Ronald A Rensink | University of British Columbia (original) (raw)

Visual Attention & Scene Perception by Ronald A Rensink

Phenomenal Qualities: Sense, Perception, and Consciousness, Aug 2015

It is suggested that the relationship between visual attention and conscious visual experience ca... more It is suggested that the relationship between visual attention and conscious visual experience can be simplified by distinguishing different aspects of both visual attention and visual experience. A set of principles is first proposed for any possible taxonomy of the processes involved in visual attention. A particular taxonomy is then put forward that describes five such processes, each with a distinct function and characteristic mode of operation. Based on these, three separate kinds—or possibly grades—of conscious visual experience can be distinguished, each associated with a particular combination of attentional processes.

Psychological Science, 1997

Oxford Handbook of Cognitive Psychology, 2013

Our visual experience of the world is one of diverse objects and events, each with particular col... more Our visual experience of the world is one of diverse objects and events, each with particular colors, shapes, and motions. This experience is so coherent, so immediate, and so effortless that it seems to result from a single system that lets us experience everything in our field of view. But however appealing, this belief is mistaken: there are severe limits on what can be visually experienced. Performance is evidently affected by a factor within the observer which enables certain kinds of perception to occur, but is limited in some way. This factor is generally referred to as attention. This article surveys several of the major issues in our understanding of attention, and how it relates to perception. Among other things, it organizes the known body of research results into five main classes, each corresponding to a particular type of attentional mechanism.

Psyche, 16(1), 68-78, 2010

This paper discusses several key issues concerning consciousness and human vision. A brief overvi... more This paper discusses several key issues concerning consciousness and human vision. A brief overview is presented of recent developments in this area, including issues that have been resolved and issues that remain unsettled. Based on this, three Hilbert questions are proposed. These involve three related sets of issues: the kinds of visual experience that exist, the kinds of visual attention that exist, and the ways that these relate to each other.

Emerging Trends in the Social and Behavioral Sciences: An Interdisicplinary, Searchable, and Linkable Resource, 2015

This article discusses several key issues concerning the study of attention and its relation to v... more This article discusses several key issues concerning the study of attention and its relation to visual perception, with an emphasis on behavioral and experiential aspects. It begins with an overview of several classical works carried out in the latter half of the 20th century, such as the development of early filter and spotlight models of attention. This is followed by a survey of subsequent research that extended or modified these results in significant ways. It covers current work on various forms of induced blindness and on the capabilities of nonattentional processes. It also includes proposals about how a "just-in-time" allocation of attention can create the impression that we see our surroundings in coherent detail everywhere, as well as how the failure of such allocation can result in various perceptual deficits. The final section examines issues that have received little consideration to date, but may be important for new lines of research in the near future. These include the prospects for a better characterization of attention, the possibility of more systematic explanations, factors that may significantly modulate attentional operation, and the possibility of several kinds of visual attention and visual experience.

Trends in Cognitive Sciences, 2005

Annual Review of Psychology, 2002

Progress in Brain Research, 2002

It is argued that change perception can provide a powerful way to explore various aspects of visi... more It is argued that change perception can provide a powerful way to explore various aspects of vision, such as visual attention and the accumulation of information across saccades. Several studies of change perception are discussed, and their results consolidated with existing knowledge to cast new light on our understanding of the visual system.

Vision and Attention, 2001

In Encyclopedia of Consciousness, Vol 1. W. Banks (ed). New York: Elsevier. pp. 47-59. , 2009

As observers, we generally have a strong impression of seeing everything in front of us at any mo... more As observers, we generally have a strong impression of seeing everything in front of us at any moment. But compelling as it is, this impression is false – there are severe limits to what we can consciously experience in everyday life. Much of the evidence for this claim has come from two phenomena: change blindness (CB) and inattentional blindness (IB). CB refers to the failure of an observer to visually experience changes that are easily seen once noticed. This can happen even if the changes are large, constantly repeat, and the observer has been informed that they will occur. A related phenomenon is IB – the failure to visually experience an object or event when attention is directed elsewhere. For example, observers may fail to notice an unexpected object that enters their visual field, even if this object is large, appears for several seconds, and has important consequences for the selection of action. Both phenomena involve a striking failure to report an object or event that is easily seen once noticed. As such, both are highly counterintuitive, not only in the subjective sense that observers have difficulty believing they could fail so badly at seeing but also in the objective sense that these findings challenge many existing ideas about how we see. But as counterintuitive as these phenomena are, progress has been made in understanding them. Indeed, doing so has allowed us to better understand the limitations of human perception in everyday life and to gain new insights into how our visual systems create the picture of the world that we experience each moment our eyes are open.

Inattentional Blindness (IB) is the failure to see the presence of an item when it is not attende... more Inattentional Blindness (IB) is the failure to see the presence of an item when it is not attended. Previous studies (e.g., Neisser & Becklen, 1975; Mack & Rock, 1998) relied on having the observer attend to one part of a visual display and then presenting an unexpected—and thus unattended—part that the observer is subsequently queried about. But the need for an unexpected stimulus creates problems. For example, the test stimulus is unexpected only the first time it appears, making extensive exploration of IB difficult. And at the theoretical level, it leaves open the possibility that IB is not really a failure to see the stimulus, but rather is a failure to remember it long enough to be queried about it (Wolfe, 1999).

