Editing Attention (section)

===Philosophical period===
Psychologist [[Daniel Berlyne|Daniel E. Berlyne]] credits the first extended treatment of attention to philosopher [[Nicolas Malebranche]] in his work "The Search After Truth". "Malebranche held that we have access to ideas, or mental representations  of the external world, but not direct access to the world itself."<ref name="Johnson 2004 1–24"/> Thus in order to keep these ideas organized, attention is necessary.<ref>Andrew Brook and Julian Wuerth
https://plato.stanford.edu/entries/kant-mind/</ref> Otherwise we will confuse these ideas. Malebranche writes in "The Search After Truth", "because it often happens that the understanding has only confused and imperfect perceptions of things, it is truly a cause of our errors.... It is therefore necessary to look for means to keep our perceptions from being confused and imperfect.  And, because, as everyone knows, there is nothing that makes them clearer and more distinct than attentiveness, we must try to find the means to become more attentive than we are".<ref>{{cite book| vauthors = Malebranche N |title=The Search After Truth|year=1674|pages=411–412}}</ref> According to Malebranche, attention is crucial to understanding and keeping thoughts organized.

Philosopher [[Gottfried Wilhelm Leibniz]] introduced the concept of [[apperception]] to this philosophical approach to attention.  Apperception refers to "the process by which new experience is assimilated to and transformed by the residuum of past experience of an individual to form a new whole."<ref>{{cite book | veditors = Runes DD | title = Dictionary of Philosophy | publisher = Littlefield, Adams, and Company | location = Totowa, NJ | date = 1972 }}</ref> Apperception is required for a perceived event to become a conscious event. Leibniz emphasized a reflexive involuntary view of attention known as exogenous orienting. However, there is also endogenous orienting which is voluntary and directed attention. Philosopher [[Johann Friedrich Herbart]] agreed with Leibniz's view of apperception; however, he expounded on it in by saying that new experiences had to be tied to ones already existing in the mind. Herbart was also the first person to stress the importance of applying mathematical modeling to the study of psychology.<ref name="Johnson 2004 1–24"/>

Throughout the philosophical era, various thinkers made significant contributions to the field of attention studies, beginning with research on the extent of attention and how attention is directed. In the beginning of the 19th century, it was thought that people were not able to attend to more than one stimulus at a time. However, with research contributions by [[Sir William Hamilton, 9th Baronet]] this view was changed.  Hamilton proposed a view of attention that likened its capacity to holding marbles. You can only hold a certain number of marbles at a time before it starts to spill over. His view states that we can attend to more than one stimulus at once. [[William Stanley Jevons]] later expanded this view and stated that we can attend to up to four items at a time.<ref>{{Cite journal| vauthors = Jevons WS |date=9 February 1871|title=The Power of Numerical Discrimination|url=https://archive.org/details/paper-doi-10_1038_003281a0/mode/2up|journal=Nature}}</ref>