Difference Between Humans and Animals, Part XX

It's always fun when two of your thought hobbies cross paths. If you've read this blog for any length of time you know I'm continually fascinated with the differences (and similarities) between humans and animals. Also, recently I did a short series on issues I was wrong about to remind myself of the self-verification bias. Here's an interesting study using macaques and a computer game covering both topics:

The animals were trained to judge the density of a pixel box that appeared at the top of the screen as either sparse or dense. To give their answer, the monkeys simply moved a cursor towards a letter S or a letter D. 

When the animals chose the correct letter, they were rewarded with an edible treat. There was no punishment for choosing the wrong answer, but the game briefly paused, taking away - for a few seconds - the opportunity for the animals to win another treat. 

But the monkeys had a third option - choosing a question mark - which skipped the trial and moved on to the next one. This meant no treat, but it also meant no pause in the game.
The scientists saw that the macaques used this option in exactly the same way as human participants who reported that they found a trial too tricky to answer; they chose to "pass" and move on.

So monkeys know when they might be wrong, do you? Even weirder, chimpanzees know that other chimpanzees make assumptions:

If chimpanzees are faced with two opaque boards on a table, in the context of searching for a single piece of food, they do not choose the board lying flat (because if food was under there it would not be lying flat) but, rather, they choose the slanted one— presumably inferring that some unperceived food underneath is causing the slant. Here we demonstrate that chimpanzees know that other chimpanzees in the same situation will make a similar inference. In a back-and-forth foraging game, when their competitor had chosen before them, chimpanzees tended to avoid the slanted board on the assumption that the competitor had already chosen it. Chimpanzees can determine the inferences that a conspecific is likely to make and then adjust their competitive strategies accordingly.

When you assume it makes an ass out of u and me.