By Wendy Barnaby
Love confessions, chocolate tasting and a dog called Haydn captured the audience at Dr Harry Witchell’s tour of chemical pleasure at the Festival of Science on Tuesday. Arousal, he said, makes good things better and bad things worse. It was therefore no surprise that, by the end, everyone was in the mood to hear what he really wanted us to know: that the workings of our brains mean that, when we are aroused, we will associate whatever we see at the time with pleasure.
This means that one pleasurable experience - whether skydiving or taking heroin - will lead us on to another. It also means that it can be extremely difficult to break an addiction.
Pavlov was able to make dogs salivate simply by ringing a bell, after a period of ringing it only when he gave them food. Similarly, our brains are wired with powerful mechanisms called Hebbian synapses. The way they work means that we come to associate certain things together after they have occurred together, even if they don’t seem to be connected for anyone else. “Inputs that fire together, wire together,” as neuroscientist Mark Bear puts it. Hence the heroin addict who, having come off the drug, still found that the sight of needles gave him pleasure. “After I got clean, I still occasionally shot up stuff – amino acids; whiskey; other things. Not for the effect, but just to use the needle. I worshipped the damn thing,” he told Witchell.
Hence also another drug addict who found she had to move cities in order to kill her habit. Familiar places and spaces were too suggestive of the pleasure of the drug for her to get off it in the city where she’d been addicted.
Compare these with young men who met a pretty woman, some when they were aroused by crossing the scary-looking Capilano Canyon suspension bridge in Vancouver, and some who were not. When given the opportunity to contact the woman later, most of the men who called her were those who’d met her on the bridge.
Dr Witchell, who was giving his BA Charles Darwin Award lecture, took straw polls of his audience by asking us what we look for in a love affair: a soul mate, a romantic or passion. The soul-mate mindset narrowly won, followed closely by passion. We ate little pieces of chocolate, and discovered that we preferred the peppery molecule in the second because we’d been primed for pleasure by the blander one first. And Haydn had a live ECG, to show what happens to the heartbeat when the body experiences pleasure. (Well, Haydn thought a raw carrot was pleasurable.)
Surrounded by bits of chocolate, carrot ends and stepping over the dog basket, Harry Witchell cast new light on Hamlet’s saying: “There is nothing either good or bad, but thinking makes it so.”