Figure 4.

Bernoulli values at all levels of severity for five selected sentence structures, as computed for the Pr-C metric (top row), Mx-S metric (middle row), and Pr-S metric (bottom row). The five sentence structures included here are active voice (black), subject clefts (blue), passive voice (purple), subject–object relative (red), and subject–subject relative (green). The panels in the left column show the Bernoulli values derived with the assumption that subjects never apply an Agent–Theme heuristic. The middle and right columns show the Bernoulli values if subjects always accept a heuristically generated interpretation whenever syntax fails. The values in the middle column were computed with the assumption that aphasia does not degrade the patient’s ability to apply the heuristic (impervious heuristic). Those in the right column were computed with the assumption that aphasia degrades heuristic skills to a degree proportional to the severity of the aphasia (vulnerable heuristic).