In the field of direct mind-machine interactions, prior art devices and methods do not provide sufficiently fast and reliable results. Mental influence detectors (100, 140, 400, 430) and corresponding methods provide fast and reliable results useful for detecting an influence of mind and hidden or classically non-inferable information. An anomalous effect detector (100) includes a source (104) of non-deterministic random numbers (110), a converter (114) to convert a property of numbers, a processor to accept converter output (118) and to produce an output signal (124) representative of an influence of mind. The processor output signal (124) contains fewer numbers than the input (110). A quantum computer (400) includes a physical source of entropy (404) to generate output numbers (405); a source (406) of test numbers (407); a measurement processor 410) to accept output numbers (405) and to measure a relationship between process numbers and at least one test number to produce an output (414) representative of an influence of mind.