Philip Hensher: The mysteries of humanity know no end

There doesn't seem to be a clear evolutionary advantage in acting unselfishly

Why do we kiss? Or dream? Or pick our noses – yes, madam, you at the back there, don't think I can't see you. That reminds me – blushing. What's all that about? Some people go red upon hearing a particular word spoken on the radio. Others wouldn't blush if they were suddenly deprived of clothes in the middle of Piccadilly Circus. What causes the rush of blood to the head and face? What purpose does it serve?

The journal New Scientist has had the nice idea of setting out aspects of human behaviour which science can't explain. Baffled by the human developmental stage of adolescence, they say that "no other species has teenagers," though I really don't know how they would know that about chimpanzees, let alone goldfish. There is no conclusive answer to the question of why humans have pubic hair.

On the subject of dreams, science has moved far away from the certainties of Freud without coming up with any kind of conclusion.

Unselfishness seems to baffle science to a worrying extent, and altruism is, naturally, on the list. There doesn't seem to be a clear evolutionary advantage in acting unselfishly, though many people have independently observed that generalised kindness, even to strangers, is good for the mind and a good example for society to follow. Obviously, we have to learn altruism; without it, human society would be impossible, and life for the individual of the species very much worse. Isn't that a sufficient answer?

Perhaps in some of New Scientist's subjects, a lack of respect for the objects the mind creates is evident. It doesn't have any real answer for the existence of superstition, or, by implication, religion. The obvious answer is that any belief system which can't, by definition, be falsified, which holds out the promise of luck if obeyed, contains the seeds of its own propagation and a defence against its dismissal.

It takes a strong-minded person to place a hat on a bed after he's been told that a close death in the family may follow, and it needs no death to confirm the riskiness of the behaviour.

And New Scientist doesn't understand the purpose of art. Is it an exuberant display, like a peacock's tail? Is it a means of conveying information in permanently memorable form? Is it, as at least one academic believes, a means of "exploring new horizons in a safe environment" – so that looking at The Family of Darius Before Alexander is a safe primer for what to do, should you and your family ever be conquered by a military genius whose face you can't recognise? No one knows.

I do think that, like superstition or religion, but on a much higher level, art, music and literature have lives of their own. In the individual case, what they do can't be reduced to what they do for us.

We might like to ask New Scientist to come up with some solutions to some smaller, but just as curious, questions of human behaviour. Why, in the name of evolution, are some of us left-handed, or homosexual, or ginger? Why can't men ask for directions, even if left without a map in an unfamiliar town? Why does it come as a great surprise to women at the head of a queue in the supermarket when they are asked for money, and only then will they start looking for means of paying, deep in their bags? And, roughly divided between the sexes, why are people programmed to say: "I'll leave it for you to decide", and, after the decision, start to explain what they would have done instead?

Memorable, humane and irreverent: the movies of Hughes

I heard some unexpected but very sincere expressions of sadness at the news that the director John Hughes had died last week, suddenly, at 59.

He was not really the sort of director for solemn music and misspelt poetic tributes at the gates of the mansion. But how much he enriched our lives, by just making the perfect statement of a moment in time.

Sixteen Candles, The Breakfast Club and that wonderful, underrated and deeply caustic study of class differences in America, Planes, Trains and Automobiles, all looked like fluff, but have survived very well into the 21st century.

Hughes's best of all is a movie which is just as much a masterpiece as Vittorio De Sica's Bicycle Thieves is: Ferris Bueller's Day Off.

The lightness of spirit, the inventiveness, the delicious escalation of the action, and the warmth generating the froth will be loved as long as there are teenagers to watch movies.

Now that the 1980s have gone down to cultural history as a grim, shallow, money-obsessed decade, we ought to watch this undeniably materialistic movie about rich kids, and acknowledge how much fun it all could be.

Memorable, humane, and irreverent, Hughes's best movies as director – and there are surprisingly few of them – show what could be done by taking seriously the dreams of unimportant lives.

Rock stars now are as pompous as priests

A rock band called Raygun had not crossed my radar, when one of those viral alerts dropped into my inbox linking to an online video promo. On the surface, a completely straight interview with the up-and-coming indie band, it proved unbelievably funny in the Spinal Tap manner.

"I kind of share that thing," its lead singer said, "of not being able to play anything fluently or competently, and even with the style of production stuff, not being able to use equipment properly but experimenting, and that's what a lot of our band is about really, coming up with noises, weird noises. Very much into the sort of Berlin Bowie period."

Whether or not it is a spoof, it certainly captures the unbelievable pomposity of even quite baby rock musicians. Contrary to reputation, classical musicians are, in my experience, self-effacing, practical and often quite modest people. Rock musicians these days are often as pompous as an archdeacon in Trollope.

Adam Clayton of U2 the other day said: "The biggest misconception about me was that I was some kind of wild, crazy rock'n'roll firework... I'd like to think I was a little deeper than that." Can anyone read that "I'd like to think" without wincing?

There can't be anybody at all who still believes that rock musicians have any connection with ordinary reality, or the slightest idea of what they look like to the outside world.