In this paper, we propose a computational model of the recognition of real world scenes that bypasses the segmentation and the processing of individual objects or regions. The procedure is based on a very low dimensional representation of the scene, that we term the Spatial Envelope. We propose a set of perceptual dimensions (naturalness, openness, roughness, expansion, ruggedness) that represent the dominant spatial structure of a scene. Then, we show that these dimensions may be reliably estimated using spectral and coarsely localized information. The model generates a multidimensional space in which scenes sharing membership in semantic categories (e.g., streets, highways, coasts) are projected closed together. The performance of the spatial envelope model shows that specific information about object shape or identity is not a requirement for scene categorization and that modeling a holistic representation of the scene informs about its probable semantic category.

Modeling the Shape of the Scene: A Holistic Representation of the Spatial Envelope

Recent studies of eye movements in reading and other information processing tasks, such as music reading, typing, visual search, and scene perception, are reviewed. The major emphasis of the review is on reading as a specific example of cognitive processing. Basic topics discussed with respect to reading are (a) the characteristics of eye movements, (b) the perceptual span, (c) integration of information across saccades, (d) eye movement control, and (e) individual differences (including dyslexia). Similar topics are discussed with respect to the other tasks examined. The basic theme of the review is that eye movement data reflect moment-to-moment cognitive processes in the various tasks examined. Theoretical and practical considerations concerning the use of eye movement data are also discussed.

/pdf/eye-movements-in-reading-and-information-processing-20-years-3z5ay8hdwc.pdf

Eye movements in reading and information processing: 20 years of research.

There has been substantial interest in mindfulness as an approach to reduce cognitive vulnerability to stress and emotional distress in recent years. However, thus far mindfulness has not been defined operationally. This paper describes the results of recent meetings held to establish a consensus on mindfulness and to develop conjointly a testable operational definition. We propose a two-component model of mindfulness and specify each component in terms of specific behaviors, experiential manifestations, and implicated psychological processes. We then address issues regarding temporal stability and situational specificity and speculate on the conceptual and operational distinctiveness of mindfulness. We conclude this paper by discussing implications for instrument development and briefly describing our own approach to measurement.

/pdf/mindfulness-a-proposed-operational-definition-39h3glfkax.pdf

Mindfulness : A proposed operational definition

With each eye fixation, we experience a richly detailed visual world. Yet recent work on visual integration and change direction reveals that we are surprisingly unaware of the details of our environment from one view to the next: we often do not detect large changes to objects and scenes ('change blindness'). Furthermore, without attention, we may not even perceive objects ('inattentional blindness'). Taken together, these findings suggest that we perceive and remember only those objects and details that receive focused attention. In this paper, we briefly review and discuss evidence for these cognitive forms of 'blindness'. We then present a new study that builds on classic studies of divided visual attention to examine inattentional blindness for complex objects and events in dynamic scenes. Our results suggest that the likelihood of noticing an unexpected object depends on the similarity of that object to other objects in the display and on how difficult the priming monitoring task is. Interestingly, spatial proximity of the critical unattended object to attended locations does not appear to affect detection, suggesting that observers attend to objects and events, not spatial positions. We discuss the implications of these results for visual representations and awareness of our visual environment.

/pdf/gorillas-in-our-midst-sustained-inattentional-blindness-for-2kd2pettjh.pdf

Gorillas in our midst: sustained inattentional blindness for dynamic events.

Many current neurophysiological, psychophysical, and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The outside world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the governing laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Several lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual \"filling in,\" visual stability despite eye movements, change blindness, sensory substitution, and color perception.

A sensorimotor account of vision and visual consciousness-Authors' Response-Acting out our sensory experience

Three areas of high-level scene perception research are reviewed. The first concerns the role of eye movements in scene perception, focusing on the influence of ongoing cognitive processing on the position and duration of fixations in a scene. The second concerns the nature of the scene representation that is retained across a saccade and other brief time intervals during ongoing scene perception. Finally, we review research on the relationship between scene and object identification, focusing particularly on whether the meaning of a scene influences the identification of constituent objects.

/pdf/high-level-scene-perception-43hajvrzu2.pdf

High-level scene perception

http://psycnet.apa.org/journals/xhp/25/1/210.pdf

The effects of semantic consistency on eye movements during complex scene viewing

The nature of the information retained from previously fixated (and hence attended) objects in natural scenes was investigated. In a saccade-contingent change paradigm, participants successfully detected type and token changes (Experiment 1) or token and rotation changes (Experiment 2) to a target object when the object had been previously attended but was no longer within the focus of attention when the change occurred. In addition, participants demonstrated accurate type-, token-, and orientationdiscrimination performance on subsequent long-term memory tests (Experiments 1 and 2) and during online perceptual processing of a scene (Experiment 3). These data suggest that relatively detailed visual information is retained in memory from previously attended objects in natural scenes. A model of scene perception and long-term memory is proposed. Because of the size and complexity of the visual environments humans tend to inhabit, and because high-acuity vision is limited to a relatively small area of the visual field, detailed perceptual processing of a natural scene depends on the selection of local scene regions by movements of the eyes (for reviews, see Henderson & Hollingworth, 1998, 1999a). During scene viewing, the eyes are reoriented approximately three times each second by saccadic eye movements to bring the projection of a local scene region (typically a discrete object) onto the area of the retina producing the highest acuity vision (the fovea). The periods between saccades, when the eyes are relatively stationary and detailed visual information is encoded, are termed fixations and last an average of approximately 300 ms during scene viewing. During each brief saccadic eye movement, however, visual encoding is suppressed (Matin, 1974). Thus, the visual system is provided with what amounts to a series of snapshots (corresponding to fixations), which may vary dramatically in their visual content over a complex scene, punctuated by brief periods of blindness (corresponding to saccades).

/pdf/accurate-visual-memory-for-previously-attended-objects-in-3bapb9err1.pdf

Accurate visual memory for previously attended objects in natural scenes

http://www2.psychology.uiowa.edu/faculty/hollingworth//documents/christetal_cogpsych01.pdf

Thematic roles assigned along the garden path linger.

Publisher Summary
Vision is a dynamic process in which representations are built up over time from multiple eye fixations. The study of eye movement patterns during scene viewing contributes to an understanding of how information in the visual environment is dynamically acquired and represented. The interaction among vision, cognition, and eye movement control can be seen as a scientifically tractable testing ground for theories of the interaction between input, central, and output systems. The chapter focuses on static scenes. Eye movement behavior during scene viewing is divided into two relatively discrete temporal phases, fixations, or periods of time when the point of regard is relatively still, and saccades, or periods of time when the eyes are rotating at a relatively rapid rate to reorient the point of regard from one spatial position to another. Useful pattern information is acquired during the fixations, with less useful pattern information derived during the saccades due to a combination of visual masking and central suppression. It is vital exactly where the fixation position tends to be centered and how long the position tends to remain centered at a particular location in a scene.

Andrew Hollingworth

Papers

High-level scene perception

The effects of semantic consistency on eye movements during complex scene viewing

Accurate visual memory for previously attended objects in natural scenes

Thematic roles assigned along the garden path linger.

Eye Movements During Scene Viewing: An Overview