Mark May

Imaginal Perspective Switches in Remembered Environments: Transformation versus Interference Accounts.

Imaginal perspective switches are often considered to be difficult, because they call for additional cognitive transformations of object coordinates (transformation hypothesis). Recent research suggests that problems can also result from conflicts between incompatible sensorimotor and cognitive object location codes during response specification and selection (interference hypothesis). Three experiments tested contrasting predictions of both accounts. Volunteers had to point to unseen object locations after imagined self-rotations and self-translations. Results revealed larger pointing latencies and errors for rotations as compared to translations, and monotic latency and error increases for both tasks as a function of the disparity of object directions between real and imagined perspective. Provision of advance information about the to-be-imagined perspective left both effects unchanged. These results, together with those from a systematic error analysis, deliver clear support for an interference account of imaginal perspective switches in remembered surroundings.

Homing in Virtual Environments: Effects of Field of View and Path Layout

Triangle completion (ie homing to the starting point after completing two legs of a triangle) is a widely used method for examining path-integration abilities in animals and humans. Two experiments are reported in which homing was used to examine the efficiency of purely visual mechanisms (eg optical flow) for spatial-information coding and integration. Adult observers had to complete triangles in an interactively simulated three-dimensional environment which consisted of two critical objects and a homogeneous set of white cylinders serving as background. Each participant completed twenty-seven triangles corresponding to a factorial combination of three geometrical fields of view (40°, 60°, or 80°) and nine triangle layouts (with variations of the first turning angle and the second leg). Homing performances revealed strong effects of triangle layout, but no effect of geometrical fields of view: variations in the amount of simultaneous visible spatial information did not influence the acquisition of spatial knowledge in the environments used. Applying the encoding-error model to the data revealed severe systematic errors of picking up directional information while moving through visually simulated environments. These results are discussed with respect to informational differences between situations of purely visual and nonvisual navigations in space.

Path integration while ignoring irrelevant movement.

Participants attempted to return to the origin of travel after following an outbound path by locomotion on foot (Experiments 1-3) or in a virtual visual environment (Experiment 4). Critical conditions interrupted the outbound path with verbal distraction or irrelevant, to-be-ignored movements. Irrelevant movement, real or virtual, had greater effects than verbal or cognitive distraction, indicating inability to ignore displacement during path integration. Effects of the irrelevant movements direction (backward vs. rightward) and location (1st vs. 2nd leg of path) indicated that participants encoded a configural representation of the pathway and then cognitively compensated for the movement, producing errors directly related to the demands of compensation. An encoding-error model fit to the data indicated that backward movement produced downward rescaling, whereas movement that led to implied rotation (rightward on 2nd leg) produced distortions of shape and scale.

Visual perspective taking and laterality decisions: Problems and possible solutions.

Perspective taking plays an important role in different areas of psychological and neuroscientific research. Visual perspective taking is an especially prominent approach generally using one of two experimental tasks: in the own-body-transformation task observers are asked to judge the laterality of a salient feature of a human figure (e.g., is the glove on the left or right hand?) from the figure’s perspective. In the avatar-in-scene task they decide about the laterality of objects in a scene (e.g., is the flower on the left or right?) from the avatar’s point of view. Increases in latencies and/or errors are interpreted as originating from additional cognitive processes predominately described as observer-based perspective transformations. A closer look reveals that such an account is disputable on grounds related to the use of laterality judgments. Other transformation accounts, i.e., object or array transformations, as well as non-transformational accounts, i.e., extra processing due to spatial conflicts, have not been adequately considered, tested, or ruled out by existing research. Our review examines visual perspective tasks in detail, identifies problems and makes recommendations for future research.

Separating mental transformations and spatial compatibility effects in the own body transformation task

Laterality judgments about the left or right hand of a schematic human figure, made from the perspective of the figure, are faster and more accurate when the figure is presented in back-facing view as compared to front-facing view. Mental perspective transformation accounts of this finding have recently been challenged on grounds of a confounding of facing direction with spatial stimulus–response (S-R) compatibility (Gardner and Potts in Acta Psychol 137: 371–381, 2011). We report two experiments that introduced stimulus figures in an orientation that was neutral in terms of spatial S-R compatibility. Results revealed a stable back-facing advantage that cannot be explained by compatibility conflicts. Comparisons of these neutral stimuli and conditions with figures presented in upright or upside-down orientation, however, confirmed a substantial impact of spatial S-R compatibility in the latter conditions. The present experiments show that it is possible to distinguish between mental transformation and incompatibility costs allowing future work to focus on the specialized mental spatial transformation processes.

Spatial Orientation in Virtual Environments: Background Considerations and Experiments

Spatial orientation strongly relies on visual and whole-body information available while moving through space. As virtual environments allow to isolate the contribution of visual information from the contribution of whole-body information, they are an attractive methodological means to investigate the role of visual information for spatial orientation. Using an elementary spatial orientation task (triangle completion) in a simple virtual environment we studied the effect of amount of simultaneously available visual information (geometric field of view) and triangle layout on the integration and uptake of directional (turn) and distance information under visual simulation conditions. While the amount of simultaneously available visual information had no effect on homing errors, triangle layout substantially affected homing errors. Further analysis of the observed homing errors by means of an Encoding Error Model revealed that subjects navigating under visual simulation conditions had problems in accurately taking up and representing directional (turn) information, an effect which was not observed in experiments reported in the literature from similar whole-body conditions. Implications and prospects for investigating spatial orientation by means of virtual environments are discussed considering the present experiments as well as other work on spatial cognition using virtual environments.

Functional role theories of representation and content explanation: with a case study from spatial cognition

The aim of this paper is to show that the widespread opinion, according to which functional role theories of representation fail to account for content explanations of human and animal behaviour, cannot be confirmed with respect to each type of functional role theory. Functional resemblance theories (as referred to by O’Brien and Opie in Representation in mind, Elsevier, 2004) allow for content explanations of successfully performed cognitive abilities as much as for explanations of systematic errors resulting from misrepresentation. How functional roles do their explanatory work in actual scientific research examples is shown by a detailed exploration of model assumptions about homing performances based on path integration mechanisms in humans and animals.

What a Theory of Knowledge-How Should Explain - A Framework for Practical Knowledge beyond Intellectualism and Anti-Intellectualism

We argue against both intellectualist and anti-intellectualist approaches to knowledge-how. Whereas intellectualist approaches are right in denying that knowledge-how can be convincingly demarcated from knowledge-that by its supposed non-propositional nature (as is assumed by the anti-intellectualists), they fail to provide positive accounts of the obvious phenomenological and empirical peculiarities that make knowledge-how distinct from knowledge-that. In contrast to the intellectualist position, we provide a minimal notion of conceptuality as an alternative demarcation criterion. We suggest that conceptuality gives a sound basis for a theory of knowledge-how which is empirically fruitful and suitable for further empirical research. We give support to this suggestion by showing that, by means of an adequate notion of conceptuality, five central peculiarities of knowledge-how as compared to knowledge-that can be accounted for. These peculiarities are its context-bound, impenetrable and implicit nature, as well as the automatic and continuous forms of processing that are connected to it.

Preparing the Ground for an Empirical Theory of Knowing-How

The commentary gives a clear and instructive summary of our main arguments against both, intellectualist and anti-intellectualist accounts of knowing-how. But the aim of our account is not correctly described as an attempt to give an explanation of certain cognitive capacities that are taken to be expressions of knowledge-how in terms of underlying mental representations. ( Glauer this collection , p.10). What we aim at is not an empirical theory of knowing-how, but a framework that would be useful for cognitive scientific research on phenomena of knowing-how.