Leading article: Winter of content

HERE WE are at the solstice, the official depths of winter, when it's dark when we wake up and dark when we leave work. The temptation is to shut down all systems, put off what work we can and just wait it out. We even have a phrase for our disinclination to get on with things - Seasonal Affective Disorder (SAD) - at this time of the year. But now, science has made some disturbing discoveries. One hundred Norwegians living above the Arctic Circle, where they have two solid months of night, have been tested in winter and summer for reaction time, memory recall and "confusability". All of which are better, it seems, in the dark and cold.

This is disturbing news for those of us who like to find an excuse for putting our minds into winter storage. Summer's easy: with the lethargy induced by enervating heat, and the distractions of summer sports, no one could expect us to settle down to a spell of what the psychologists call cognition. The rising sap of spring creates its own irresistible demands, and autumn is traditionally a time of harvest celebration and sociability.

But now winter's fillip to our mental acuity can no longer be ignored: so hurry up before the days grow long. It's time to write that book, paint that picture, learn that language. Cerebrate.