These pictures include some of the mostfamous psychologistsas well as other great thinkers who made important contributions to psychology.

He is perhaps best known for his concept of the inferiority complex.

Erikson is also famous for his concept of the identity crisis.

Alfred Adler sitting in his office

Hulton Archive / Stringer / Getty Images

While Horney was a neo-Freudian, she also challenged many of Sigmund Freud’s theories about female psychology.

In one ranking of the most eminent psychologists of the 20th century, Rogers was ranked at number six.

Wilhelm Wundt

Wilhelm Wundtis best-known for establishing the very first psychology lab in Leipzig, Germany.

Alfredo Binet

Materialscientist / Wikimedia Commons / Public Domain

Whiteman SD, McHale SM, Soli A.Theoretical perspectives on sibling relationships.J Fam Theory Rev.

2011;(3)2:124-139. doi:10.1111/j.1756-2589.2011.00087.x

Michell J.Alfred Binet and the concept of heterogeneous orders.Front Psychol.

Oxfordshire, UK: Routledge; 2016.

Psychologist Erik Erikson sitting at a desk

Corbis via Getty Images / Getty Images

De Sousa A.Freudian theory and consciousness: a conceptual analysis.Mens Sana Monogr.

2011;(9)1:210-7. doi:10.4103/0973-1229.77437

American Psychological Association.Former APA presidents.

2014;6(4):32-39. doi:10.5897/IJPC2014.0250

Goodman R.William James.Stanford Encyclopedia of Philosophy.

Sigmund Freud standing outdoors

Hans Casparius / Getty Images

Storr A.The Essential Jung: Selected and Introduced by Anthony Storr.

Princeton, NJ: Princeton University Press; 2013.

Rowan J.Directions for humanistic psychology.Self Soc.

G Stanley Hall

Tryphon / Wikimedia Commons / Public Domain

2013;40(3):40-41. doi:10.1080/03060497.2013.11084282

Harvard University Department of Psychology.Hugo Munsterberg.

2017;(11)8:ZC111-ZC115.

2016;20(2):155-170. doi:10.1037/gpr0000067

Karen Horney smiling

Bettmann / Getty Images

William James

Materialscientist / Wikimedia Commons / Public Domain

Carl Jung

Imagno / Hulton Archive / Getty Images

Abraham Maslow smiling

Bettmann Archive / Getty Images

Hugo Munsterberg

Vindicator, Rickert / Wikimedia Commons / Public Domain

Ivan Pavlov

National Library of Medicine / Public Domain

Jean Piaget smoking a pipe

Keystone / Hulton Archive / Getty Images

Carl Ransom Rogers sitting in front of a plant, looking away

Bettmann Archive / Getty Images

B. F. Skinner with his hands on top of his hand

New York Times Co. / Getty Images

Wilhelm Wundt

Bettmann Archive / Getty Images