[Epistemic status: Very speculative!! Not science!! Armchair evo-psych is bad for you etc., but there are some important questions we currently don’t have a better way to try to answer, so.]

[TL;DR: The intensity of suffering, an evolved motivational state, is likely to vary even between species with generally similar levels of sentience. I describe four principles which could suggest that as a result of their evolutionary history, social animals typically suffer more than asocial ones.]

Introduction

There’s a lot of research going on about sentience and moral patienthood: which creatures are phenomenally conscious and to what extent is one of the first things to consider when figuring out what exactly deserves our moral consideration. However, consciousness itself is arguably a neutral property, much like existing as a material object is a neutral property. Even if a creature has subjective experiences, if these experiences solely consists of being aware of stuff – with no desires, aversions, or other subjectively felt motivations towards anything – it’s not really good or bad that such creatures exist or that things happen to them. Only the capacity to experience states with emotional valence makes something a moral patient (unless you insist on consciousness itself as a terminal value, which some people do of course – I think it’s aesthetically interesting and okay I guess, but distinct from morally important properties, which need to be tied to hedonic tone or motivations or preferences to make sense).

If our aim is to minimize suffering in some conventionally defined sense, it is obviously not enough to know if an animal is conscious. If we accept that life or even consciousness don’t necessarily imply a capacity to suffer, we need to estimate the extent to which the animal reacts to stress with subjective distress. Most mobile creatures produced by the brutal evolutionary processes we’re familiar with show clear behavioural signs of nociception when physically hurt, such as avoidance and attempts to disrupt the sensory pain signal if possible; and the closer an animal is to our own physiological, behavioural, and taxonomical type, the greater is also the probability that these signs really do imply subjective suffering as well, instead of just reflexive or mechanical reactions (this blatantly anthropocentric line of evidence is far from conclusive, of course, it’s just that it’s almost all the evidence we currently have).

However, assuming that suffering is a product of evolutionary processes, there are good reasons to believe that the intensity of subjective suffering varies between species just like other evolved properties do: according to their historical usefulness during the unique evolution of a given population. Even if every tetrapod has four limbs, different environments and niches have formed different uses and adaptations for these limbs. The capacity to suffer is more fundamental than that and its uses are probably more unified, but slightly different adaptations are to be expected, depending on what sort of things an animal is motivated to do and what kind of an environment it has been shaped by.

This seems likely because contrary to the standard biology textbook view, suffering is more than just a signal of a harmful situation. Intense suffering especially is primarily a motivational state that facilitates not only direct avoidance of harmful acts and environments but also complex decisions under threat or risk, long-term learning, social investment and bonding, competition and communicating, all depending on the other aspects of an animal’s evolutionary history, cognition, and lifestyle.

Behaviourally and, uh, anecdotally, it seems that humans have the capacity to suffer a lot. A defining feature of our species is the immensely complicated social behaviour we develop when surrounded by other people, and it has probably shaped our subjective experience more than any other aspect of our cognition has. So, in this post, I try to pin down some principles and hunches that suggest that a social evolutionary history in particular could produce species that suffer intensely – though significant suffering is still probably present in all conscious animals – and then take a brief look at the implications of this possibility.



The extended homeostasis of social animals



Suffering as a motivational state is typically the mental component of an animal’s homeostatic regulation, i.e. the processes that keep all the relevant physiological variables between healthy parameters. Most things that threaten your homeostasis in a way that humans have historically been able to survive when motivated to do so will cause some kind of suffering: thirst when your blood volume starts to drop, pain when a wound opens and leaves you vulnerable to pathogens and blood loss, sickness when you have ingested toxins and need to expel them. When the threat isn’t currently actual but can pretty reliably be predicted to come true unless you take physiological or behavioural precautions, your species will evolve predictive homeostatic processes. Many of these predictive processes are cognitive or emotional in nature, e.g. people often feel distress in darkness and high places – things that cause absolutely no damage in themselves, but correlate with future homeostatic disturbances.



Among social animals that habitually rely on others to survive and thrive, predictive homeostasis is extended to social relations as well, so that an individual without sufficient relationships suffers from loneliness and other emotional disturbances. Not all social relationships are homeostatically maintained: the drive to acquire social status probably doesn’t really settle around a set point or anything, as it has more to do with mating opportunities than with survival. Social belonging, on the other hand, can somewhat accurately be defined as the part of social relationships that is indeed homeostatic – maintained by feedback loops within a certain dynamic range, where a lack of it leads to negative emotions, and an excess is quite naturally dropped due to time constraints and/or social stress.



