Self-Doubting Monkeys Know What They Don't Know

The number of traits chalked up as "distinctly human" seem to dwindle each year. And now, we can't even say that we're uniquely aware of the limits of our knowledge: It seems that some monkeys understand uncertainty too. A team of researchers taught macaques how to maneuver a joystick to indicate whether the pixel density on a screen was sparse or dense. Given a pixel scenario, the monkeys would maneuver a joystick to a letter S (for sparse) or D (for dense). They were given a treat when they selected the correct answer, but when they were wrong, the game paused for a couple seconds. A third possible answer, though, allowed the monkeys to select a question mark, and thereby forgo the pause (and potentially get more treats). And as John David Smith, a researcher at SUNY Buffalo, and Michael Beran, a researcher at Georgia State University, announced at the ...