People who multitask all the time may be the worst at doing two things at once，a new research suggests.The findings，based on performances and selfevaluations by about 275 college students，indicate that many people multitask not out of a desire to increase productivity，but because they are easily distracted (分心) and can’t focus on one activity.And “those people turn out to be the worst at handling different things，”said David Sanbonmatsu，a psychologist at the University of Utah.
Sanbonmatsu and his colleagues gave the students a set of tests and asked them to report how often they multitasked，how good they thought they were at it，and how sensationseeking (寻求刺激) or impulsive (冲动)they were.They then evaluated the participants’multitasking ability with a tricky mental task that required the students to do simple mathematical calculations while remembering a set of letters.
Not surprisingly，the scientists said，most people thought they were better than average at multitasking，and those who thought they were better at it were more likely to report using a cellphone while driving or viewing multiple kinds of media at once.But those who frequently deal with many things at the same time were found to perform the worst at the actual multitasking test.They also were more likely to admit to sensationseeking and impulsive behavior，which connects with how easily people get bored and distracted.
“People multitask not because it’s going to lead to greater productivity，but because they’re distractible，and they get sucked into things that are not as important，”Sanbonmatsu said.
Adam Gazzaley，a researcher at the University of California，San Francisco，who was not a member of the research group，said one limitation of the study was that it couldn’t find out whether people who start out less focused tend toward multitasking or whether people’s recognizing and understanding abilities change as a result of multitasking.
The findings do suggest，however，why the sensationseekers who multitask the most may enjoy risky distracted driving.“People who are multitasking are generally less sensitive to risky situations.”said Paul Atchley，another researcher not in the group.“This may partly explain why people go in for these situations even though they’re dangerous.”
The research led by Sanbonmatsu indicates that people who multitask________.

A．seek high productivity constantly

B．prefer handling different things when getting bored

C．are more focused when doing many things at a time

D．have the poorest results in doing various things at the same time

When Sanbonmatsu and his colleagues conducted their research，they________.

A．assessed the multitasking ability of the students

B．evaluated the academic achievements of the students

C．analyzed the effects of the participants’tricky mental tasks

D．measured the changes of the students’understanding ability

According to Sanbonmatsu，people multitask because of their________.

A．limited power in calculation

B．interests in doing things differently

C．inability to concentrate on one task

D．impulsive desire to try new things

From the last paragraph，we can learn that multitaskers usually________.

A．drive very skillfully

B．go in for difficult tasks

C．fail to react quickly to potential dangers

D．refuse to explain the reasons for their behavior