As the number of things you need to consciously attend to when maintaining your homeostasis increases, so does the probability that something is missing, which plausibly leads to more suffering. In a community, your wellbeing becomes directly tied to the wellbeing of others, which again increases the number of things that can go wrong: not only do you care about how others treat you to ensure your direct wellbeing, their interests are now inherently important to you too, so that you feel some of their pain even when it’s directly irrelevant to you. Empathy, especially its affective aspects, is a major mechanism by which this extension of homeostatic suffering becomes possible, since it motivates you to make sure your companions survive and thrive as well, and in a silly metaphorical sense moves you closer to becoming a single organism (only with multiple simultaneous consciousnesses, and so increased maximum suffering levels).



Suffering and contingent social commitment

A lot of human suffering comes in the form of worry or grief over lost social bonds. Evo-psych hypotheses about the origins of social grief are based on the utility found in maintaining close relationships and seeking reunion on pain of distress (e.g. Archer 1998). When an important bond is permanently broken and little to no chance of reunion remains, the normally useful reaction becomes temporarily maladaptive. Prolonged, intense, and public displays of grief probably serve a signalling purpose as well, providing evidence that you’ll emotionally commit to maintaining a social bond: this can only apply to animals whose social attachments are contingent and based on reciprocity, individual recognition, and familiarity, whereas eusocial animals (primarily social insects) may not need to experience such loyalty towards specific individuals. The exact evolutionary processes at play are poorly understood, but it remains likely that most other cognitively advanced, conditionally social animals also experience emotional separation distress, and that the accompanying behaviour aids an individual’s commitment to maintaining social bonds.

All of this should work in synchrony with the social homeostasis model sketched above. Indeed, Hofer (1984) found two distinct behavioural patterns in nonhuman animals separated from their companions. An immediate, acute reaction to a specific loss appears as distress, searching, preoccupation, and even aggression. This reaction quite naturally helps an animal to reunite with its lost companion should it still be possible. Another reaction develops afterwards or simultaneously but over a longer time period, and involves passivity, inactivity, and disturbances in biological rhythms, presumably in the absence of familiar sensory regulators provided by the lost companion or group. This is probably not directly adaptive in itself, but a byproduct of the otherwise useful state of being able to consistently rely on cues from others (possibly persisting again as an exaptation due to signalling or other indirectly adaptive reasons).



Some of human grief can also be modelled as a combination of these two processes, but might there be a difference between the typical separation distress that many social animals feel, and the cognitively heavy, temporally complex pain that human social suffering involves? Some intuitions suggest that animal suffering, even when subjectively experienced, is qualitatively different from human suffering since most animals lack the psychological layers of future-directed worry, advanced processing and rumination, and the resulting elements of subtle despair and hopelessness that intense human suffering typically involves. I’m not sure how likely this is regarding suffering in general, but I do think long-term social suffering is at least greater in humans, who rely on personal social commitments more than most other animals do. There are tons of unexplored nuances both in human grief and animal separation distress, but the strongest function may simply be that by making social relations part of the necessary conditions we feel miserable without, we successfully blackmail ourselves to seek company, and also prove ourselves loyal to others in the same predicament.

Violence: probably literally the worst thing



An obvious source of distress to social animals is intraspecific violence, which to the victim is likely to differ dramatically from other kinds of tissue damage. For an asocial animal, violence is not really an applicable concept: literal violence requires social intentionality of some sort. Much like a shark attacking a human isn’t really violent (just uh, various other kinds of suboptimal), for asocial animals conspecifics and other animals alike are basically forces of nature that may or may not harm you according to their non-negotiable whims. It’s typically useful to fear these things and of course suffer when damaged by them – but embedded in a social lifestyle where the risk of game-theoretically regulated intentional harm from others is possible but not inevitable, and often dependent on your communication and the community around you, suffering serves more functions than that. So new layers of intense suffering have developed to organize and guide individuals in violent populations – in addition to tissue damage, violence causes purely psychological harms like terror, long-term anxiety, disgust and distrust, hate, extreme despair, and of course vengefulness and the perpetuation of conflicts, again depending on the species in question.



