Probably the most telling result of the study is that the more we fight an earworm, the harder it is to turn off.

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He said companies could use the same technique to study how employees respond to different compensation schemes, for example, or whether they work harder if the company is involved in local charities.

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In their study, the US researchers found that animals worked harder to get doses of Nocaine than to receive a saline solution, but less hard than they did to obtain doses of cocaine.

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And the same study shows that the longer you're out of work, the harder it is to get a new job.

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But in the longer term, students and their parents are likely to think a lot harder about whether to study full time or part-time, how long for, in what subject and where.

ECONOMIST: Education economics