Bees were once thought to be reflex machines, but new research shows them to be intelligent and most likely conscious.

The French philosopher René Descartes (1596–1650) held that animals lack any form of mind or thought or reason. The view that consciousness is a uniquely human attribute still resonates today with many scholars. But we are currently seeing the beginnings of a new Copernican revolution: increasing numbers of scientists recognize that humans are not alone as conscious beings (Chittka & Wilson 2019). Sophisticated minds are all around us in the animal queendom – not just in chimps and ravens, but also “aliens from inner space” such as the octopus (Birch et al. 2020). As I show in my new book, The Mind of a Bee, even the tiny-brained bees are profoundly intelligent creatures that can memorize not just flowers but also human faces (Figure 1; Dyer et al. 2005), have basic numerical skills (Figure 2; Chittka & Geiger 1995), solve problems by thinking rather than by trial and error, and learn to use tools by observing skilled bees (Loukola et al. 2017). They even appear to have the capacity to experience basic emotions. The possibility of sentience in these animals raises important ethical questions for their ecological conservation, their treatment in the crop pollination industry, and in research laboratories (Chittka 2022).

Fig 1. A honey bee learns to associate a man’s photo with a reward (drops of sugar water on the landing pad) (Photo: Adrian Dyer)

Fig. 2 Bees can count landmarks. Here the animals learned to fly from their hive (to the left of the left landmark) to a feeding station after the third landmark.
Photo: Lars Chittka

Social insects are traditionally thought of as “reflex machines” – entities that accomplish complex nest building and efficient division of labor by innate behaviors, but are stupid as individuals, with complexity only emerging at the group level (Figure 3). You might thus ask, what on Earth prompts your author to postulate that an animal with a brain the size of a pinhead can think? We need to contrast the inner world of thought with a mode of being in which an animal lives entirely in the present, responding only with hard-wired responses to currently incoming stimuli. For example, bees are flexible in accessing autobiographical memories.  A master storyteller of the mysteries of memory, Marcel Proust describes in “À la recherche du temps perdu” how the narrator, after tasting a tea-soaked madeleine, suddenly recalls long-lost childhood memories in vivid detail. Similarly, a scent experienced by a bee inside its hive can bring back the distant memory of a flower patch with the same scent (Reinhard et al. 2004).  My team has shown that bees can, in a sense, picture things in their minds. Bees which first learn that balls but not cubes are linked to a sugar reward by seeing these shapes through Plexiglas, can subsequently identify the same shapes by touch alone, indicating a form of mental image that can be accessed from more than one sensory modality (Solvi et al. 2020).

Fig.3 Honey bees constructing new wax combs. Are these complex social behaviors really fully instinctive, as is often assumed? (Photo: Helga Heilmann)

Bees also solve problems in a manner that indicates an understanding of the desired outcome of the task. For example, they can learn a string-pulling task – where they have to extract an artificial flower from underneath a Plexiglas table to gain access to a sugar reward. The vast majority of bees require stepwise training to solve this puzzle – but a small minority solved the task spontaneously, without any training procedure (Figure 4, Alem et al. 2006). In one experiment, bees learned to roll a ball to a goal area. Untrained bees that observed a skilled ball-rolling bee did not simply “ape” what they saw, but spontaneously improved the technique in which the problem was solved. They could only conjure up these solutions by accessing the desired goal through a kind of mental exploration (Figure 5; Loukola et al. 2017). This indicates a form of intentionality that was previously only found in large-brained, classical models of animal intelligence, such as chimps.

Fig.4. Bumblebees learn to pull a string to get a sugar water reward in an artificial flower placed by scientists under a transparent screen (Photos: Sylvain Alem & Lars Chittka)

We also now have evidence for emotion-like states, using the same criteria as are used for domestic animals such as goats or horses, when researchers are trying to gauge whether such animals are kept in appropriate conditions that result in a positive outlook on life, or whether the conditions are detrimental to the animals’ wellbeing. We were able to show that surprising rewards induce an “optimistic state of mind” in bumblebees, making them spontaneously more curious about new stimuli (Solvi et al. 2016). Bumblebees even appear to display a form enjoyment when manipulating objects, in a manner akin to play behavior: when they are offered small balls to roll about, they will repeatedly go out of their way to do so, even when there is no appetitive reward present (Galpayage Dona et al. 2022)

Fig. 5 A bumblebee rolls a ball backwards towards a target to receive a sweet reward. New research even shows that bees will roll balls “just for fun”, even when no appetitive reward is present. Photo: Iida Loukola

The latest research indicates that bees are also capable of pain experiences, with important implications for the ethical treatment of insects (Gibbons et al. 2022). Unpleasant experiences can have very long-term effects on bees. For example, a negative emotional state can be induced by predator attacks. There are species of spiders that sit on flowers and try to catch pollinating insects. We recreated this in the lab and constructed a spider plastic model with a mechanism by which a bumble bee is momentarily held between two sponges and then released. Their behavior changed fundamentally: the bumblebees seemed more nervous for days after such attacks. Even if there were flowers without a robotic spider, they sometimes fled from a threat that didn’t even exist – so called false-alarm responses (Ings & Chittka 2008). They behaved almost as if they were “seeing ghosts”.

