A Displacement Activity on Displacement Activities
or Evolution Is True But Not Always Fun (especially if you’re a Hyaena)
Anyone following my twitter feed a couple of weekends ago would have noticed that I had taken leave of my usual zoology/chip-music theme to instead concern myself with the Watersprite International short film festival that was held here in Cambridge*. As I had recently taken over as co-editor of BlueSci Films I had thought it a good idea to pop along and delve into panel discussions on documentary filming, audiences with HBO producers and, well, drink too much whilst laughing at Tom Hollander’s belittling of the industry that made him a reluctant star.
One evening I found myself talking to a terribly well-bespectacled, media-type chap. When conversation wandered over to what I did during the week and how I’d ended up with a fairly time consuming extra-curricular activity I heard myself utterly betraying my zoologist-roots to a less-and-less interested man (in a more-and-more interesting floral shirt):
“You know Mr. ——-, some birds, when they’re faced with a predator whilst sitting on their eggs, get a bit confused. They don’t know whether to fly away and protect themselves or protect their eggs. Either choice has pretty dire consequences and so, instead, they end up outstretching a wing and preening themselves, which isn’t so smart. So, yeah, I’m approaching the end of my PhD [pause] and I suppose I should be either writing up or finishing off my research. Hmm. I guess [extending sip and pause] I’m preening.”
In fact, the adoption of a ‘displacement activity’ by an animal confronted by a threat isn’t just confined to a few particular birds unsure whether to save themselves or their chicks. For instance, when meeting another male at the edge of their territory, male sticklebacks first dip their heads and grab a mouthful of sand rather than engage with their rival and Anna’s Hummingbirds lick and wipe their bills before chasing intruders. And I’d been flippant: the preening bird doesn’t get confused: there are two options. Either it can escape, or it can attack. The resulting ‘fight or flight’ choice and response is as well known a behavioural dogma as any, and its principles are at least vaguely known by everyone.
Whether the ‘appropriate’ behavior is a sprint away from danger or an attack on an intruder (or – how I’m more used to experiencing it – to give an entertaining presentation or to run very quickly away from the conference auditorium), a mosaic of bodily responses has been tuned through millions of years of natural selection with the result of the very most of the body’s assets being squeezed out of it following a nice, good scare. Last night I stumbled upon the physiological responses of mammals to a threat within the agreeable prose of Barbara Ehrenreich’s Blood Rites: The Origin and History of the Passions of War:
“At the sight of danger, the heart and respiratory rate increase, and blood is withdrawn from the surface of the body and the viscera in favor [sic] of the voluntary muscles (hence the “gut-wrenching” feelings and blanching of the skin) – all in preparation for the sudden exertion of fighting or fleeing. Subtler changes take place, too: The pupils dilate, the bronchi distend, glucose is released by the liver for use by muscles, and blood is sped up in anticipation of wounds. All these changes are automatic, taking place within a few seconds or minutes of the perception of a threat, without any conscious intervention”.
So why on earth do non-appropriate behaviours occur given the good sense of fight or flight? Not surprisingly, a suite of prominent zoologists tackled this question in the 1940s. Chief among them was the ethologist Niko Tinbergen, who shared the Nobel Prize in Physiology and Medicine with Karl von Frisch and Konrad Lorenz for their work on behaviour, and who would later tutor Desmond Morris and Richard Dawkins (the former being responsible for the beautiful abstract painting The Expectant Valley, used on the cover of The Selfish Gene’s first edition). He also worked with Hugh Falkus on The World About Us which remains one of the greatest natural history film series of all time (if for nothing more than the superb opening sequence typography, sound recording, and Niko’s excellent impression of a very angry ornithologist).
The important factor to remember when thinking about displacement activities is that there is a conflict evident between the two options: “Fly, and I lose my chicks which I have invested heavily in. Fight, and I risk injury and death: this cat has teeth, I don’t”. What was instantly apparent, however, was that the behaviours expressed weren’t unique freakish ticks, but rather rituals that appeared usually during the species’ life, or normal motor patterns: Tinbergen in 1951, for instance, realised that the behaviour shown by the sticklebacks digging in the sand was an activity that usually took place during the start of nest digging and in 1959 described how the threat position adopted by the herring gull has parts of both fear (the stretched neck) and aggression (the downwards pointing bill) within it.
Tinbergen’s initial idea was that when a surplus of motivation is presented (for instance BOTH the need to fly away from certain death and the need to protect one’s young) the discharge of normal behaviours is prevented…somehow. Although this was a neat theory, the way that the conflict of two strongly activated antagonistic drives creating an overload in the bird’s brain wasn’t known.
Tinbergen’s theory is known as overflow theory, an easily visualized idea that could be boiled down to thinking of an animal as having to do something, ANYTHING, with the need to respond to a stimulus. If the appropriate behaviour (to fly away) was blocked (by a need to look after chicks) the response would overflow into a behavioural system that wasn’t blocked. Like preening. In fact anybody that’s come across Freud’s theory of displacement and sublimation of libido would recongise the idea, but Freud was thinking about sexual desire expressed in art, not nest building.
