Cognition(noun)-mental processes

“The study found that a set of volunteer who suffered from depression improve their cognition, which is that they could that they could remember s string of digits, and could repeat them both forward and backward after a 50 minutes walk through a woodland park, better than those who a walk in a busy city street.” – The Telegraph-Journal “Age, grace, and the art of walking outside” 

When reading the sentence I could not understand what Cognition means. Looking up the word online, I now understand what the word means. The word Cognitions means mental process, this includes perception, memory, thinking, and emotion.