 Therefore, Wundt suggests, the science of psychology must depend upon the attentive observation of mental processes as they occur. He argues that those who think attention necessarily distorts the target mental process are too pessimistic. A subclass of mental processes remains relatively unperturbed by attentive observation—the “simpler” mental processes, especially of perception (1896/1902, 27–28). The experience of seeing red, Wundt claims, is more or less the same whether or not one is attending to the psychological fact that one is experiencing redness. Wundt also suggests that the basic processes of memory, feeling, and volition can be observed systematically and without excessive disruption. These alone, he thinks, can be studied by introspective psychology (see also Wundt 1874 [1904]; 1896 [1902]; 1907). Other aspects of our psychology must be approached through non-introspective methods such as the observation of language, mythology, culture, and human and animal development.