Original ArticleSeven dimensions of personality pathology are under sexual selection in modern Spain
Introduction
The idea that personality disorders (PDs) are alternative strategies rather than illnesses is gaining ground (Brüne et al., 2010, Troisi, 2005). Although it is mostly believed that psychopaths have dysfunctional self-regulation and affiliation systems, it has also been proposed that they may be implementing a successful sociosexual strategy based on promiscuity and exploitation (Glenn et al., 2011, Jonason et al., 2009, Mealey, 1995). Schizotypy may be a milder form of schizophrenia, but some schizotypal features may function as a fitness indicator signaling good quality to potential mates (Del Giudice, 2014, Nettle and Clegg, 2006). In addition the recurrent fears and miseries of many neurotic patients may result either from the dysregulation of alarm circuits or from their normal, survival-enhancing operation (Bateson et al., 2011, Ein-Dor et al., 2010, Lafreniere, 2009, Nesse, 2001a). At present, we lack data to establish whether certain maladaptive personalities really are failures or in fact high-risk shortcuts to fitness.
Increasingly, the evidence suggests that normal-range personality variation has adaptive functions rather than being random noise around a behavioral optimum (Bergmüller and Taborsky, 2010, Buss, 2009, Kight et al., 2013, Réale et al., 2010, Sih et al., 2004, Wolf and Weissing, 2010). This variation largely takes place along the same universal axes from insects to humans (Gosling & John, 1999); it is moderately heritable (Bouchard, 2004, Penke et al., 2007); and it has a substantial impact on resource acquisition, mating, reproduction, and survival (Ozer and Benet-Martínez, 2006, Roberts et al., 2007, Smith and Blumstein, 2008). In consequence, personality must be subject to the same selective pressures as many other traits (Stearns, Byars, Govindaraju, & Ewbank, 2010). As personality ultimately is the axial organization of enduring motivations, emotions, cognitions and behaviors that determine the effective adaptation to the environment (DeYoung, 2015, MacDonald, 2012), it may even be a major target for selection.
All the above is harder to defend in the case of PDs, extreme personality traits that cause problems in everyday living. Inordinate levels of any trait—anxiousness, impulsivity, asociality, aggressiveness, eccentricity—have been reported to harm career opportunities, social adaptation, family life, health, longevity, and well-being (Tyrer, Reed, & Crawford, 2015). Significantly, PDs shorten life expectancy by about 18 years (Fok et al., 2012), so their permanence in the population, without being eroded by selection, is a conundrum (Keller and Miller, 2006, Troisi, 2005). Nevertheless, their maladaptivity is not undisputed: the detrimental consequences are not the same for all pathological traits (Ullrich et al., 2007, Vall et al., 2015), nor is clinical adaptation the same as biological fitness (Nesse, 2001b). For example, unlike most other mental disorders, PDs do not globally harm reproductive success (Keller & Miller, 2006), and some subtypes definitely enhance resource accrual or multiply mating success (Gutiérrez et al., 2013, Sansone et al., 2011, Ullrich et al., 2007). It is our contention that studying PDs is essential to evolutionary psychology not only because of their high prevalence (about 10% of us have extreme traits, Tyrer et al., 2015) but also because examining the entire range of phenotypic variation, beyond normal-range traits, may provide a fuller picture of the evolutionary dynamics of personality. Indeed, if personality is about deleterious variation around an optimum, subjects with PDs will be the most maladapted; if it is about alternative strategies, they will be the most extreme strategists. In either case, PDs hold unique keys to understand why we are all different, and why some of these differences bring trouble.