To address these concerns, a “locked onset” technique was developed in which a test stimulus appeared the moment the observer attended to some other part of the display. In each trial, observers viewed a set of items that briefly appeared and then made a sudden change; a test stimulus then appeared in the center of this display on half the trials. Observers were asked to report whether the monitored items did or did not change uniformly, and whether the test stimulus appeared. The onset of this stimulus was locked to the moment the monitored changes occurred, so that attention could not be easily given to it. Detection rates therefore indicate whether or not observers are blind to an unattended stimulus even when it is expected.

Results showed blindness rates comparable to those reported in previous studies, even when there were 192 trials per observer, and test stimuli were displayed for 400 ms. Since observers were prepared to respond to the test stimulus, this shows that IB is due to a failure to see rather than a failure to remember. These results also suggest that the locked onset technique may form a simple and practical basis for the exploration of IB.

Behavioral and Brain Sciences, 2001

Encyclopedia of Perception. (E. Bruce Goldstein, ed.) , 2009

Change detection is the noticing of change in the world around us. For example, when driving in t... more Change detection is the noticing of change in the world around us. For example, when driving in traffic, the vehicles around us constantly change their position, and sometimes their speed and direction as well. In order to avoid collisions, we must notice any such changes and respond to them. More generally, the ability to detect change is important for coping with everyday life; humans (and most animals) are consequently very good at it. However, our knowledge of how changes are detected remains incomplete. The progress that has recently been made owes its existence to two related developments: (i) a realization of some of the confusions and assumptions built into our previous ideas about change, and (ii) new methodologies that allow it to be more effectively isolated and studied.

An important step is to clarify the meaning of the terms themselves. As used here, "change detection" is restricted to the noticing of a change (i.e., the observer seeing that a change exists) via the use of vision. This can include the related abilities of identifying the change (i.e., seeing what it is), as well as localizing it (i.e., seeing where it is), although these abilities likely involve somewhat different mechanisms.

An adequate understanding of change detection has been difficult to achieve. Part of this is due to the nature of change itself. Although the concept of change appears simple, attempts to formalize it have shown otherwise. For example, change requires that some aspect of an object remain constant while another aspect does not, a situation that has not been completely resolved by present-day philosophers. Furthermore, our intuitions about change detection are often highly inaccurate. For example, we generally believe that we could easily detect any change in front of us provided that its size is sufficiently large. But we can be amazingly "blind" to such changes, failing to detect them even when they are large, repeatedly made, and are expected. Such change blindness is a phenomenon strikingly at odds with our intuitions about how change detection should work. However, such counterintuitive results have taught us much about what change detection is and how it works.

Phenomenal Qualities: Sense, Perception, and Consciousness, Aug 2015

Psychological Science, 1997

Oxford Handbook of Cognitive Psychology, 2013

Psyche, 16(1), 68-78, 2010

Emerging Trends in the Social and Behavioral Sciences: An Interdisicplinary, Searchable, and Linkable Resource, 2015

Trends in Cognitive Sciences, 2005

Annual Review of Psychology, 2002

Progress in Brain Research, 2002

Vision and Attention, 2001

In Encyclopedia of Consciousness, Vol 1. W. Banks (ed). New York: Elsevier. pp. 47-59. , 2009

Behavioral and Brain Sciences, 2001

Encyclopedia of Perception. (E. Bruce Goldstein, ed.) , 2009

Attention, Perception and Psychophysics, Jun 2016

East Asians and Westerners differ in various aspects of perception and cognition. For example, vi... more East Asians and Westerners differ in various aspects of perception and cognition. For example, visual memory for East Asians is believed to be more influenced by the contextual aspects of a scene than is the case for Westerners (Masuda & Nisbett in Journal of Personality and Social Psychology, 81, 922–934, 2001). There are also differences in visual search: For Westerners, search is faster for a long line among short ones than for a short line among long ones, whereas this difference does not appear to hold for East Asians (Ueda et al., 2016). However, it is unclear how these group-level differences originate. To investigate the extent to which they depend upon environment, we tested visual search and visual memory in East Asian immigrants who had lived in Canada for different amounts of time. Recent immigrants were found to exhibit no search asymmetry, unlike Westerners who had spent their lives in Canada. However, immigrants who had lived in Canada for more than 2 years showed performance comparable to that of Westerners. These differences could not be explained by the general analytic/holistic processing distinction believed to differentiate Westerners and East Asians, since all observers showed a strong holistic tendency for visual recognition. The results instead support the suggestion that exposure to a new environment can significantly affect the particular processes used to perceive a given stimulus.

