The secret of quick thinking: The invention of mental speed in America, 1890–1925

In the early 20th century, mental speed became a dominant measure of intelligence in the United States. For both cultural and technical reasons, this had not always been the case. For 19th-century Americans, quickness of speech and thought often signified lack of self-discipline. Unlike with other objects of temporal measurement and rationalization such as factory work, little scientific or popular consensus existed over how to clock the invisible phenomenon of thought. The cultural and scientific ascent of mental speed thus poses an unsolved historical problem: how and why did Americans adopt this new ideal of intelligence? This essay offers an answer in the introduction and popularization of a new and controversial practice: the timed test. The first timed tests did not so much formalize an existing conception of mental efficiency as establish a new one, using one of the key tools of measurement available to experimental psychology, the mechanical time-keeper. Initially frustrated in their efforts to correlate their subjects' laboratory-measured reaction time with socially recognized achievements such as academic grades, psychologists in the late 1890s borrowed a still-obscure concept from stenography and telegraphy: words per minute. At first, few scientists or members of the public equated reading, speaking, writing, and listening rate with intelligence. Only after American educators, military recruiters, and vocational guidance experts began to adopt timed testing in the 1910s for administrative convenience did mental speed begin to indicate intelligence and knowledge. What began as a way to test minds efficiently evolved almost inadvertently into a test of their efficiency.

Virtual Reality Training Improves Real-World Performance on a Speeded Task

We investigated whether virtual reality (VR) training transfers to real-world performance. Participants were trained to complete a real-world maze task, which involved quickly moving an object through a tabletop maze without hitting the maze walls. Participants either trained in VR, trained by physically simulating the task (PS), or received no training (NT). After five timed training trials (or no training in the control condition), participants completed five timed test trials using the real-world maze. The VR training condition completed the maze significantly faster than the other conditions across each test trial. Other than the initial test trial where the NT condition was the slowest, the PS and NT conditions were comparable on the remaining test trials. These results suggest that VR provided trainees with an opportunity for meaningful encoding of the task, beyond the act of physically simulating the motions of the task.

Apathy and Reduced Speed of Processing Underlie Decline in Verbal Fluency following DBS

Objective. Reduced verbal fluency is a strikingly uniform finding following deep brain stimulation (DBS) for Parkinson’s disease (PD). The precise cognitive mechanism underlying this reduction remains unclear, but theories have suggested reduced motivation, linguistic skill, and/or executive function. It is of note, however, that previous reports have failed to consider the potential role of any changes in speed of processing. Thus, the aim of this study was to examine verbal fluency changes with a particular focus on the role of cognitive speed.Method. In this study, 28 patients with PD completed measures of verbal fluency, motivation, language, executive functioning, and speed of processing, before and after DBS.Results. As expected, there was a marked decline in verbal fluency but also in a timed test of executive functions and two measures of speed of processing. Verbal fluency decline was associated with markers of linguistic and executive functioning, but not after speed of processing was statistically controlled for. In contrast, greater decline in verbal fluency was associated with higher levels of apathy at baseline, which was not associated with changes in cognitive speed.Discussion. Reduced generativity and processing speed may account for the marked reduction in verbal fluency commonly observed following DBS.