ABSTRACT
The psychophysical methods described for the detection task can be fairly directly adapted for the estimation of difference thresholds. A standard stimulus value is chosen together with a series of comparison or variable stimulus values ranging about the standard. Methods for estimating detection thresholds inevitably involve the use of a range of stimuli which are chosen to extend both above and below the threshold value. The main difference between the methods concerns the way in which the different stimulus values are presented to the observer. The task may require the subject to identify the stimulus although die term 'recognition' is used quite commonly. Recognition is reserved by some authorities to describe the situation where a limited set of alternatives is specified and known to the subject. An intriguing application of Signal detection theory (SDT) was reported by W. R. Clark and J. S. Goodman who set out to investigate the effect of instruction on the detection of pain.
