Approaches to an Evolutionary Personality Psychology: The - edoc

254 Pages·2007·1.01 MB·English

by  Lars Penke

D i s s e r t a t i o n
Approaches to an Evolutionary
Personality Psychology:

The Case of Sociosexuality

zur Erlangung des akademischen Grades doctor rerum naturalium (Dr. rer. nat.)
im Fach Psychologie
an der Mathematisch-Naturwissenschaftlichen Fakultät II
der Humboldt-Universität zu Berlin
eingereicht von
Dipl.-Psych. Lars Penke
geb. am 02. September 1978 in Detmold
Dekan: Prof. Dr. Wolfgang Coy
Präsident der Humboldt-Universität zu Berlin
Prof. Dr. Christoph Markschies
Gutachter: 1. Prof. Dr. Jens B. Asendorpf
2. Prof. Dr. Steven W. Gangestad
3. Prof. Dr. Peter Borkenau
eingereicht: 10. Mai 207
Datum der Promotion: 17. Juli 2007
This thesis is dedicated to my son Richard.
Table of Contents

Abstract (English)
Abstract (German)
Introduction

Part I: The Evolutionary Genetic Approach to Personality
The Evolutionary Genetics of Personality
Lars Penke, Jaap J. A. Denissen and Geoffrey F. Miller
22 Open Peer Commentaries
by Timothy C. Bates, Anne Campbell, Niels J. Dingemanse, Harald Euler, Aurelio
José Figueredo & Paul Gladden, David C. Funder, Steven W. Gangestad, Kerry L.
Jang, Wendy Johnson, Matthew C. Keller, James J. Lee, W. John Livesley, Gerald
Matthews, Robert R. McCrae, Denis Réale, Irene Rebollo & Dorret I. Boomsma, Gad
Saad, Andrew Sih & Alison M. Bell, Susan C. South & Robert F. Krueger, Alexander
Strobel, Alfonso Troisi, and Kees van Oers
Author’s Response: Genes, Evolution, and Interdisciplinary Personality Research
Lars Penke, Jaap J. A. Denissen and Geoffrey F. Miller
Part II: The Life History Approach to Personality
Single Attribute Implicit Association Tests (SA-IAT) for the Assessment of Unipolar
Constructs: The Case of Sociosexuality
Lars Penke, Jan Eichstaedt and Jens B. Asendorpf
Beyond Global Sociosexual Orientations: A More Differentiated Look at
Sociosexuality and its Effects on Courtship and Romantic Relationships
Lars Penke and Jens B. Asendorpf)
Abstract
Evolutionary approaches have not been as successful in personality psychology as they
were in other areas of psychology, arguably because of the misfit between modern
evolutionary psychology’s strong focus on universal adaptations and the study of (mostly
heritable) individual differences in personality psychology. In this thesis, two alternative
evolutionary approaches, which appear more suitable for personality psychology, are
discussed and applied. The evolutionary genetic approach asks why genetic variance in
personality differences exists. In the first part of this thesis, three evolutionary genetic
mechanisms that could explain genetic variance in personality differences are assessed:
selective neutrality, mutation-selection balance, and balancing selection. Based on
evolutionary genetic theory and empirical results from behavior genetics and personality
psychology, it is concluded that selective neutrality is largely irrelevant, that mutation-
selection balance seems best at explaining genetic variance in intelligence, and that
balancing selection by environmental heterogeneity seems best at explaining genetic
variance in personality traits. A general model of heritable personality differences is
presented, which conceptualizes intelligence as a fitness component and personality traits as
individual reaction norms of genotypes across environments, with different fitness
consequences in different environmental niches. Complementary to the evolutionary genetic
approach, the life history approach starts with how people allocate their resources to
evolutionarily relevant life tasks. It asks how individual differences in these allocation
decisions emerge from the interplay of various developmental components, including
personality differences. In the second part of this thesis, differences in the allocation to long-
term versus short-term mating tactics (as reflected in the construct of sociosexuality) are
used as a case to exemplify this approach. Two new measures for the assessment of
sociosexuality components are presented. While the revised Sociosexual Orientation
Inventory (SOI-R) is a questionnaire that assesses the facets Behavior, Attitude and Desire,
the sociosexuality Single-Attribute Implicit Association Test (SA-IAT) is a new methodic
development aimed to assess implicit sociosexuality indirectly. Both measures showed
