One of the Most Nightmarish Behavioral Tests Ever Devised for Rats

The behavior of lab rats is often used as a model for the behavior of humans. One test, the Open Field Test, is so simple and yet so like a horror movie, that it makes me wonder what real humans would do in the same situation.

Lab rats are put through a lot of behavioral tests. This is not because we're passionately interested in rats, but because we think that their behavior serves to inform us of what a human would do under comparable circumstances. One test is simple and, it seems, useful. It's called the Open Field Test. It is exactly what it sounds like. Rats are placed, usually from a carrying cage, into a large empty enclosure. Sometimes there's a piece of food in the center of the enclosure, but that's about it for visual clues.

One of the Most Nightmarish Behavioral Tests Ever Devised for Rats

The enclosure is marked out with a grid, and an overhead camera, or overhead observers, will record how many lines the rat crosses in its explorations over a certain span of minutes. They'll also record changes in direction, grooming behaviors, and signs of nervousness like freezing, visible sickness, or defecation. This test is, at its simplest, meant to show how anxious a mouse is when confronted with a new situation in which it has no cover, but also no apparent threat. How long does it take before the mouse starts exploring? Does it rear up and look around? What pattern does it use to explore? And how does its behavior change over time?

The Open Field Test can be a good test for things like sedatives or stimulants, which depress or increase exploration activity respectively. Surprisingly, anti-anxiety medications do little to change mouse activity in the Open Field Test. Although the test was first used to measure anxiety - another thing researchers look for is obsessive compulsive or self-soothing behavior - maybe it just shows outright fear instead of anxiousness.

It would certainly provoke fear in humans. The idea is so simple that it's actually cinematic. How many horror movies start out with a protagonist dumped in an unfamiliar room and slowly deciding to explore? It makes me wonder how an actual person in that situation would behave. I would think most people would be even more reluctant to explore than the rats are. After all, we have more control over our environment. If we're put somewhere unfamiliar, with no one around, for no reason we can fathom, most of us would reasonably decide we were in big trouble and be hesitant to court more. Or perhaps, I'm wrong. Maybe most people would run around the room looking for an exit right away, and I'm just the scaredy-mouse willing to sit in one corner.

What do you think you would do if you were suddenly put in an Open Field Test? Would you explore? Rear up and look around? Groom yourself? I like to think I'd resist the urge to nervously defecate, but maybe that's just vanity talking.

[Via A Detailed Analysis of the Mouse Open Field Test, Open Field.]