''Because lust is there to essentially lead us to pursue people into bed, which is a very current goal, it tends to focus our minds on the present and on detail,'' he says. ''People in a lustful state are more detailed [in their thinking], focused on the trees rather than the forest'', which leads to ''decomposition of a problem into smaller pieces'', he says.

Even a relatively tepid form of lust, induced by nude pictures or certain words, causes people in experiments to perform better on analytic reasoning problems that involve working through details step by step, he says.

His book, The Joy of Sin, musters evidence from psychology experiments by researchers worldwide to argue that the seven deadly sins (lust, gluttony, greed, sloth, wrath, envy and pride) are not necessarily bad.

''Under certain circumstances these things can bring about a range of benefits, including making one happier, smarter, more creative and increasing pro-social behaviour,'' he says.

People feeling proud of themselves will stick at a task longer and achieve greater success. People with time to spare are more sensitive to the needs of others and more likely to help.

Dr Laham said he did not feel the need to amplify the point that the seven deadly sins can be bad for you, too. Most people already have a sense of that, he believes.

Research also shows, for example, that high lust levels can trigger risk-taking sexual behaviour and sexual aggression.