My BOOK on consciousness will be out in June 2011
CHANGE BLINDNESS DEMOS
J. Kevin O'Regan
Laboratoire Psychologie de la Perception
Centre National de Recherche Scientifique
Institut Paris Descartes de Neurosciences et Cognition
45, rue des Saints Pères
75270 Paris cedex 06, France
last updated 4 November 2010
I am director of the Laboratoire Psychologie de la Perception, which specializes in human visual and auditory perception both in babies and adults. Thanks to my co-directors Jacqueline Fagard and Andrei Gorea, and also thanks to the team leaders and technical and administrative staff, we manage to effectively run our rather large lab: it has about 80 members, of which 25 are permanent researchers, 7 are technical and administrative personnel, plus about 45 doctoral and postdoctoral students and visitors. The lab occupies about 800 m2 at the Institute of Neuroscience and Cognition of Paris Descartes University, at the Saints Pères Biomedical Center. The lab also has space at the Département d'Etudes Cognitives of Ecole Normale Supérieure. It is co-financed by the Centre National de Recherche Scientifique and Université Paris Descartes.
After doing my first degree at Sussex University and the first part of my PhD at Cambridge in mathematical physics, I switched my PhD topic to psychology to work on eye movements in reading, and moved to the Centre National de Recherche Scientifique in Paris. My most important early work was the discovery of an "optimal viewing position" for the eye to fixate in words. Recognition is fastest at that position and drops off to either side, making it useful for the eye to fixate there for efficient reading. From this I developed what I called a "strategy-tactics" theory of eye movement control in reading which explains why the eye goes where it does in reading. The idea is that the eye adopts a general strategy of moving a little to the left of the middle of the next longish word, and makes correction tactics as a function of ongoing processing if necessary. The theory is a compromise between the old "rhythm strategy" theory according to which the eye just plods along at a fairly constant rhythm without taking account of what is being read, and the (in the 1970's and 80's) fashionable theory according to which the eye reacts moment by moment, at every instant changing where it goes as a function of ongoing cognitive processing.What I am most cited for is change blindness, which I discovered with collaborators Ron Rensink and Jim Clark. Change blindness is a phenomenon where a person looks at a picture of a scene, but doesn't see enormous changes that occur in that scene when the changes are accompanied by a brief interruption like a cinema cut, a blank, or even small distractors like mudsplashes on a car windscreen. You can see more demos below. The phenomenon at first seems similar to the phenomenon of "inattentional blindness", where you don't see something that is fully in view because you are busy attending to something else. But change blindness is conceptually a different effect, since it depends crucially on the occurrence of a brief transitory event in the visual field that distracts your attention, instead of depending on the fact that you are consciously attending to something else.
Today my main interest is one particular aspect of the problem of consciousness, namely the "what it's like" of sensory experience: why red seems red to us rather than seeming, say, green, or like the sound of a bell, or even like nothing at all.
This so-called "phenomenal" aspect of consciousness is considered by philosophers to be the "hard" problem of consciousness, also known as the problem of "qualia". Other questions like the question of why we have selves or why we can become aware of things and use them in our rational actions and thought, are considered not so hard. Most theories of consciousness that neuroscientists talk about concern the second, "easier" form of consciousness. Brain mechanisms like large scale neural integration, feedback, recurrence or synchrony of neural discharges may be able to account for this "easier" type of consciousness. On the other hand, many people think there is a fundamental obstacle in dealing with the "hard" problem of consciousness. There seems to be a kind of "explanatory gap" between the physical mechanisms of the brain and the real, nitty gritty "what it's like" of sensations like red.
My work on change blindness and on eye movements has led me to a new way of thinking about the "hard" kind of consciousness. In this, I consider that the feel of a sensory experience is not something which is somehow generated by the brain, but is rather a quality of how we interact with our environment. I have set out what I call the "sensorimotor" theory in various articles, and have just finished a book on the subject which should be appearing in the next year or so. The book is for the general public and will probably have the title: "Feeling: Why red looks red rather than sounding like a bell".
The new theory makes predictions and suggests breakthroughs in understanding consciousness which I have been exploring in the last years. Some of this work concerns what is called "sensory substitution", that is the possibility of using one sense (e.g. hearing) to replace another (e.g. vision), and so, for example, help the blind to see with their ears. I did this with Malika Auvray during her PhD in my lab.