Perception, 2004

We show that cast shadows can have a significant influence on the speed of visual search. In par... more We show that cast shadows can have a significant influence on the speed of visual search. In particular, we find that search based on the shape of a region is affected when the region is darker than the background and corresponds to a shadow formed via lighting from above. Results support the proposal that an early-level system rapidly identifies regions as shadows and then discounts them, making their shapes more difficult to access. Several constraints used by this system are mapped out, including constraints on the luminance and texture of the shadow region, and on the nature of the item casting the shadow. Among other things, this system is found to distinguish between line elements (items containing only edges) and surface elements (items containing visible surfaces), with only the latter deemed capable of casting a shadow.

We show that early vision can use monocular cues to rapidly complete partially-occluded objects. ... more We show that early vision can use monocular cues to rapidly complete partially-occluded objects. Visual search for easily-detected fragments becomes difficult when the completed shape is similar to others in the display; conversely, search for fragments that are difficult to detect becomes easy when the completed shape is distinctive. Results indicate that completion occurs via the occlusion-triggered removal of occlusion

Psychological Review, 1995

Psychological Science, 1990

Psychological Review, 1991

Proceedings of the Thirteenth Annual Conference of the Cognitive Science Society, 1991

Journal of Experimental Psychology: General, 2022

Four experiments investigated the extent to which abstract quantitative information can be convey... more Four experiments investigated the extent to which abstract quantitative information can be conveyed by basic visual features. This was done by asking observers to estimate and discriminate Pearson correlation in graphical representations where the first data dimension of each element was encoded by its horizontal position, and the second by the value of one of its visual features; perceiving correlation then requires combining the information in the two encodings via a common abstract representation. Four visual features were examined: luminance, color, orientation, and
size. All were able to support the perception of correlation. Indeed, despite the strikingly different appearances of the associated stimuli, all gave rise to performance that was much the same: just noticeable difference was a linear function of distance from complete correlation, and estimated correlation a logarithmic function of this distance. Performance differed only in regards to the level of noise in the feature, with these values compatible with estimates of channel capacity encountered in classic experiments on absolute perceptual magnitudes. These results suggest that quantitative information can be conveyed by visual features that are abstracted at relatively low levels of visual processing, with little representation of the original sensory property. It is proposed that this is achieved via an abstract parameter space in which the values in each perceptual dimension are normalized to have the same means and variances, with perceived correlation based on the shape of the joint probability density function of the resultant elements.

Journal of Vision, 2021

Traditionally, vision science and information/data visualization have interacted by using knowled... more Traditionally, vision science and information/data visualization have interacted by using knowledge of human vision to help design effective displays. It is argued here, however, that this interaction can also go in the opposite direction: the investigation of successful visualizations can lead to the discovery of interesting new issues and phenomena in visual perception. Various studies are reviewed showing how this has been done for two areas of visualization, namely, graphical representations and interaction, which lend themselves to work on visual processing and the control of visual operations, respectively. The results of these studies have provided new insights into aspects of vision such as grouping, attentional selection and the sequencing of visual operations. More generally yet, such results support the view that the perception of visualizations can be a useful domain for exploring the nature of visual cognition, inspiring new kinds of questions as well as casting new light on the limits to which information can be conveyed visually.

Psychonomic Bulletin & Review, 2017

For scatterplots with gaussian distributions of dots, the perception of Pearson correlation r can... more For scatterplots with gaussian distributions of dots, the perception of Pearson correlation r can be described by two simple laws: a linear one for discrimination, and a logarithmic one for perceived magnitude (Rensink & Baldridge, 2010). The underlying perceptual mechanisms, however, remain poorly understood. To cast light on these, four different distributions of datapoints were examined. The first had 100 points with equal variance in both dimensions. Consistent with earlier results, just noticeable difference (JND) was a linear function of the distance away from r = 1, and the magnitude of perceived correlation a logarithmic function of this quantity. In addition, these laws were linked, with the intercept of the JND line being the inverse of the bias in perceived magnitude. Three other conditions were also examined: a dot cloud with 25 points, a horizontal compression of the cloud, and a cloud with a uniform distribution of dots. Performance was found to be similar in all conditions. The generality and form of these laws suggest that what underlies correlation perception is not a geometric structure such as the shape of the dot cloud, but the shape of the probability distribution of the dots, likely inferred via a form of ensemble coding. It is suggested that this reflects the ability of observers to perceive the information entropy in an image, with this quantity used as a proxy for Pearson correlation.

Oncology Informatics: Using Health Information Technology to Improve Processes and Outcomes in Cancer Care, ch. 15, Mar 25, 2016

Recent years have seen an explosion in the use of medical informatics, the application of computi... more Recent years have seen an explosion in the use of medical informatics, the application of computing power to medicine. This development has created great opportunities for improving the science and practice of oncology and cancer care, as illustrated in many other chapters in this volume. In principle, getting more information faster should let us make better, more informed decisions. However, any such system must face a critical bottleneck: the human being who must make sense of this information. An oncology informatics system typically presents information visually—for example, in the form of a dashboard, a graph, or a digital mammogram. But the nature of this bottleneck—the limitations of the human observer—is often not well understood, and so often is not adequately considered when designing a medical informatics system. This can cause problems.

