train of thought

do u ever get those trains of thoughts (grammar?) that literally go on for minutes until you realise what ur thinking about and retrace your thought to your original subject... i read somewhere ages ago that ppl did tests on others trains of thought and it somehow established fully how their minds work,ther methods of thinking and their levels of practicality,concentration span that sorta thing.

[Edited on 18-2-2004 by happyk]