Human contact and universal generosity

Does this apply to glad-handers and close talkers? Anyway, we should probably be more generous with our pats on the back.

From the Economist, A touch of generosity

"PEOPLE touch each other a lot, even strangers. We shake hands, slap backs, kiss and caress. Such behaviour can increase co-operation, which is good from an evolutionary point of view. It has even been shown that waitresses who touch patrons tend to be tipped more generously."