Publications

In Press
Graziano, M. S. A. (In Press). Rethinking Consciousness: A Scientific Theory of Subjective Experience . W. W. Norton.
Graziano, M. S. A., & Morsella, E. (In Press). A new motor approach to consciousness: Implications for the simulation of future behavior. In Z. Radman (Ed.), Acting Ahead of Actuality.
Graziano, M. S. A. (In Press). Human emotional expression and the peripersonal margin of safety. In F. de Vignemont & A. Serino (Ed.), Peripersonal Space . Oxford, UK, Oxford University Press.Abstract
The brain evolved to give special representation to the space immediately around the body. One of the most obvious adaptive uses of that peripersonal space is self-protection. It is a safety buffer zone, and intrusions can trigger a suite of protective behaviors. Perhaps less obvious is the possible relationship between that complex protective mechanism and social signaling. Standing tall, cringing, power poses and hand shakes, even coquettish tilts of the head that expose the neck, may all relate in some manner to that safety buffer, signaling to others that one’s protective mechanisms are heightened (when anxious) or reduced (when confident). Here I propose that some of our most fundamental human emotional expressions such as smiling, laughing, and crying may also have a specific evolutionary relationship to the buffer zone around the body, deriving ultimately from the reflexive actions that protect us.
Graziano, M. S. A. (In Press). We are machines that claim to be conscious. Journal of Consciousness Studies.
2019
Graziano, M. S. A. (2019). Attributing awareness to others: The attention schema theory and its relationship to behavioral prediction. Journal of Consciousness Studies , 26 (3-4), 17-37. Publisher's VersionAbstract
The attention schema theory provides a single coherent framework for understanding three seemingly unrelated phenomena. The first is our ability to control our own attention through predictive modeling. The second is a fundamental part of social cognition, or theory of mind – our ability to reconstruct the attention of others, and to use that model of attention to help make behavioral predictions about others. The third is our claim to have a subjective consciousness – not merely information inside us, but something else in addition that is non-physical – and to believe that others have the same property. In the attention schema theory, all three phenomena stem from the same source. The brain constructs a useful internal model of attention. This article summarizes the theory and discusses one aspect of it in greater detail: how an attention schema may be useful for predicting the behavior of others. The article outlines a hypothetical, artificial system that can make time-varying behavioral predictions about other people, and concludes that attributing some form of awareness to others is a useful computational part of the prediction engine.
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Guterstam, A., Kean, H. H., Webb, T. W., Kean, F. S., & Graziano, M. S. A. (2019). Implicit model of other people's visual attention as an invisible, force-carrying beam projecting from the eyes. Proceedings of the National Academy of Sciences U. S. A. , 116 (1), 328-333. Publisher's VersionAbstract
As a part of social cognition, people automatically construct rich models of other people's vision. Here we show that when people judge the mechanical forces acting on an object, their judgments are biased by another person gazing at the object. The bias is consistent with an implicit perception that gaze adds a gentle force, pushing on the object. The bias was present even though the participants were not explicitly aware of it and claimed that they did not believe in an extramission view of vision (a common folk view of vision in which the eyes emit an invisible energy). A similar result was not obtained on control trials when participants saw a blindfolded face turned toward the object, or a face with open eyes turned away from the object. The findings suggest that people automatically and implicitly generate a model of other people's vision that uses the simplifying construct of beams coming out of the eyes. This implicit model of active gaze may be a hidden, yet fundamental, part of the rich process of social cognition, contributing to how we perceive visual agency. It may also help explain the extraordinary cultural persistence of the extramission myth of vision.
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2018
Graziano, M. S. A. (2018). The Spaces Between Us: A Story of Neuroscience, Evolution, and Human Nature . Oxford University Press.
Graziano, M. S. A., & Webb, T. W. (2018). Understanding consciousness by building it. In D. Jacquette (Ed.), Bloomsbury Companion to Philosophy of Consciousness (pp. 187-210) . Bloomsbury.Abstract

In the attention schema theory, awareness is an impossible, physically incoherent property that is described by a packet of information in the brain. That packet of information is an internal model and its function is to provide a continuously updated account of attention. It describes attention in a manner that is accurate enough to be useful but not so accurate or detailed as to waste time or resources. In effect, subjective awareness is a caricature of attention. One advantage of this theory of awareness is that it is buildable. No part of it requires a metaphysical leap from chemistry to qualia. In this article we consider how to build a conscious machine as a way to introduce the attention schema theory.

