An exploratory study concerned with the measurement of perseveration, or persistence, as a personality variable was based on the work of G.V. Hamilton, an early investigator in the field. Persistently maladaptive behavior was hypothesized to be a chief characteristic of neurosis. An experimental problem-solving situation was designed to demonstrate how neurotic reaction tendencies could be clinically diagnosed through measurement of perseveration. Subjects were presented with an insoluble nonverbal problem. Because the problem was insoluble, persistent attempts to solve it represented neurotic behavior. Results indicated that 75% of the subjects attempted 45 or fewer trials, while less than 20% attempted more than 50 trials, a statistic indicative of neurotic behavior. The instrument, procedures and concepts of this study may be of direct value in the clinical identification of neurosis, but much more experimental work is needed to evaluate their utility. (CS)