Emotional selection (evolution)

El vínculo de pareja se refiere a la formación de un vínculo emocional fuerte, exclusivo y duradero entre dos individuos. Fellmann y Walsh argumentan que la pareja, como un subgrupo social distinto, transforma la selección sexual al ir más allá de la reproducción para unir a los miembros de la pareja emocionalmente. ^{[ 1 ]} El beneficio evolutivo reside en el surgimiento de la identidad personal; tales vínculos también pueden haber proporcionado ventajas en entornos donde la descendencia requería cuidados prolongados. Para los primeros cazadores-recolectores , se propone que los vínculos de pareja transformaron el deseo sexual en amor y compromiso, ^{[ 1 ]} un desarrollo considerado fundamental para el éxito cultural de la especie humana.

Humans experience pair-bonds as committed romantic relationships characterised by attachment, euphoria, trust and comfort.^[6] Romantic attachment has been described as functioning as a “commitment device,” focusing attention on a single partner and promoting long-term investment.^[7] This is evolutionarily significant given the extended period of dependency in human offspring. Pair-bonding has also been linked to the development of the multilevel organisation of human social groups, with pair-bonded family units forming the foundation of hunter-gatherer bands and other wider communities.^[10]

Empirical research suggests that stable pair-bonds are associated with positive health outcomes.^[7] For example, married individuals have been found to show lower mortality rates following cancer diagnosis and heart failure and slightly increased life expectancy at older ages.^[11][12] These effects have been partially linked to biological mechanisms such as oxytocin signalling,^[6] although causality remains complex and influenced by multiple factors.

Within the social environment of pair-bonded groups, a form of selection pressure distinct from natural and sexual selection emerged, which was termed psychosocial selection.^[1] While natural and sexual selection operate through physical competition and mate signalling, psychosocial selection operates through social and emotional complexity. Traits such as the capacity to detect, interpret and respond to a partner’s emotional states and needs became reproductively advantageous, as individuals with greater emotional responsiveness formed stronger bonds and raised more successful offspring.^[1] Sympathy and the sense of belonging are identified as foundational to this process, with humans developing these into higher-order emotions.^[1]

Supporting evidence from personality psychology demonstrates that the Big Five personality traits reflect evolutionary trade-offs, with no single optimal personality type – different emotional and behavioural profiles grant different advantages across social environments.^[13] The breadth of personality variation has also been recognised as one of many explanatory challenges within evolutionary psychology, and emotional selection has been proposed as a framework for addressing it.^[14] Empathy, agreeableness and emotional stability have been proposed as products of selection pressure operating within long-term pair-bonds, a claim supported by evidence that personality traits are heritable and associated with reproductive success across diverse human populations.^[15][16]

However, the extent to which personality differences require a distinct evolutionary mechanism remains debated.

A major criticism of emotional selection is that it may not constitute a genuinely distinct form of selection. David Buss (2009) argues that personality differences can be accounted for within the existing sexual selection framework through frequency-dependent selection and costly signalling, suggesting that emotional selection as a separate category may be redundant.^[14] Nettle and Clegg (2008) similarly demonstrate empirical links between personality traits and mating success within a sexual selection framework, suggesting that emotional and personality traits are already captured by established theory without requiring an additional mechanism.^[17] From this perspective, emotional traits are simply part of the broader set of characteristics shaped by mate choice and competition.

In response, Fellmann and Walsh argue that these critiques do not account for the subjective, experiential dimension of human emotion.^[1] While sexual selection explains the evolution of physical indicators of mate quality, Fellmann and Walsh argue that it does not explain the emergence of personal identity, self-consciousness, or the capacity for romantic love. Their central argument is that the pair-bond generates forms of emotional experience and personal identity that underpin the cultural and cognitive capacities of the human species.^[1] These outcomes cannot be accounted for within competitive mate-choice logic.

However, this distinction remains contested. Critics argue that subjective experiences do not necessarily require a separate evolutionary mechanism, as they may emerge from cognitive processes shaped by natural and sexual selection. In this view, emotional selection risks re-describing existing processes rather than identifying a fundamentally new one.^[14]

As a result, the status of emotional selection remains contested. Wider research argues that it does not constitute a separate evolutionary mechanism, but rather reframes processes already explained by natural and sexual selection.^[17]