Inverting a face impairs perception of its features and recognition of its identity. Whether faces are special in this regard is a current topic of research and debate. Kanizsa studied the role of facial features and environmental context in perceiving the emotion and identity of upright and inverted faces. He found that observers are biased to interpret faces in a retinal coordinate frame, and that this bias is readily overruled by increased realism of facial features, but not easily overruled by (...) environmental context. An additional factor contributing to a retinal coordinate-frame interpretation may be the ambiguous nature of the face stimuli. Since his facial expressions are interpretable both upright and inverted, they may in both orientations activate an endogenous attentional process for faces. We present visual search and change-blindness experiments that explore how inversion, negation, and facial emotion affect visual attention to static faces. We find that attention to faces is impaired by inversion and negation. We also find that the parts of the face that receive greater attention can be influenced by the emotional expression of the face. We propose to extend these experiments to dynamic faces. To this end, we develop a theory of the visual representation of dynamic faces, in which faces are represented by classes of `spacetime fragments'-moving regions of the face with high informational content. We then present ideas for future experiments which are motivated by the spacetime fragment theory, and which should serve to constrain its further development. (shrink)

Descriptive metaphysics investigates our naïve ontology as this is articulated in the content of our perception or of our pre-reflective thought about the world. But is access to such content reliable? Sceptics about the standard modes of access (introspection, or language-driven intuitions) may think that investigations in descriptive metaphysics can be aided by the controlled findings of cognitive science. Cognitive scientists have studied a promising range of representational advantages, that is, ways in which cognition favours one type of entity over (...) another. The notion of representational advantage is investigated and some scepticism is expressed as to its appropriateness for use in descriptive metaphysics. (shrink)

What is the relation between Kanizsa's bias towards convexity and the Gestaltists' demonstrations that perceptual organization obeys a principle of pragnänz, or simplicity? Why should either kind of bias exist? Textbook accounts assign no functional role for these biases. Geon theory (Biederman 1987) proposes that we can understand these biases in terms of fundamental processes by which complex objects are decomposed into convex (or singly concave) regions at points of matched cusps according to the transversality regularity (Hoffman and Richards 1985). (...) Such decomposition yields simple, convex parts segmented between the concavities. A shape that contains concavities is generally regarded as complex insofar as it can be decomposed into the regions, or parts, between the concavities. It is these simple parts that are the stable elements of shape, not the whole object. In fact, geon theory leads to the expectation that shape recognition proceeds most efficiently when the parts are good (in the pragnänz sense) but the object is bad! (shrink)

A coin rotating back in depth in some sense presents a changing, elliptical shape. How are we to understand such (in this case) ‘appearances of ellipticality’? How is the experiential sense of such shifting shape appearances related to the experiential sense of enduring shape definitive of perceived shape constancy? Is the experiential recovery of surface shape based on the prior (perhaps more fundamental) recovery of point or element 3D spatial locations?—or is the perception of shape a largely independent perceptual achievement? (...) Do we gain access to enduring shape properties by first detecting and working from ‘shape appearances’? These are some of the topics taken up in this paper. (shrink)

Minor entities provide an interesting testbed for metaphysical theories, but also for investigating the structure of concepts, as their concepts appear to be tributary of different representational systems.

You can perceive things, in many respects, as they really are. For example, you can correctly see a coin as circular from most angles. Nonetheless, your perception of the world is perspectival. The coin looks different when slanted than when head-on, and there is some respect in which the slanted coin looks similar to a head-on ellipse. Many hold that perception is perspectival because you perceive certain properties that correspond to the “looks” of things. I argue that this view is (...) misguided. I consider the two standard versions of this view. What I call the PLURALIST APPROACH fails to give a unified account of the perspectival character of perception, while what I call the PERSPECTIVAL PROPERTIES APPROACH violates central commitments of contemporary psychology. I propose instead that perception is perspectival because of the way perceptual states are structured from their parts. (shrink)

Fundamental to spatial knowledge in all species are the representations underlying object recognition, object search, and navigation through space. But what sets humans apart from other species is our ability to express spatial experience through language. This target article explores the language ofobjectsandplaces, asking what geometric properties are preserved in the representations underlying object nouns and spatial prepositions in English. Evidence from these two aspects of language suggests there are significant differences in the geometric richness with which objects and places (...) are encoded. When an object is named (i.e., with count nouns), detailed geometric properties – principally the object's shape (axes, solid and hollow volumes, surfaces, and parts) – are represented. In contrast, when an object plays the role of either “figure” (located object) or “ground” (reference object) in a locational expression, only very coarse geometric object properties are represented, primarily the main axes. In addition, the spatial functions encoded by spatial prepositions tend to be nonmetric and relatively coarse, for example, “containment,” “contact,” “relative distance,” and “relative direction.” These properties are representative of other languages as well. The striking differences in the way language encodes objects versus places lead us to suggest two explanations: First, there is a tendency for languages to level out geometric detail from both object and place representations. Second, a nonlinguistic disparity between the representations of “what” and “where” underlies how language represents objects and places. The language of objects and places converges with and enriches our understanding of corresponding spatial representations. (shrink)

