Oscar Wilde once said that marriage is the triumph of imagination over intelligence. Now scientists have shown that the best advice for people contemplating matrimony is to put their gut instinct ahead of wishful thinking.
A study of 135 newly-wed couples who were followed over a four-year period found that what people say about their partner is not always what they think deep down - but it is this gut reaction that matters for future marital happiness.
The optimism shown by all the couples at the outset of their marriage generally declined over time but the level of growing dissatisfaction with their spouse was directly related to the inner-most feelings at the outset - which they actively suppressed, the scientists found.
Those who harboured the most negative gut reaction to their partners after six months of marriage were also the ones who felt the most dissatisfied and unhappy after four years of marriage, according to Professor James McNulty of Florida State University in Tallahassee, who led the study published in the journal Science.
"Everyone wants to be in a good marriage and in the beginning many people are able to convince themselves of that at a conscious level," Professor McNulty said.
"But these automatic, gut-level responses are less influenced by what people want to think. You can't make yourself have a positive response through a lot of wishful thinking," he said.
Measuring gut feelings was not straightforward and the researchers used an established psychological technique for determining someone's subconscious thoughts by measuring the time it took for them to react to photographs of a spouse.
The experiment involved flashing a photograph of someone's partner on a computer screen for just one third of a second, followed by a positive word such as "awesome" or "terrific" or a negative word such as "awful" or "terrible.
The subjects had to respond to whether the words were positive or negative by pressing a computer key and their reaction times were measured down to thousandths of a second. But it takes longer to respond to negative words if someone's gut feelings toward their spouse also tends to be negative, Professor McNulty said.
"It's generally an easy task, but flashing a picture of their spouse makes people faster or slower depending on their automatic attitude towards their spouse," he said.
"People who have really positive feelings about their partners are very quick to indicate that words like 'awesome' are positive and very slow to indicate that words like 'awful' are negative words," he added.
People with negative gut feelings towards their partner had a harder time overcoming the negative reaction they momentarily felt on seeing their spouse's photograph, which delayed their reaction time to the positive words.
Perhaps not surprisingly, this negative gut reaction had little connection to what the couples were saying about their partners. Whether they realised it or not they were supressing their gut feelings, Professor McNulty said.
Yet, it was clear that gut reactions were a better predictor of future happiness or dissatisfaction than conscious appraisals of partners at the outset of a marriage, the study found.
"The more positive spouses' automatic attitudes were at baseline, the less their marital satisfaction declined over time," the researchers concluded.
Professor McNulty said: "I think the findings suggest that people may want to attend a little bit to their gut. If they can sense that their gut is telling them that there is a problem, then they might benefit from exploring that, maybe even with a professional marriage counsellor."