Donald Hoffman
University of California, Irvine, Cognitive Science, Faculty Member
Research Interests:
Marr proposed that human vision constructs “a true description of what is there”. He argued that to understand human vision one must discover the features of the world it recovers and the constraints it uses in the process. Bayesian... more
Marr proposed that human vision constructs “a true description of what is there”. He argued that to understand human vision one must discover the features of the world it recovers and the constraints it uses in the process. Bayesian decision theory (BDT) is used in modern vision research as a probabilistic framework for understanding human vision along the lines laid out by Marr. Marr's contribution to vision research is substantial and justly influential. We propose, however, that evolution by natural selection does not, in general, favor perceptions that are true descriptions of the objective world. Instead, research with evolutionary games shows that perceptual systems tuned solely to fitness routinely outcompete those tuned to truth. Fitness functions depend not just on the true state of the world, but also on the organism, its state, and the type of action. Thus, fitness and truth are distinct. Natural selection depends only on expected fitness. It shapes perceptual systems...
Research Interests:
Pylyshyn's target article argues that perception is not inferential, but this is true only under a narrow construal of inference. A more general construal is possible, and has been used to provide formal theories of many visual... more
Pylyshyn's target article argues that perception is not inferential, but this is true only under a narrow construal of inference. A more general construal is possible, and has been used to provide formal theories of many visual capacities. This approach also makes clear that the evolution of natural constraints need not converge to the “veridical” state of the world.
Research Interests:
Research Interests:
Visual images are ambiguous. Any image, or collection of images, is consistent with an infinite number of possible scenes in the world. Yet we are generally unaware of this ambiguity. During ordinary perception we are generally aware of... more
Visual images are ambiguous. Any image, or collection of images, is consistent with an infinite number of possible scenes in the world. Yet we are generally unaware of this ambiguity. During ordinary perception we are generally aware of only one, or perhaps a few of these possibilities. Human vision evidently exploits certain constraints—assumptions about the world and images formed of it—in order to generate its perceptions. One constraint that has been widely studied by researchers in human and machine vision is the generic-viewpoint assumption. We show that this assumption can help to explain the widely discussed fact that outlines of blobs are ineffective inducers of illusory contours. We also present a number of novel effects and report an experiment suggesting that the generic-viewpoint assumption strongly influences illusory-contour perception.
Research Interests:
Perception is a product of evolution. Our perceptual systems, like our limbs and livers, have been shaped by natu-ral selection. The effects of selection on perception can be studied using evolutionary games and genetic algorithms. To... more
Perception is a product of evolution. Our perceptual systems, like our limbs and livers, have been shaped by natu-ral selection. The effects of selection on perception can be studied using evolutionary games and genetic algorithms. To this end, we define and classify perceptual strategies and al-low them to compete in evolutionary games in a variety of worlds with a variety of fitness functions. We find that verid-ical perceptions—strategies tuned to the true structure of the world—are routinely dominated by nonveridical strategies tuned to fitness. Veridical perceptions escape extinction only if fitness varies monotonically with truth. Thus, a perceptual strategy favored by selection is best thought of not as a win-dow on truth but as akin to a windows interface of a PC. Just as the color and shape of an icon for a text file do not entail that the text file itself has a color or shape, so also our percep-tions of space-time and objects do not entail (by the Invention of Space-Time ...
Research Interests: Psychology, Cognitive Science, Experimental Psychology, Computer Science, Philosophy, and 15 morePerception, Cognition, Complex Networks, Categorization, Learning, Memory, Cognitive Sciences, Planning, Computation, Predictive coding, Cognitive systems, Reference Frame, Behavioral and Social Science Research, Representation Politics, and Active Inference
Research Interests:
We propose that selection favors nonveridical perceptions that are tuned to fitness. Current textbooks assert, to the contrary, that perception is useful because, in the normal case, it is veridical. Intuition, both lay and expert,... more
We propose that selection favors nonveridical perceptions that are tuned to fitness. Current textbooks assert, to the contrary, that perception is useful because, in the normal case, it is veridical. Intuition, both lay and expert, clearly sides with the textbooks. We thus expected that some commentators would reject our proposal and provide counterarguments that could stimulate a productive debate. We are pleased that several commentators did indeed rise to the occasion and have argued against our proposal. We are also pleased that several others found our proposal worth exploring and have offered ways to test it, develop it, and link it more deeply to the history of ideas in the science and philosophy of perception. To both groups of commentators: thank you. Point and counterpoint, backed by data and theory, is the essence of science. We hope that the exchange recorded here will advance the scientific understanding of perception and its evolution. In what follows, we respond to th...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Do images provide a foundation for interstellar communication that is relatively unam- biguous? Is there something special about images that makes them a universal medium of communication, likely to be understood with little difficulty by... more
Do images provide a foundation for interstellar communication that is relatively unam- biguous? Is there something special about images that makes them a universal medium of communication, likely to be understood with little difficulty by extraterrestrial intelli- gences sufficiently advanced that they attempt to contact us via, say, radio or laser? This is the question we address in this chapter. It is natural to suppose pretheoretically that images are a particularly easy medium of communication, one that requires little if any interpretation. Our own subjective experience when we view images is that the process of seeing is usually effortless and almost instantaneous. Moreover, if we wish to create road signs that can be understood by drivers of different native languages, we use pic- tures rather than words, and the pictures are so effective that we trust them to guide the actions of drivers even in cases where a misinterpretation of a sign could have serious consequences. Since...