Now, we can’t directly compare suffering levels even between humans attacked by other humans and humans attacked by lions or harmed by tornadoes. We do seem to fear and avoid intentional violence significantly more than other sources of harm, though: guns, murderers, and terrorists cause widespread panic and behavioural changes, whereas similar non-intentional harms are easier to bear, more quickly forgotten, and rarely get people to instantly rally around political causes or radically change their habits or anything. A stronger argument for violence feeling worse than non-social harms is that post-traumatic stress disorder – presumably the long-term consequence of going through something maximally upsetting and horrifying while equipped with a predisposing genetic makeup – is disproportionately often seen in humans after interpersonal harm, as opposed to accidents, natural disasters, and especially diseases (Kessler 1998). There are other possible explanations for this depending on the actual etiology of PTSD, but the simplest explanation seems to be that violence is indeed worse than other forms of damage, suffering-wise.



For social animals that have a grasp of humans as intentional agents, it is possible that humans hurting them is also experienced as violence of some kind. This grasp doesn’t necessarily mean that they have a solid theory of mind or anything, just that they model humans as agents a bit like their conspecifics – something you can somewhat personally trust or distrust based on external cues, and possibly communicate with. Animals that are known to exhibit PTSD-like behaviour after human mistreatment include dogs, elephants, chimps, and possibly cetaceans, all animals with complex and relatively personal, communicative social structures. Most of the research on animal PTSD is based on captive animals and human mistreatment, so we currently don’t know what conditions typically lead to similar pathologies in the wild, if any – but being social and somewhat cognitively advanced again seems like a prerequisite for this type of suffering. Even if all of them don’t process violence as intensely as humans do, it seems plausible that for these vulnerable animals, it’s also more traumatizing than other kinds of tissue damage. Since it is such a powerful way to build hierarchies and organize group behaviour, violence and its threat plays a part in the life of most other social creatures as well, and it probably adds a few extra layers of stress and suffering to every unstable social situation even among less cognitive animals.

Also, the best way to reduce the lethality of intraspecific violence is probably having a clear signal of submission, i.e. a credible display of sufficiently intense pain; among social organisms, showing suffering is a straightforward way to signal many other things as well, such as a need for help from allies when challenged. Asocial animals receive no benefits from displaying their suffering and typically have no purposeful external signals for communicating injuries or pain – on the contrary, being able to conceal your injuries as best as you can is crucial when calling for help is not even a comprehensible option for you and showing weakness typically leaves you vulnerable to predators. Social animals, on the other hand, usually do have signals for suffering – and since suffering more intensely makes your signals stronger and more credible, suffering more in these situations has also been adaptive to an extent.



Having friends: an exciting opportunity to suffer more than you otherwise could have afforded to



What else does suffering give you in a social environment? If your species is mostly prosocial, potentially a lot. When ill or injured, an animal feels long-term pain and distress, which discourages it from using and stressing damaged body parts and makes it keep still and use the available energy to recover – all of which also effectively prevents it from seeking food, shelter, or other necessities. Therefore, a member of an asocial species faces a straightforward survival tradeoff: prolonged and intense suffering, while protective, is also severely limited by the animal’s need to actively gather resources and defend itself. When you’re a social animal surrounded by basically sympathetic and reciprocal companions and relatives, however, this tradeoff could become slanted towards a greater intensity of suffering. If others can temporarily take care of your resource needs and protect you from threats, it suddenly becomes possible to spend a lot more time resting and recovering – as long as you’re in the right motivational state to do so, e.g. preoccupied with how unbearable your current existence is.



This is a more fundamental mechanism than any of the others above. Just having more potential homeostatic disturbances doesn’t necessarily mean they are experienced as more frequent or more intense suffering: maybe internal motivation levels are roughly calibrated between species so that where a social animal feels extreme agony over separation from its companions, an asocial animal can afford to be more sensitive to hunger or thirst since it naturally lacks the things social animals are debilitated without, and so feels similarly intense suffering under even a milder starvation threat. Maybe violence is the worst thing that can happen to a social animal, but asocial animals again experience similar fear and pain from natural causes, which social animals just have to rank as lower pains on a basically similar gradient in order to stay functional. But having prosocial companions could shift the absolute cap of your species’ suffering just by allowing individuals to wallow in all-consuming pain and misery without simply dying of hunger in a couple of days. (Friendship is magic.)



