High-flying students who gain first-class degrees enjoy their courses more than their lower-achieving classmates and do much less paid work, according to a survey of more than 4,000 undergraduates.
The results, which uncovered the damage that paid work can inflict on academic achievement, also reveal that top students are more fun loving than their introverted bookish stereotype suggests.
According to the psychologists who carried out the survey, there is a positive link between happiness and degree classification.
More than 80 per cent of students who gained firsts ranked their enjoyment of their course as four or five on a five-point scale. Some 69 per cent of students gaining a 2:1 ranked their course enjoyment as four or five. Less than than half of those who achieved a lower second did so.
Bridgette Bewick, part of the survey team at Leeds University, said students gaining firsts worked a mean of 2.17 hours a week compared with a mean of 7.31 hours for those achieving 2:1.
The finding should be a warning to universities, according to Alan Smithers, professor of education at Liverpool University.
He said: "Courses are still geared towards full-time students, so if you are spending your evenings working unsocial hours you cannot be as alert and focused as you will need to be to get a first.
"This is not a straightforward conflict between work and study, it is to do with the way courses are organised, offering little or no flexibility towards the needs of today's students."
Ms Bewick said many of the results had surprised researchers. "Students gaining firsts did not seem to perceive any difference in the degree of difficulty of their academic work compared with other students in the survey. Neither could we find any meaningful difference in the perceptions of workload. But it was clear that students achieving a first generally had a more positive outlook."
While students gaining lower degree classifications were more likely to admit to not coping as well with their academic commitments, they graded their workloads similarly to high achievers.
'I enjoyed my lectures but I am not obsessive'
Jen Dickinson, a postgraduate geographer at Leeds University who gained a first-class degree, said: "I enjoyed my lectures and going to the library but I am not obsessive.
"I felt I had to do as well as I could and would not hand in any work unless it was the very best I could do. I always started assignments early, it was very important to me to get a first and I worked very hard. I wanted to feel different fromeveryone else."
The Quality of Life and Learning survey questioned students eight times (once pre-registration, three times during their first year, twice during their second year and twice during their final year).