In order to understand ongoing activity, observers segment it into meaningful temporal parts. Segmentation can be based on bottom‐up processing of distinctive sensory characteristics, such as movement features. Segmentation may also be affected by top‐down effects of knowledge structures, including information about actors' intentions. Three experiments investigated the role of movement features and intentions in perceptual event segmentation, using simple animations. In all conditions, movement features significantly predicted where participants segmented. This relationship was stronger when participants identified larger units than (...) when they identified smaller units, and stronger when the animations were generated randomly than when they were generated by goal‐directed human activity. This pattern suggests that bottom‐up processing played an important role in segmentation of these stimuli, but that this was modulated by top‐down influence of knowledge structures. To describe accurately how observers perceive ongoing activity, one must account for the effects of distinctive sensory characteristics, the effects of knowledge structures, and their interactions. (shrink)

Because the visual system cannot process all of the objects, colors, and features present in a visual scene, visual attention allows some visual stimuli to be selected and processed over others. Most research on visual attention has focused on spatial or location-based attention, in which the locations occupied by stimuli are selected for further processing. Recent research, however, has demonstrated the importance of objects in organizing (or segregating) visual scenes and guiding attentional selection. Because of the long history of spatial (...) attention research, theories of spatial attention are more mature than theories of other visual processes, such as object segregation and object attention. In the present paper, I outline a biased competition account of object segregation and attention, following similar accounts that have been developed for spatial attention (Desimone and Duncan, 1995). In my biased competition account, I seek to understand how some objects can be segregated and selected over other objects in a complex visual scene. Under this account, there are two sources of visual information that allow an object to be processed over other objects: bottom-up information carried by the physical stimulus and top-down information based on an observer's goals. I use the biased competition account to combine many diverse findings from the object segregation and attention literatures into a common framework. (shrink)

This is a revised and extended version of the formal theory of holes outlined in the Appendix to the book "Holes and Other Superficialities". The first part summarizes the basic framework (ontology, mereology, topology, morphology). The second part emphasizes its relevance to spatial reasoning and to the semantics of spatial prepositions in natural language. In particular, I discuss the semantics of ‘in’ and provide an account of such fallacious arguments as “There is a hole in the sheet. The sheet is (...) in the drawer. Ergo *there is a hole in the drawer”. (shrink)

Can we really perceive absences, i.e., missing things? Sartre tells us that when he arrived late for his appointment at the café, he saw the absence of his friend Pierre. Is that really what he saw? Where was it, exactly? Why didn’t Sartre see the absence of other people who were not there? Why did other people who were there not see the absence of Pierre? The perception of absences gives rise to a host of conundrums and is constantly on (...) the verge of conceptual confusion. Here I focus on the need to be clear about four sorts of distinctions: (i) the difference between perceiving an absence and perceiving something that is absent; (ii) the difference between perceiving an absence and an absence of perceiving; (iii) the difference between perceiving an absence and perceiving something as an absence; and (iv) the difference between perceiving an absence and perceiving that something is absent. (shrink)

Purely parallel neural networks can model object recognition in brief displays – the same conditions under which illusory conjunctions have been demonstrated empirically. Correcting errors of illusory conjunction is the “tag-assignment” problem for a purely parallel processor: the problem of assigning a spatial tag to nonspatial features, feature combinations, and objects. This problem must be solved to model human object recognition over a longer time scale. Our model simulates both the parallel processes that may underlie illusory conjunctions and the serial (...) processes that may solve the tag-assignment problem in normal perception. One component of the model extracts pooled features and another provides attentional tags that correct illusory conjunctions. Our approach addresses two questions: How can objects be identified from simultaneously attended features in a parallel, distributed representation? How can the spatial selectional requirements of such an attentional process be met by a separation of pathways for spatial and nonspatial processing? Our analysis of these questions yields a neurally plausible simulation of tag assignment based on synchronizing feature processing activity in a spatial focus of attention. (shrink)

Summary The present article is a partly ontological, partly Gestalt-psychological discussion of the thinkability of structures in which parts and whole are interdependent (MI). In the first section, I show that in the framework of E. Husserl’s formal part–whole ontology, the conceptualization of such an interdependence leads to (mereo)logical problems. The second section turns to and affirms the experience of this interplay between parts and whole, exemplified with B. Pinna’s recent research on meaningful Gestalt perception. In the final section, I (...) take the experienceability of MI as a justification to suggest a way of rethinking it. This entails an implementation of the process of foregrounding and backgrounding displayed by reversible figures and originally described by E. Rubin. This can avoid both an identity relation between parts and whole and their mutual exclusion as well as hierarchization due to their apparent differences. It would also guarantee the inherent dynamics of interdependence. (shrink)