A Five-Person Marijuana Study Found Simple Motor Scores More Sensitive Than Complex Tasks
A 1975 study of five adults found dose-related performance impairment across its tests, with simple automatic motor measures showing greater sensitivity than more complex tasks. Complexity alone did not determine which test detected the larger effect.
The design used repeated measurements
Participants received graded smoked-marijuana doses and completed tests varying in cognitive involvement. Response speed was a central measure. Repeated observations within a small group can describe dose patterns but do not substitute for a large independent sample.
The task ranking challenged a simple assumption
The report found significant dose-response impairment across test scores, while automatic motor abilities were more sensitive than the more complex tests. It would be inaccurate to assume that the hardest-sounding task must always be the most sensitive drug test. Measurement range, task structure and practice can affect sensitivity.
Tolerance was reported without a detailed abstract account
The abstract states that evidence of tolerance was presented but does not supply a complete timeline or endpoint breakdown. No precise tolerance magnitude, individual recovery interval or mechanistic explanation can be responsibly added from that statement alone.
The experiment's useful contribution is a direct comparison of task sensitivity under graded exposure. Its five-person sample and historical smoking conditions sharply limit generalization. It cannot establish that a normal score on a complex task excludes impairment elsewhere or provide a personal safe-use threshold.
Related: interpreting cannabis tolerance claims.
Research cited
Borg J; Gershon S; Alpert M. Dose effects of smoked marihuana on human cognitive and motor functions. Psychopharmacologia (1975). doi:10.1007/BF00421258. Findings discussed from the study abstract.
