New Research Suggests Attention as Analyzer, Consciousness as Synthesizer

I am sometimes frustrated with the materialist/reductionist aspect of neuroscience research. On the other hand, some of what they are discovering about brain function is both important in understanding how we function as human beings, and it also points to subjective skill-sets we can develop in contemplative experience.

In a study from a team including Chrisof Koch, they have found the neuroimaging points to a functional dissociation in the brain: attention as analyzer and consciousness as synthesizer. I am not sure on a first read what the implications of this might be, but I am very intrigued.

Citation:
Van Boxtel JJ, Tsuchiya N and Koch C (2010). Consciousness and Attention: On sufficiency and necessity. Front. Psychology doi: 10.3389/fpsyg.2010.00217

Here is the abstract.

Consciousness and Attention: On sufficiency and necessity

Jeroen J. Van Boxtel^1*, Naotsugu Tsuchiya^{2, 3} and Christof Koch^{1, 4, 5}

• ¹Division of Biology, California Institute of Technology, USA
• ²Division of Humanities and Social Sciences, California Institute of Technology, USA
• ³ Brain Science Institute, Tamagawa University, Japan
• ⁴Division of Engineering and Applied Science, California Institute of Technology, USA
• ⁵Brain and Cognitive Engineering, Korea University, Korea (South)

Recent research has slowly corroded a belief that selective attention and consciousness are so tightly entangled that they cannot be individually examined. In this review, we summarize psychophysical and neurophysiological evidence for a dissociation between top-down attention and consciousness. The evidence includes recent findings that show subjects can attend to perceptually invisible objects. More contentious is the finding that subjects can become conscious of an isolated object, or the gist of the scene in the near absence of top-down attention; we critically re-examine the possibility of ‘complete’ absence of top-down attention. We also cover the recent flurry of studies that utilized independent manipulation of attention and consciousness. These studies have shown paradoxical effects of attention, including examples where top-down attention and consciousness have opposing effects, leading us to strengthen and revise our previous views. Neuroimaging studies with EEG, MEG and fMRI are uncovering the distinct neuronal correlates of selective attention and consciousness in dissociative paradigms. These findings point to a functional dissociation: attention as analyzer and consciousness as synthesizer. Separating the effects of selective visual attention from those of visual consciousness is of paramount importance to untangle the neural substrates of consciousness from those for attention.

Provisional PDF of the full article is open access. Here is the introduction to get your interest.

Introduction
Although often used in everyday speech and in the scholarly literature, “selective attention” and “consciousness” lack clear definitions. Partly because of this deficit there exists a lively debate on the relationship between the two. For clarity, we start with stating our usage of the terms “attention” and “consciousness”. We use the term “attention” to imply selective attention, rather than the processes that control the overall level of arousal and alertness. We focus on top-down, goal-directed endogenous attention and not on bottom-up, saliency-driven exogenous attention (Itti & Koch, 2001). We do so because top-down attention and consciousness can be independently manipulated without changing the visual inputs (e.g. van Boxtel, Tsuchiya, & Koch, 2010), while bottom-up attention, almost by definition, needs to be manipulated by changing the physical properties of a cueing stimulus, such as its visual features or its spatio-temporal relationship with a target stimulus. Thus it is difficult to disentangle bottom-up attention from consciousness (but see (Chica, Lasaponara, Lupianez, Doricchi, & Bartolomeo)). By consciousness, we refer to the content of consciousness (sometimes also referred to as awareness), and not to states or levels of consciousness (e.g., wakefulness, dreamless sleep or coma). Furthermore, we restrict this review to visual attention and visual consciousness, as the psychology and the neurophysiology of vision is much better understood than those of other modalities.

It is generally acknowledged that attention and perceptual consciousness share an intimate relationship. When an observer pays attention to an object, he or she becomes conscious of its various attributes; when attention shifts away, the object seems to fade from consciousness. Because of this tight relationship some scholars posit that these two processes are inextricably entangled, if not identical (Chun & Wolfe, 2000; De Brigard & Prinz, 2010; Jackendoff, 1996; Mack & Rock, 1998; Merikle & Joordens, 1997; Mole, 2008; O'Regan & Noe, 69 2001; Posner, 1994; Prinz, 2010; Velmans, 1996). Others, however, hold the position that attention and consciousness are distinct phenomena, with distinct functions and neuronal mechanisms that can be dissociated through clever experimentation (Baars, 2005; Bachmann, 2006; Block, 2005; Dehaene, Changeux, Naccache, Sackur, & Sergent, 2006; Hardcastle, 1997; Iwasaki, 1993; Kentridge, Heywood, & Weiskrantz, 2004; Koch, 2004; Koch & Tsuchiya, 2007; Lamme, 2003; Naccache, Blandin, & Dehaene, 2002; Tsuchiya & Koch, 2008a, 2008b; Woodman & Luck, 2003; Wundt, 1874).

Recently, there has been a growing interest in the relationship between attention and consciousness. Many studies have shown a dissociation between attention and consciousness using psychophysics and neurophysiological measurements such as EEG, MEG and fMRI. This review gives an update of our previous overviews (Koch & Tsuchiya, 2007; Tsuchiya & Koch, 2008a, 2008b). In the first half, we closely examine the question of the necessity and sufficiency of attention for conscious perception. In the second half, we review experiments published after our previous reviews. These studies contrast the effects of attention and consciousness for a given percept by independently manipulating the two. Some studies successfully dissociate attention and consciousness, while some even show opposing effects of attention and consciousness.

As consciousness is notoriously difficult to define, we here use an operational definition. We will equate consciousness for an object or event, say a stationary grating, with stimulus visibility. As long as the subject can see the grating, he or she is conscious of the grating or of one or more of its attributes (location, orientation, contrast). Other operational definitions involve subjective confidence or wagering procedures (e.g., Persaud, McLeod, & Cowey, 2007; Wilimzig, Tsuchiya, Fahle, Einhauser, & Koch, 2008).

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