Similarity, feature discovery, and the size principle

In this paper we consider the “size principle” for featural similarity, which states that rare features should be weighted more heavily than common features in people’s evaluations of the similarity between two entities. Specifically, it predicts that if a feature is possessed by n objects, the expected weight scales according to a 1/n law. One justification of the size principle emerges from a Bayesian analysis of simple induction problems (Tenenbaum and Griffiths, 2001a, Tenenbaum and Griffiths, 2001b), and is closely related to work by Shepard (1987) proposing universal laws for inductive generalization. In this article, we (1) show that the size principle can be more generally derived as an expression of a form of representational optimality, and (2) present analyses suggesting that across 11 different data sets in the domains of animals and artifacts, human judgments are in agreement with this law. A number of implications are discussed.

Weight scales for stress

Stress placement in words is often affected by syllable weight, stress being attracted to heavy syllables. Weight in such cases is usually binary (heavy vs. light) but often instantiates more complex scales. This chapter focuses especially on the phonological analysis of ternary and higher order scales, featuring case studies of several languages set in Optimality Theory. It argues that such scales must be analyzed in terms of vowel prominence rather than moraic coercion or coda prominence. The relation of geminates to stress also features prominently, as it is maintained that geminates can be analyzed as uniformly moraic for stress. Finally, several cases of gradient weight for stress are surveyed, including English. In these systems, stress placement responds statistically to weight, which manifests a fine-grained continuum rather than a simple categorical opposition and often includes onset and sonority effects.

Accessible Health Care: More Than Just Getting Through the Door

FEATURE AT A GLANCE: Access to health care requires more than mere access to a health care facility. It requires access to medical equipment and devices. Currently, many older adults and people with disabilities have difficulty accessing medical equipment, including examination chairs and tables, weight scales, and exercise and rehabilitation equipment. This article outlines the problem and its consequences for patients and describes the ergonomics requirements that must be met to ensure accessibility of this equipment for all patients.

Removing Barriers to Medical Devices for Users with Impairments

Accessing routine medical equipment is often difficult or impossible for many patients and providers with disabilities. We present a novel approach for conducting physical accessibility evaluations of some commonly used medical equipment, including an examination table, two dental chairs, two hospital beds, and two weight scales. Participants with various disabilities used each device while being recorded by three cameras; psychometric survey data were also collected to help us understand each participant's experiences. “Accessibility barrier” occurrences were documented using a novel task analysis method, and the results enabled us to illustrate key distinctions between accessibility and usability methodology. Using insights from the analysis, we provide suggestions to aid designers in improving the accessibility of commonly used medical equipment for users with disabilities.