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Bio, B. J., Webb, T. W., & Graziano, M. S. A. (2018). Projecting one's own spatial bias onto others during a theory-of-mind task. Proceedings of the National Academy of Sciences U. S. A. , 115 (7), E1684-E1689. Publisher's VersionAbstract
Many people show a left-right bias in visual processing. We measured spatial bias in neurotypical participants using a variant of the line bisection task. In the same participants, we measured performance in a social cognition task. This theory-of-mind task measured whether each participant had a processing-speed bias toward the right of, or left of, a cartoon agent about which the participant was thinking. Crucially, the cartoon was rotated such that what was left and right with respect to the cartoon was up and down with respect to the participant. Thus, a person's own left-right bias could not align directly onto left and right with respect to the cartoon head. Performance on the two tasks was significantly correlated. People who had a natural bias toward processing their own left side of space were quicker to process how the cartoon might think about objects to the left side of its face, and likewise for a rightward bias. One possible interpretation of these results is that the act of processing one's own personal space shares some of the same underlying mechanisms as the social cognitive act of reconstructing someone else's processing of their space.
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Graziano, M. S. A. (2018). The temporoparietal junction and awareness. Neuroscience of Consciousness , 4 (1). Publisher's VersionAbstract
Visual attention and awareness can be experimentally separated. In a recent study (Webb , Cortical networks involved in visual awareness independently of visual attention. 2016a;113:13923-8), we suggested that awareness was associated with activity in a set of cortical networks that overlap the temporoparietal junction. In a comment, Morales (Measuring away an attentional confound? 2017;3:doi:10.1093/nc/nix018) suggested that we had imperfectly controlled attention thereby jeopardizing the experimental logic. Though we agree that attention behaves differently in the presence and absence of awareness, we argue it is still possible to roughly equate the level of attention between aware and unaware conditions, and that an imbalance in attention probably does not explain our experimental results.
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2017
Graziano, M. S. A. (2017). The Attention Schema Theory: A foundation for engineering artificial consciousness. Frontiers in Robotics and AI. Publisher's VersionAbstract

The purpose of the attention schema theory is to explain how an information-processing device, the brain, arrives at the claim that it possesses a non-physical, subjective awareness, and assigns a high degree of certainty to that extraordinary claim. The theory does not address how the brain might actually possess a non-physical essence. It is not a theory that deals in the non-physical. It is about the computations that cause a machine to make a claim and to assign a high degree of certainty to the claim. The theory is offered as a possible starting point for building artificial consciousness. Given current technology, it should be possible to build a machine that contains a rich internal model of what consciousness is, attributes that property of consciousness to itself and to the people it interacts with, and uses that attribution to make predictions about human behavior. Such a machine would “believe” it is conscious and act like it is conscious, in the same sense that the human machine believes and acts.