A critical reader might observe that each of the abilities listed above could also be programmed into a non-conscious robot. They would be correct – but such a robot would only be able to succeed at exactly the tasks that the programmer built into it. The robot would fail at tasks that bees will be discovered to succeed at next year, and the year after. Nature has no room for such profligacy as to generate beings that just pretend that they are sentient. Thus while there is still no accepted formal proof for consciousness in any animal or machine, common sense dictates that as we accumulate ever more pieces of evidence, this nudges the probability further in direction that an animal is indeed conscious.

The observation that bees are most likely sentient beings has important ethical implications. There is now widespread awareness that many species of bees are threatened by pesticides and wide-scale habitat loss, and that this spells trouble because we need bees to pollinate our crops. But is bees’ utility for humans the only reason that they should be protected? I don’t think so. The insight that bees have a rich inner world, a unique perception, and like humans are able to think, to enjoy and to suffer, commands respect for the diversity of minds in the natural world. With it comes an obligation to protect the environments that shaped these other minds. Common migratory beekeeping practices in industrialized agriculture involve the frequent shipping of millions of hives across continents on trailers, a practice that not only spreads disease, but is most likely detrimental to bees’ psychological wellbeing which weakens their health further. Finally, countless insects are sacrificed annually in research laboratories and the insect food industry; the methods of keeping and slaughtering insects are currently entirely unregulated. It is entirely plausible that our findings about bees’ capacity to suffer also extend to other insects, and this should be considered in future legislation regulating the treatment of insects.

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References:

Alem S., Perry C.J., Zhu X., Loukola O.J., Ingraham T., Søvik E. & Chittka L. (2016) Associative Mechanisms Allow for Social Learning and Cultural Transmission of String Pulling in an Insect. PLoS Biology 14(10): e1002564. doi:10.1371/journal. pbio.1002564.

Birch, J. Schnell, A.K., Clayton, N.S. (2020) Dimensions of Animal Consciousness. Trends in Cognitive Sciences, 24(10), 789-801

Chittka, L. (2022) The Mind of a Bee. Princeton University Press

Chittka, L. & Geiger, K. (1995). Can honeybees count landmarks? Animal Behaviour, 49: 159-164

Chittka L. & Wilson C. (2019) Expanding consciousness. American Scientist, 107(6):364-369. DOI: https://doi.org/10.1511/2019.107.6.364

Dyer, A., Neumeyer, C., Chittka, L. (2005). Honeybee (Apis mellifera) vision can discriminate between and recognise images of human faces. Journal of Experimental Biology, 208: 4709-4714

Galpayage Dona, H. S., Solvi, C., Kowalewska, A., Mäkelä, K., MaBouDi, H, Chittka, L., (2022) Do bumble bees play? Animal Behaviour, https://doi.org/10.1016/j.anbehav.2022.08.013

Gibbons, M., Versace, E., Crump, A. Baran, B., Chittka, L. (2022) Motivational trade-offs and modulation of nociception in bumblebees. Proc Natl Acad Sci USA, 119 No. 31 e2205821119 https://doi.org/10.1073/pnas.2205821119

Ings, T.C. & Chittka, L. (2008). Speed accuracy tradeoffs and false alarms in bee responses to cryptic predators. Current Biology, 18: 1520-1524

Loukola, O.J., Solvi, C., Coscos L. & Chittka L. (2017) Bumblebees show cognitive flexibility by improving on an observed complex behavior. Science 355(6327): 833-836. DOI: 10.1126/science.aag2360

Reinhard, J., Srinivasan, M. & Zhang, S. (2004) Scent-triggered navigation in honeybees. Nature 427: 411 https://doi.org/10.1038/427411a

Solvi, C., Baciadonna L. & Chittka L. (2016). Unexpected rewards induce dopamine-dependent positive emotion–like state changes in bumblebees. Science 353(6307):1529-1531; DOI: 10.1126/science.aaf4454

Solvi C., Gutierrez Al-Khudhairy S. & Chittka L. (2020) Bumble bees display cross-modal object recognition between visual and tactile senses. Science 367, 910-912. DOI:http://doi.org/10.1126/science.aay806

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