A second theory, proposed by Sevenster in 1961, took a slightly different tact. He posited that when there are both strongly activated behaviours and weakly activated behaviours and the strongly activated behaviours inhibit weakly activated systemsexcept when there are two antagonistic strongly activated behaviours the weakly activated behaviours are suddenly devoid of inhibition and are free to be expressed…
It’s like this:
Weakly activated behaviour: Alan Grant wants to leave the visitors’ centre.
Strong activated behaviour #1: Velociraptors want to eat Alan Grant.
Strong activated behaviour #2: T. rex wants to eat Alan Grant.
So, when two strongly activated behaviors are activated and the inhibition they result on each other releases the inhibition on the weak behaviour:
Velociraptors and T. rex meet in the visitors’ centre, they start fighting each other and Alan Grant escapes (however, he does decide not to indorse Mr. Hammond’s park).
As everything else in life, it’s easiest to describe as a Jurassic Park simile and, either way, displacement activity sounds pretty daft.
But evolution doesn’t always create perfection. So many times in zoology, we find physical structures that don’t excel at their function, but only do the best they can with limited resources tugged towards certain solutions. Sometimes this is due to sex (the female spotted hyena has an extended clitoris referred to as a ‘pseudo-penis’ that is a pretty much perfect anti-rape device, but makes for a less than ideal apparatus when giving birth), or due to being constrained in developing forms from previous not-ideal anatomies.
For instance, a raptor’s wing looks like a raptor’s wing because natural selection only had the dinosaur arm-bones and chest musculature to ‘play with’, develop and, ultimately, improve during bird evolution. It does a very, very good job but a kestrel would probably find the continuous propulsion of helicopter-style rotor-blades far more energy efficient when scouting for prey on a roadside than the up-and-down wing-beating it has to make do with.
As someone who has been a fan of biomimicry research for sometime, it is important to remain conscious of the fact that, sometimes, we can do better. My co-editor’s new Canon EOS 6D, for example, has a better eye than I do. In fact, I’d go as far as to say that it’s better than any eye that belongs to any animal with a backbone. This is because the light sensitive chip in the camera, the beautiful lens and everything else that constitutes its construction, has been designed to within an inch of its life in order to capture the most information as possible when the shutter opens.
In comparison, every single eye on every single vertebrate on the planet is an engineering disaster and, thanks to the evolutionary path our first vertebrate ancestorstarted us on 525 million years ago, we can’t do anything about it. Instead of light entering the eye, dancing over outwards facing light-sensitive cells, and then nervous responses being sent to the brain through nicely packed, neat synapses behind the wall at the back of the eyeball, the retina is built back to front. Instead of those nice, neat nerves being tucked away, they drag over their surface of the retina, only to amass around a pit plunging back towards the brain through the optic nerve. The resulting tangle blocks out any light that might reach the surrounding photoreceptor cells and render goldfish, chameleons, turtles, tenrecs, magpies, humans and any other animal with a backbone you can mention, with a ‘blind spot’. The octopus, on the other hand, which derived its eye independently, has its light-reception cells organised the ‘right way’ around, all dapper and ship-shape, so doesn’t have this trouble.
I have digressed. Which I suppose has been the point of this post: Another reason why displacement activities are so well known to the student of zoology is that with it brings hope that procrastination – the bane of the undergraduate’s life (and the post-graduate, I feel qualified to add) – is just a hardwired, instinctive response to stress. I’ve spent many hours playing with garageband when I should have been writing papers, and that can be explained as a displacement. I want to finish the paper and be an academic superstar, but I also want to run away and chop wood. So I make a sandwich, or some chip music, or check twitter. Sandwiches and twitter are things that I like to do, though. So if I was pushed to put my money on either of the theories above, I’d go with Sevenster’s, as the weakly activated behaviour is constantly running in the background.
In fact I’m working pretty hard right now (see *) which is why this blog and the output of BlueSci Films progresses at a snail’s pace (although check the site later this month for two more films). I apologize, will quit Zelda, and will write more soon, whilst avoiding film festivals. Although I didn’t get a card out of it, that night I learnt an important lesson: that you can never judge a man’s knowledge of behavioural ecology theory by his tailor: Mr. ——-, for all his I-work-in-the-coolest-office-in-the-world-and-wear-really-nice-shoes-whilst-working-in-it-ness, had never heard of displacement activity.
So there. Now you’re better than him.
*I say ‘here’, but I’m actually writing this in Montpellier, displacing the energy I should be investing in getting my head around the geometric morphometrics of the mammalian vestibular system whilst avoiding the rivers of Ricard, the insanely lovely sunshine outside my office and this guy’s really bad jokes.