In this article, we focus on the definition and application of the sliding scale of capacity. We show that the current interpretations of the sliding scale confound distinct features of the medical decision, such as its urgency, its severity, or its complexity, that do not always covary. We propose that the threshold for assessing capacity should be adjusted based solely on the cognitive complexity of the decision at hand. We further suggest that the complexity of a decision should be identified based on a patient’s particular cognitive deficits. We utilize the current research on the types of deficits that characterize amnestic dementias and examine which types of medical decisions might be most complex for patients with that type of dementia. We conclude that applying the sliding scale based on individualized judgments of cognitive complexity will improve accuracy of assessment of capacity and enable capable patients to participate in medical decision making.

Endorsing the view that commonsense conceptions are shaped by scientific claims provides an explanation for why microbiota-gut-brain (MGB) research might become incorporated into commonsense notions of health. But scientific claims also shape notions of personal identity, which accounts for why they can become entrenched in common sense even after they have been refuted by science.