Ronald A. Rensink -- Research Projects


Particular projects include:


1.     Change blindness.  This phenomenon is a striking inability of observers to notice large changes in visual stimuli whenever the change is made the same time as a transient motion elsewhere.  Originally encountered by researchers who found that large changes could go unnoticed if made during eye movements and film cuts, I helped to discover that the cause was much more general--namely that attention is needed to see change.  This was done by the development of a "flicker paradigm", in which an original and changed image continually alternated, with a brief blank interval between them.  Under these conditions subjects have a very difficult time seeing the change between the two pictures, even when the changes are large, and the subjects are expecting them. Evidently, attention is required to see change; without it, people will look at but not see the change.  This phenomenon challenges the idea that vision involves building up an internal picture in our heads; instead, much more dynamic representations must be used.  Also, given that attention is needed to see change, change blindness can be used as a new source of information about the nature of visual attention.    (Take a look at some examples!)


2.     Intelligent rapid processing.  Until recently, it was believed that the rapid "preattentive" processing at early levels of vision was obtained by reducing the complexity of the operations, i.e., only simple tasks--such as determining orientation or color--could be done quickly.  However, work I did (with Jim Enns and Patrick Cavanagh) shows that the preattentive system is capable of much more. For example, it can recover properties of the scene, such as three-dimensional orientation and lighting direction.  It can also carry out grouping, and can rapidly identify shadows and highlights.  In my PhD thesis, I developed a computational account of how such "intelligent" processing could obtain speed by reducing reliability slightly.  In other words, much of preattentive processing has a quick and dirty nature; even though the processes will not succeed under all conditions, they will do so often enough.  Current work on this is focused on the representation of size, showing that the relevant factor is perceived (physical) size rather than size on the retina.


3.     Connecting Vision Science and Information Visualization.  This work attempts to integrate vision science and information visualization.  It includes (i) developing displays based on our knowledge of human vision, (ii) designing new methods of evaluation based on methods from vision science, and (iii) developing simplified versions of real-world visualizations that can allow us to investigate that perceptual mechanisms involved.  Among the more interesting results is the finding (Psychonomic Bulletin & Review, 2017) that correlation perception in scatterplots obeys simple laws, with the results strongly suggesting that humans can rapidly perceive entropy.  I have given papers, talks, and workshops on these issues at various international conferences.  Recent developments include helping to develop a closer link between these two fields—see e.g., the special issue of Journal of Vision on vision and information visualization.


4.     The Science of Magic.  During the past few years have worked with various magicians to investigate how magic works.  This project has received considerable interest, including the cover story in Trends in Cognitive Sciences (Sep 2008), and several papers (with Gustav Kuhn) in a recent special issue of Frontiers in Psychology on the psychology of magic.  I have also (with two former students) mapped out the perceptual and cognitive characteristics of common playing cards; this work is intended to be a foundation for future studies of card magic.  More recent work based on this (in Consciousness and Cognition) shows that the control of apparently voluntary choice (based on principles used by magicians) can be successfully achieved in the lab.


5.     Mindsight.  Under certain conditions observers can sense a change, but not see it (i.e., have a visual experience of it) for several seconds (Psychological Science, 2004).  Essentially, observers can reliably feel "in their gut" that something is happening, even though they have no visual experience of it.  (It should be pointed out that this effect is still mediated visually--the signal must still come in through the eyes.)  In a way, this effect is similar to blindsight, except that (a) the experience is still a conscious one of "something happening", and (b) it is obtained from normal observers rather than patients with lesions.  It may be that this effect corresponds to what is commonly believed to be the "sixth sense".  Controversy exists as to the ultimate cause of this phenomenon, but several recent studies (e.g., Galpin et al., 2008, Busch et al, 2010; Howe & Webb, 2014) support the original proposal.


6.     Inattentional blindness.  When an item is not attended by an observer, it often goes unnoticed.  The nature of this inattentional blindness is currently being investigated--i.e., whether attention is actually necessary for visual experience, and whether the inability to report an unattended item is actually created by a lack of perception, or a lack of memory.  A related issue also being investigated is the kinds of perceptual processes that can and cannot be carried out during an event reported as unseen.


7.     Nonconscious intelligence.  This project looks at whether there might exist a cognitive subsystem that is nonconscious but nevertheless can still carry out important aspects of cognition.  Earlier work in our lab suggested there may exist knowledge that cannot be accessed consciously, but that can be accessed via nonconscious responses such as Ouija movements.  Current work is further investigating the nature of this divide, and whether similar results can be obtained using other forms of nonconscious response.




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Last updated 12 Jun 2021