The apparatus demonstrates the phenomenon of
Habit Interference with the underlying fact that time taken to accomplish a
practiced task is less than time taken to accomplish a new task. The apparatus
consists of a tray with many numbered boxes and number indicating cards
according to the number of boxes. Work to be done is to make the subject place
the numbered cards in the same numbered box. Different situations can be
created like the number of the boxes is in serial order or the number of the
boxes can be jumbled. Or the subject is made to use right hand first and then
left hand. Time taken in different situations is recorded.
