David H. Warren

Contributions of audition and vision to temporal rate perception.

Two experiments demonstrated that when both vision and audition are providing information about temporal rates in the range of 4 to 10 Hz, audition has a much stronger influence on the bimodal percept than does vision. This case of auditory “dominance” over vision was shown to be neither the result of a difference between the sensory modalities in perceived intensity nor all artifact of the magnitude estimation procedure used by the subject to indicate perceived rate. It was concluded that these results provide support for a “modality appropriateness” hypothesis of the relative contribution of various sensory modalities in multimodal perception.

The role of visual-auditory “compellingness” in the ventriloquism effect: Implications for transitivity among the spatial senses

A magnitude estimation response procedure was used to evaluate the strength of visualauditory intersensory bias effects under conditions of spatial discrepancy. Maj or variables were the cognitive compellingness of the stimulus situation and instructions as to the unity or duality of the perceptual event. With a highly compelling stimulus situation and single-event instructions, subjects showed a very high visual bias of audition, a significant auditory bias of vision, and a sum of bias effects that indicated that their perception was fully consonant with the assumption of a single perceptual event. This finding reopens the possibility that the spatial modalities function as a transitive system, an outcome that Pick, Warren, and Hay (1969) had expected but did not obtain. Furthermore, the results support the model for intersensory interaction proposed by Welch and Warren (1980) with respect to the susceptibility of intersensory bias effects to several independent variables. Finally, a new means of assessing intersensory bias effects by the use of spatial separation threshold was demonstrated.

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.

Intermodality relations in localization in blind and sighted people

Developmental data were gathered on the relative importance of vision, audition, and proprioception in determining spatial direction in a conflict situation. Age trends did not support the hypothesis that information from different modalities becomes better differentiated with age. In a follow-up study, blind children of different ages were tested under auditory-proprioceptive conflict conditions. No age changes were found. The possibility of a visual involvement in auditory and proprioceptive localization is discussed.

An examination of the relationship between visual capture and prism adaptation

The phenomena of prismatically induced “visual capture” and adaptation of the hand were compared. In Experiment 1, it was demonstrated that when the subject’s hand was transported for him by the experimenter (passive movement) immediately preceding the measure of visual capture, the magnitude of the immediate shift in felt limb position (visual capture) was enhanced relative to when the subject moved the hand himself (active movement). In Experiment 2, where the dependent measure was adaptation of the prism-exposed hand, the opposite effect was produced by the active/passive manipulation. It appears, then, that different processes operate to produce visual capture and adaptation. It was speculated that visual capture represents an immediate weighting of visual over proprioceptive input as a result of the greater precision of vision and/or the subject’s tendency to direct his attention more heavily to this modality. In contrast, prism adaptation is probably a recalibration of felt limb position in the direction of vision, induced by the presence of a registered discordance between visual and proprioceptive inputs.

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.

Auditory localization: The importance of eye movements and a textured visual environment

Two experiments were designed to investigate the factors involved in the visual facilitation of auditory localization. In both experiments, adult human Ss pointed to targets in a variety of visual conditions. The results of the first experiment showed that target-directed eye movements were important. In the second experiment, eye localization was assessed, along with pointing localization. Both eye and hand localization of the hidden auditory targets were better when target-directed eye movements were made in a lighted environment than when made in the dark. Data also suggested that Ss have better knowledge of their eye position in the light. Possible mechanisms for the involvement of eye movements were suggested, and the theoretical importance of the results was discussed.

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 the VP conflict situations are discussed with regard to the feasibility of generating a unitary explanation of localization conflict results. Several further factors are discussed that must be explored before undertaking such a unitary formulation.

Map Alignment in Traveling Multisegment Routes

Two hypotheses were based on previous research with simple path maps and you-are-here maps. First, when given a choice, observers prefer to align a map with the environment that it represents; second, performance on way finding tasks is better when the map is aligned than when it is not aligned with the environment. This latter phenomenon is called the map alignment effect. Both hypotheses were strongly supported in two experiments conducted in a relatively structured environment using four-segment paths. A third experiment was conducted in a larger, wooded, hilly environment. The observers carried the map and consulted it at will while finding a route from a starting point to a goal. In this setting, both hypotheses again found support. Observers did not consult the map at every turn, but when they did, they turned the map into map/environment alignment on two thirds of the instances. Errors occurred with greater frequency when the map was not aligned with the environment. The generality of the map alignment effect was thus demonstrated for larger and more complex environments than have previously been studied and with more naturalistic map-use procedures than have been used. Finally, there was clear evidence that observers acquired incidental knowledge about the spatial structure of the environment while using a map to negotiate the environment, despite the fact that there was no explicit requirement to learn. Questions remain about the nature of the learning and retention of information so acquired.

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.