Constancy of individual exponents for category production of inspired lung volume

Individual exponents for production of inspired lung volume were compared both within experimental sessions (after a delay of 5 to 10 min.) and between sessions (after a delay of 1 yr.). Reliable correlations were observed between pairs of individual exponents regardless of the time elapsed between repetitions of the task. Constancy of exponents may reflect a propensity for subjects to respond in characteristic ways to psychophysical scaling tasks.