Human brains do statistics at a low level. This is what the experiment tested.
An example experiment would be if you gave someone a rewards with different probabilities after some random event like clicking, and the brain would learn to estimate the probability that a sequence of clicks would lead to a reward.
On a high level this obviously breaks down. The brain doesn't have thousands of examples of slaughtering cows leading to starvation. Cognitive biases all operate at a high level of reasoning, and involve verbal arguments and stuff. But on a low level, the brain is absolutely statistically based.