Lecturer's Précis - James (1890)

Copyright Notice: This material was written and published in Wales by Derek J. Smith (Chartered Engineer). It forms part of a multifile e-learning resource, and subject only to acknowledging Derek J. Smith's rights under international copyright law to be identified as author may be freely downloaded and printed off in single complete copies solely for the purposes of private study and/or review. Commercial exploitation rights are reserved. The remote hyperlinks have been selected for the academic appropriacy of their contents; they were free of offensive and litigious content when selected, and will be periodically checked to have remained so. Copyright © 2018, Derek J. Smith.


First published online 11:58 GMT 7th March 2002, Copyright Derek J. Smith (Chartered Engineer). This version [2.1 - link to graphic] dated 09:00 BST 2nd July 2018


James's (1890) "Hemispheric Loop-Line" Omega

William James (1842-1910) trained originally as a physician, but gradually specialised in philosophy and psychology. He founded the first North American experimental psychology laboratory at Harvard University in 1875, and between 1878 and 1890 wrote "The Principles of Psychology", soon to be recognised as one of the classical textbooks of psychological science. Here, from that textbook, is his attempt to provide what he called a "general notion" (p20) of the physiological layout of the nervous system. The resulting general notion is that "the lower centres act from present sensational stimuli alone; the hemispheres act from perceptions and considerations" (ibid.; italics original). Here is that notion, summarised graphically:

James (1890): Here is a nice metaphor for the three-layer omega. Circle C (green circle, central) represents the nervous system below the level of the cerebral hemispheres, and H (tan, top) represents the hemispheres themselves. There is a large and constant flow of information from the senses (bottom right) to C. This information is then analysed and used to support behaviour of the muscles (bottom left). James describes this basic biological layout as the "direct line". He then describes the hemispheres as adding a "long circuit" or "loop-line" "through which the [nervous] current may pass when for any reason the direct line is not used" (p21). We show the direct line as solid black lines, red arrowed, and the loop-line as dotted black lines, blue arrowed. James provided this diagram in an introductory context, so it does not pretend to be a precise engineering blueprint, merely an attempt to convey a complex principle as vividly as possible to newcomers to the subject. He therefore chose not to differentiate between higher (brainstem) and lower (spinal) reflex levels, which must both be seen as functions of Circle C.

If this diagram fails to load automatically, it may be accessed separately at



Redrawn from a black and white original in James (1890:21, Figure 2). This version Copyright © 2002, Derek J. Smith.



James, W. (1890). The Principles of Psychology. New York: Holt.

Recommended Reading

"The Principles of Psychology"

James (1890/1995)

To see an abstract, or to order this book, click here

[James (1890)jacket]