Some quite mathematical work to test the sensorimotor theory was done for his PhD in my lab by David Philipona and concerns the nature of color and space. David's work on color is particularly interesting because it predicts, better than ever before, well-known anthropologists' findings about why certain colors like red and yellow are considered more basic than colors like pink and purple. It also explains, better than previously, exactly which hues of red, yellow, blue and green seem "pure" to us. It seems to me that this work is getting very close to answering the age-old question of why red looks red rather than green. David Philipona's work on space is also very fundamental and has applications to robotics.
Other work done in my lab to test the sensorimotor theory was done by PhD student Aline Bompas. She confirmed my theory's prediction that the perceived quality of color should depend on eye movements. Finally, most recently with students Ed Cooke and Camila Valenzuela Moguillansky we have been looking at the "rubber hand illusion" and pain.
slideshow of the talk on "How to make a robot that feels" that I gave in Zurich at CogSys 2010 in January 2010. It summarizes the essence of my approach to the problem of phenomenal consciousness, and includes material on the sense of self. And here are the videos (Part 1, Part 2, Part 3) of my talk on "Why red things look red: the sensorimotor approach to phenomenal consciousness" given in September 2009 at the Barcelona Cognition Brain and Technology Summer School.
My "magnum opus" is a rather long paper setting out the sensorimotor approach for vision and visual consciousness in the "peer review" journal Behavioral and Brain Sciences, where there were 40 replies from eminent scientists and my responses to them. Philosopher Alva Noë collaborated on the paper, but since then he has continued in a somewhat different, more philosophical direction.
An easy to read introduction to the sensorimotor theory of phenomenal experience is this slideshow, which is an expanded version of a talk I gave at the Association for the Scientific Study of Consciousness in Brussels, June 29-July 2, 2000, and at Bressanone, Jan 21-26, 2001. Another easy paper to read introducing the main ideas of the theory is this, written with Alva Noë.
My recent work supercedes the earlier papers by extending the sensorimotor theory to understanding the "feel" of all types of sensations, not just vision. Several papers on this were written with Erik Myin. This, this, and this are easy to read and introduce the concepts of "bodiliness" and "grabbiness" in order to explain why there is something it's like, rather than nothing it's like, to have a sensory experience.
The sensorimotor theory had its origins in a old paper I wrote which is often cited, and where I claimed that the visual world is like an "outside memory".
Spongeman's Sensorimotor Manifesto is a wiki for collaborative work attempting to define as precisely as possible the terms used in the sensorimotor approach. Contributions invited! Why "spongeman"? Because in the sensorimotor approach, I use the analogy suggested by my collaborator Erik Myin of squishing a sponge in order to explain the "what it's like" of the feel of softness.
(Feel free to copy these demos but if you use them in presentations or publications, please be so kind as to credit J. Kevin O'Regan and mention my website http://nivea.psycho.univ-paris5.fr)
Change blindness is a phenomenon in which a very large change in a picture will not be seen by a viewer, if the change is accompanied by a visual disturbance that prevents attention from going to the change location. The easiest way to demonstrate change blindness is to take a picture, and change some object in it. If you view the original and the changed picture in sequence, but with some brief visual disturbance like a blank field or "flicker" in between the original and changed picture, the change sometimes is quite hard to see:
If you take out the blank field however, then the change pops out immediately:
Instead of using a flicker, it is possible also to use small disturbances like mudsplashes on a car windscreen:
You can also get change blindness by making the change so slow that attention is not captured by the changing element, as shown by this animation by my ex-student Renaud Chabrier:
If the change is part of what is the center of interest of the picture, attention is more likely to go to that part of the picture, and the change is easier to detect, as here:The change is easy to see if it is part of the "Center of Interest"
The change can also be very difficult to detect if it occurs in a film sequence at the moment of a film cut. This is brilliantly shown by an ad by the London Transport Office warning that cyclists can sometimes be very hard to see if you do not happen to be attending to them:
Daniel Simons at the Beckman Institute in Illinois has made wonderful demonstrations of this kind of thing occurring in real life. Some portion of road traffic accidents may occur because a small, brief distracting event (e.g. a windshield wiper or mudsplash crossing the visual field) masks a change (like a child running into the street).
