Simulating a skilled typist: a study of skilled cognitive-motor performance

We review the major phenomena of skilled typing and propose a model for the control of the hands and fingers during typing. The model is based upon an Activation-Trigger-Schema system in which a hierarchical structure of schemata directs the selection of the letters to be typed and, then, controls the hand and finger movements by a cooperative, relaxation algorithm. The interactions of the patterns of activation and inhibition among the schemata determine the temporal ordering for launching the keystrokes. To account for the phenomena of doubling errors, the model has only “type” schemata—no “token” schemata—with only a weak binding between the special schema that signals a doubling, and its argument. The model exists as a working computer simulation and produces an output display of the hands and fingers moving over the keyboard. It reproduces some of the major phenomena of typing, including the interkeystroke interval times, the pattern of transposition errors found in skilled typists, and doubling errors. Although the model is clearly inadequate or wrong in some of its features and assumptions, it serves as a useful first approximation for the understanding of skilled typing.     

Impairment of voice and face recognition in patients with hemispheric damage

Voice and face recognition were tested in 21 left- and 9 right-hemisphere-damaged patients. Test materials were photographs and recordings of famous political and entertainment personalities. Pathological face recognition (prosopagnosia) and voice recognition (phonagnosia) were both significantly more prevalent in the right-hemisphere group. Only one instance of prosopagnosia and one of phonagnosia were observed in the left-hemisphere group, all of whom were aphasic. Of the right-hemisphere cases, there were four instances of each agnosia, with three patients showing a dual impairment. These findings are discussed in relation to differential modes of processing by the two cerebral hemispheres.     

Literal meaning and psychological theory

This paper evaluates the psychological status of literal meaning. Most linguistic and philosophical theories assume that sentences have well-specified literal meanings which represent the meaning of a sentence independent of context. Recent debate on this issue has centered on whether literal meaning can be equated with context-free meaning, or whether a sentence's literal meaning is determined only given a set of background assumptions. Neither of these positions meet the demands of a psychological theory of language understanding. Sentences do not have well-defined literal meanings, regardless of whether these are determined in light of a set of background assumptions. Moreover, the putative literal meanings of sentences do not contribute in systematic ways toward the understanding of speakers' utterance meanings. These observations suggest that the distinctions between literal and metaphoric meanings, and between semantics and pragmatics, have little psychological validity.