No; what follows is that they must have been (not be) successful behaviour (not the most successful behaviour) for human beings to have. Evolution selects for things that work, not for things that are best, not least because possible adaptations that never actually turn up don't get the chance to be selected for.
It's almost certainly true that the heuristics built into our brains work better in practice than you'd think from a here's-how-we're-irrational description. But they still cost us sometimes, and it's good to be aware of them and look out for them in cases where we need the best answers we can get rather than the best we can get in ten seconds.
It's almost certainly true that the heuristics built into our brains work better in practice than you'd think from a here's-how-we're-irrational description. But they still cost us sometimes, and it's good to be aware of them and look out for them in cases where we need the best answers we can get rather than the best we can get in ten seconds.