In your everyday life you may take your ability to count for granted, but take a few (count them…) moments to stop and think about it and you will find determining quantity guides much of our decision making. Is it the same for bees, who live short lives full of decisions essential to their individual and genetic survival?
By Dave Black
By now, we shouldn’t be surprised that honey bees count; by many accounts, lots of animals can. We can imagine an evolutionary advantage gained by being able to select numerically superior food sources for one thing. Being numerate makes all sorts of decisions, about reproductive strategies, social belonging, navigating, hunting, and so on, simpler and more effective — in evolutionary terms it has ‘adaptive value’[i]. Maybe numeracy is even inevitable.
If we look at different animals ‘counting’ (using a medical imaging technique like MRI) we can associate specific areas (plural) of the brain with specific numerical states, the same kind of topographical ‘map’ that sensing other stimuli produces[ii]. For small numbers of items counting seems intuitive, that’s called subitising, a glance being enough to assess the quantity. For quantities of around five or more it seems to take a bit more effort, and we either ‘count’ a sequence or assess subitised groups to reach a total.
How we count depends on where we were born because, for us anyway, we think counting is a cultural, linguistic process[iii]. MRI shows different brain region activations for English and Chinese speakers using the same numeral set[iv]. Humans all around the world have very different ways to count, ways they have learnt from their peers. Language is what links the empirical presence of a quantity of items to cultural information about what that ‘number’ means and how it should be treated. For example, do we mean four cars (the cardinal, counting number), the fourth car, (the ‘ordinal’, positional number) or the ‘No.4’ car (a nominal assignment, a label). For humans, numerosity is not just a matter of empirical, objective, collective quantity, it is also an abstraction, it involves a sign or symbol (a ‘numeral’) and relationships to other numbers (...greater than/less than etc.).
It’s at this point scientists start to argue about ‘bees counting. Sure, they can do the non-symbolic ‘subitising’ bit and maybe a little better, but can they make the symbolic abstraction that arithmetic depends on, or, does arithmetic depend on symbols at all? Is training them merely communicating the ‘rules’ they must apply to solve foraging teases? Surely the ability to count is not synonymous with the ability to understand numbers?[v] Is ‘zero’ cultural artifice or artifact?
The Significance of Zero
The ultimate challenge must be the number ‘0’, the number with no quantity. Five thousand years old and far from universal, it was just a placeholder, merely a punctuation mark, not a number. Essentially it meant, ‘this position is empty’, and it had to be written. In a conceptual leap two thousand years ago it became what we think of as a number, in Arabic as-sifr, ‘the empty’ (which gave us the word cipher), but it didn’t become fundamental until the 17th century and the invention of graphs and calculus. We have to be taught the significance and rules for ‘zero’. We understand it now as the set of things that contains nothing (‘0’), which comes before the set of things that contains ‘1’, in turn coming before the set containing ‘2’ things, and so on, but that assumes you know what ‘set’ means, and what ‘no-thing’ refers to. Young children have to learn the contra-literal that ‘nothing’ is less than ‘1’.
Zero must be the ultimate abstraction, a symbolic tool. It’s nothing and everything. For you to imagine zero, there must be nothing, or at least nothing relevant. Zero is the absence of a stimulus, nothing for your senses to perceive. It’s not entirely clear how we or anything else ‘invents’ nothing, the brain has to internally translate ‘no stimulus’ into a ‘stimulus-absence’ representation itself. Without zero, we’d have no computers, no calculus; no fancy engineering, no modern science. It therefore seems either pretty unlikely or pretty remarkable that ‘bees make use of the concept ‘zero’.
Scarlett Howard at Monash University in Melbourne has been using honey bees to untangle these ideas and provide some insight both into the capability of non-human animals, how and when this ‘number-sense’ developed, whether it always existed, or whether it’s a skill arrived at separately over time by different species. Her work[vi] doesn’t just aim to tell us something about ‘bees, but something about ourselves too. Howard shows intuitive and learnt number skills are not uniquely human. Motivated honey bees (it turns out motivation is important — who knew...)[vii] demonstrate some ability to count and discriminate between different quantities[viii], understand simple relationships between quantities[ix], and understand no quantity, ‘nothing’, has a value less than any ‘something’[x]. At the moment it seems unlikely they could spontaneously represent a quantitative value with a symbol they have chosen, and then use that symbol in other contexts, but they can associate some symbols we give them with a quantity or a task. In other words, for ‘bees, sums are possible, algebra is not.
