The ability to track the time-varying postures of our hands and the forces they exert plays a key role in our ability to dexterously interact with objects. However, how precisely and accurately we sense hand kinematics and kinetics has not been completely characterized. Furthermore, the dominant source of information about hand postures stems from muscle spindles, whose responses can also signal isometric force and are modulated by fusimotor input. As such, one might expect that changing the state of the muscles – for example, by applying a load – would influence perceived finger posture. To address these questions, we measure the acuity of human hand proprioception, investigate the interplay between kinematic and kinetic signals, and determine the extent to which actively and passively achieved postures are perceived differently. We find that angle and torque perception are highly precise; that loads imposed on the finger do not affect perceived joint angle; that joint angle does not affect perceived load; and that hand postures are perceived similarly whether they are achieved actively or passively. The independence of finger posture and load perception contrasts with their interdependence in the upper arm, likely reflecting the special functional importance of the hand.

Speech intelligibility involves integration of temporally and spectrally distributed acoustic information into higher-order perceptual categories to obtain individual words. In 1950, Miller and Licklider pioneered a simple but powerful method of interrupting speech that has been extensively used to investigate factors that make speech signals perceptually robust. Among numerous subsequent studies, a consistent finding has been a nonmonotonic relationship between intelligibility and interruption rate. As interruption rate increases, and the duration of speech fragments in each interruption cycle decreases, a U-shaped rate-intelligibility function with a dip around 1–5 Hz frequently emerges. While many factors (e.g., speech materials, task parameters, listener age, or hearing status) have been shown to influence performance at specific interruption rates, reasons for the appearance and location of the dip in the function have remained obscure. Previous work indicates that the location of the dip in the rate-intelligibility function can be altered predictably with changes in the temporal structure of the interrupted speech stream, and may vary with the duration of the corresponding perceptual units. These findings will be considered in the context of neurophysiological and information-processing models of interrupted speech, and used to suggest a framework to guide future research and practical applications.

Recognition of individual words is frequently used to investigate speech intelligibility and underlying perceptual processing. Traditionally, the majority of such studies in English have utilized monosyllabic and, on occasion, disyllabic words and spondees. Although multisyllabic words have been used extensively to investigate visual processing and lexical organization in reading, little research exists on the auditory perception of spoken multisyllabic English words. The present database was designed to provide materials to facilitate further research into the intelligibility and perceptual processing of spoken multisyllabic words. The database consists of five sections of 1–5 syllable words each. Individual words in each section were generated from the English Lexicon Project website. All words in the database were recorded by a male native speaker of American English, separated into individual word audio files and equalized in root-mean-square energy. Each syllable section contains 1125 words that vary in duration, frequency of occurrence and phonological neighborhood density. With a large number of words in each syllable section, shorter word lists can be selected from each section and matched on specific lexical characteristics. The database recordings are available free of charge for research purposes to improve understanding of perceptual processing of multisyllabic words.