concurrent validity in online studies, but only the SOI-R facets were predictive of mating
tactics, including observed flirting behavior, as well as for the number of sexual partners and
changes in romantic relationship status over the following 12 months. Furthermore, distinct
sex differences, developmental trends, degrees of assortative mating, and effects on a
romantic partner were found for the three SOI-R facets, indicating their unique roles in the
development of mating tactics.
Zusammenfassung
Evolutionäre Herangehensweisen hatten in der Persönlichkeitspsychologie nicht den
gleichen Erfolg wie in anderen Bereichen der Psychologie, vermutlich wegen der Fehl-
passung des starken Fokus auf universele Adaptationen in der modernen
Evolutionspsychologie mit der Untersuchung (größtenteils erblicher) individueler
Unterschiede in der Persönlichkeitspsychologie. In dieser Dissertationsschrift werden zwei
alternative evolutionäre Herangehensweisen diskutiert und angewendet, welche passender
für die Persönlichkeitspsychologie erscheinen. Die evolutionsgenetische Herangehensweise
fragt, warum genetische Varianz in Persönlichkeitsunterschieden existiert. Im ersten Teil
dieser Dissertationsschrift werden verschiedene evolutionsgenetische Mechanismen, die
genetische Varianz erklären können, verglichen. Auf Grundlage evolutionsgenetischer
Theorie und empirischen Befunden aus der Verhaltensgenetik und
Persönlichkeitspsychologie wird geschlussfolgert, dass ein Mutations-Selektions-
Gleichgewicht genetische Varianz in Intelligenzunterschieden gut erklären kann, während
ausgleichende Selektion durch Umweltheterogenität die plausibelste Erklärung für
genetische Unterschiede in Persönlichkeitseigenschaften ist. Es wird ein allgemeines Modell
vorgeschlagen, welches Inteligenz als Fitnesskomponente konzeptualisiert und
Persönlichkeitseigenschaften als individuelle Reaktionsnormen von Genotypen auffasst,
welche unterschiedliche Fitnesskonsequenzen in unterschiedlichen Umweltnischen haben.
Komplementär zur evolutionsgenetischen Herangehensweise beginnt die „Life History“-
Herangehensweise damit, wie Menschen ihre Ressourcen in evolutionär relevante
Lebensbereiche investieren. Sie fragt, wie Unterschiede in diesen Investitions-
entscheidungen aus dem Zusammenspiel verschiedener Entwicklungsomponenten
entstehen, einschließlich Persönlichkeitsunterschiede. Im zweiten Teil der Dissertations-
schrift wird diese Herangehensweise am Beispiel von Investitionsunterschieden in Langzeit-
versus Kurzzeit-Paarungstaktiken (wie im Konstrukt der Soziosexualität abgebildet) erläutert.
Zwei neue Maße zur Erfassung von Soziosexualitätskomponenten werden vorgestellt.
Während das revidierte Soziosexuelle Orientierungsinventar (SOI-R) ein Fragebogen zur
Erfassung der Facetten „bisheriges Verhalten“, „Einstellung“ und „Begehren“ ist, wurde mit
dem „Single-Attribute“ Impliziten Assoziationstest (SA-IAT) eine neue Methode zur indirekten
Erfassung impliziter Soziosexualität entwickelt. Beide Maße zeigten konkurrente Validität in
Onlinestudien, aber nur die SOI-R-Facetten erwiesen sich als prädiktiv für Paarungstaktiken,
einschließlich beobachtetem Flirtverhalten sowie der Zahl der Sexualpartner und
Veränderungen im Beziehungsstatus innerhalb der nächsten 12 Monate. Weiterhin wurden
für die SOI-R-Facetten distinkte Geschlechtsunterschiede, Entwicklungsverläufe, Grade
selektiver Partnerwahl, und Effekte auf den Beziehungspartner gefunden, was ihre
spezifischen Rollen in der Entwicklung von Paarungstaktiken unterstreicht.
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Introduction
Over the last two decades, evolutionary approaches had a great deal of success in
various branches of psychology (e.g. Buss, 2005; Dunbar & Barrett, 2007). However,
personality psychology apparently withstands this general trend. While some notable
theoretical attempts toward an evolutionary personality psychology have been made as early
as 1990 (Buss, 1990; Tooby & Cosmides, 1990), not much has happened since then, and
the current state must be regarded as unsatisfactory (Miller, 2000; Nettle, 2006). An
evolutionary account for personality differences is generally acknowledged as a valuable
goal for personality psychology in the long run (e.g. McAdams & Pals, 2006), but
evolutionary approaches have clearly not pervaded mainstream personality research. The
