[3][4] The Coca-Cola Company, facing a lawsuit from the federal government under the Pure Food and Drug Act, approached Hollingworth (after James McKeen Cattell and several other psychologists turned them down)[5] about investigating the psychological effects of caffeine on humans.

Aware of the stigma associated with applied work, as well as possible concerns about the scientific integrity of research funded by a corporation, Hollingworth included several conditions in his contract with Coca-Cola.

Furthermore, to reduce any questions about the integrity of his research Hollingworth designed his three caffeine studies to include blind and double-blind conditions.

[3][4] These studies generated a huge amount of data which, because of Hollingworth’s “catastrophobia,” had to be duplicated following each night’s analysis and housed in a separate location.

Following Hollingworth’s testimony at the trial, and the favourable media coverage that accompanied it, he received an incredible number of requests for further applied work.

In the late 1930s Hollingworth returned to applied research as a favor to a friend, investigating the reasons why people chew gum.