Emotional Rollercoaster, by Claudia Hammond

Are you really pleased to see me?

In the 1950s it was discovered that if you apply a weak electric current to the part of a rat's brain that produces dopamine the rat rather likes it. When provided with a lever by which they could control the current themselves, the rats pressed the lever about 2,000 times an hour, for hours on end. If the rats were given a choice between feeding or pressing the lever, they would starve to death rather than miss out on the current.

In the 1950s it was discovered that if you apply a weak electric current to the part of a rat's brain that produces dopamine the rat rather likes it. When provided with a lever by which they could control the current themselves, the rats pressed the lever about 2,000 times an hour, for hours on end. If the rats were given a choice between feeding or pressing the lever, they would starve to death rather than miss out on the current.

Apparently, if you ask people whether they would like to have the human equivalent of the rats' lever they almost always say "no". They think it wouldn't make them feel truly happy. Or maybe they're just worried about what kind of figure they would cut with bleeding electrodes in their skulls and wires trailing everywhere. Besides, there are the more socially acceptable dopamine levers available for humans, such as drugs, alcohol, eating and sex. Or reading books like Emotional Rollercoaster.

According to the jacket, Claudia Hammond's book "asks how the brain and body interact to produce emotions, and what, if anything, we can do to harness them". And so we go on a "journey" through nine chapters entitled Joy, Sadness, Disgust, Anger, Fear, Jealousy, Love, Guilt and Hope. Sadly, this journey isn't quite as effective a dopamine lever as sex, drugs, alcohol, eating or electrodes, but it is quite interesting. And I've filleted some of the most interesting bits out for you.

Apparently, a smile is hard to fake, because most people can't voluntarily contract all the muscles used in spontaneous smiling. The way to check if someone is really happy to see you is note whether the cheeks move higher and the eyebrows tip down slightly.

Apparently, men and women from the US cried the most often, while Bulgarian men and Icelandic and Romanian women cried the least.

Apparently, people who sit in a quiet room in a comfortable old leather armchair for the same length of time as an exercise session, felt just as good afterwards. Hot baths have a similar effect. Experiments involving people exercising vigorously with their heads and shoulders under cold water have shown that they feel no better afterwards. Maybe it's because they found the experience rather unpleasant.

Apparently, people who express their anger suffer from more heart disease than those who hold back from shouting. Other studies however contradict these findings; some show no link, some that the suppression of anger correlates with high blood pressure. The man who gets angry occasionally, as opposed to the angry man and the bottler-upper, may be the healthiest.

Apparently, men's hearts beat almost five beats a minute faster when they imagine their partner's sexual infidelity compared with emotional infidelity. Women's heart rates were the same for both. It was thought that this experiment measured jealousy and proved men were more jealous about sexual infidelity than the emotional kind; it was later discovered that men were merely getting turned on by the thought of sex.

Apparently, when men believe they are talking to a beautiful woman on the phone, the women become more animated, confident and socially skilled. The women treated as unattractive become withdrawn and awkward.

Apparently, men tend to be jealous of rivals who possess the qualities they most desire for themselves. Women tend to be most jealous of characteristics they think their partner desires in a woman. These rivals are the same women they would most like to be their friends.

Apparently, people who have asymmetrical faces (ie they're ugly) tend to be more possessive.

Apparently, the perception that passionate love decreases over time and is replaced by companionate love which gets stronger is mistaken. Although passionate love does decrease, so, generally, does companionate love.

Apparently, when men were played slower or faster heartbeats than their own while being shown pictures of women, and told the sound was of their own heartbeat, those who believed their heart to have been beating faster rated the women as more attractive than those with a slower heartbeat.

While I was reading Emotional Rollercoaster in a comfortable old leather armchair, I didn't hear my heart beat, and I didn't check my pulse or my perspiration levels. I think that, for the most part, I enjoyed the experience, but without a control experiment it's difficult to be sure.

We don't really learn much that is useful for harnessing those pesky, fickle emotions either, but Hammond, in her enthusiastic, popularising way, does throw up some intriguing research, at the same time as revealing how little is known for sure in this rather immature area of scientific study. In the end, this rather tentative enquiry is probably best seen as a dinner party resource for conversational gambits of the kind which begin: "Apparently..."

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