To date, the possibility that personality traits are under sexual selection has not been studied in depth (Schuett, Tregenza, & Dall, 2010). Sexual selection favors those traits that enhance access to mates. The literature has identified it as the strongest selective force in nature, as mating success impacts on reproductive output more directly than any other component of fitness (Geher et al., 2008, Kingsolver and Diamond, 2011). In fact, sexual selection can spread traits even if they reduce survival chances (Fritzsche and Booksmythe, 2013, Hosken and House, 2011, Jones and Ratterman, 2009). In humans, height, body shape, physical attractive, voice pitch, or masculinity have shown some evidence of being under sexual selection (Hill et al., 2013, Jokela, 2009, Stulp et al., 2013). Similarly, traits like psychopathy, aggressiveness, anxiousness, extraversion, eccentricity, insecure attachment and narcissism have been hypothesized to enhance mating success or to form part of alternative sexual strategies (Belsky, 2012, Ein-Dor et al., 2010, Holtzman and Donnellan, 2015, Holtzman and Strube, 2011, Lafreniere, 2009, Nettle, 2006, Nettle and Clegg, 2006). Unfortunately, the evidence regarding the most fundamental aspects is very limited: whether and how sexual selection really affects personality; which evolutionary processes (mutation-selection balance, tradeoffs, fluctuating selection, frequency-dependent selection, condition-dependent selection) are at work (Buss, 2009, Kight et al., 2013, Wolf and Weissing, 2010); whether selective forces are similar or different in each sex (Fritzsche & Booksmythe, 2013); what mechanisms (number of mates, earlier reproduction, stable relationships, status, wealth, prestige) mediate the relationships between personality and fitness (Berg et al., 2013, Lyon and Montgomerie, 2012); and whether the answers to all the above questions are the same or different for each personality trait.
To approach these questions, we use an improved personality pathology system (Gutiérrez, Vall, Peri, Gárriz, & Garrido, 2014). This system overcomes the limitations of traditional psychiatric diagnoses, which are poorly conceived mixtures of heterogeneous traits (Widiger & Trull, 2007). For example, we know that borderline PD doubles the number of sexual partners (Sansone et al., 2011) but not which of its constituent traits—impulsivity, negative emotionality, insecure attachment, aberrant perceptions—account for this effect. The system is also comprehensive, covering previously underexplored traits as well as the pathological extremes of each trait. Indeed, although extraversion has been shown to increase fitness and neuroticism to decrease it (Jokela et al., 2011, Roberts et al., 2007), we lack information on other important traits, and results in normal-range traits do necessarily say anything about extreme variants. Finally, this model is in line both with forthcoming taxonomies (Tyrer et al., 2015) and with evolutionarily-based classificatory proposals (DeYoung, 2015, MacDonald, 2012). On the other hand, in the present study we try to look deeper into some previously neglected aspects (Fritzsche and Booksmythe, 2013, Jones and Ratterman, 2009, Schuett et al., 2010). We measured a wide range of life history variables encompassing mating success, reproductive success and status/wealth; we analyzed selective pressures separately in both sexes; we examined the strength of directional, stabilizing, disruptive, and correlational selection on mating and reproduction; and we traced the entire path from personality to status, to mating success, and to reproductive success.
Our aim is to know whether, and how, sexual selection acts on personality pathology. To this end, in a sample of 959 outpatients we examined a comprehensive set of pathological dimensions and explored which ones bring advantages for either mating or reproduction, in which sex, and through which evolutionary processes and mediating mechanisms. In this way we seek to extend previous knowledge of the evolutionary nature of pathological personalities and of the causes of its persistence in the population.
Section snippets
Participants
The sample was composed of 959 outpatients aged 16 to 67 (mean 34.5, SD 10.7), 53% female, consecutively referred to the Personality Disorder Unit of a General Hospital in Barcelona during a 6-year period. A quarter of the sample were currently studying. Among those employed, 19.9% were skilled and 33.0% were semiskilled workers. The sample did not differ from the general Spanish population in key parameters such as study level, salary, or average maternal age (www.ine.es). However, it was a
Sex differences in personality and life history
Differences between males and females were generally small (Table 1). Males showed lower negative emotionality than females, as well as higher asociality, impulsivity, and antagonism. They also had significantly more short-term mates and fewer long-term mates, with no differences in the duration of the longest relationship. Reproduction began earlier in females, but reproductive output was the same across the sexes. As for variability, standard deviation was greater in males for short-term
Personality pathology is under sexual selection
Our results show that, to varying extents, each of our seven dimensions of personality pathology is under sexual selection. Selective pressures are not homogeneously purifying, as would be expected if they were diseases (Keller & Miller, 2006). Instead, some dimensions are selected for, others against, and still others show tradeoffs, either between fitness costs and benefits or between the sexes. Thus, whereas evolutionary forces contribute to the maintenance of some pathological traits, no
Conflicts of interest
None.
Supplementary Materials
The following are the Supplementary data to this article.
Acknowledgments
This work was partially supported by grants from Spain's Ministerio de Educación y Ciencia (FIS 07/0033 and ETES 08/90434) awarded to F. Gutiérrez.
References (111)
- et al.
Does the contraceptive pill alter mate choice in humans?