In this chapter, we start with the view that any system for processing information is incomplete unless the human observer—the person supposed to explore, analyze, and ultimately use the information—is taken into account. We do not pretend that this is a new insight. There is a considerable body of work on improving the effectiveness of systems to convey quantitative information visually. To date, however, this has been a fairly empirical tradition. In contrast, we suggest here that oncology informatics could be substantially improved by drawing on basic research in visual perception to offer a better understanding of how best to present data and images. To this end, we begin with an introduction to the functional properties of the human visual system. We follow this with a general discussion of how knowledge of vision science can be applied to the field of visualization, which is concerned with developing effective ways of conveying information visually. Then, to illustrate how this approach can be applied to the design of improved informatics systems, we discuss in detail two specific examples: the effective display of quantitative data, and the effective display of medical images.

Handbook of Human Centric Visualization, 2014

This paper explores the extent to which a scientific framework for visualization might be possibl... more This paper explores the extent to which a scientific framework for visualization might be possible. It presents several potential parts of a framework, illustrated by application to the visualization of correlation in scatterplots. The first is an extended-vision thesis, which posits that a viewer and visualization system can be usefully considered as a single system that perceives structure in a dataset, much like "basic" vision perceives structure in the world. This characterization is then used to suggest approaches to evaluation that take advantage of techniques used in vision science. Next, an optimal-reduction thesis is presented, which posits that an optimal visualization enables the given task to be reduced to the most suitable operations in the extended system. A systematic comparison of alternative designs is then proposed, guided by what is known about perceptual mechanisms. It is shown that these elements can be extended in various ways—some even overlapping with parts of vision science. As such, a science of some kind appears possible for at least some parts of visualization. It would remain distinct from design practice, but could nevertheless assist with the design of visualizations that better engage human perception and cognition.

Computer Graphics Forum, 29, 1203-1210, 2010

We present a rigorous way to evaluate the visual perception of correlation in scatterplots, based... more We present a rigorous way to evaluate the visual perception of correlation in scatterplots, based on classical psychophysical methods originally developed for simple properties such as brightness. Although scatterplots are graphically complex, the quantity they convey is relatively simple. As such, it may be possible to assess the perception of correlation in a similar way.Scatterplots were each of 5.0° extent, containing 100 points with a bivariate normal distribution. Means were 0.5 of the range of the points, and standard deviations 0.2 of this range. Precision was determined via an adaptive algorithm to find the just noticeable differences (jnds) in correlation, i.e., the difference between two side-by-side scatterplots that could be discriminated 75% of the time. Accuracy was measured by direct estimation, using reference scatterplots with fixed upper and lower values, with a test scatterplot adjusted so that its correlation appeared to be halfway between these. This process was recursively applied to yield several further estimates.Results of the discrimination tests show jnd(r) = k (1/b – r), where r is the Pearson correlation, and parameters 0 < k, b < 1. Integration yields a subjective estimate of correlation g(r) = ln(1 – br) / ln(1 – b). The values of b found via discrimination closely match those found via direct estimation. As such, it appears that the perception of correlation in a scatterplot is completely described by two related performance curves, specified by two easily-measured parameters.

IEEE Transactions on Visualization and Computer Graphics, 2014

We describe a method for assessing the visualization literacy (VL) of a user. Assessing how well ... more We describe a method for assessing the visualization literacy (VL) of a user. Assessing how well people understand
visualizations has great value for research (e. g., to avoid confounds), for design (e. g., to best determine the capabilities of an audience), for teaching (e. g., to assess the level of new students), and for recruiting (e. g., to assess the level of interviewees). This paper proposes a method for assessing VL based on Item Response Theory. It describes the design and evaluation of two VL tests for line graphs, and presents the extension of the method to bar charts and scatterplots. Finally, it discusses the reimplementation of these tests for fast, effective, and scalable web-based use.

IEEE Computer Graphics and Applications, 35, Mar 2015

Visual analytics (VA) combines the strengths of human and machine intelligence to enable the disc... more Visual analytics (VA) combines the strengths of human and machine intelligence to enable the discovery of interesting patterns in challenging datasets. Historically, most attention
has been given to developing the machine component—for example, machine learning or the human-computer interface. However, it is also essential to develop the abilities of the analysts themselves, especially at the beginning of their careers.

Proceedings of the Second International Symposium on Smart Graphics, 2002

Human Attention in Digital Environments, 2011

Integrated Models of Cognitive Systems, 2007

Encyclopedia of Perception. (E. Bruce Goldstein, ed.), 2009

Visual displays are depictions that convey information by means of elements beyond pure text. Exa... more Visual displays are depictions that convey information by means of elements beyond pure text. Examples include diagrams, maps, and computer interfaces. The common factor in all of these is their reliance on the "visual intelligence" of humans to organize graphically-presented information in a way that makes it easier to understand. The design of an effective visual display is based on general principles involving both the nature of human vision and the nature of the task. The particular medium used--paper, canvas, computer monitor, etc.--is irrelevant.

