"There are times when, due to a previous history of events, one is unable to benefit from the present. In this case, the optimal course of action is not determined purely by the set of potentials and values that make up the current situation, but rather by the conditions at an earlier point in time.
Knowing that someone is happy may lead to benefit, by previously mentioned mechanisms regarding situational complexity"
"Physical exercise and a change in mental focus." There are many ways to influence one's own thoughts, but excess mental activity is as much a problem at the physical level of thought as it is a psychological one.