Saturday, March 15, 2008

A fishy tale

I had an e-mail request from M. for a column I wrote four or five years ago for the Boston Globe, about goldfish memory. Herewith a much abbreviated version (the complete column to M. by return e-mail):

As dumb as a goldfish.

I mean, what could be dumber than swimming around in murky water all day -- glassy eyed, slimy scaled, cold blooded -- waiting for someone to sprinkle food flakes into the pond or tank. On a scale of smarts, goldfish would seem to fall somewhere between a limpet and a stone.

Conventional wisdom has it that fish have a memory span of about a second.

But conventional wisdom, it turns out, is wrong. Goldfish are not the dummies they are made out to be.

Scientists at Plymouth University in England have successfully trained goldfish to push a lever to get food, and -- get this -- to do it at the same hour every day. And the fish remember what they have been taught for months.

Not exactly the science story of the year, but it does cause one to reflect on the nature of memory. What's going on in those tiny ichthyic brains that lets the goldfish remember when and where to go for dinner?

Scientists now overwhelming believe that memories are stored as webs of connections between spider-shaped brain cells called neurons.

Each neuron is connected through electrochemical connections to thousands of others. According to the current view, experience fine-tunes the connections, strengthening some, weakening others, creating a different "trace" of interconnected cells for each memory.

As the goldfish were trained by the British scientists, a cobwebby tangle of neurons was established in their brains: "Over here, push the lever. It's supper time."

If there is something in the human body that can fairly be called a soul, it is surely that ineffable electrochemical web of connections that was partly bequeathed to us by our genes and partly records a lifetime of experience -- including, of course, the cultural preferences we absorbed from our parents and teachers.

Some folks are put off by the idea of an electrochemical soul, and prefer the older notion of a self that is independent of our physical bodies. As for myself, I love the notion of that effervescent cobweb of neuronal connections contrived of the ineluctable stuff of creation by 4 billion years of evolution.

And I love too the way the new idea of soul binds us in a seamless web to all other creatures, goldfish included, and to the fabric of the universe itself.