Abstract
People with aphasia demonstrate language impairments evident in both performance accuracy
and processing speed, but the direct relationship between accuracy and speed requires
further consideration. This article describes two recent attempts to make quantitative
progress in this domain using response time modeling: the diffusion model (Ratcliff,
1978) applied to two-choice tasks and a multinomial ex-Gaussian model applied to picture
naming. The diffusion model may be used to characterize core linguistic processing
efficiency and speed–accuracy tradeoffs independently, and research suggests that
maladaptive speed–accuracy tradeoffs lead to performance impairments in at least some
people with aphasia. The multinomial ex-Gaussian response time model of picture naming
provides a simple and straightforward way to estimate the optimal response time cutoffs
for individual people with aphasia (i.e., the cutoff where additional time is unlikely
to lead to a correct response). While response time modeling applied to aphasia research
is at an early stage of development, both the diffusion model and multinomial ex-Gaussian
response time model of picture naming show promise and should be further developed
in future work. This article also provides preliminary recommendations for clinicians
regarding how to conceptualize, identify, and potentially address maladaptive speed–accuracy
tradeoffs for people with aphasia.
Keywords
speed–accuracy tradeoff - response time modeling - aphasia - anomia
