Cognitive Daily has an excellent article on the fascinating SNARC effect, where we react quicker to numbers with the hand that most approximates their position in space as if they were written out in front of us.
In other words, people react faster with their left hand for small numbers, and faster with their right hand for big numbers. This suggest that our number concepts are mapped partly mapped out in space.
Of course, this has largely been tested on English readers, who all read left to right, but Cognitive Daily reports on some new research that tested Arabic readers, for whom larger numbers would be on the left, and found that they show show the same effect, but in reverse.
Finally, the study investigated the effect on Israeli students, who know both left-right and right-left texts, as they learn both English and Arabic, and found that the effect didn’t appear.
In case you’re wondering, SNARC stands for the rather unwieldy phrase ‘spatial numerical association of response codes’.
While we’re on the subject of the excellent Cognitive Daily blog, you may be interested to know that they’ve started a new in-depth feature called ‘Cognitive Monthly‘ which you can download to your computer, iPhone or Kindle reader for $2.
They kindly sent me a free copy of the first edition, on the psychology of film and theatre, and I can heartily recommend it as excellent.
Link to post on culture and the SNARC effect.
Link to Cognitive Monthly details.
Mind Hacks 
Warren McCulloch would be pleased, somewhat.
Just thought somebody should point out that while Arabic *letters* are written right-to-left, Arabic *numbers* are written left-to-right – same as in Enlgish!