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Biomedical subjects

D H Warren

Publications and source records attributed to D H Warren.

8 recordsLinked to original sources

Finding locations in the environment: the map as mediator.

When an observer (O) uses a map (M) whose orientation does not correspond to the orientation of the environment (E) in which performance occurs, substantial errors occur: these are called map alignment effects. Much of the prior research on map/environment (M/E) alignment has involved maps of simple paths, although alignment effects have also been demonstrated for you-are-here (YAH) maps. A study is reported in which simple YAH maps were used to test the hypothesis that errors with misaligned maps would fall into categories predictable from the application of inappropriate cognitive operations to the misaligned maps, as demonstrated earlier by Rossano and Warren. Further, performance under conditions of M/E misalignment was compared with performance under map/observer (M/O) misalignment, the situation in which the map is sideways or upside-down with respect to the observer. The major hypothesis was supported: predictable errors occurred under conditions of M/E misalignment. Errors under conditions of M/O misalignment were significantly smaller. Furthermore, when given the choice of using M/E or M/O alignment, each at the expense of the other, the overwhelming choice was to retain M/E rather than M/O alignment. This pattern of results occurred even when environmental features were represented by words rather than by lines and shapes on the map. The results underscore the robustness of map alignment effects.

Adult

Misaligned maps lead to predictable errors.

Three experiments were conducted to investigate the ability of subjects to make judgments of direction when using misaligned maps. Two hypotheses were proposed (i) errors would fall into two lawful categories--mirror-image errors and alignment errors; (ii) the effect of map orientation would generalize to a different mode of responding than has been used in previous studies. Support for both hypotheses was obtained. The results are discussed in terms of the mental processes used to align maps to spaces, and the task demands required by different response modes.

Adult

The importance of alignment in blind subjects' use of tactual maps.

An experiment was conducted to test for the presence of alignment effects (previously found in sighted map users) in blind and visually impaired subjects using tactual maps. The term 'alignment effects' refers to the fact that when points represented as further up on a map do not correspond to points forward from the user in the environment, errors in the directional judgments made by subjects are greatly increased. The results show that alignment effects do exist in blind and visually impaired map users. Blind subjects encoded maps using the 'up equals forward' rule, and demonstrated some similarity to sighted subjects in the types of errors made. There was also some indication of improved performance over repeated trials. Differences between blind and sighted subjects were also found and were tentatively attributed to visual experience with object transformations and/or representational variables. Subject background variables were also investigated and some relationships between background of the subject and performance were drawn.

Adult

Spatial localization under conflict conditions: is there a single explanation?

Visual--auditory (VA) and visual--proprioceptive (VP) localization conflict paradigms were varied to explore the comparability of the conflict situations. In experiment 1 various attempts were made to decrease the dominance of visual information over proprioceptive and auditory target information. Pairing auditory with proprioceptive information against conflicting visual information did not lessen the visual dominance, nor did dimming the visual field. A 'cognitive' manipulation, in which the subject was led to doubt the reliability of the visual information, reduced visual dominance over audition but not visual dominance over proprioception. This difference between the two conflict situations was further explored and corroborated in experiment 2. In experiment 3 no attempt was made to lead the subject to believe that paired discrepant targets were related, and the visual dominance of audition was strong while the visual dominance of proprioception did not occur. The apparent differences between the VA and VP conflict situations are discussed with regard to the feability of generating a unitary explanation of localization conflict results. Several further factors are discussed that must be explored before undertaking such a unitary formulation.

Cognition

On the plasticity of visual-proprioceptive bias effects.

Recent research has suggested that attentional factors play a role in determining the direction of intermodality adaptation. The present work explored the role of such factors in the visual/proprioceptive dominance, or bias, paradigm. In a preliminary experiment, an instructional approach was used and proved totally ineffective in shifting dominance. In Experiments 1 and 2, an active pointing approach was used, in which the subject was caused to concentrate on one modality or the other by having him localize a large number of unconflicted targets in that modality. This approach was successful in changing the normal dominance relation. Such an altered dominance relation may indeed be a necessary part of the shifting of normal adaptation patterns.

Attention

Measures of visual-auditory integration and their relations to reading achievement in early grades.

Several tests of visual-auditory integration were designed to represent the various tasks that have been found to correlate with reading achievement in the early grades. The battery of tests was administered to about 100 first, 84 second, and 110 third graders. Several questions were posed: (1) Do the various tests of integration measure the same underlying ability or are there separate abilities that are tapped by the various tests? (2) Are the various tests correlated with reading because they tap a common integrative ability that is related to reading or are there several abilities, each related to reading independently to the others? (3) To what extent are the relationships between the integrative abilities and reading separate from the relationship between reading and IQ? Results indicated that there are separate integrative abilities, and multiple regression analyses showed that several of the integrative measures were correlated with reading independently of the other measures. Further, several of the integrative measures accounted for significant reading variance beyond that accounted for by IQ tests. The results were discussed in the context of the need to differentiate adequately between various patterns of perceptual weakness in the diagnosis and remediation of perceptually based reading difficulties.

Achievement