The red-beard evolutionary explanation of human sociality

HPLS (2021) 43:123 https://doi.org/10.1007/s40656-021-00471-x ORIGINAL PAPER The red‑beard evolutionary explanation of human sociality Vaios Koliofotis1 Received: 5 November 2020 / Accepted: 11 October 2021 © The Author(s) 2021 Abstract Recent evolutionary studies on cooperation devote specific attention to non-verbal expressions of emotions. In this paper, I examine Robert Frank’s popular attempt to explain emotions, non-verbal markers and social behaviours. Following this line of work, I focus on the green-beard explanation of social behaviours. In response to the criticisms raised against this controversial ultimate explanation, based on resources found in Frank’s work, I propose an alternative red-beard explanation of human sociality. The red-beard explanation explains the emergence and evolution of emotions, a proximate cause, rather than patterns of behaviour. In contrast to simple evolutionary models that invoke a green-beard mechanism, I demonstrate that the red-beard explanation can be evolutionary stable. Social emotions are a common cause of a social behaviour and a phenotypic marker and therefore cooperative behaviour cannot be suppressed without also changing the marker. Keywords Altruism · Cooperation · Emotion · Evolution · Green-beard · Signal 1 Introduction Emotion-based communication is a key feature of our daily life, with human interactions being replete with many forms of verbal and non-verbal emotional expressions. Verbal exchanges include speech intonation and the use of language while non-verbal interactions consist of gestures, bodily postures, facial expressions, blushing or perspiration used to convey emotional states. Both verbal and non-verbal * Vaios Koliofotis ; 1 Erasmus Institute for Philosophy and Economics, Erasmus University Rotterdam, Burgemeester Oudlaan 50, 3062 PA Rotterdam, Netherlands 13 Vol.:(0123456789) 123 Page 2 of 17 V. Koliofotis expressions of emotions appear to facilitate communication in the social world by providing quick information to others. Non-verbal displays of emotions have been extensively studied by disciplines such as psychology, neuroscience, economics and biology. Darwinian evolution is widely acknowledged as a key for understanding human emotions. Since Charles Darwin’s classic book “The Expression of the Emotions in Man and Animals” (Darwin, 1872), evolutionary research on emotions was mostly concerned with identifying and characterizing non-verbal manifestations of discrete emotional states (e.g. Ekman, 1993; Izard, 2010). Joy, fear, surprise, anger, sadness and disgust1 are considered evolved human characteristics expressed by particular facial expressions across human groups. More recently, evolutionary theorists systematically link evolutionary explanations of human non-verbal emotional expressions to animal signalling theory (e.g. Dezecache et al., 2013; McCullough & Reed, 2016). Moreover, the theoretical study of the biological evolution of social behaviours or social evolution theory examines phenotypic markers that facilitate assortment and the evolution of cooperation (e.g. Frank, 1987, 1988; Nesse, 2001; Riolo et al., 2001). This work has incited a recent trend in empirical research that investigates whether smiles (e.g. Reed et al., 2012; Centorrino, Djemai, Hpfensitz, Milinki, & Seabright, 2015), tears (e.g. Gračanin, Bylsma, & Vingerhoets, 2018; Reed et al., 2019), blushing faces (e.g. Dijk et al., 2011) and expressions of anger (e.g. Reed et al., 2014) are associated with social behaviours. Philosophical research in evolutionary ethics often relies on Robert Frank’s older theorizing on social emotions like love, anger, sympathy or jealousy and social behaviours (e.g. Heath & Rioux, 2018; James, 2011; Joyce, 2006). Following this line of work, I discuss recent attempts to explain the evolution of emotional markers and social behaviours. Despite the diversity of evolutionary models in social evolution theory and animal signalling theory, even a cursory look at this literature reveals that a certain issue arises again and again in different contexts. At the theoretical level, many of these evolutionary studies rely on a simple but controversial green-beard complex to explain the evolution of altruistic cooperation (e.g. Cohen, 2012; Gardner & West, 2009; Handfield et al., 2018; West & Gardner, 2010). Evolutionary theorists have long emphasized that the green-beard explanation of social behaviours are inherently unstable or short lived. Without opportunities for reciprocation, a correlation between marker and social behaviour can be disrupted by the spread of a mutant gene, which adopts the phenotypic marker of cooperative individuals and elicits a favorable behavioural response. In what follows I will not review or evaluate empirical research and experiments that test hypotheses about different emotional expressions2. It is also beyond 1 Different theorists have different lists of basic emotions. For a recent review, see Keltner et al. (2019). It is an open empirical question which emotions are associated with social behaviours and distinct external markers or whether there are emotional expressions that can be recognized with accuracy higher than random guessing. What complicates empirical investigation is that a given emotion may be associated with a variety of expressions, while various emotions may be related to the same expression. More experimental research is required to demonstrate if there are some emotions that are exclusively connected to few markers and particular social behaviours. 2 13 The red‑beard evolutionary explanation of human sociality Page 3 of 17 123 the scope of this paper to present different theories in evolutionary ethics. Instead, I focus on Robert Frank’s account (Frank, 1987, 1988, 2005) and the arguments raised against it (e.g. Gardner & West, 2009; Heath & Rioux, 2018). My goal is to strengthen the case for the value of Frank’s theoretical work in explaining the evolution of human sociality. In particular, I argue that recent well put criticism against Frank’s account of social behaviour does not render his ideas useless. Using resources found in Frank’s work, I distinguish between the red-beard evolutionary explanation that targets proximate causes such as emotions that govern behaviour and phenotypic markers and the green-beard explanation provided by Robert Frank’s evolutionary model that focuses on behaviour and fitness outcomes. Once we distinguish between these two different kinds of evolutionary explanation, it transpires that we do not need to abandon the idea of evolutionary stable communication between individuals based on emotions. In the red-beard explanation there a causal link between human emotions, social behaviour and phenotypic markers and this makes a substantial difference in the way one addresses the stability problem. Social emotions are a common cause of a social behaviour and a phenotypic marker and therefore cooper (...truncated)