Trends in Ecology & Evolution
(2010) - et al.
Personality is differentially associated with planned and non-planned pregnancies
Journal of Research in Personality
(2013) - et al.
Animal personality due to social niche specialisation
Trends in Ecology & Evolution
(2010) Means, variances, and ranges in reproductive success: Comparative evidence
Evolution and Human Behavior
(2012)- et al.
Bateman's principles and human sex roles
Trends in Ecology & Evolution
(2009) - et al.
Why do humans form long-term mateships? An evolutionary game-theoretic model
Advances in Experimental Social Psychology
(2015) Cybernetic Big Five theory
Journal of Research in Personality
(2015)Dominance and reproductive success among nonhuman animals: A cross-species comparison
Ethology and Sociobiology
(1995)- et al.
Life expectancy at birth and all-cause mortality among people with personality disorder
Journal of Psychosomatic Research
(2012) - et al.
Evolutionary theory and psychopathy
Aggression and Violent Behavior
(2011)
The evolutionary fitness of personality traits in a small-scale subsistence society
Evolution and Human Behavior
Fitness costs and benefits of personality disorder traits
Evolution and Human Behavior
A hierarchical model of normal and abnormal personality up to seven factors
Comprehensive Psychiatry
Quantifying the strength and form of sexual selection on men's traits
Evolution and Human Behavior
Sex differences in the relationship between status and number of offspring in the contemporary U.S.
Evolution and Human Behavior
Sexual selection
Current Biology
What is genetic quality?
Trends in Ecology & Evolution
Physical attractiveness and reproductive success in humans: Evidence from the late 20th century United States
Evolution and Human Behavior
Condition-dependent calibration of men's uncommitted mating orientation: Evidence from multiple samples
Evolution and Human Behavior
Human sexual selection
Current opinion in psychology
Regional inequalities in the use of contraception in Spain: A multilevel approach
Health & Place
Behavioral syndromes: An ecological and evolutionary overview
Trends in Ecology and Evolution
Wealth, status, and fitness: A historical study of Norwegians in variable environments
Evolution and Human Behavior
Fitness consequences of personality: A meta-analysis
Behavioral Ecology
Personality and reproductive success in a high-fertility population
Proceedings of the National Academy of Sciences
Precursors of young women's family formation pathways
Journal of Marriage and Family
Anxiety: An evolutionary approach
Canadian Journal of Psychiatry
Fluctuating selection: The perpetual renewal of adaptation in variable environments
Philosophical Transactions of the Royal Society of London B
The development of human reproductive strategies: Progress and prospects
Current Directions in Psychological Science
Genetic influence on human psychological traits. A survey
Current Directions in Psychological Science
Does borderline personality disorder reflect the pathological extreme of an adaptive reproductive strategy? Insights and hypotheses from evolutionary life-history theory
Clinical Neuropsychiatry
How can evolutionary psychology successfully explain personality and individual differences?
Perspectives on Psychological Science
Women's long-term mating strategies
The relationship between hypothesized psychological genetic fitness indicators and indices of mating success
Journal of Social, Evolutionary, and Cultural Psychology
The Temperament and Character Inventory (TCI): A guide to its development and use
Social network- and community-level influences on contraceptive use: Evidence from rural Poland
Proceedings of the Royal Society of London B
An evolutionary life history framework for psychopathology
Psychological Inquiry
Recent models for adaptive personality differences: A review
Philosophical Transactions of the Royal Society of London B
The attachment paradox: How can so many of us (the insecure ones) have no adaptive advantages?
Perspectives on Psychological Science
Fundamental dimensions of environmental risk: The impact of harsh versus unpredictable environments on the evolution and development of life history strategies
Human Nature
Personality and health, subjective well-being, and longevity
Journal of Personality
The measurement of sexual selection on females and males
Current Zoology
Sexually antagonistic coevolution: Theory, evidence, and implications for patterns of human mating and fertility
The evolution of human mating: Trade-offs and strategic pluralism
Behavioral and Brain Sciences
Sexual selection and the evolution of human sex differences
Psychological Topics
Mating intelligence: Toward an evolutionarily informed construct
Low fertility increases descendant socioeconomic position but reduces long-term fitness in a modern post-industrial society
Proceedings of the Royal Society of London B
Personality dimensions in nonhuman animals: A cross-species review
Current Directions in Psychological Science
Personality and adolescent pregnancy outcomes
Journal of Advanced Nursing
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