Science Buddies: "Ask an Expert"

Hello,
I have recently finished my science fair experiment, and my question was, "How Does Background Noise Affect Cognitive Efficiency?"
My hypothesis was that when background noise was added to an environment the task completion time would be extended (Take longer).
But, my experiment does not support my hypothesis, and I don't know why. All of the research I did before the experiment supported my hypothesis, but the data did not. My data concluded that it takes longer to complete tasks without noise. I'm stumped as to why this occurred. Does anyone have any input or suggestions? Help is greatly appreciated!

What sort of noise did you use? Was it music? If so, I know I personally work much more efficiently when I have music on in the background than when I have no music (but it has to be the right kind of music). What task(s) did you have people do? How many people did you study? If you could post back with this information, we can try to find out what happened in your experiment.

Thanks for your reply!
I used different everyday noises, like a cell phone ringing, and traffic.
I tested 50 people, because that was all that time allowed.
The survey I gave out was a simple, ten-question, test. With basic information, such as name, favorite color, and other simple questions.
Does that information help?

I prefer a little background noise when I work. For some reason it helps me to focus. In college, if I tried to study in the library, I would often fall asleep.
Personal stories aside, I'm still not 100% clear about your procedure. Where did you conduct the experiment? Did you play recordings of those sounds while people filled out the survey? Were the surveys always done in the same place, same time of day, etc, or are there possible uncontrolled variables that might have affected your results?
Looking forward to hearing more,
Chris

Thanks for the input!
The experiment was conducted in the same place each time, which was a secluded teacher workroom. The noise was played for every other test, so the group without noise could be my control. And yes, the noise was played as the subjects filled out the survey.
The survey times were between 11:15 and 1:30 each time, so there was a large window of time, which might have something to do with it.
I hope the helps! ^_^

Okay, I think I'm understanding this better now. First, you're absolutely right that large variance in time it took to complete the test could affect your results. Could you speak to the students who took a long time and ask why it took so long? (Maybe they had a hard time deciding what their favorite color was, etc.)

Also, how many students were in each group? If there were only a few, this could also affect your results--if just by chance some of the indecisive students were in your control group, you might see the pattern you found.

If you still have time, one possibility would be to re-test the students using a different but similar questionnaire, using the opposite treatment you used on them before. Then you could compare each students' timing with and without noise. This might control for the effects of someone being indecisive or wanting to take extra time so they didn't have to do something else. If you can't do something like this, it's OK--but you might want to talk about doing something like this in the future in your discussion.

Hope that helps!

The survey times were between 11:15 and 1:30 each time,

When was lunch, before or after, or did it vary? When people are hungry, you tend to get a wider variation from intelligence and aptitiude type tests. You also get a wider variation on similar tests just after lunch. Just another thought on a possible uncontrolled factor.

One more thought - how confident are you that the questionnaire you provided tested "cognitive efficiency"? Did your test subjects finish the questions as fast as they possibly could, or did they choose a pace that felt comfortable? It's possible the the variations you saw in times relate in part to people's comfort level in the test environment. In the presence of annoying background noise, some people would prefer to hurry and leave. In a peaceful quiet environment, some people might choose to linger.
Good luck with interpreting your interesting results.
Chris