While customers increase their tip in proportion to the size of the first smile from the waiter or waitress, one in 10 knock money off at the sight of a flower in the hair.
Just why a flower shouldcause offence is not clear - but then neither is the reason why 11 per cent of customers give a bigger tip if the waiter has physical contact with them during the meal. A touch on the hand, it seems, is worth a tip averaging 16.7 per cent, compared with the norm of 10 to 15 per cent.
These and other mysteries of the tip - the word supposedly standing for To Insure Promptness - appear in The Psychology of Money, a new book by two of Britain's leading psychologists, Professor Adrian Furnham and Professor Michael Argyle, to be published soon by Routledge.
There is still confusion over the real motives for tipping. Economists argue that it is done for better service, while sociologists see a tip as a form of social control where the customer is indebted to the provider. Psychologists, however, say that tipping is a form of ego massage calculated to enhance the self-image of the tipper.
While a sunny day means that 14 per cent of people increase their tips, a bad mood results in people giving less. Guilt, too, has an effect and Catholics are much more likely to give money to a charity on their way to confession than returning from it.
The authors say that men mostly tip more than women, but they also point out - perhaps stating the obvious - that physically attractive waitresses get bigger tips. Women can also attract a better gratuity by drawing a happy, smiling face on the back of the bill, a strategy that does not work for men because it is considered "gender inappropriate".Reuse content