By studying honey bees, rather than, say, apes or parrots, Howard increases the evolutionary distance between ‘us’ and ‘them’, some 600 million years. That even this moderately complicated numerical facility is apparent in honey bees with a very different brain structure suggests that nature, ‘evolution’, has converged on a similar solution from different beginnings, rather than conserved an ability that existed for all this time. Honey bees may understand zero, but they must ‘understand’ it in a very different way.
When a bee flies from a hive she needs to be able to discriminate between various patches of flowers if she’s going to forage effectively, although determining an incremental gain of two flowers to 251 flowers rather than 249 isn’t likely to be significant. Choosing between twenty flowers and two hundred is the easy bit, she can just judge ‘more’, yet discriminating small quantities, small numbers, can be important. She also has to get there in the first place, and many observations show counting landmarks on her way there and back is something else she must ‘keep in mind’. If she joins the dance-floor on her return, a sense of the ‘quorum’ for the dances might inform her next trip. There are lots of occasions when a ‘bee might be ‘conscious of’ numbers.
Honey bees live short, complex lives. Their ability to synthesise a rich world-view from simple perceptions must be essential. Even if honey bees don’t truly count, can’t really accomplish mathematics, and must somehow conceive ‘nothing’ in some currently unimaginable way, the evidence that they can almost do it is surely astonishing.
Dave Black is a commercial-beekeeper-turned-hobbyist, now retired. He is a regular science writer providing commentary on “what the books don't tell you”, via his Substack Beyond Bee Books, to which you can subscribe here.
References
[i] Nieder, A., 2020. The Adaptive Value of Numerical Competence. Trends in Ecology & Evolution 35, 605–617. https://doi.org/10.1016/j.tree.2020.02.009
[ii] Harvey, B.M., Klein, B.P., Petridou, N., Dumoulin, S.O., 2013. Topographic Representation of Numerosity in the Human Parietal Cortex. Science 341, 1123–1126. https://doi.org/10.1126/science.1239052
[iii] Wiese, H., 2007. The co-evolution of number concepts and counting words. Lingua 117, 758–772. https://doi.org/10.1016/j.lingua.2006.03.001
[iv] Tang, Y., Zhang, W., Chen, K., Feng, S., Ji, Y., Shen, J., Reiman, E.M., Liu, Y., 2006. Arithmetic processing in the brain shaped by cultures. Proc. Natl. Acad. Sci. U.S.A. 103, 10775–10780. https://doi.org/10.1073/pnas.0604416103
[v] Núñez, R.E., 2017. Is There Really an Evolved Capacity for Number? Trends in Cognitive Sciences 21, 409–424. https://doi.org/10.1016/j.tics.2017.03.005
[vi] Howard, S.R., 2018. Numerical cognition in honeybees: rule learning enables quantity discrimination, zero comprehension, simple arithmetic, and symbol use by an insect. Thesis: RMIT University, Melbourne, Australia.
[vii] Howard, S.R., Avarguès-Weber, A., Garcia, J.E., Greentree, A.D., Dyer, A.G., 2019. Surpassing the subitizing threshold: appetitive–aversive conditioning improves discrimination of numerosities in honeybees. Journal of Experimental Biology 222, jeb205658. https://doi.org/10.1242/jeb.205658
[viii] Howard, S.R., Schramme, J., Garcia, J.E., Ng, L., Avarguès-Weber, A., Greentree, A.D., Dyer, A.G., 2020. Spontaneous quantity discrimination of artificial flowers by foraging honeybees. Journal of Experimental Biology 223, jeb223610. https://doi.org/10.1242/jeb.223610
[ix] Howard, S.R., Avarguès-Weber, A., Garcia, J.E., Greentree, A.D., Dyer, A.G., 2019. Numerical cognition in honeybees enables addition and subtraction. Sci. Adv. 5, eaav0961. https://doi.org/10.1126/sciadv.aav0961
[x] Howard, S.R., Avarguès-Weber, A., Garcia, J.E., Greentree, A.D., Dyer, A.G., 2018. Numerical ordering of zero in honey bees. Science 360, 1124–1126. https://doi.org/10.1126/science.aar4975
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