As a result of his experiment, Külpe determined that visual perception is determined not only by external stimulation but also by "Aufgabe", which is another word for the task or directive. Since he varied the "Aufgabe" (task) slightly in each session of the experiment, he was able to find a correlation between the range of attention and degree of consciousness. He found that the wider one’s span of attention, the lower one’s degree of consciousness is to any specific aspect, and vice versa. He concluded that there is a limited amount of energy driving attention and that this limitation is constant. He also concluded that the abstraction process is based on apprehension, rather than sensational differences in presentation, and that these two concepts are distinct.