overarching goal of this thesis is to provide and exemplify evolutionary approaches that are
suitable for personality research.
One of the main reasons for the low impact that evolutionary psychology had on
personality research is likely that modern evolutionary psychology has focused very much on
adaptations. Adaptationistic evolutionary psychology studies domain-specific solutions to
reoccurring adaptive problems in the universal design of the human species. A defining
characteristic of these adaptations is that they have been fixed in the human genome, which
means that they show no genetic variation. They are inherited, but not heritable (Tooby &
Cosmides, 1990, 2005). This severely limits the value of the adaptationistic approach to
personality research: while it can be used to explain sex differences (Mealey, 2000) and
some individual differences resulting from conditional developmental reactions to
environmental factors (e.g. attachment styles, e.g. Buss & Greiling, 1999), it is unable to
explain heritable individual differences (Tooby & Cosmides, 1990) – and a heritable
component has been established for virtually all personality differences (Plomin, DeFries,
McClearn & McGuffin, 2001; Turkheimer, 2000).
Alternative to the adaptationistic approach, an evolutionary genetic approach can explain
genetic differences between individuals from an evolutionary perspective. Evolutionary
genetics studies the effects of processes like mutation, selection, genetic drift, and migration
on genetic variation between individuals and across populations (Maynard Smith, 1998; Roff,
1997).In the first part of this thesis, comprised by the theoretical target article “The
evolutionary genetics of personality” (Penke, Denissen & Miller, in press a), 22 peer
commentaries, and the author’s reply (Penke, Denissen & Miller, in press b), it is argued that
evolutionary genetics provides a more suitable approach to personality psychology than
adaptationism. While some evolutionary genetic mechanisms have already been alluded to
in earlier evolutionary treatises on personality (Buss, 1990, 1991; MacDonald, 1995; Nettle,
2006; Tooby & Cosmides, 1990), these articles have not exploited the full potential of an
evolutionary genetic approach. Penke et al. (in press a, b) argue that the degree of
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elaboration of modern evolutionary genetic models and the wealth of data on human
personality allows us to infer which evolutionary genetic mechanisms are most plausibly
responsible for the existence and maintenance of genetic variation in personality differences.
They conclude that a small set of evolutionarily independent dimensions of genetic
personality differences exist in humans, of which the one underlying the g factor of
intelligence is most likely maintained by a balance of new mutation and counteracting
selection, while those underlying broad personality domains (as for example represented in
the Five Factor Model of personality) most likely still exist because spatial or temporal
heterogeneity in our (physical and social) environment causes balanced selection pressures
on them. Penke et al. (in press a, b) also provide insights into how an evolutionary
perspective might help to understand the complex interplay between genes and
environmental factors in producing personality phenotypes.
Evolutionary genetics thus offers a “bottom-up” approach to an evolutionary personality
psychology, one where the genetic level is linked to individual differences in abstract
behavioral dispositions (i.e., personality traits and abilities). However, such dispositions can
only be evolutionarily relevant if they translate into consequential behaviors. More
specifically, they have to influence how well people are able to extract resources (ultimately
energy) from their environments, and how they invest these resources into conflicting life
domains of evolutionary relevance (i.e., growth, survival, reproduction, and the support of
genetic relatives). These potentials and allocation decisions, which influence reproductive
success and ultimately fitness, are studied in evolutionary anthropology and behavioral
ecology within the framework of life history theory (Kaplan & Gangestad, 2005). The life
history approach thus deals with individual differences in highly complex behavioral and
developmental strategies and tactics for the allocation of resources across the lifespan. Life
