Two Thurstonian theories, designed to account for the adverse effect of increased
signal range on absolute identification, were contrasted and tested. The range
theory of Braida and Durlach partitions the variance underlying the d′ perfor-
mance measure into a sensory term, which is assumed to be unaffected by signal
range, and a criterial term, which is affected by it. The attention-band theory of
Green and Luce assumes that the signal representation arises from a distribution
with either a small or a large variance depending upon whether or not it happens
to fall within the band. It attributes the effect of range to changes in the proba-
bility that signals fall in the band. In addition, they suggested that the band
location is affected by two tendencies: to be at the ends of the signal range, which
accounts for edge effects in the data, and to track the previous signal, which
accounts for sequential effects. They placed no emphasis on criterion effects.

Examination of data from a number of experiments leads to several conclu-
sions about these theories. An analysis in terms of the Braida-Durlach framework
of a multiple-observation AI experiment showed range to affect both sensory and
criterion variance. This suggests that both theories are incorrect, the one for
assuming range does not affect the sensory component and the other for assum-
ing that it does not affect the criterion component. Detailed sequential analyses
make clear that the major component of the one-trial sequential effects is system-
atic shifts in response criteria, not changes in sensitivity as had been postulated in
the original version of the attention-band model. The band does not track signals
on a trial-by-trial basis. Nonetheless, a number of experiments all based upon
some form of clustering of signals to attract attention make clear that sizable
changes in sensitivity can be produced. It appears that attention is drawn in a
somewhat sluggish fashion to the region where "the action is," but it is not
drawn there in a single trial. Among these studies were ones in which the range,
spacing, and distribution of signals were the same as in the usual random design,
and the clustering was effected by means of sequential dependencies in the
presentation schedule. Pronounced changes in d′ were in accord with the atten-
tion idea, but inconsistent with the range theory since range was not changed.

Berliner J. E., & Durlach N. I. "Intensity perception. IV. Resolution in roving-level discrimination".
Journal of the Acoustical Society of America, 1973, 53, 1270-1287.

Braida L. D., & Durlach N. I. "Intensity perception. II. Resolution in one-interval paradigms".
Journal of the Acoustical Society of America, 1972, 51, 483-502.

Chase S., Bugnacki P., Braida L. D., & Durlach N. I. "Intensity perception. XII. Effect of
presentation probability on absolute identification". Journal of the Acoustical Society of America,
1983, 73, 279 - 284.

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