The Muscle-Readers, a Historical Sketch

Abstract

The notion that subtle nonverbal cues play an important role in social interaction is relatively uncontroversial. What the upper bounds of this capacity might be, however—how much and what kind of information can be conveyed through these channels—remains unclear and, at present, under-explored. In the present work, we consider possible answers to the question and ways in which it could be addressed by considering an historical line of investigation known as muscle reading. Spurred by public interest in mentalism and the specific popularity of thought-readers, researchers in the late 19th and early 20th centuries began investigating the possibility that information about our thoughts and inclinations could be “read” from muscle tension, unconscious vocalizations, and other subtle cues. While covering some of the same ground as contemporary research on nonverbal communication, the literature of this era contains many reports that go well beyond this. Feats such as locating a hidden object, guessing the suit of a card, and determining words or names held in another’s mind were said to be achieved in controlled conditions or by academic researchers themselves. In some cases, subtle but telling movements were also said to be captured by early biometric apparatuses. While we believe that such claims should be interpreted with caution, we contend that the reports of these early researchers should not be dismissed merely because of their age and that a better understanding of this literature offers important leads for investigators today.