predicts that animal decision makers should be rational, meaning that they consistently choose fitness-maximizing options. Despite this, violations of rationality have been found repeatedly in humans and other animals. The significance of these violations remains controversial, but many explanations point to cognitive limitations that prevent animals from adequately processing the information needed for fully rational choice. Instead, they rely on heuristics that usually work well but yield systematic errors in specific contexts. Although past research on rationality has focused on individuals, many highly integrated groups, such as ant colonies, regularly make consensus choices among food sources, nest sites, or other options. These collective choices emerge from local interactions among many group members, none of whom take on the whole burden of decision making. We hypothesized that groups may evade the irrational consequences of individual limitations by distributing their decision making across many group members. We tested this in the well-studied case of collective nest-site selection by Temnothorax ants. We found that individual ants, but not colonies, strongly violated rationality when presented with a challenging nest-site choice. Specifically, isolated individuals irrationally switched their preference between 2 alternative nest sites based on their experience of an unattractive decoy. Given the same choice, intact colonies maintained consistent preferences regardless of the decoy's presence. Previous studies have stressed how distributed decision making can filter out random errors made by group members. Our results show that collectives can also suppress systematic errors that emerge from the decision heuristics of cognitively limited individuals.",
keywords = "collective cognition, decision-making, dynamic systems, rationality",
author = "Takao Sasaki and Stephen Pratt",
year = "2011",
month = "3",
doi = "10.1093/beheco/arq198",
language = "English (US)",
volume = "22",
pages = "276--281",
journal = "Behavioral Ecology",
issn = "1045-2249",
publisher = "Oxford University Press",
number = "2",

}

TY - JOUR

T1 - Emergence of group rationality from irrational individuals

AU - Sasaki, Takao

AU - Pratt, Stephen

PY - 2011/3

Y1 - 2011/3

N2 - Evolutionary theory predicts that animal decision makers should be rational, meaning that they consistently choose fitness-maximizing options. Despite this, violations of rationality have been found repeatedly in humans and other animals. The significance of these violations remains controversial, but many explanations point to cognitive limitations that prevent animals from adequately processing the information needed for fully rational choice. Instead, they rely on heuristics that usually work well but yield systematic errors in specific contexts. Although past research on rationality has focused on individuals, many highly integrated groups, such as ant colonies, regularly make consensus choices among food sources, nest sites, or other options. These collective choices emerge from local interactions among many group members, none of whom take on the whole burden of decision making. We hypothesized that groups may evade the irrational consequences of individual limitations by distributing their decision making across many group members. We tested this in the well-studied case of collective nest-site selection by Temnothorax ants. We found that individual ants, but not colonies, strongly violated rationality when presented with a challenging nest-site choice. Specifically, isolated individuals irrationally switched their preference between 2 alternative nest sites based on their experience of an unattractive decoy. Given the same choice, intact colonies maintained consistent preferences regardless of the decoy's presence. Previous studies have stressed how distributed decision making can filter out random errors made by group members. Our results show that collectives can also suppress systematic errors that emerge from the decision heuristics of cognitively limited individuals.

AB - Evolutionary theory predicts that animal decision makers should be rational, meaning that they consistently choose fitness-maximizing options. Despite this, violations of rationality have been found repeatedly in humans and other animals. The significance of these violations remains controversial, but many explanations point to cognitive limitations that prevent animals from adequately processing the information needed for fully rational choice. Instead, they rely on heuristics that usually work well but yield systematic errors in specific contexts. Although past research on rationality has focused on individuals, many highly integrated groups, such as ant colonies, regularly make consensus choices among food sources, nest sites, or other options. These collective choices emerge from local interactions among many group members, none of whom take on the whole burden of decision making. We hypothesized that groups may evade the irrational consequences of individual limitations by distributing their decision making across many group members. We tested this in the well-studied case of collective nest-site selection by Temnothorax ants. We found that individual ants, but not colonies, strongly violated rationality when presented with a challenging nest-site choice. Specifically, isolated individuals irrationally switched their preference between 2 alternative nest sites based on their experience of an unattractive decoy. Given the same choice, intact colonies maintained consistent preferences regardless of the decoy's presence. Previous studies have stressed how distributed decision making can filter out random errors made by group members. Our results show that collectives can also suppress systematic errors that emerge from the decision heuristics of cognitively limited individuals.

KW - collective cognition

KW - decision-making

KW - dynamic systems

KW - rationality

UR - http://www.scopus.com/inward/record.url?scp=79953837259&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79953837259&partnerID=8YFLogxK

U2 - 10.1093/beheco/arq198

DO - 10.1093/beheco/arq198

M3 - Article

VL - 22

SP - 276

EP - 281

JO - Behavioral Ecology

JF - Behavioral Ecology

SN - 1045-2249

IS - 2

ER -