Today, we ask children to explain bicycles. The
University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
The psychologist Jean Piaget
asked young children how a bicycle works. Their
answers help us see how our machines teach us. He
begins with four-year-olds. They see the bicycle as
a whole -- a thing that goes entirely of itself. We
listen as a psychologist questions a child:
How does this bicycle go?
And how do the wheels turn?
The bicycle makes them turn.
With the handle-bar.
How does the handle-bar make the bicycle go?
With the wheels.
And what makes the wheels turn?
And so forth. Parts are called into the explanation
and just as quickly dropped -- for the bike is
entire unto itself.
When children are closer to six, they start
referring to parts, but not in any orderly
cause-and-effect way. Your hear things like:
What makes the chain turn?
What makes the wheels turn?
Those brake wires.
As the child approaches 8, he starts using
cause-and-effect sequences that pass from one part
to another. But he has trouble getting them right.
The feet turn the pedals, and they drive the chain,
and it turns the sprocket, which drives the wheel.
But he's not sure what turning the handle-bar has
to do with propelling the bike.
Only as they approach 9 can most children sketch a
bike from memory and explain how the parts work.
It's a lesson for all of us, surrounded as we are
by so many machines we don't understand. Suppose
you ask a person how his computer works. He might
You turn it on.
What does it do?
It writes letters and does math.
You type on the keyboard.
What's that whirring sound?
That's its motor.
What does it do?
It helps figure out the answer.
And so forth. The machine we don't understand is a
machine entire unto itself. Parts that we don't
understand aren't elements in a causal chain.
They're only aspects of a functioning whole.
Piaget's children and their bicycles tell us how we
ourselves come to understand things. It's a
peculiarity of Western thinking that we
analytically decompose things into cause-and-effect
sequences. What Piaget doesn't tell us is that, at
the last, we have to put the parts back together.
We have to reclaim the child's view.
The truest answer to the question, "How does the
bicycle work?" is that you and the machine become a
single thing. The wheels, chain, and sprocket are
forgotten as you sail down the road with the wind
blowing through your hair.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds