Which side of the brain rotates a mental picture?
Consider the simple situation in which you are walking around the kitchen and decide to pick up your own cup of tea, which is identical to others lying on the table. Your brain chooses the correct cup of tea by using different types of information that you have stored about the position of the cup in relation to the kitchen table. The information can be represented in qualitative terms (left, right, above, below) or quantitative terms (distances and angles). Previous studies have claimed that the brain's left hemisphere is critical for processing qualitative (technically 'categorical'), information and the right for quantitative ('metric') processing. However, new neuropsychological findings published in the February 2011 issue of Cortex show that this is not the case...