Here are some more demos of change blindness, of varying degrees of difficulty.Gunner (mudsplash)
Some other change blindness demos:
Change blindness to very slow changes (needs shockwave plugin).
Change blindness should be distinguished from "inattentional blindness". Inattentional blindness is a phenomenon in which you are looking at a video sequence or real life event, and your attention is so captured by the task you are doing that something totally obvious, perfectly visible, and in fact, something that you may actually be looking at directly, is not noticed. Transport for London has a demonstration of this on youtube.
This demo is actually a copy of an even more striking "gorilla" demo that was made by Daniel Simons, which itself was based on an experiment performed by Neisser and Becklen. You can find all this and more demos of inattentional blindness on Dan Simons' website, as well as discussion of the issues involved.
Inattentional blindness is at the basis of one of the main causes of road accidents: people "Look but fail to see" (LBFTS) some quite obvious and perfectly visible obstruction in the road.
My collaborator Malika Auvray has made a nice alternative version of Simon's "gorilla" video. You must track the coin and see if you can accurately determine which cup it ends up under. Only after you've done it, read here
O'Regan, J.K. (2009). Sensorimotor approach to (phenomenal) consciousness. In Baynes, T., Cleeremans, A. & Wilken, P. (Eds) Oxford Companion to Consciousness. (pp. 588-593). Oxford: Oxford University Press. [-]
Myin, E., & O'Regan, J.K. (2008). Situated perception and sensation in vision and other modalities: form an active to a sensorimotor account. In P. Robbins & A. Aydede (Eds.) (Ed) Cambridge Handbook of Situated Cognition. (pp. 185-200). Cambridge: Cambridge University Press. [OS]
Myin, E., & O'Regan, J.K. (2007). Phenomenal Consciousness Lite: No Thanks! Behavioral and Brain Sciences, 30, 520-521. [ACL] [IF=12.818]
O'Regan, J.K., Myin, E., & Noë, A. (2004). Towards an Analytic phenomenology: the concepts of "bodiliness" and "grabbiness". In Carsetti, A. (Eds) Seeing, thinking and knowing: Meaning and self-organisation in visual cognition and thought. Dordrecht: Kluwer. [-]
Noe, A., & O'Regan, J.K. (2002). On the brain-basis of visual consciousness: A sensorimotor account. In Noe, Alva Thompson, Evan (Eds) Vision and mind: Selected readings in the philosophy of perception. (pp. 567-598). Cambridge, MA, US: MIT Press. [-]
O'Regan, J.K., & Noë, A. (2001). What it is like to see: A sensorimotor theory of visual experience. Synthèse, 129(1), 79-103. [-] [IF=0.477] html
Auvray, M., & O'Regan, J.K. (2003). Influence of semantic factors on blindness to progressive changes in visual scenes / L'influence des facteurs sémantiques sur la cécité aux changements progressifs dans les scènes visuelles. L'année Psychologique, 103(1), 9-32. [ACL] [IF=0.280]
Blindness to scene changes caused by "mudsplashes". by J.K. O'Regan, R.A. Rensink, R.A. & J.J. Clark, in Nature, 398, 34, 1999.
Change blindness, by J. K. O'Regan, in Encyclopedia of Cognitive Science, Nature Publishing group, in press.
Attention and the Grand Illusion, by Alva Noë & J. K.
Rensink, R.A., O'Regan J.K., & Clark, J.J. To see or not to see: the need for attention to perceive changes in scenes. Psychological Science, 8:368-373. 1997
O'Regan, J.K., Deubel, H., Clark J.J. & Rensink, R..A. Picture changes during blinks: looking without seeing and seeing without looking. Visual Cognition, 7, 1, 191-212, 2000. html
Rensink, R.A., O'Regan, J.K. & Clark, J.J. On the failure to detect changes in scenes across brief interruptions. Visual Cognition, 7, 1, 127-146, 2000. pdf
O'Regan, J.K. Thoughts on Change Blindness. in: L.R.
Jenkin (Eds.) Vision and Attention. Springer, 2001, pp. 281-302. view
Nov. 1, 1999 draft.