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Graziano, M. S. A. (2017). The Attention Schema Theory of Consciousness. In R. Gennaro (Ed.), Routledge Handbook of Consciousness (pp. 174-187) . Routledge.Abstract
The attention schema theory of consciousness describes how an information-processing machine can make the claim that it has a consciousness of something. In the theory, the brain is an information processor that is captive to the information constructed within it. The challenge of explaining consciousness is not, “How does the brain produce an ineffable internal experience,” but rather, “How does the brain construct a quirky self description, and what is the useful cognitive role of that self model?”
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Igelström, K. M., Webb, T. W., & Graziano, M. S. A. (2017). Functional Connectivity Between the Temporoparietal Cortex and Cerebellum in Autism Spectrum Disorder. Cerebral Cortex , 27 (4), 2617-2627. Publisher's VersionAbstract
The neural basis of autism spectrum disorder (ASD) is not yet understood. ASD is marked by social deficits and is strongly associated with cerebellar abnormalities. We studied the organization and cerebellar connectivity of the temporoparietal junction (TPJ), an area that plays a crucial role in social cognition. We applied localized independent component analysis to resting-state fMRI data from autistic and neurotypical adolescents to yield an unbiased parcellation of the bilateral TPJ into 11 independent components (ICs). A comparison between neurotypical and autistic adolescents showed that the organization of the TPJ was not significantly altered in ASD. Second, we used the time courses of the TPJ ICs as spatially unbiased "seeds" for a functional connectivity analysis applied to voxels within the cerebellum. We found that the cerebellum contained a fine-grained, lateralized map of the TPJ. The connectivity of the TPJ subdivisions with cerebellar zones showed one striking difference in ASD. The right dorsal TPJ showed markedly less connectivity with the left Crus II. Disturbed cerebellar input to this key region for cognition and multimodal integration may contribute to social deficits in ASD. The findings might also suggest that the right TPJ and/or left Crus II are potential targets for noninvasive brain stimulation therapies.
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Igelström, K. M., & Graziano, M. S. A. (2017). The inferior parietal lobule and temporoparietal junction: A network perspective. Neuropsychologia , 105, 70-83. Publisher's VersionAbstract
Information processing in specialized, spatially distributed brain networks underlies the diversity and complexity of our cognitive and behavioral repertoire. Networks converge at a small number of hubs - highly connected regions that are central for multimodal integration and higher-order cognition. We review one major network hub of the human brain: the inferior parietal lobule and the overlapping temporoparietal junction (IPL/TPJ). The IPL is greatly expanded in humans compared to other primates and matures late in human development, consistent with its importance in higher-order functions. Evidence from neuroimaging studies suggests that the IPL/TPJ participates in a broad range of behaviors and functions, from bottom-up perception to cognitive capacities that are uniquely human. The organization of the IPL/TPJ is challenging to study due to the complex anatomy and high inter-individual variability of this cortical region. In this review we aimed to synthesize findings from anatomical and functional studies of the IPL/TPJ that used neuroimaging at rest and during a wide range of tasks. The first half of the review describes subdivisions of the IPL/TPJ identified using cytoarchitectonics, resting-state functional connectivity analysis and structural connectivity methods. The second half of the article reviews IPL/TPJ activations and network participation in bottom-up attention, lower-order self-perception, undirected thinking, episodic memory and social cognition. The central theme of this review is to discuss how network nodes within the IPL/TPJ are organized and how they participate in human perception and cognition.
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2016
Graziano, M. S. A. (2016). Consciousness engineered. Journal of Consciousness Studies , 23 (11-12), 98-115. Publisher's VersionAbstract

The attention schema theory offers one possible account for how we claim to have consciousness. The theory begins with attention, a mechanistic method of handling data in which some signals are enhanced at the expense of other signals and are more deeply processed. In the theory, the brain does more than just use attention. It also constructs an internal model, or representation, of attention. That internal model contains incomplete, schematic information about what attention is, what the consequences of attention are, and what its own attention is doing at any moment. This “attention schema” is used to help control attention, much like the “body schema,” the brain’s internal simulation of the body, is used to help control the body. Subjective awareness – consciousness – is the caricature of attention depicted by that internal model. This article summarizes the theory and discusses its relationship to the approach to consciousness that is called “illusionism.”

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Graziano, M. S. A., & Webb, T. W. (2016). From sponge to human: The evolution of consciousness. In J. Kaas (Ed.), Evolution of Nervous Systems (2nd ed. Vol. 2, pp. 547–554) . Elsevier.Abstract

The attention schema theory is a proposed explanation for the brain basis of conscious experience. The theory is mechanistic, testable, and supported by at least some preliminary experiments. In the theory, subjective awareness is an internal model of attention that serves several adaptive functions. This chapter discusses the evolution of consciousness in the context of the attention schema theory, beginning with the evolution of attentional mechanisms that emerged more than half a billion years ago and extending to human consciousness and the social attribution of conscious states to others.

