Are you reading this while checking email, chatting on IM, waiting for your purchase to clear PayPal and signing your mum’s birthday card?

If so, please set all that aside for a moment and take note.

A study published in the Proceedings of the National Academy of Science suggests that people who tend to involve themselves in multiple media-oriented activities at the same time perform relatively poorly on tests requiring them to shift attention from one task to another.

To reach these conclusions, Clifford Nass and colleagues at Stanford administered a survey to 262 college students which elicited a history of media utilization and whether or not they tendened to engage in multiple tasks simultaneously.

They collected information regarding the use of computer games, online video and audio, TV, cell phones, text and instant messaging, and computer software like word processors.

After completing the survey, the students underwent a battery of tests in which they had to evaluate certain colored triangles while ignoring other ones, categorize words, alternate between classifying numbers and letters, and press a certain button when they saw a match between 2 symbols presented at different times.

The scientists found that heavy multitaskers executed these functions more slowly than with those who rarely used more than one medium at a time. The multitaskers, it turned out, were more easily distracted by irrelevant information because they retained it in their short-term memories for a longer period of time.

The difference amounted to about a half-second delay on most tests, a difference large enough to cause noticeable problems in everyday life. (more…)