The usefulness of this hypothesized system varies a lot between different species. Clever and reasonably adaptive animals, such as humans, have some ways to protect an individual from harm and many to bring them suitable food and water when necessary. Elephants – while smart, prosocial, and exceptionally good at weighing several tons and so protecting weak herd members from predators – are grazers and browsers with a nutritionally unimpressive diet. This makes it immensely difficult for others to bring an injured individual all the food it needs, so at least some level of activity needs to be maintained even when ill (one should hope this means that an elephant’s maximum amount of physical suffering can’t be as intense and devastating as it sounds like to us). A good but heartbreaking rule of thumb might be that whenever we hear an uplifting story about an animal taking care of its weak or injured companion, we’re also looking at a species capable of experiencing the worst feelings of suffering in the biosphere. Maybe.





Implications and conclusions



Should we conclusively find that an animal’s natural degree of social behaviour is a good predictor of how much it suffers in various situations – both social and nonsocial – we would obviously have better tools for building policies and other solutions to effectively reduce suffering. Future research confirming similar conclusions could direct our attempts to improve animal welfare: for example, seafood is currently estimated to be one of the most suffering-dense protein sources to consume due to the small size of fish (which leads to a low meat/consciousness ratio) compared to cattle or pigs – but since the large herbivorous mammals typically grown as livestock are very social, their capacity to suffer may be greater quite independently of their other cognitive capabilities, which might eventually turn out to outweigh their large size. Chickens, unlike fish, have a very social lifestyle, which combined with their small size would make them one of the absolute worst animal-based foods to eat. Still, I’m wary of this approach to animal welfare now that veganism is heavily trending anyway (I hope? At least in Finland?) and our knowledge base is so severely lacking. It’s probably best to just ride the wave and focus on advocating better plant-based protein sources as well as in vitro meat as soon as it becomes a real option.

What about wild-animal suffering? Ecosystems whose fauna primarily consist of solitary herbivores may be more desirable than systems with lots of social animals even in the absence of predators, as social animals may react to other inevitable disturbances with greater suffering. When designing interventions to aid animals in the wild (emotionally compelling small-scale example here), social animals should possibly be prioritized, and long-term ecoengineering solutions developed for these species in particular. Other people have written at length about possible utopian interventions to manage suffering in wild ecosystems, and while it is currently unknown how feasible these goals are and what the relevant timescales could realistically look like, more research on the nature of suffering and the differences between species is probably useful before choosing any interventions becomes relevant, to make sure we actually prioritize reducing suffering.

A practical limitation to making use of these principles, should they turn out to be true, is that even minimally social animals must usually have ways to communicate and get along with conspecifics in order to mate, and many otherwise asocial animals still care for and invest in their offspring for a while. So, while some animals are clearly exceptional in their social bonding and commitment, purely asocial animals can’t really be found to use as points of comparison, and some of the principles above may apply to a varying extent to most sexually reproducing animals. Another complicating factor is that in the case of many animals, sexes are dimorphic so that females are typically more social than males, who may even live entirely alone. Is a significant sex difference in suffering plausible? There are a lot of confounders here, but human data says yeah maybe – gender differences in sociability are comparatively small in humans, though, and so is the difference between experienced intensity of pain in women and men, so the signal isn’t exactly clear.

Anyway, to reiterate, there are four main mechanisms that could cause a social evolutionary history to produce species that suffer more than otherwise similar asocial ones: 1) the extended homeostasis principle based on the fact that more things can go wrong (hence feel bad) for a naturally social animal simply due to the increased number of things to keep tabs on, 2) social commitment, which is purposefully fueled by psychological pain such as grief, worry, and empathetic pain, 3) purposeful violence, which only happens among social animals and plausibly feels subjectively worse than other kinds of tissue damage due to complicated signalling and group organizing things, and 4) the fact that fully utilizing the rest-and-recovery functions of suffering when physically injured or ill only becomes possible when your resource gathering needs can temporarily be covered by friends and you can afford to stay preoccupied with the pain. Due to the hypothetical nature of these principles, they are probably not super relevant to practical ethics or policy decisions or anything really until we know more, but maybe consider forever being extra nice to dogs, the blessed animal we purposely bred for maximum personal sociability, cooperation, dependency, and companionship. Thank you.