The use of visual displays has a long history. Drawings were used tens of thousand of years ago, likely for teaching. With the advent of writing, text became the dominant means of transmitting information, and reduced the involvement of visual perception to that of recognizing characters or words. But the use of drawings never completely disappeared. And displays such as maps were discovered to be a highly effective way of describing the two-dimensional surface of the Earth. More generally, it has been found that when a visual display draws on the appropriate mechanisms of visual perception, it can present information in a way that allows a viewer to understand it far more quickly, accurately, and memorably than if presented by text alone. It has also been found that successful design techniques sometimes point to previously unknown mechanisms.

When used to convey more abstract information by more metaphoric means, visual displays cross over into the domain of fine art. The two domains have a great deal of overlap, drawing on many of the same perceptual mechanisms. They are also very compatible—an effective visual display can have great esthetic appeal. However, the focus of visual display design is on the communication of relatively concrete information, with emphasis on speed and accuracy. As such, different principles are often involved, principles that depend on the nature of the task and on the tradition in which they were developed.

A brief review is presented of recent work in vision science showing important limits on the abil... more A brief review is presented of recent work in vision science showing important limits on the ability of observers to carry out various tasks. First, it has been found that only a few moving items can be tracked at any time, even after considerable practice. Second, observers can often miss the appearance of unexpected objects or events, even if these are large. Third, observers can often miss changes that occur in front of them, even when these changes are large, repeated, and expected. Finally, observers simply cannot see two changes at a time, no matter how hard they try. The explanation for these effects is briefly discussed, along with the reasons why these limits are not usually noticed. Some suggestions are also given about what (if anything) can be done to mitigate their effects in regards to the visual monitoring task of the anesthesiologist.

Our perceptual experience is largely based on prediction, and as such can be influenced by knowle... more Our perceptual experience is largely based on prediction, and as such can be influenced by knowledge of forthcoming events. This susceptibility is commonly exploited by magicians. In the Vanishing Ball Illusion, for example, a magician tosses a ball in the air a few times and then pretends to throw the ball again, whilst secretly concealing it in his hand. Most people claim to see the ball moving upwards and then vanishing, even though it did not leave the magician’s hand (Kuhn & Land, 2006; Triplett, 1900). But what exactly can such illusions tell us? We investigated here whether seeing a real action before the pretend one was necessary for the Vanishing Ball Illusion. Participants either saw a real action immediately before the fake one, or only a fake action. Nearly one third of participants experienced the illusion with the fake action alone, while seeing the real action beforehand enhanced this effect even further. Our results therefore suggest that perceptual experience relies both on long‐term knowledge of what an action should look like, as well as exemplars from the immediate past. In addition, whilst there was a forward displacement of perceived location in perceptual experience, this was not found for oculomotor responses, consistent with the proposal that two separate systems are involved in visual perception.

(For paper, go to http://authors.elsevier.com/a/1SHZj2Hx2Q8yv)

Forcing occurs when a magician influences the audience’s decisions without their awareness. To i... more Forcing occurs when a magician influences the audience’s decisions without their awareness. To investigate the mechanisms behind this effect, we examined several stimulus and personality predictors. In Study 1, a magician flipped through a deck of playing cards while participants were asked to choose one. Although the magician could influence the choice almost every time (98%), relatively few (9%) noticed this influence. In Study 2, participants observed rapid series of cards on a computer, with one target card shown longer than the rest. We expected people would tend to choose this card without noticing that it was shown longest. Both stimulus and personality factors predicted the choice of card, depending on whether the influence was noticed. These results show that combining real-world and laboratory research can be a powerful way to study magic and can provide new methods to study the feeling of free will.

Frontiers in Psychology, Feb 2, 2015

Over the centuries, magicians have developed extensive knowledge about the manipulation of the hu... more Over the centuries, magicians have developed extensive knowledge about the manipulation of the human mind—knowledge that has been largely ignored by psychology. It has recently been argued that this knowledge could help improve our understanding of human cognition and consciousness. But how might this be done? And how much could it ultimately contribute to the exploration of the human mind?

We propose here a framework outlining how knowledge about magic can be used to help us understand the human mind. Various approaches—both old and new—are surveyed, in terms of four different levels. The first focuses on the methods in magic, using these to suggest new approaches to existing issues in psychology. The second focuses on the effects that magic can produce, such as the sense of wonder induced by seeing an apparently impossible event. Third is the consideration of magic tricks—methods and effects together—as phenomena of scientific interest in their own right. Finally, there is the organization of knowledge about magic into an informative whole, including the possibility of a science centered around the experience of wonder.

The past few years have seen a resurgence of interest in the scientific study of magic. Despite ... more The past few years have seen a resurgence of interest in the scientific study of magic. Despite being only a few years old, this "new wave" has already resulted in a host of interesting studies, often using methods that are both powerful and original. These developments have largely borne out our earlier hopes (Kuhn, Amlani, & Rensink, 2008) that new opportunities were available for scientific studies based on the use of magic. And it would seem that much more can still be done along these lines.

