Opposition to inbreeding between close kin reflects inclusive fitness costs

Jan Antfolk, Debra Lieberman, Christopher Harju, Anna Albrecht, Andreas Mokros, Pekka Santtila

Research output: Contribution to journalArticle

Abstract

Due to the intense selection pressure against inbreeding, humans are expected to possess psychological adaptations that regulate mate choice and avoid inbreeding. From a gene's-eye perspective, there is little difference in the evolutionary costs between situations where an individual him/herself is participating in inbreeding and inbreeding among other close relatives. The difference is merely quantitative, as fitness can be compromised via both routes. The question is whether humans are sensitive to the direct as well as indirect costs of inbreeding. Using responses from a large population-based sample (27,364 responses from 2,353 participants), we found that human motivations to avoid inbreeding closely track the theoretical costs of inbreeding as predicted by inclusive fitness theory. Participants were asked to select in a forced choice paradigm, which of two acts of inbreeding with actual family members they would want to avoid most. We found that the estimated fitness costs explained 83.6% of participant choices. Importantly, fitness costs explained choices also when the self was not involved. We conclude that humans intuit the indirect fitness costs of mating decisions made by close family members and that psychological inbreeding avoidance mechanisms extend beyond self-regulation.

Original languageEnglish (US)
Article number2101
JournalFrontiers in Psychology
Volume9
Issue numberOCT
DOIs
StatePublished - Nov 2 2018

Fingerprint

Inbreeding
Costs and Cost Analysis
Consanguinity
Ego
Psychological Adaptation
Motivation
Psychology
Pressure

Keywords

  • Inbreeding
  • Inbreeding avoidance
  • Inclusive fitness theory
  • Mate choice
  • Social cognition

ASJC Scopus subject areas

  • Psychology(all)

Cite this

Opposition to inbreeding between close kin reflects inclusive fitness costs. / Antfolk, Jan; Lieberman, Debra; Harju, Christopher; Albrecht, Anna; Mokros, Andreas; Santtila, Pekka.

In: Frontiers in Psychology, Vol. 9, No. OCT, 2101, 02.11.2018.

Research output: Contribution to journalArticle

Antfolk, Jan ; Lieberman, Debra ; Harju, Christopher ; Albrecht, Anna ; Mokros, Andreas ; Santtila, Pekka. / Opposition to inbreeding between close kin reflects inclusive fitness costs. In: Frontiers in Psychology. 2018 ; Vol. 9, No. OCT.
@article{343deb98476240a59b5b72b3eb30b10e,
title = "Opposition to inbreeding between close kin reflects inclusive fitness costs",
abstract = "Due to the intense selection pressure against inbreeding, humans are expected to possess psychological adaptations that regulate mate choice and avoid inbreeding. From a gene's-eye perspective, there is little difference in the evolutionary costs between situations where an individual him/herself is participating in inbreeding and inbreeding among other close relatives. The difference is merely quantitative, as fitness can be compromised via both routes. The question is whether humans are sensitive to the direct as well as indirect costs of inbreeding. Using responses from a large population-based sample (27,364 responses from 2,353 participants), we found that human motivations to avoid inbreeding closely track the theoretical costs of inbreeding as predicted by inclusive fitness theory. Participants were asked to select in a forced choice paradigm, which of two acts of inbreeding with actual family members they would want to avoid most. We found that the estimated fitness costs explained 83.6{\%} of participant choices. Importantly, fitness costs explained choices also when the self was not involved. We conclude that humans intuit the indirect fitness costs of mating decisions made by close family members and that psychological inbreeding avoidance mechanisms extend beyond self-regulation.",
keywords = "Inbreeding, Inbreeding avoidance, Inclusive fitness theory, Mate choice, Social cognition",
author = "Jan Antfolk and Debra Lieberman and Christopher Harju and Anna Albrecht and Andreas Mokros and Pekka Santtila",
year = "2018",
month = "11",
day = "2",
doi = "10.3389/fpsyg.2018.02101",
language = "English (US)",
volume = "9",
journal = "Frontiers in Psychology",
issn = "1664-1078",
publisher = "Frontiers Research Foundation",
number = "OCT",

}

TY - JOUR

T1 - Opposition to inbreeding between close kin reflects inclusive fitness costs

AU - Antfolk, Jan

AU - Lieberman, Debra

AU - Harju, Christopher

AU - Albrecht, Anna

AU - Mokros, Andreas

AU - Santtila, Pekka

PY - 2018/11/2

Y1 - 2018/11/2

N2 - Due to the intense selection pressure against inbreeding, humans are expected to possess psychological adaptations that regulate mate choice and avoid inbreeding. From a gene's-eye perspective, there is little difference in the evolutionary costs between situations where an individual him/herself is participating in inbreeding and inbreeding among other close relatives. The difference is merely quantitative, as fitness can be compromised via both routes. The question is whether humans are sensitive to the direct as well as indirect costs of inbreeding. Using responses from a large population-based sample (27,364 responses from 2,353 participants), we found that human motivations to avoid inbreeding closely track the theoretical costs of inbreeding as predicted by inclusive fitness theory. Participants were asked to select in a forced choice paradigm, which of two acts of inbreeding with actual family members they would want to avoid most. We found that the estimated fitness costs explained 83.6% of participant choices. Importantly, fitness costs explained choices also when the self was not involved. We conclude that humans intuit the indirect fitness costs of mating decisions made by close family members and that psychological inbreeding avoidance mechanisms extend beyond self-regulation.

AB - Due to the intense selection pressure against inbreeding, humans are expected to possess psychological adaptations that regulate mate choice and avoid inbreeding. From a gene's-eye perspective, there is little difference in the evolutionary costs between situations where an individual him/herself is participating in inbreeding and inbreeding among other close relatives. The difference is merely quantitative, as fitness can be compromised via both routes. The question is whether humans are sensitive to the direct as well as indirect costs of inbreeding. Using responses from a large population-based sample (27,364 responses from 2,353 participants), we found that human motivations to avoid inbreeding closely track the theoretical costs of inbreeding as predicted by inclusive fitness theory. Participants were asked to select in a forced choice paradigm, which of two acts of inbreeding with actual family members they would want to avoid most. We found that the estimated fitness costs explained 83.6% of participant choices. Importantly, fitness costs explained choices also when the self was not involved. We conclude that humans intuit the indirect fitness costs of mating decisions made by close family members and that psychological inbreeding avoidance mechanisms extend beyond self-regulation.

KW - Inbreeding

KW - Inbreeding avoidance

KW - Inclusive fitness theory

KW - Mate choice

KW - Social cognition

UR - http://www.scopus.com/inward/record.url?scp=85055909641&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85055909641&partnerID=8YFLogxK

U2 - 10.3389/fpsyg.2018.02101

DO - 10.3389/fpsyg.2018.02101

M3 - Article

AN - SCOPUS:85055909641

VL - 9

JO - Frontiers in Psychology

JF - Frontiers in Psychology

SN - 1664-1078

IS - OCT

M1 - 2101

ER -