Attention as Visual Determinacy: Merleau-Ponty, James and the cognitive neuroscience of attention

Brain Scans and Consciousness

Brain-imaging techniques are said to reveal that some so-called ‘vegetative state’ patients, who cannot communicate their experiences through speech or movement, are conscious of their surroundings. If true, this has enormous ethical implications for how we should treat patients who find themselves in this terrifying position, and evidence of this kind has in fact been cited in legal arguments about whether patients should be kept on life support. But is it true? To assess this, we will consider how longstanding philosophical problems about consciousness bear on the claim that consciousness is detectable through brain imaging. I’ll argue that we can achieve a satisfactory answer only by paying closer attention to the connection between consciousness and freedom than most scientists and philosophers in this area usually do.

Rational Agency and the Limits of Self-Attribution


Rationality Without Self-Attribution

According to a grand philosophical tradition, the distinctive rational role of human consciousness turns on a conscious human’s capacity to attribute the contents of consciousness to herself, as contents of her psychological states. Against this I argue that, in a rational human, higher order reflection is less sensitive than first order belief and action to the contents of consciousness: what we can self-attribute, even under optimal conditions, is less fine-grained than the contents of consciousness which confer epistemic and practical justification. I explore some consequences for broadly internalist conceptions of the rational role of consciousness, concerning non-factive reasons and supposedly non-intentional details of our actions.

Rationality Without Self-Attribution

Partial Report Experiments Couldn’t Possibly Support Overflow

I argue that there are deep problems with appealing to partial report experiments to support claims about the independence of consciousness from cognition. The basic problem is that, due to the ‘explanatory gap’, our knowledge of the functional role of consciousness is limited to its role in thought and report. As a result, where partial report experiments show that more information is processed than is taken up in thought or reported, two interpretations are equally well supported: the contents of consciousness might (i) ‘overflow’ what’s reported, or they might (ii) be just as partial as what’s reported. The experiments provide no support for (i) over (ii). If introspection provided a form of access to consciousness that was independent of thought and report, introspection might—as some theorists claim—cast doubt on (ii). But there is good reason to doubt that introspection has this structure. I argue that this problem is not overcome by recent elaborations of the partial report paradigm, which show for example that the overflowing information exhibits Kanisza grouping (Vandenbroucke, Sligte, Fahrenfort, Ambroziak, & Lamme, PLoS ONE 2012). Such functional roles for the overflowing information do not support the claim that the overflowing information characterizes consciousness, since our knowledge of the functional role of consciousness is limited to its role in thought and report.

Consciousness is Not Awareness of Mental Qualities

  • 14th April 2016, at a British Academy funded workshop, ‘Discriminación perceptiva y consciencia’ (part of my collaboration with Miguel Sebastián), Instituto de Investigaciones Filosóficas, UNAM, Mexico City:

Partial Report, Consciousness and the Introspective Evidence

Does consciousness require cognition? Yes or no? Recent work has shown that either answer is consistent with the results of partial report experiments. Nonetheless, ongoing elaborations of the partial report paradigm are said to provide important defeasible evidence that consciousness is independent of cognition. I argue that this popular claim underestimates the challenge from alternative interpretations of the experiments. The experiments could in fact provide such evidence only given a controversial view about how we know our own conscious states – a view associated with the idea of ‘mental paint’. This view presupposes a contrast between consciousness and cognition, in terms of how we know them through introspection. What’s more, there are good introspective reasons to doubt that consciousness differs from cognition in the way presupposed. Partial report is the wrong place to look for evidence that consciousness is independent of cognition.

Self-Knowledge, Perceptual Evidence and the Significance of Consciousness

What makes consciousness a distinctive source of knowledge? The answer is often thought to lie in the fact that the contents of consciousness are available to higher order reflection. A related, traditional view holds that one’s perceptual evidence sometimes consists in one’s conscious perceptual states. Against these views I argue that, in a rational human, higher order reflection is less sensitive than first order belief to the contents of conscious perception. Therefore the epistemic significance of consciousness lies in its first order cognitive role, and one’s perceptual evidence consists in objects of first order perceptual experience, not in one’s perceptual states. Since this conclusion applies in cases of radical illusion, such as traditional sceptical scenarios, it also suggests that there is nonfactive perceptual evidence.

Self-Knowledge, Perceptual Evidence and the Significance of Consciousness

  • 1st December 2015, at the Mind, Metaphysics, and Psychology seminar, King’s College London (4.30-6.30pm):

Self-Knowledge, Perceptual Evidence and the Significance of Consciousness

  • 20th-21st November 2015, Conference on Consciousness and Accessibility, CNRS, Paris:

Access, Consciousness and Higher-Order Inexactness

The notion of cognitive access to a mental state M is ambiguous between (1) cognition which represents M, and (2) cognition which takes M as computational input. I’ll argue that these forms of cognition are dissociated in experiences of phenomenal continua, in that (1) is less sensitive than (2) to the contents of conscious perceptual states. I’ll then show how this dissociation can be leveraged into arguments to the best explanation, first against ‘higher-order’ theories according to which consciousness consists in (1), and secondly against standard formulations of the ‘global broadcasting’ theory according to which consciousness consists in a species of (2). The result is prima facie reason to accept that consciousness is independent of cognitive access.

