Subject and experimenter errors in behavioral research with particular reference to motor behavior

Sources of error stemming from S and E and their interaction were identified, their prevalence in behavioral science research discussed, and means for eliminating or discounting them suggested. The findings reviewed indicated that E may bias his findings by indicating to S the demand characteristics of the experimental situation. S errors include such behavior as trying to be over-helpful, attempting to defeat E's intentions, and the Hawthorne effect. Errors from E may arise by transmitting subtle cues to S as to the hypothesized outcome of the experiment, E's various characteristics, situational factors, and intentional errors. The applicability of these errors to mo tor behavior research was discussed.