history strategies and tactics can be conceptualized as the final outcome of (1) interacting
systems of adaptations (Kaplan & Gangestad, 2005, 2007; White, Dill & Crawford, 2007),
which are often sensitive to an individual’s own potential (i.e., condition) and to the
environment (e.g. Gangestad & Simpson, 2000), and (2) genetic differences within these
systems (Roff, 2002). However, the step from broad and complex strategies and tactics to
domain-specific adaptations and genetic differences is a big one - from the very
“downstream” to the very “upstream” in terms of the watershed model that Penke et al. (in
press a) adopted from Cannon and Keller (2005). Therefore, it might be worthwhile (if not
necessary) to take an intermediate step and start with studying the mid-level components of
life-history strategies and tactics, as well as their interactions with each other and with
relevant environmental factors across the lifespan. Since these mid-level developmental
components include personality differences (both heritable and environmental-contingent),
life history theory offers a “top-down” approach to an evolutionary personality psychology.
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The life history approach is thus complementary to the evolutionary genetic “bottom-up”
approach: While the former connects personality to fitness, the latter connects genes to
personality.
The second part of this thesis uses the life history trade-off between long-term and short-
term mating tactics as an exemplary case for the life history approach to personality. Long-
term mating tactics include developing and protecting an exclusive and committedromantic
relationship, usually accompanied by high levels of parental investment in potential offspring.
In contrast, short-term mating tactics include investing greater efforts in finding and courting
potential mates, in order to have sexual affairs with either many mates or mates of especially
high quality. Individual differences along this dimension of mating tactics are often equated
with sociosexual orientations, which describes individual differences in the willingness to
have uncommitted sex (Simpson et al., 2004). Both papers in the second part of this thesis
were aimed to contribute to a dissection of this broad life history trait into its mid-level
components.
Penke and Asendorpf (2007) developed a revised version of the Sociosexual Orientation
Inventory (SOI; Simpson & Gangestad, 1991), a short self-report questionnaire which is the
most established measure of sociosexuality. The new SOI-R assesses three facets of global
sociosexuality (desire, attitude, and past behavioral experiences). Penke, Eichstaedt and
Asendorpf (2006) deviated from the usual reliance on self-reports and attempted to develop
an indirect measure of implicit sociosexuality. This latter work was inspired by the recent
trend in social psychology to explain behavior as the outcome of two different cognitive
systems, distinguished by their reliance on automatic versus reflective information
processing. It has been argued that the automatic systems is more involved in the generation
of spontaneous, impulsive behavior, while the reflective system is responsible for deliberate
behavior (Strack & Deutsch, 2004). Since Implicit Association Tests (IATs) are assumed to
be capable of assessing individual differences in implicit personality self-concepts (Schnabel,
Greenwald & Asendorpf, in press), and have indeed shown incremental validity over explicit
self-report measures in the prediction of spontaneous behavior in some studies (e.g.
Asendorpf, Banse & Mücke, 2002), Penke et al. (2006) developed a variant of the IAT
procedure, the Single-Attribute IAT (SA-IAT), for the assessment of implicit sociosexuality.
The rationale here was that if some of the psychological components that influence mating
tactics operate on the automatic level, they might be better captured by an indirect measure
like the sociosexuality SA-IAT than by an explicit self-repot measure like the SOI or SOI-R.
(Note that, while Barrett, Frederick, Haselton and Kurzban, 2006, recently argued that
evolved psychological mechanisms do not have to operate at the automatic level, it is
possible that some of them do. Characterizing the level of operation for psychological
adaptations might help us to understand them better.)