Harry McGurk

Visual influences on speech perception processes

An experiment is reported, the results of which confirm and extend an earlier observation that visual information for the speaker’s lip movements profoundly modifies the auditorv perception of natural speech by normally hearing subjects. The effect is most pronounced when there is auditory information for a bilabial utterance combined with visual information for a nonlabial utterance. However, the effect is also obtained with the reverse combination, although to a lesser extent. These findings are considered for their relevance to auditory theories of speech perception.

Pictorial Depth Perception in Scottish and Ghanaian Children, A Critique of Some Findings with the Hudson Test

Abstract Published research employing the Hudson Test is critically examined, leading to the conclusion that differences in methods and procedures make direct comparisons of the outcome of different studies inappropriate. Some limitations of the test itself are pointed out, in particular the ignoring of chance expectations, failure to exclude the operation of response sets, and ambiguities about the scoring. Tentative generalizations emerging from previous research are summarized, and the object of the study is to verify them. A newly developed test of three-dimensional perception is described, which also consists of pictures but requires less reliance upon verbal instructions. Samples of 60 Scottish and 60 Ghanaian primary school children in classes 2, 4 and 6 were tested with both the Hudson and the new test. While results still indicated a significant cultural difference in the performance on both tests, Ghanaian children experienced much less difficulty with the new test and the gap between them and S...

Pictorial Depth Perception by Children in Scotland and Ghana

An experimental study of the development of pictorial depth perception, conducted in Scotland and Ghana, is reported. Subjects constructed three-dimensional models representing the size and spatial relationships between figures in pictorial scenes in which three depth cues-elevation, texture gradient, and linear perspective-were manipulated. For both samples size accuracy increased with the amount of depth information available; it also increased with age in the Scottish but not in the Ghanaian sample. Spatial accuracy increased with age in both samples, but was influenced by type of depth cue only in the Scottish sample. Scottish children were more accurate throughout than Ghanaian children. However, the evidence reported does not support the view that African children are grossly deficient in perceiving pictorial depth.

Infant discrimination of orientation

Abstract Infants in four age groups—3, 6, 9 and 12 months—were exposed to an experimental procedure designed to assess the extent to which such subjects were capable of discriminating between different orientations of the same form, and the extent to which they were capable of recognizing the identity between different orientations of the same form. Results revealed that from at least as early as 6 months infants manifest both kinds of perceptual ability.

Utilization of static and kinetic information for depth by young Malaŵians.

The utilization of static and kinetic information for depth by Malaŵian children and young adults in making monocular relative size judgments was investigated. Subjects viewed pairs of objects or photographic slides of the same pairs and judged which was the larger of each pair. The sizes and positions of the objects were manipulated such that the more distant object subtended a visual angle equal to, 80% of, or 70% of the nearer object. Motor parallax information was manipulated by allowing or preventing head movement. All subjects displayed sensitivity to static information for depth when the two objects subtended equal visual angles. When the more distant object was larger but subtended a smaller visual angle than the nearer object, subjects tended to base their judgments on retinal size. Motion parallax information increased accuracy of judgments of three-dimensional displays but reduced accuracy of judgments of pictorial displays. Comparisons are made between these results and those for American subjects.

A developmental study of the acquisition of colour terms in Setswana

We report a study of the acquisition of colour terms by speakers of Setswana, the language of Botswana in Southern Africa. This was carried out as a test of Berlin & Kays theory of colour term universals, on a language with less than the maximum complement of eleven basic colour terms, and in order to document changes in Setswana under the impact of economic development. Seventy-seven five- to nine-year-olds were studied on two colour tasks: elicited lists and colour naming. In general the data were consistent with Berlin & Kays theory: the rank order of frequency of correct use of colour terms was similar to the order of the Berlin & Kay hierarchy; and primary colour terms were offered more frequently and were more likely to be used correctly than secondary colour terms. The use of English colour terms was prevalent, especially amongst the younger groups, but they functioned as substitutes for Setswana terms, rather than as a means to fill the vacant basic colour term slots.

Linguistic Basicness and Colour Information Processing

Abstract Berlin and Kays notion of basicness was defined by a combination of linguistic and psychological criteria. but they suggested that the psychological criteria might be extended. The experiments reported here were designed to explore a possible extension by searching for perceptual effects of basicness. Russian speakers who have two basic terms for the blue region of colour space were compared with English speakers who have only one basic term for the same region on two perceptual tasks. The first two experiments sought for greater Stroop interference for the Russians than for the English for the critical “blue” stimuli, and the third experiment sought greater perceptual differentiation for the Russians in the blue region. All experiments clearly replicated standard findings, but all singularly failed to find the predicted differences between the two groups. It is argued that whilst the results are consistent with there being no psychological effect of basicness, it is necessary to search for poss...

Auditory-Visual Coordination in the First Year of Life

Two competing hypotheses concerning the nature of inter-modal development are outlined. The first sees the development proceeding from a state of discrete, independent sensory systems towards integration and synthesis between modalities. This is contrasted with a second viewpoint in which the early responsiveness of the organism is seen as a-modal and the developmental sequence as one of increasing sensory differentiation. A number of studies which have investigated auditory-visual co-ordination in young human infants, are reviewed. It is concluded that the data support the notion of ontogenetic development being a process of integration between sensory systems that are initially relatively independent.

A simple procedure for accurately manipulating face-voice synchrony when dubbing speech onto videotape

A system is described involving an audio-video tape recorder, a control device, and a delay timer that dubs speech sounds onto prerecorded lip movements on videotape. Accuracy of synchrony or measured asynchrony between the sound and lip movements is a few milliseconds.

Some Methodological Issues in Developmental Research

Developmental psychology can be defined as the systematic study of mental and behavioural development in humans. Its concern is to understand those changes in ability and behaviour which are associated with increasing age. The task of the developmental psychologist, therefore, is to specify the nature of the psychological processes underlying age-related changes in ability and behaviour. The task, in effect, is a twofold one: firstly, to identify and describe developmental phenomena—changes in behaviour occurring along the dimension of age—and, secondly, to provide an explanatory account of the phenomena thus identified. It bears stressing in this context that age itself cannot be regarded as an explanatory variable; growing older does not cause behavioural change. Ten-year-old children can do many things that five-year-olds cannot, but the explanation for this does not lie in the fact that the former are five years older than the latter. Chronological age is simply a convenient way of measuring the passage of time since birth, but the mere passage of time does not explain behavioural change. It is for this reason that age is sometimes referred to as a carrier or index variable, a dimension within which the processes which do cause behavioural development may be located. These processes—experiential, maturational, physiological—co-vary with increasing age simply because they require time in which to occur. Ultimately, however, explanations for developmental phenomena are sought in terms of the variables which moderate the course of the changes in ability and behaviour that are observed to take place with increasing age. It is with some of the methodological issues which arise in the study of age-related changes in behaviour that this chapter is concerned.