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Webb, T. W., Igelström, K. M., Schurger, A., & Graziano, M. S. A. (2016). Cortical networks involved in visual awareness independent of visual attention. Proceedings of the National Academy of Sciences U. S. A. , 113 (48), 13923-13928. Publisher's VersionAbstract
It is now well established that visual attention, as measured with standard spatial attention tasks, and visual awareness, as measured by report, can be dissociated. It is possible to attend to a stimulus with no reported awareness of the stimulus. We used a behavioral paradigm in which people were aware of a stimulus in one condition and unaware of it in another condition, but the stimulus drew a similar amount of spatial attention in both conditions. The paradigm allowed us to test for brain regions active in association with awareness independent of level of attention. Participants performed the task in an MRI scanner. We looked for brain regions that were more active in the aware than the unaware trials. The largest cluster of activity was obtained in the temporoparietal junction (TPJ) bilaterally. Local independent component analysis (ICA) revealed that this activity contained three distinct, but overlapping, components: a bilateral, anterior component; a left dorsal component; and a right dorsal component. These components had brain-wide functional connectivity that partially overlapped the ventral attention network and the frontoparietal control network. In contrast, no significant activity in association with awareness was found in the banks of the intraparietal sulcus, a region connected to the dorsal attention network and traditionally associated with attention control. These results show the importance of separating awareness and attention when testing for cortical substrates. They are also consistent with a recent proposal that awareness is associated with ventral attention areas, especially in the TPJ.
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Webb, T. W., Kean, H. H., & Graziano, M. S. A. (2016). Effects of Awareness on the Control of Attention. Journal of Cognitive Neuroscience , 28 (6), 842-851. Publisher's VersionAbstract
Previous studies show that it is possible to attend to a stimulus without awareness of it. Whether attention and awareness are independent or have a specific relationship, however, remains debated. Here, we tested three aspects of visual attention with and without awareness of the visual stimulus. Metacontrast masking rendered participants either subjectively aware or not aware of the stimulus. Attention drawn to the stimulus was measured by using the stimulus as a cue in a spatial attention task. We found that attention was drawn to the stimulus regardless of whether or not people were aware of it. However, attention changed significantly in the absence of awareness in at least three ways. First, attention to a task-relevant stimulus was less stable over time. Second, inhibition of return, the automatic suppression of attention to a task-irrelevant stimulus, was reduced. Third, attention was more driven by the luminance contrast of the stimulus. These findings add to the growing information on the behavior of attention with and without awareness. The findings are also consistent with our recently proposed account of the relationship between attention and awareness. In the attention schema theory, awareness is the internal model of attention. Just as the brain contains a body schema that models the body and helps control the body, so it contains an attention schema that helps control attention. In that theory, in the absence of awareness, the control of attention should suffer in basic ways predictable from dynamical systems theory. The present results confirm some of those predictions.
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Graziano, M. S. A. (2016). Ethological Action Maps: A Paradigm Shift for the Motor Cortex. Trends in Cognitive Sciences , 20 (2), 121-132. Publisher's VersionAbstract
The map of the body in the motor cortex is one of the most iconic images in neuroscience. The map, however, is not perfect. It contains overlaps, reversals, and fractures. The complex pattern suggests that a body plan is not the only organizing principle. Recently a second organizing principle was discovered: an action map. The motor cortex appears to contain functional zones, each of which emphasizes an ethologically relevant category of behavior. Some of these complex actions can be evoked by cortical stimulation. Although the findings were initially controversial, interest in the ethological action map has grown. Experiments on primates, mice, and rats have now confirmed and extended the earlier findings with a range of new methods.
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Igelström, K. M., Webb, T. W., Kelly, Y. T., & Graziano, M. S. A. (2016). Topographical Organization of Attentional, Social, and Memory Processes in the Human Temporoparietal Cortex. eNeuro , 3 (2). Publisher's VersionAbstract
The temporoparietal junction (TPJ) is activated in association with a large range of functions, including social cognition, episodic memory retrieval, and attentional reorienting. An ongoing debate is whether the TPJ performs an overarching, domain-general computation, or whether functions reside in domain-specific subdivisions. We scanned subjects with fMRI during five tasks known to activate the TPJ, probing social, attentional, and memory functions, and used data-driven parcellation (independent component analysis) to isolate task-related functional processes in the bilateral TPJ. We found that one dorsal component in the right TPJ, which was connected with the frontoparietal control network, was activated in all of the tasks. Other TPJ subregions were specific for attentional reorienting, oddball target detection, or social attribution of belief. The TPJ components that participated in attentional reorienting and oddball target detection appeared spatially separated, but both were connected with the ventral attention network. The TPJ component that participated in the theory-of-mind task was part of the default-mode network. Further, we found that the BOLD response in the domain-general dorsal component had a longer latency than responses in the domain-specific components, suggesting an involvement in distinct, perhaps postperceptual, computations. These findings suggest that the TPJ performs both domain-general and domain-specific computations that reside within spatially distinct functional components.
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