ABSTRACT
Sensory thresholds are ill-defined in theory (Lawless and Heymann, 1998; Morrison, 1982). A good determination requires hundreds of comparisons with a control, and results do not reproduce well at all (Brown et al., 1978; Stevens et al., 1988; Marin et al., 1988).Published group thresholds (Fazzalari, 1978; Van Gemert et al., 1984; Devos et al., 1990)vary by a factor of 100 for quinine sulfate in water and by much more in complex systems. Swets (1964)doubts even the existence of a sensory threshold. One’s first reaction is that it is futile to invest time and money in threshold studies. However, in situations such as those described in the next paragraph, the threshold approach is still the best available.
