Too clever by half?

Well, here's a nifty device (hat tip Surviving the Workday): an anti-theft lunch bag. How does it work, you ask? Is it perhaps equipped with a motion-sensor device and a flamethrower? No, it's much more low-tech and clever than that. The bags are printed with green splotches so that your yummy tuna-on-wheat looks disgusting and moldy. Like so:

There's lots of potential problems here, obviously: perhaps you don't like sandwiches; if the sandwich is handled, the deception will become obvious; once someone sees you eat the sandwich, the jig is up. But what I wonder is whether or not the sandwich-owner themselves would find the "defaced" sandwich less appealing. I could easily prevent co-workers from eating my tasty homemade brownies by molding them (the brownies) into the shape of dog feces, but I wouldn't want to eat them myself, after that.

Here is a recipe for a rather delicious-sounding cake. The ingredients are as follows:

1 spice or German chocolate cake mix
1 white cake mix
2 large packages vanilla instant pudding mix, prepared
1 large package vanilla sandwich cookies
green food coloring
12 small Tootsie Roll candies

Sounds pretty good, no?

And here is what it looks like when you prepare and serve it correctly:

A great joke cake for Halloween, of course, but the recipe itself warns that you'd better have other food on hand, because most people won't eat this. Loads of experiments have been done on disgust and contamination--people won't drink orange juice that has been stirred with a comb, even if they saw the comb being removed from its packaging; they won't drink or eat out of new, sterile bedpans; they won't eat food from a jar marked "Poison" even when they know perfectly well it's not poison; they often won't even eat from a container marked "NOT Poison," because of the sheer contaminative power of the word "poison."

Are we credulous nuts?

No. Our overreaction to signs of contamination is a feature, not a bug. As omnivores, we evolved to be very, very careful about what we ate. It's an advantage to be able to eat a lot of different things, but it requires you to invest a lot of cognitive resources in your eating habits. Koala bears don't really have to think a lot about what's for dinner: it's eucalyptus leaves. (Which, incidentally, makes koala pee one of the weirdest-smelling liquids on the planet, but that's not really relevant.) We pay a lot of attention to what other humans around us eat. This isn't a human thing, it's an omnivore thing; rats are more likely to eat a novel food if they've smelled it on the breath of another rat. We develop aversions for foods if we've gotten sick after eating them, even if we know perfectly well that it wasn't the food that made us sick. This is why chemo patients are sometimes given an odd-tasting and non-nutritious food, like butterscotch Lifesavers, after treatment--okay, so you'll puke your guts out and never again want to eat a butterscotch Lifesaver. It's no big loss. Social learning and instant food aversions are mechanisms that help keep us omnivores safe from toxins.

And so is an overactive disgust reflex. Everyone makes mistakes, but some mistakes bear higher costs than others. If you're going for a job interview, for example, it's better to err on the side of being too well-dressed than not well-dressed enough. With food, the cost of not eating something that is in fact harmless is momentary hunger. The cost of eating something that is contaminated is sickness or death. So we evolved to err on the side of not eating things if there is the slightest doubt about them. Which means that even when we know full well, consciously, that these are brownies, that the chamber pot is sterile, that it's not really cat litter, that we're throwing up from chemo and not the Lifesavers, there's still a huge part of our brain that's screaming, "NO!" And that's the part of your brain that your gut tends to listen to.

So: would you feel completely comfortable eating the sandwich in the anti-theft bag? Would you feel that a co-worker who used one was being vaguely disgusting?