It's impossible to say, really. Yes, some kind of approximation in rational thinking is necessary for building a practical brain. But it's also a fallacy to think evolution created the perfect thinking machine that is optimally fit, even for its environment. Our brains are obviously suboptimal in many areas (and in my personal opinion are deeply and horrifyingly suboptimal in most areas). It's hard to say, though, whether something is a feature or a bug without examining the neural circuitry behind them in detail.