Academic journal article Trames

Binocular Rivalry as a Function of Spatial Quantisation of the Images of Faces: Precategorical Level Controls It

Academic journal article Trames

Binocular Rivalry as a Function of Spatial Quantisation of the Images of Faces: Precategorical Level Controls It

Article excerpt

1. Introduction

Preamble. The concept of consciousness holds one of the central roles in social science and humanities. But its connotations in modern scientific research may be quite surprising for many philosophers, sociologists, linguists and psychologists. The phenomenal aspects of consciousness that are related to immediate awareness of the perceptual objects have become a subject matter of research of a very active and rather numerous international group of researchers who regard consciousness as an experimental variable that can be studied by neuroscientific and psychophysical methods. Several specialists such as Bernard Baars, Francis Crick, Christof Koch, Gerald Edelman, Nikos Logothetis and others stress the importance of this strategy in taking steps towards clarification of this quite controversial concept. Some leading philosophers like John Searle, Paul Churchland, David Chalmers also believe in importance of empirical research on this subject. Understanding the nature of consciousness is one of the biggest challenges before science. It is still unsurpassed despite many centuries long quest for understanding.

In the present article I will show one example how experimental methods can be used for getting empirical data about the ways our brain/mind processes deal with perceptual information so as to create phenomenal experience for some of it and deprive some of it from this property. First, I will introduce the phenomenon. Subsequently an exploratory experiment will be described and its results interpreted. Hopefully, introduction of an exploratory experimental study of consciousness-related processes to the readers who may be more familiar with traditional speculative approaches could enrich their set of perspectives for dealing with this elusive property of living creatures--consciousness--theoretically.

The phenomenon. If two sufficiently different images are presented dichoptically--one to the right eye and the other to the left eye--, they will not blend into a combined percept that would include explicit information from both eyes simultaneously. Instead, the images begin to alternate in the awareness of the observer. Conscious perception "accepts" images one at a time. This phenomenon has been known as binocular or interocular rivalry. Typical rates of alternation or reversal have values from about 0.5 to about several seconds. In order to experience wholistic exclusive rivalry (i.e., where all what is experienced corresponds to the input from one eye only), the sizes of the competing images should not be larger than about 2 degrees of the visual angle.

Binocular rivalry has become one of the mainstream experimental paradigms in tackling important problems of visual cognition such as what is the nature of the mechanisms of visual awareness, figure-ground segregation, feature binding, and interactions of perception and attention (Andrews 2001, Blake and Logothetis 2002, Bonneh et al. 2001, Crick 1994, Fries et al. 1997, Kreiman et al. 2002, Leopold and Logothetis 1996, 1999, Sasaki and Gyoba 2002, Sheinberg and Logothetis 1997, Sengpiel 1997, Tong and Engel 2001, Tononi et al. 1998, Wilson et al. 2001, Wolfe 1996). The main emphasis has gradually shifted from the analysis of the involvement of relatively low level mechanisms such as brightness contrast, local lateral inhibition, or mutual inhibition of alternative monocular channels, to the analysis of relatively higher level processes of figural selection, object coding, and spontaneous attention (Logothetis, Leopold and Sheinberg 1996, Sengpiel 1997). Indeed, what seems to be the basis of rivalry in conscious vision is, according to what some authors claim, primarily related to the formation and selection of cognitive representations for unequivocally interpretable objects regardless of from which one of the two eyes the input is coming, rather than to the low-level competition between the sensory signals provided by different eyes (Logothetis Leopold and Sheinberg 1996, Kovacs et al. …

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