Mental influence detectors and corresponding methods are useful for detecting an influence of mind and hidden or classically non-inferable information. An anomalous effect detector includes a source of non-deterministic random numbers, a converter to convert a property of numbers, a processor to accept converter output and to produce an output signal representative of an influence of mind. The processor output signal contains fewer numbers than the input. A quantum computer includes a physical source of entropy to generate output numbers; a source of test numbers; a measurement processor to accept output numbers and to measure a relationship between process numbers and at least one test number to produce an output representative of an influence of mind.