Humans are a highly prosocial species, which does not only mean that they cooperate in good times but also that they – under certain conditions – support each other in need (Fabrega, Reference Fabrega1997; Gurven, Stieglitz, Hooper, Gomes, & Kaplan, Reference Gurven, Stieglitz, Hooper, Gomes and Kaplan2012; Kessler, Reference Kessler2020; Spikins et al., Reference Spikins, Needham, Wright, Dytham, Gatta and Hitchens2019; Steinkopf, Reference Steinkopf2017a, Reference Steinkopf, Shackelford and Al-Shawafin press; Sugiyama, Reference Sugiyama2004; Tilley, Reference Tilley2015). That is why expressions of weakness, incapacity, despair, vulnerability, and neediness may benefit the individual that depicts them, for example in terms of being absolved from duties, receiving assistance and material support, or motivating affiliation and integration attempts from others (Finlay & Syal, Reference Finlay and Syal2014; Hagen, Watson, & Hammerstein, Reference Hagen, Watson and Hammerstein2008; Nock, Reference Nock2008; Steinkopf, Reference Steinkopf2015). In the target article, Grossmann presents the “fearful ape hypothesis” which states that humans are more fearful than other apes because of potential affiliative responses of their particularly prosocial environment to expressions of fear. This hypothesis is in line with several similar hypothesis regarding emotions, conditions, or behaviors like pain in general (de Williams & Kappesser, Reference de Williams, Kappesser, Vervoort, Karos, Trost and Prkachin2018; Steinkopf, Reference Steinkopf2015; Wall, Reference Wall1999), labor pain in particular (Finlay & Syal, Reference Finlay and Syal2014), signs of depression (Hagen, Reference Hagen and Hammerstein2003; Henderson, Reference Henderson1974; Watson & Andrews, Reference Watson and Andrews2002), self-harm (Nock, Reference Nock2008), suicidal behavior (Syme, Garfield, & Hagen, Reference Syme, Garfield and Hagen2016) as well as sickness behavior and other symptoms of sickness (Steinkopf, Reference Steinkopf2015, Reference Steinkopf, Shackelford and Al-Shawafin press). Grossmann's “fearful ape hypothesis” could therefore be regarded as one aspect of a more general “suffering ape hypothesis.” From this perspective, pain, sickness behavior, depression, anxiety, and so on are just different channels through which need is communicated (Steinkopf, Reference Steinkopf2017b, Reference Steinkopf, Shackelford and Al-Shawafin press). As Grossmann gives a great overview and argument for the case of fear, this commentary will give a very short overview of the other aforementioned cases.

The great pain researcher Patrick Wall (Reference Wall1999) regarded pain not as an emotion or a sensation, but as a motivation or need state. That is the need to withdraw from a harmful situation, the need to spare the injured body part, and – most importantly – the need to seek care and treatment. Thereby, the often loud, pervasive, and specific expressions of pain (de Williams, Reference de Williams2002) not only serve as a warning to other, but also as a signal that help is needed (Finlay & Syal, Reference Finlay and Syal2014; Steinkopf, Reference Steinkopf2015, Reference Steinkopf2016). This is very well illustrated by the case of labor pain as presented by Finlay and Syal (Reference Finlay and Syal2014). They hypothesize that the extraordinary pain of childbirth that women experience and express in comparison to females of other species is not exclusively based on the particular difficulties of human birth (obstetric dilemma), but connected to the fact that midwifery is a human universal. In this critical situation, when two lives are at stake, having assistance may heighten the chance of survival for the mother as well as for the child. Therefore, natural selection should have favored expressive and unbearable labor pain that mobilizes support over stoic childbirth.

The same might be true for symptoms of sickness and sickness behavior. Certainly, the primary function of these bodily reactions to infection is to fight an infectious agent and create circumstances advantageous for this immune response (Aubert, Reference Aubert1999; Dantzer & Kelley, Reference Dantzer and Kelley2007; Schrock, Snodgrass, & Sugiyama, Reference Schrock, Snodgrass and Sugiyama2020). However, symptoms like social withdrawal, lack of motivation, and fever are easily discernible for others and may motivate certain behaviors, for example avoidance but also affiliation and support. Therefore, symptoms of sickness might not only be shaped for optimal immune effectiveness, but also for their communicative and social impact, that is the prevention of infection among kin and community through triggering avoidance responses as well as care and support (Kessler, Reference Kessler2020; Kessler, Bonnell, Byrne, & Chapman, Reference Kessler, Bonnell, Byrne and Chapman2017; Shakhar & Shakhar, Reference Shakhar and Shakhar2015; Steinkopf, Reference Steinkopf2015, Reference Steinkopf2017b, Reference Steinkopf, Shackelford and Al-Shawafin press; Tiokhin, Reference Tiokhin2016). Thereby, symptoms and sickness behaviors might be exaggerated above the intensity level that is optimal for immune function to optimize the mobilization of social support (Steinkopf, Reference Steinkopf2015).

In a similar way, suicidal behavior can be explained through its high-communicative value as a signal of need (Hagen, Reference Hagen and Hammerstein2003; Syme et al., Reference Syme, Garfield and Hagen2016). From this evolutionary perspective, it is not the aim to complete the suicide but to send a credible signal that one's life has become worthless and, in this way, motivate support and reintegration. Through the risk of death, the cry for help becomes pervasive and persuasive. Noteworthily, this explains why natural selection did not sort out suicidal behavior, it does not mean that suicidal individuals act consciously and strategically to extract support from others. The argument for non-suicidal self-harm is similar. From the individual, subjective perspective, self-harm helps regulating aversive emotions but, from a social perspective, self-harm is a convincing signal of neediness (Nock, Reference Nock2008). Conversely, self-harm and suicidal behavior could only evolve in a highly prosocial environment. Symptoms of depression such as social withdrawal, anhedonia, or loss of motivation are less pervasive but they may also signal surrender and need for help (Henderson, Reference Henderson1974; Price, Sloman, Gardner, Gilbert, & Rohde, Reference Price, Sloman, Gardner, Gilbert and Rohde1994; Watson & Andrews, Reference Watson and Andrews2002).

When emphasizing the benefits of suffering it is important not to forget about the obvious downsides. There are direct costs to suffering such as the energy expenditure of high fever, the risk of becoming victimized because of displayed weakness (de Williams, Gallagher, Fidalgo, & Bentley, Reference de Williams, Gallagher, Fidalgo and Bentley2016), or the reputational damage of “cowardice” (see Ackerman & Kenrick, Reference Ackerman and Kenrick2008). Also, there are opportunity costs such as a lowered chance of mating because of social withdrawal, lost opportunities for social bonding because of debilitating pain, and missed out food because of appetite loss (see Lopes, Reference Lopes2014). However, these downsides also serve an important function: They make suffering expensive and thereby credible – it is a signal that is not cheap to fake and therefore convincing (Hagen et al., Reference Hagen, Watson and Hammerstein2008; Steinkopf, Reference Steinkopf2016).

To sum up, it is not only fear and anxiety but probably all kinds of aversive states that might be more pronounced in humans because of their high prosociality. Helpfulness and suffering are two sides of the same coin. In the end, it is not even necessary to limit the hypothesis to emotions and conditions with negative valence. Not only suffering but also feelings of joy, gratitude, and love might be more pronounced in humans.