Partial Report, Consciousness and Self-Knowledge

  • 12th May 2015, Workshop with Ned Block, Centre for Philosophical Psychology, University of Antwerp:

Determination is all you need

Action, Attention and Consciousness.

  • 26th January 2015, Isaiah Berlin Society at St Paul’s School in London:

Images In and Of the Brain.

Resolution and Experience

Because visual resolution is finite, visual knowledge is inexact. For instance you cannot know, just by looking at a figure, that it’s exactly circular. Williamson and others maintain, on phenomenological grounds, that visual appearances are nonetheless specific: there is a single exact shape which the figure visually appears to have; visual knowledge is inexact insofar as it allows a margin for error in the appearances. I argue that phenomenology does not support this view, given manifest facts about our experiences of phenomenal continua. What’s more, once we give up the view that visual appearances are specific, we can connect recent empirical findings about visual resolution with classic work on visual phenomenology.

  • 30th May 2014, at a Rethinking the Senses workshop on ‘Spatial interactions across vision, audition, and touch: searching for a taxonomy’, Institute of Philosophy, University of London:

Comments on Laurence Harris, ‘Why the vestibular system should be listed in the title of this workshop’.

  • 16th-17th May 2014, at Ned Block and His Critics, a workshop at the Institut Jean-Nicod, Paris:

Introspection, Overflow and Mental Paint

Ned Block champions the use of introspective evidence together with the formal data. Using this method, he defends two different claims about visual consciousness: (i) that visual consciousness is independent of cognitive access; (ii) that the phenomenal character and representational content of visual consciousness are distinct. On the face of it Block’s arguments for (i) and (ii) are independent of one another. I suggest that the argument for (i) in fact depends on (ii), and I explore some consequences for appeals to introspection in this area.

  • 10th May 2014, at the Attention and Perceptual Activity workshop, Consciousness & Self-Consciousness Research Centre, University of Warwick:

Active Attention & Visual Processing

Recent work on voluntary attention and visual spatial resolution supports the claim that visual experience is sometimes a form of basic action (maybe).

  • 27th July 2013, at the Barnard-Columbia Perception Workshop in New York:

The Manifest and the Determinable

  • 13th June 2013, at the University of Durham’s project ‘Philosophy and Psychology: Integrating Research Across Disciplines’ – Workshop on Attention and Consciousness:

Attending, Knowing and Detecting Signals

  • 2nd May 2013, at the Centre for Cognition Research, University of Reading:
    with Andrew Glennerster:

Could the mechanisms that underlie motor control be responsible for perception?

  • 23rd March 2013, at the Mind Network in London:

Visual experience and visible properties

  • 12th February 2013, at Reading Philosophy‘s Work in Progress series (Humss 25, 2.15-4pm):

Visual experience and visible properties

  • 2nd September 2012, at Perceptual Attention, Centre for Philosophical Psychology, University of Antwerp:

Conscious Attention: Focussing the Mind

Recent philosophical work tends to characterize conscious attention as a sui generis kind of conscious experience, over and above conscious perception and conscious cognition. I argue that the nature and functional role of conscious attention are better captured by a more parsimonious analysis, according to which conscious attention consists in variations in each of these more basic forms of consciousness. I defend this analysis by appeal to both conceptual and empirical considerations, and explain how it improves the prospects for intentionalism about conscious experience.

Symposium on ‘Consciousness & Cognitive Access’, with Ned Block, Jérôme Sackur and Ilja Sligte.

  • 2nd March 2012, at Cognitive Science Speaker Series, Philosophy Program, CUNY Graduate Center:

Conscious Attention: Focussing the Mind

Comments on John Schwenkler’s ‘Vision, self-location and the phenomenology of the point of view’. Available here.

  • 20th November 2011, at Attention, Expectation & Awareness in Visual Perception, Columbia University:

Comments on Marisa Carrasco’s ‘Attention alters perception’.

  • 12th September 2011, at New York University Consciousness Project:

Attention, visual knowledge and psychophysics

Attending to the things you see is a reliable way to come to know about their visible properties. Recent experiments generate a challenge to this epistemologically important idea, because they show that attention changes the way properties appear in visual experience. To meet the challenge, I argue that visual experience represents determinable properties. More generally, I argue that we need to recognize the role of determinable properties in visual experience, if we’re to understand what experiments tell us about conscious vision.

  • 17th November 2010, UC Berkeley Philosophy Colloquium:

Attention, visual knowledge and psychophysics

  • 9th June 2010, at Phenomenal Presence Conference, EXRE Project, University of Fribourg:

The visual presence of determinable properties

I explain and defend a theoretically useful way of understanding the idea that properties, such as the shapes and colours of things, are visually present to a subject of experience. I argue that the notion of the visual presence of a property is coherent, scientifically plausible, and appropriate for epistemology, provided that the properties visually present to a subject are determinable, rather than maximally determinate.

  • 14th May 2010, at London-Berkeley Graduate Philosophy Conference:

If “attention alters appearance”, do we know what the world is really like?

  • 24th April 2010, at Berkeley-Stanford-Davis Graduate Philosophy Conference:

If “attention alters appearance”, do we know what the world is really like?