But in addition to this, we also suggested that it might be time to consider developing an outright science of magic—a distinct area of study concerned with the experience of wonder that results from encountering an apparently impossible event . To this end, we proposed a framework as to how this might be achieved (Rensink & Kuhn, 2015). A science can be viewed as a systematic method of investigation involving three sets of issues: (i) the entities considered relevant, (ii) the kinds of questions that can be asked about them, and (iii) the kinds of answers that are legitimate (T Kuhn, 1970). In the case of magic, we suggested that this could be done at three different levels, each focusing on a distinct set of issues concerned with the nature of magic itself: (i) the nature of magical experience, (ii) how individual magic tricks create this experience, and (iii) organizing knowledge of the set of known tricks in a more comprehensive way (Rensink & Kuhn, 2015). Our framework also included a base level focused on how the methods of magic could be used as tools to investigate issues in existing fields of study.

Lamont & colleagues (Lamont, 2010; Lamont, Henderson, & Smith, 2010) raised a number of concerns about the possibility of such a science, which we have addressed (Rensink & Kuhn, 2015). More recently, Lamont (2015) raised a new objection, arguing that although base-level work (i.e., applications of magic methods) might be useful, there is too little structure in magic tricks for them to be studied in a systematic way at the other levels, ruling out a science of magic. However, we argue here that although this concern raises some interesting challenges for this science, it does not negate the possibility that it could exist, and could contribute to the study of the mind.

Frontiers in Psychology, 2014

Magicians use misdirection to prevent you from realizing the methods used to create a magical eff... more Magicians use misdirection to prevent you from realizing the methods used to create a magical effect, thereby allowing you to experience an apparently impossible event. Magicians have acquired much knowledge about misdirection, and have suggested several taxonomies of misdirection. These describe many of the fundamental principles in misdirection, focusing on how misdirection is achieved by magicians. In this article we review the strengths and weaknesses of past taxonomies, and argue that a more natural way of making sense of misdirection is to focus on the perceptual and cognitive mechanisms involved. Our psychologically-based taxonomy has three basic categories, corresponding to the types of psychological mechanisms affected: perception, memory, and reasoning. Each of these categories is then divided into subcategories based on the mechanisms that control these effects. This new taxonomy can help organize the magicians’ knowledge of misdirection in a meaningful way, and facilitate the dialogue between magicians and scientists.

We examined the perceptual and cognitive characteristics of the playing cards commonly used in th... more We examined the perceptual and cognitive characteristics of the playing cards commonly used in the Western world. Specifically, we measured their visibility, memorability, likability, and verbal and visual accessibility. Based on visibility and memorability, four groups of cards were distinguished: the Ace of Spades, other Aces, number cards, and face cards. Within each of these groups, there were few differences due to value or suit. Based on likability and accessibility, three additional groups were distinguished: the Ace of Hearts, Queen of Hearts, and King of Hearts. Several interesting relations were found between how people remember, like, and access cards; some of these were similar to effects found in studies of visual perception, while others seemed entirely new. Our results demonstrate that rigorous examination of real-world stimuli can shed light on the perception of ordinary objects, as well as help us understand why magic works in the mind.

Trends in Cognitive Sciences, 2008

Frontiers in Psychology, 2014

Human vision briefly retains a trace of a stimulus after it disappears. This trace—iconic memory... more Human vision briefly retains a trace of a stimulus after it disappears. This trace—iconic memory—is often believed to be a surrogate for the original stimulus, a representational structure that can be used as if the original stimulus were still present. To investigate its nature, a flicker-search paradigm was developed that relied upon a full scan (rather than partial report) of its contents. Results show that for visual search it can indeed act as a surrogate, with little cost for alternating between visible and iconic representations. However, the duration over which it can be used depends on the type of task: some tasks can use iconic memory for at least 240 ms, others for only about 190 ms, while others for no more than about 120 ms. The existence of these different limits suggests that iconic memory may have multiple layers, each corresponding to a particular level of the visual hierarchy. In this view, the inability to use a layer of iconic memory may reflect an inability to maintain feedback connections to the corresponding representation.

Psychological Science, 2005

A modified visual search task demonstrates that humans are very good at resuming a search after i... more A modified visual search task demonstrates
that humans are very good at resuming a search after it
has been momentarily interrupted. This is shown by exceptionally
rapid response time to a display that reappears
after a brief interruption, even when an entirely different
visual display is seen during the interruption and two
different visual searches are performed simultaneously.
This rapid resumption depends on the stability of the visual
scene and is not due to display or response anticipations.
These results are consistent with the existence of an iterative
hypothesis-testing mechanism that compares information
stored in short-term memory (the perceptual hypothesis)
with information about the display (the sensory pattern).
In this view, rapid resumption occurs because a hypothesis
based on a previous glance of the scene can be tested very
rapidly in a subsequent glance, given that the initial hypothesis-
generation step has already been performed.

