If you’ve experienced a traumatic brain injury (TBI), you already know what I’m writing about. If not, here’s some insight into how our brains work.

I’m collecting environmental samples at work today, so I threw my gear into our antique Chevy Suburban. We keep it in barely useable condition to show the public how carefully we watch after their dollars, and I’m always anxious about starting it. I turned the key and, once started, I heard a faint, rhythmic squeak and wondered if a mama sandpiper built a nest underneath and was sitting on a clutch of chicks. It’s not unheard of.

The more I listened, the more I was positive that something was amiss. The truck was parked outside a trailer office, and I thought there might be a swallow’s nest atop an air conditioner. Did I make them angry by invading their space, and they were dive-bombing the truck?

I left the truck running, got out, and the peeping stopped. Ah, I thought, sandpiper chicks, silent now as they sensed my step. But to be thorough – every good scientist is thorough – I checked the back, too, and eyed the air conditioners. Nothing up there, but I heard the chirp again as if it came from inside the truck.

Great. What morsel did someone toss in here? I lifted up the door and rummaged through Cubitainers and tubing and couldn’t find a thing., not even a mouse or kitten. Very weird because something back here is still making noise. I heard it again and saw a faint black skinny swish arc across my periphery. Shocked now – we talked about snakes in our safety message this morning – I stepped back to survey the inside of the truck again.

Then – then! – I saw it and heard it again. I almost wish it was a baby cottonmouth with a mouse in its fangs, crying and squealing. Instead, it was something mundane and boring, like most mysteries. I stepped back and waited until it happened again. It was the wiper blade, dry against a dry window, with the motor pushing it hard enough to chirp.
And that’s how it works. The brain fills in empty spaces with ideas that sound reasonable and trick you.