In accident in north America, they describe a kind of accident that happen because what you learned previously is good. For example, if you learn sport climbing and you go for it on a bolt, you will think that it will work if you do the same with a stopper.
"The familiarity heuristic is the tendency to believe that our behavior is correct to the extent that we will have done it before (McCammon, 2002)
More precisely, on stressful situation the brain can not manage all the information that he received when you are leading trad. The load is too high as in this example: "Consider the difference between having to study a subject in one's native language versus trying to study a subject in a foreign language. The cognitive load is much higher in the second instance because the brain must work to translate the language while simultaneously trying to understand the new information."
As we lead in trad, we have to think about the fall and possible injury, rope management, placing gear, resting, finding the move and gave the nerve influx to the muscle. In sport, we have to think at clipping bolt, finding the move and gave the nerve influx. Many times, we don't have to think about route finding as the next bolt show us the way.
Do you know some behavior that we think that is correct because we do it before?
I think that when we rappelling in trad, we let the first climber going down on the system and after we rap on the only biner (biner is ordinarly clip to a sling, not a bolt) that we left on the route. That comportment is similar to those of the guy who felt at rumney. Because in a rappelling station we use just one biner, we think that we can do that on any route.