Half of the experimental subjects were fitted with ankle-weights – which encumbered them. They were then asked to estimate how high they could jump. It was found that experimentees generally felt they were less able to jump when fitted with the weights.
This was, however, only the primary stage of the study – for the subjects were also asked to estimate how high an associate – who was not wearing any ankle weights – could jump (this person was, in reality, an actor).
The subjects who were encumbered by the weights consistently underestimated the height that the free-jumping actor could attain . . .
The research : ‘Carrying the height of the world on your ankles: Encumbering observers reduces estimates of how high an actor can jump‘ is published in The Quarterly Journal of Experimental Psychology (Volume 61, Issue 10 October 2008 , pages 1487 – 1495 )