Grammar question: "the person that..." vs. "the person who..."

I remember that, way back in high school, one of my English teachers insisted that we use the word “that” when referring to anything non-human, and “who” when referring to a person.

Yet I hear educated people say, “the person that…” all the time. Did my English teacher make up this rule, or has anybody else been taught the same thing?

I’ve never heard that rule. I would think the “who” rule would work along the same lines as the “which” rule - if its clause can’t be set apart from the main clause by commas, use “that” instead.

I could be wrong about this though.

Well, surely you never use ‘who’ for a non-personalised object, you’d use ‘which’ if you weren’t using ‘that’

The rock upon which I sat.
The rock which shaded me.
The rock that shaded me.

But consider:

He who told me…
He that told me…

‘The man that told me…’ is better for the second version.

Here’s a classic case where ‘that’ is wrong:

He whom I call my brother.
He that I call my brother.

You’d never use the second.

Here’s another view: http://newark.rutgers.edu/~jlynch/Writing/t.html

What I had in mind was this particular usage:

The man that was arrested
The man who was arrested

I hear people use “that” all the time, and it seems to imply that the man is an inanimate object.

Well, if he’s been properly subdued…

The usual nitpick: this is a question of usage, not of grammar.

So to quote a usage guide, Theodore M. Bernstein’s The Careful Writer: A Modern Guide to English Usage:

I have tutored kids for the SAT II Writing test many times, and I state categorically that the official way is to use “that” for things, and “who” for people. Cross this up on that test, or put it in your essay, and you’ll be wrong.