Effects of forgetting on performance on various intensity scaling protocols: Magnitude estimation and labeled magnitude scale (green scale)

Judges rated the intensity of NaCl solutions using magnitude estimation and the labeled magnitude scale. They performed under four response conditions that varied in reliance on memory: (1) verbal response, (2) written response with no retasting and the response sheet removed, (3) written response with a single response sheet which allowed past scores to be reviewed and amended but with no retasting, (4) the same as '3' but with retasting. Discrimination errors tended to decrease from conditions '1' through '4', yet the major and significant effect was allowing judges to retaste stimuli. The effects of how forgetting lowered discrimination were discussed in the context of experimental design and the absolute versus relative cognitive models of scaling.