 According to Keuzenkamp (1987) "Karsten was fairly optimistic about his abilities to make prognoses, but, as he had to admit , 'at the present time this investigation can not account for economic changes which are wholly due to the element of mob-, crowd- or herd-psychology'.In general, however, Karsten's conclusion is that these psychological factors are relatively unimportant, which leads him to find reason to state that his results support "economic determinism".There is only one exception