You’re going in for the big smooch, and, as your lips touch, you close your eyes. Ever wonder why?

New research has your answer: You close your eyes when you kiss because your brain can process tactile sensations better when you don’t have any visual stimuli competing for attention. This is according to a study by cognitive psychologists Polly Dalton and Sandra Murphy at Royal Holloway, a research college that is part of the University of London.

An eyes-wide-open kiss would not only be a little awkward (and bereft of romance), it would also decrease pleasure, the study found: Using both your sense of sight and sense of touch could cause sensory numbness.

In other words, you feel things better — like a big, sloppy smooch — when you can’t see. Your brain wants to take in all of the feelings associated with the kiss, and to get the most pleasure out of it, it lets your sense of sight take the backseat.

The Royal Holloway psychologists found that your gray matter can’t register touch nearly as keenly when you’re completing visual tasks — such as crosswords or puzzles.

To come to their conclusion, the scientists asked volunteers to finish a work puzzle while also administering a vibration to the left or right hand. They found that the harder the puzzle, the less likely the subjects were able to sense the vibration.

Knowing why you shut your eyes when you kiss probably won't do any good for humanity (besides quench your curiosity), but the study has implications that may help keep you safe and aware. For example, you now know that you may be more susceptible to being robbed if you’re performing a taxing visual task, such as looking for someone in a crowd or searching for your gate number at the airport.

More important, study authors said the findings could aid the design of vehicular alert systems. The researchers explain:

“For example, some cars now provide tactile alerts when they begin drifting across lanes. Our research suggests that drivers will be less likely to notice these alerts when engaging in demanding visual tasks, such as searching for directions at a busy junction.”