“Dad, telephones dial with sound!”

Growing up in the 1970s, I developed a mental model of how push-button telephones worked.

My mental model went like this:

1. When you lifted the receiver, you heard a dial tone. That told you that you could dial.
2. When you pressed a number on the keypad, you heard a tone. That told you a number was pressed.
3. Pressing different keys on the keypad made different tones. That helped you know you’d touched different numbers.
4. When you’d pressed enough numbers, the other phone “rang” and someone might answer.

When I was fourteen, in 1984, I downloaded a program named “Silver box” from a BBS for my Commodore 64, which was output to my 10″ B&W TV.

I spent a whole Saturday trying to figure this program out.

It didn’t make any sense – when I would use the “Dial Touch Tone” function, it generated the same tones as I heard when I dialed a telephone keypad. But who wants to hear the sound a phone makes? That’s not interesting.

Finally, out of frustration, I entered my friend Robert’s phone number into the program and held my touch-tone phone near the TV speaker.

The program made the tones… just like it had for the past nine hours… and then I heard, “Hello? Marcus? Hello??”

Incredulous, I brought the phone up to my ear, “Hello? Who is this?”

“It’s Robert. You called me, goofball.”

I promptly hung up on him, shaking.

How the hell had the speaker on a TV dialed a telephone????

So, of course, I tried it again.

And again, he answered, a bit more annoyed this time.

I couldn’t put into words what had happened, but I knew something was happening.

Rushing into my father I yelled, “Dad, telephones dial with sound!!! WITH SOUND!!!”

He looked at me, confused, and kept reading the paper.

This is one of my earliest memories of having a mental model shattered.

Turns out that the tones made by the keypad are NOT for people to “know they pressed the right key” – they controlled the central office switch and dial the phone. It also turned out that operators had more keys than the normal phone, which allowed them to do some fun stuff. But that’s a story for another time…

Having a mental model about something is essential for using it.

But having an incorrect mental model creates frustration, and blinds us to reality.

In this case, I was lucky enough to make this “discovery” at an early age, and become joyfully aware that I might have wrong mental models about the world.

Tomorrow I’ll show you a tool you can use to improve your mental models.

But today, would you tell me if you’ve ever had an experience like this, where your mental model was joyfully shattered?

Best,

Marcus

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