"According to a 2007 study by Loughborough University academic, Thomas Jackson, most of us reply to e-mails immediately - many within six seconds. Then it takes at least a minute to recover our thoughts. Not long after, more e-mails arrive, with more checking, and so on.
As a result of this constant stimulus, we can become habituated. Instead of focusing on our work or home life, we're waiting for the next 'hit': clicking on 'new mail' every few minutes. King's College research commissioned by Hewlett Packard suggested that this e-mail preoccupation was reducing the mental sharpness of volunteers.
This combination of distraction and addiction also occurs with the internet. Psychologists call it a 'variable interval reinforcement schedule'."