Journal of Vision, 2010

If a display is interrupted while participants search for a target (a T among Ls) they are able t... more If a display is interrupted while participants search for a target (a T among Ls) they are able to resume search rapidly when the display reappears (Enns, Rensink, Vandenbeld & Lleras, 2003). This has been called Rapid Resumption (RR) because whereas correct responses to an initial display do not begin before 500 ms have elapsed, many responses following its reappearance are initiated within 100–400 ms. In this study we tested for the influence of high-level strategies on RR, by varying the likelihood that the display would reappear. On repeated-look trials, each presentation was 100 ms, separated by intervals of 900 ms. On single-look trials, only one 100 ms presentation occurred. Experiment 1 included a random mix of 80% repeated looks and 20% single looks; Experiment 2 contained an equal mix of repeated and single looks (50%). If RR depends on participant's strategy then it should be reduced in Experiment 2, where repeated looks were much less likely to occur. Also, when uncertain about the target identity, participants may withhold responses while waiting for confirmation if they know reappearance is likely. Consistent with a strategic component, the results for repeated-look trials showed much stronger evidence for RR in Experiment 1 than in Experiment 2. The results of the single look trials also supported this interpretation: participants were more likely to find the target in a single look when these trials were more frequent. However, neither experiment provided evidence that participants were withholding responses following a single-look: responses made once participants realized the display would not reappear contained an equal number of correct and incorrect responses. These findings show that (1) RR can be influenced by strategy, but (2) these do not include the strategic withholding of responses. Instead, RR is interpreted as an index of the interactions that normally occur between sensory input and perceptual hypotheses in everyday vision.

Attention Perception & Psychophysics, 2007

Visual search can be resumed more rapidly following a brief interruption to an old display than i... more Visual search can be resumed more rapidly following a brief interruption to an old display than it can be initiated on a new display, pointing to a critical role for memory in search (Lleras, Rensink, & Enns, 2005). Here, we examine how thisrapid resumption is affected by changes made to the display during the interruption of search. Rapid resumption was found to depend on the prior presentation of the target, not merely the distractor items (Experiment 1), and was unaffected by the relocation of all distractor items (Experiment 2). Further, whereas changes to response-irrelevant features of the target did not eliminate rapid resumption (Experiment 3), changes to response-relevant features did (Experiment 4). These results point to the target specificity of rapid resumption and are consistent with reentrant theories of visual awareness.

Perception, 29(suppl.):99-100, 2000

"Flicker" displays were created where an original and a modified image continually alternated, wi... more "Flicker" displays were created where an original and a modified image continually alternated, with brief blanks between them. Each image was an array of simple rectangles, half having one value of a feature (e.g., horizontal), the rest a different value (e.g., vertical). In half the trials, one of the items changed its value; in the remainder, no changes occurred. Observers were asked to detect whether a change was present in each trial.

As the display time in each alternation cycle is increased, search slopes become proportional to display time, with the proportionality constant a direct estimate of attentional capacity (Rensink, 2000, Visual Cognition 7, 345-376). Two display times were examined here: 80 ms and 800 ms. For orientation changes, slopes for the two conditions differed significantly, with the long-display slope corresponding to a capacity of 5.3 items. However, for contrast polarity, slopes did not differ, indicating a capacity of at least 10. It is suggested that visual attention still has a capacity of 4-5 units, but that items of similar polarity are grouped such that they effectively form a single unit. Such grouping was also found for size and color.

Journal of Vision, 2010

Previous studies of the decay of information in visual short-term memory have made the assumption... more Previous studies of the decay of information in visual short-term memory have made the assumption that all visual properties decay in the same way. The present study challenges this assumption by investigating the individual decay characteristics of size, color, and ...

Spatial Cognition and Computation, 1999

Journal of Environmental Psychology, 1997

Ideomotor actions are movements that are unconsciously initiated, associated with an absence of ... more Ideomotor actions are movements that are unconsciously initiated,
associated with an absence of any sense of agency, and convey thought rather than respond to sensory stimulation. The question examined here is whether ideomotor actions can express thoughts that are unconscious. We investigated this via the use of implicit long-term semantic memory, which is not available to conscious recall. We compared accuracy of answers to yes/no questions, using both conscious report and ideomotor response (Ouija board response). Results show that when participants believed they knew the answer, accuracies in the two response modalities
did not differ, but when they did not believe they knew it, accuracy was at chance for conscious report but was significantly higher for Ouija response. These results demonstrate that implicit semantic memory can be expressed through ideomotor actions. They also demonstrate that ideomotor actions can provide a powerful new methodology for studying implicit processes in cognition.

Psychological Science, 2004

Journal of Experimental Psychology: General, 2000

Journal of Experimental Psychology …, 2000

Journal of Experimental Psychology-general, 2002

... Collaborative Colleagues: Brian Fisher: colleagues. Sidney Fels: colleagues. Karon MacLean: c... more ... Collaborative Colleagues: Brian Fisher: colleagues. Sidney Fels: colleagues. Karon MacLean: colleagues. Tamara Munzner: colleagues. Ronald Rensink: colleagues. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2009 ACM, Inc. ...

Behavior Research Methods, 1990

Pascal routines are described for several real-time operations on Macintosh computers. Methods ar... more Pascal routines are described for several real-time operations on Macintosh computers. Methods are presented for millisecond timing and for high-speed transfer of arbitrary bit-image displays to the screen. All routines are based on Toolbox procedures available on virtually all Macintosh computers.

