This fits completely with my experience. When I am writing, or thinking a problem through and come to a dead end the most reliable way finding my way through it is to stop trying. And the best way to stop trying is to go for a walk. During the walk, as I become immersed in my surroundings, I forget to think about problem. Apparently my mind is still cooking it somewhere in the background, because what frequently happens is that a solution will suddenly pop into my head.
a study published in the British Journal of Sports Medicine evidences that green spaces lessen "brain fatigue"--that familiar (urban?) feeling of being distracted, forgetful, and flighty
And here is the summary from the abstract of the article refererenced above:
METHODS:Using Emotiv EPOC, a low-cost mobile EEG recorder, participants took part in a 25 min walk through three different areas of Edinburgh. The areas (of approximately equal length) were labelled zone 1 (urban shopping street), zone 2 (path through green space) and zone 3 (street in a busy commercial district). The equipment provided continuous recordings from five channels, labelled excitement (short-term), frustration, engagement, long-term excitement (or arousal) and meditation.
RESULTS:A new form of high-dimensional correlated component logistic regression analysis showed evidence of lower frustration, engagement and arousal, and higher meditation when moving into the green space zone; and higher engagement when moving out of it.
CONCLUSIONS:Systematic differences in EEG recordings were found between three urban areas in line with restoration theory. This has implications for promoting urban green space as a mood-enhancing environment for walking or for other forms of physical or reflective activity. British Journal of Sports Medicine