People in long-lasting marriages know less about their partners than people in shorter relationships, says a new research.

The study, conducted by two University of Basel psychologists, Benjamin Scheibehenne and Jutta Mata, and psychologist Peter Todd of Indiana University in Bloomington, found that couples married for an average of 40 years know less about one another''s food, movie and kitchen-design preferences than do partners who have been married or in committed relationships for a year or two.