In the fall 2007 issue of the American Journal of Psychology, an article by Roger Thomas (U. Georgia) presented the cases of five erroneous stories that frequently appear in history of psychology textbooks. The episodes included (1) what Santayana really said about people who don’t know the past, (2) the events surrounding Pavlov’s mugging in New York in 1923, (3) Broca’s 1861 “discovery” of a speech center in the brain, (4) the misrepresentation of Morgan’s canon, and (5) the reasons Descartes gave for locating the soul in the pineal gland.

The first of these, although a relatively minor error, is particularly ironic in the context. Thomas found that textbooks by Hergenhahn and by Thorne and Henley identically attributed to Santayana the claim, “Those who do not know history are doomed to repeat it.” In fact, what the Harvard philosopher said in the first volume of Life of Reason (1905) was “Those who cannot remember the past are condemned to repeat it.”

In the second, a wide array of textbooks seem to repeat a version of the story of Pavlov’s mugging in which he laid his wallet beside him on a seat at New York’s Grand Central Station and, upon discovering it missing after an extended intellectual reverie, philosophically mused “one must not put temptation in the way of the needy.” In fact, according to the contemporary New York Times account of the event, Pavlov and his son were confronted by a three men after having boarded a train and had their money forcibly taken from them.

In the third instance, although it is true that Paul Broca presented his findings with respect to the brain of a patient, “Tan” (whose actual name was LeBourgne) to an 1861 meeting of the Paris Anthropological Society, the theory he was attempting to confirm in his report had been articulated by Ernest Auburtin and Jean-Baptiste Bouillaud earlier in the year. Although one might quibble whether credit for the “discovery” should go the person who developed the theory or the person who presented the first widely-accepted evidence of it, Broca himself gave credit to gave full credit to Bouillaud. It was later writers who named the relevant portion of the left frontal lobe “Broca’s Area.” Thomas notes that author of textbooks in the history of neuroscience are typically more judicious in their attribution of credit here than are authors of textbooks in the history of psychology.

In the fourth case, Morgan’s canon is usually represented by the passage, “in no case may we interpret an action as the outcome of the exercise of a higher psychical faculty, if it can be interpreted as the outcome of the exercise of one which stands lower in the psychological scale.” Thomas argues, however, that this has “long been misrepresented as psychology’s special case of the law of parsimony, Ockham’s razor,” and as “expressing Morgan’s opposition to anthropomorphism.” On the contrary, Thomas notes, Morgan himself wrote that “we do not know enough about the causes of variation to be rigidly bound by the law of parcimony [sic]” and that it may be “simpler to explain the higher activities of animals as the direct outcome of reason or intellectual thought, than to explain them as the complex results of mere intelligence or practical sense experience.”

In the final situation, it appears that a variety of distorted and false reasons are attributed to René Descartes for having selected the pineal gland as the seat of the soul. First among these is that the structure is uniquely human, which not only was not cited by Descartes, but is false and would have been known to be so by Descartes. A second is that the pineal gland lies at the base of the brain. A third erroneous claim by some authors (though not one attributed to Descartes) is that the pineal gland is now known to be a “vestigial” organ of no functional significance.

In addition to the value inherent in correcting the errors themselves, Thomas’ article serves as an important case study in how textbook authors appear sometimes to copy each other, rather than checking primary sources, thereby allowing false “facts” and questionable interpretations to reverberate around the educational literature for decades at a time.

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Thomas, R. K. (2007). Recurring errors among recent history of psychology textbooks. American Journal of Psychology, 120, 477-495.