The issue of RSI and other physical problems associated with the hours people spend in front of computer and video screens is only the tip of the ice-berg. Less visible, and more dangerous are the mental effects of multi-tasking, a constant stream of information and the ease with which we can cut and paste. I am not advocating that we turn off the internet and smash our computers - they are useful tools, but let us use them with deliberation and think about their negative effects as well as their positive ones.

Computers, with their multi-tasking abilities and instant alert features give us the illusion that it is possible to do many things simultaneously. But this is only an illusion. Just as a child who turns on the television and sits down to do his homework will probably take twice as long and do a poor job of it, so we find that with instant email alerts, twitter and other programs constantly letting us know that something new has come in we are far less effective than we used to be. David Allen, productivity guru and author of "Getting Things Done" says, "You can do ANYthing you like, but not EVERYthing at onc

Computers and the internet allow us to access so much information from so many sources that we are paralyzed by the quantity. As a result we have become quoters and dabblers, unable to produce a coherent analysis of a situation, let alone a reasoned argument supporting or opposing an issue. We can talk for hours about what has been said, but we have difficulty thinking it through carefully and separating hysteria from fact. Some recent examples of this include the debates over Intelligent Design, Wikileaks, and Man-Made Global Warming, in which a lot more propaganda has been conveyed than solid fact. Even people who are supposedly educated tend to parrot the party-line from one side or the other, and rarely stop to come to grips with the arguments of the other side except to refute them. It is as though we feel obligated to expose ourselves to everything that is being said, rather than to restrict ourselves to an amount of information which we can absorb.

In the days before computers with their cut and paste ability, when words needed to be laboriously written by hand or typed out, when a correction meant that you had to rewrite the whole page people thought before they put pen to paper. They prepared their argument in their mind and formed sentences and phrases to express it fittingly, and through long practice and training they could do so with great speed, effectiveness, and accuracy, because they had thought deeply about the issues they were addressing, they had marshaled the necessary facts to support their own argument and demolish that of their opponents. They might write many drafts, but each was a deliberate improvement on its predecessor and the product of focus and effort. Today, we churn out words at record speed, with little attention to spelling (because the spell-check will highlight any problems) and we save thinking about them for later because it is so easy to move them around and change them on a whim. This feature has many advantages but it is largely responsible for the inability of students to write or speak eloquently, and even worse has led to an enormous problem with plagiarism.

Our complex world calls for men and women who can think quickly and incisively, who can juggle many different streams of work simultaneously, and who can respond to urgent calls for action appropriately, yet the very tool which drives that need is destroying our ability to use it wisely. We need to evaluate our use of the computer carefully, and make sure that it remains a servant rather than a master.