Do nonhuman animals know they’re not alone? Of course they must know there are lots of things in the world around them – rocks, water, trees, other creatures and what have you. But do they know that they inhabit a world populated by minded creatures – that the animals around them see and know things, that they have beliefs, intentions and desires? Can they attribute mental states to other animals, and use those attributions to predict or explain their behaviour? If so, then they’re what philosophers and psychologists call ‘mindreaders’.
Whether animals are mindreaders has been a contested question in comparative cognition for around forty years (beginning with Premack & Woodruff, 1978), and it remains controversial. My interest in this post is not so much whether animals are mindreaders but rather, if animals are mindreaders, what kind of mindreaders might they be? The motivating thought is this: even if animals do represent and reason about the mental states of others, their understanding of mental those states might be somewhat different from ours.
The idea that animals might have a limited or ‘minimal’ understanding of mental states has been explored in a number of places (see, for instance, Bermúdez, 2011; Butterfill & Apperly, 2013; Call & Tomasello, 2008). These proposals differ, but they have in common the idea that animals don’t construe mental states as representations – that is, as states which represent the world, and which can do so accurately or inaccurately. If these proposals are right, animals might be able to represent others as having factive mental states like seeing or knowing, but would not be able to make sense of another agent having a false belief, or any state that misrepresents the world.
Recent work on mindreading in chimpanzees puts pressure on this sort of proposal. Christopher Krupenye and colleagues (Krupenye, Kano, Hirata, Call, & Tomasello, 2016) found that chimpanzees were able to predict the behaviour of a human with a false belief. It’s not uncontroversial (see Andrews, 2018 for discussion), but for the sake of argument let’s say that this is indeed evidence that chimps understand false beliefs, as states that misrepresent the world. Does that mean that chimps’ understanding of mental states is essentially the same as our own?
I’ve argued that it doesn’t. That’s because there are important ways in which mindreaders might differ from one another, even if they represent mental states as representational. To see that, let’s think a bit more about representations. A representation has a content – how it represents the world as being – which can be accurate or inaccurate. The sentence ‘Santa is in the chimney’ is a representation whose content is that Santa is in the chimney.It’s accurate if Santa is in the chimney, and inaccurate if he’s somewhere else. But a representation also has a format– it exploits a particular representational system in order to represent what it represents. ‘Santa is in the chimney’ is a representation with a sentential, linguistic format. But we could represent the same content in a number of other formats. For instance, we might represent it pictorially by drawing Santa in the chimney, as in Figure 1. Or we might draw up a map representing the same thing, as in Figure 2.
Given that representations may differ with respect to the representational format they exploit, mindreaders might differ with respect to the representational format they take mental states to have. Some might treat beliefs as something like ‘sentences in the head’. Others might treat them as more picture-like. Still others might be what I’ve called ‘mindmappers’ (Boyle, 2019) – they might take literally the idea that a belief is a ‘map of the neighbouring space by which we steer’ (Ramsey, 1931).
This matters, because the representational format one takes mental states to have has a significant impact on one’s mindreading abilities – because different representational formats themselves differ from one another in systematic ways.
Take maps. As I’m using the term, a map makes use of a lexicon of icons, each of which stands for a particular (type of) thing, which it combines according to the principle of spatial isomorphism. Simply put, by placing two icons in a particular spatial relationship on a map, one thereby represents that the two things denoted by the icons stand in an isomorphic spatial relationship in reality. That’s all there is to it.
If you want to represent the spatial layout of a number of objects in a particular region of space, there are lots of advantages to using a map: it’s a very natural and user-friendly way to represent that kind of information. A single map can contain an awful lot of information about the spatial layout of a region. To convey the content of a map in language would usually require a large and unwieldy set of sentences (or a very lengthy sentence). And updating information in a map without introducing inconsistency is easy to do. Updating the represented location of an object by moving an icon thereby also updates the represented relationships between that object and everything else on the map, keeping the whole consistent. If one represented all of this spatial information sententially, it would be easy to introduce inconsistencies. (See Camp, 2007 for a fuller discussion of maps’ representational features.)
For all that, maps are an extremely limiting representational format: all they can really represent is the spatial layout of objects in a region. If you want to represent that Christmas is coming, that the goose is getting fat, or that Santa is really your dad, a map would be a poor format to choose. These are not the kinds of contents that a map can express. For that kind of thing, you need a more expressively powerful format – like language.
The point is that the distinctive strengths and weaknesses of representational formats will show up in their mindreading abilities and behaviour. Humans can ascribe an apparently unlimited range of beliefs – beliefs about Santa’s true identity, about death and resurrection, about possible presents with no known location. I think this is good evidence that we take mental states to be linguistic, or at least to have a format which mirrors language’s expressive power.
But animals might not be like us in that respect: they might think of beliefs as maps in the head. If they do, they would be able to capture what others think about where things are to be found, but they wouldn’t be able to make sense of beliefs about object identities or about non-spatial properties – and nor could they make sense of someone having a belief about an object whilst having no belief about its location. To my knowledge, whether animals can represent these non-spatial beliefs has not been investigated. So, it remains an open empirical question whether they treat beliefs as map-like, linguistic, or having some other format. But it’s a question worth investigating. If animals construed mental states as having a non-linguistic format, there would remain a significant sense in which animals’ mindreading abilities differed qualitatively from ours.
Andrews, K. (2018). Do chimpanzees reason about belief? In K. Andrews & J. Beck (Eds.), The Routledge Handbook of Philosophy of Animal Minds. Abingdon: Routledge.
Bermúdez, J. L. (2011). The force-field puzzle and mindreading in non-human primates. Review of Philosophy and Psychology, 2(3), 397–410. https://doi.org/10.1007/s13164-011‑0077‑9
Boyle, A. (2019). Mapping the minds of others. Review of Philosophy and Psychology. https://doi.org/10.1007/s13164-019–00434‑z
Butterfill, S. A., & Apperly, I. A. (2013). How to construct a minimal theory of mind. Mind & Language, 28(5), 606–637.
Call, J., & Tomasello, M. (2008). Does the chimpanzee have a theory of mind? 30 years later. Trends in Cognitive Sciences, 12(5), 187–192.
Camp, E. (2007). Thinking with maps. Philosophical Perspectives, 21, 145–182.
Krupenye, C., Kano, F., Hirata, S., Call, J., & Tomasello, M. (2016). Great apes anticipate that other individuals will act according to false beliefs. Science, 354(6308), 110–114. https://doi.org/10.1126/science.aaf8110
Premack, D., & Woodruff, G. (1978). Does the chimpanzee have a theory of mind? Behavioral and Brain Sciences, 4, 515–526.
Ramsey, F. P. (1931). The Foundations of Mathematics. London: Kegan Paul.