On 6 May I posted up my notes on a talk given in Edinburgh by Ian Deary on processing speed, and now here is the written up version of that talk by Ian Deary and Stuart Ritchie which gives much better descriptions of the concepts and the findings.
If you click on the third item “10 quick questions about processing speed” you can download the pdf. I should warn you it contains photos of the participants at the conference, but those can be avoided by readers of a nervous disposition.
As you read the paper, reflect on the fact that it may be the last time you read something from Edinburgh while it is still part of the United Kingdom. Thus, it will have historical as well as intellectual significance.