Behavior Research Methods, 1991

We describe an update to our visual search software for the Macintosh line of computers. The new ... more We describe an update to our visual search software for the Macintosh line of computers. The new software, VSearch Color, gives users access to the full-color capabilites of the Macintosh II line. One of the key features of the new software is its ability to treat graphics information separately from color information. This makes it easy to study color independently of form, to design experiments based on isoluminant stimuli, and to incorporate texture segregation, visual identification, number discrimination, adaptation, masking, and spatial cuing into the basic visual search paradigm.

Behavior Research Methods, 1990

In this paper, we describe software that turns a Macintosh computer into an off-the-shelf tool fo... more In this paper, we describe software that turns a Macintosh computer into an off-the-shelf tool for experiments on visual search. Our design goals included portability (between members of the Macintosh computer family and between various research settings), user-friendliness (equivalent to Macintosh programming standards), flexibility (to allow replication and extension of important experiments on visual search), and adaptability (very short design-to-data and data-to-analysis turnaround times). We describe how the software meets these goals in three major phases of an experiment: stimulus construction, experimental control, and statistical analysis. We then list several landmark studies of visual search that can be easily designed and extended with the software. Finally, we outline plans for expanding the experimental variations that will be supported in future versions of the software.

Behavior Research Methods, Instruments, &amp Computers, 1990

This work investigates the ability of the human visual system to discriminate self-similar Gaussi... more This work investigates the ability of the human visual system to discriminate self-similar Gaussian random textures. The power spectra of such textures are similar to themselves when rescaled by some factor h > 1. As such, these textures provide a natural domain for testing the hypothesis that texture perception is based on a set of spatial-frequency channels characterized by filters of similar shape.

Journal of Vision, Oct 20, 2020

Journal of Vision, Sep 6, 2019

Journal of Vision, Sep 1, 2018

Journal of Vision, Sep 1, 2016

Journal of Vision, Aug 31, 2017

Abstract The development of medical informatics—the application of computing power to medicine—ha... more Abstract The development of medical informatics—the application of computing power to medicine—has greatly improved the science and practice of oncology and cancer care, allowing us to make more informed decisions. Despite the development of these new technologies, however, informatics systems are still limited by the nature of the human beings who make sense of the information they process. In this chapter we focus on the problems and the opportunities that result from using human vision to explore datasets and communicate results. We begin with an introduction to the functional properties of the human visual system. This is followed by a discussion of how this knowledge can help us to develop effective ways of visualizing information, effectively “amplifying” the intelligence of the visual system to enable it to detect trends and outliers in a dataset. We then discuss two examples of how this approach can be applied to the design of improved informatics systems: the effective display of quantitative data, and the effective display of medical images.

Journal of Vision, Jul 25, 2013

Peer reviewe

Journal of Experimental Psychology: General, 2000

Journal of Vision, Sep 1, 2016

Journal of Experimental Psychology: General

Magicians have developed a wide range of techniques to influence and control spectators’ choices ... more Magicians have developed a wide range of techniques to influence and control spectators’ choices of such things as card, word, or number. These techniques are what is called forcing. The present paper develops a psychologically-based taxonomy of forcing techniques with two goals in mind. Firstly, it should help uncover the different psychological mechanisms that underlie forcing techniques. Secondly, it should facilitate knowledge transfer between magicians and psychologists. The main division present two basic categories that can be used as a way of focussing separately on (1) decision-making processes and external influences on choices, and (2) links between sense of agency over action and outcome as well as the illusion of control over this outcome. This taxonomy allows us to clearly differentiate between forces in which there is or is not a free choice, and whether this choice has an impact on the following events.

A computational theory is developed that explains how line drawings of polyhedral objects can be ... more A computational theory is developed that explains how line drawings of polyhedral objects can be interpreted rapidly and in parallel at early levels of human vision. The key idea is that a time-limited process can correctly recover much of the three-dimensional structure of these objects when split into concurrent streams, each concerned with a single aspect of scene structure. The work proceeds in five stages. The first extends the framework of Marr to allow a process to be analyzed in terms of resource limitations. Two main concerns are identified: (i) reducing the amount of nonlocal information needed, and (ii) making effective use of whatever information is obtained. The second stage traces the difficulty of line interpretation to a small set of constraints. When these are removed, the remaining constraints can be grouped into several relatively independent sets. It is shown that each set can be rapidly solved by a separate processing stream, and that co-ordinating these streams...

Perception, 1996

High-level allocation of attention is required for detecting changes in images under ‘flicker’ co... more High-level allocation of attention is required for detecting changes in images under ‘flicker’ conditions, ie when an original and a modified image are repetitively alternated, with a blank field between each display (R A Rensink, J K O'Regan, J J Clark, 1995 Perception24 Supplement, 26). But how many items can attention ‘grab’ and compare during each display? To determine this capacity, search experiments were carried out under flicker conditions, with displays formed of arrays of rectangles. In half the trials, displays differed by the position of one of the rectangles; in the other half, displays remained the same. Subjects were asked to determine if a change was occurring between the two displays. Performance was measured for several durations of displays and blank fields. In all cases, search showed a clear serial deployment of attention. Comparing the rate of this deployment against the rate of display alternation yielded the number of items compared at a time. Results ind...