We analyze the properties of a dynamic color-spreading display created by adding narrow colored flanks to rigidly moving black lines where these lines fall in the interior of a stationary virtual disk. This recently introduced display... more
We analyze the properties of a dynamic color-spreading display created by adding narrow colored flanks to rigidly moving black lines where these lines fall in the interior of a stationary virtual disk. This recently introduced display (Wollschläger et al, 2001 Perception30 1423–1426) induces the perception of a colored transparent disk bounded by strong illusory contours. It provides a link between the classical neon-color-spreading effect and edge-induced color spreading as discussed by Pinna et al (2001 Vision Research41 2669–2676). We performed three experiments to quantitatively study (i) the enhancing influence of apparent motion; (ii) the degrading effect of small spatial discontinuities (gaps) between lines and flanks; and (iii) the spatial extent of the color spreading. We interpret the results as due to varying degrees of objecthood of the dynamically specified disk: increased objecthood leads to increased surface visibility in both contour and color.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests: Neuroscience, Psychology, Perception, Magnetic Resonance Imaging, Motion perception, and 15 moreMedicine, Humans, Form perception, Human Motion, Female, Male, Human Animation, Biological Motion, Motion, Adult, Neuropsychological Tests, photic stimulation, Psychology and Cognitive Sciences, human characteristics, and Medical and Health Sciences
The ability to see complete objects despite occlusion is critical to humans' visual success. Human vision can amodally complete visual objects that are partially occluded, and modally complete visual objects that occlude other... more
The ability to see complete objects despite occlusion is critical to humans' visual success. Human vision can amodally complete visual objects that are partially occluded, and modally complete visual objects that occlude other objects. Previous experiments showed that the perceived strength of a completed contour depends on its support ratio: the ratio of the length of the physically specified contour to the total length of the contour. Other experiments showed that human vision prefers to make modal completions as short as possible, an effect known as Petter's rule. The experiment reported here examined the relationship between Petter's rule and support ratio, showing that both affect modal completion in figures of homogeneous color, but that when they compete Petter's rule dominates. Finally, our results confirm that Petter's rule is an effect of relative gap lengths and not of relative size.
Research Interests:
The perception of transparency is a remarkable feat of human vision: A single stimulation at the retina is interpreted as arising from two (or more) distinct surfaces, separated in depth, in the same visual direction. This feat is... more
The perception of transparency is a remarkable feat of human vision: A single stimulation at the retina is interpreted as arising from two (or more) distinct surfaces, separated in depth, in the same visual direction. This feat is intriguing because physical transparency is neither necessary nor sufficient for phenomenal transparency. Many conditions for phenomenal transparency have been studied, including luminance, chromaticity, stereo depth, apparent motion, and structure from motion. Figural conditions have also been studied, primarily by Gestalt psychologists, resulting in descriptive laws. Here we extend, and make precise, these laws using the genericity principle and the minima rule for part boundaries. We report experiments that support the psychological plausibility of these refinements. The results suggest that the formation of visual objects and their parts is an early process in human vision that can precede the representation of transparency.
Research Interests:
What strategies does human vision use to attend to faces and their features? How are such strategies altered by 2-D inversion or photographic negation? We report two experiments in which these questions were studied with the flicker task... more
What strategies does human vision use to attend to faces and their features? How are such strategies altered by 2-D inversion or photographic negation? We report two experiments in which these questions were studied with the flicker task of the change-blindness literature. In experiment 1 we studied detection of configural changes to the eyes or mouth, and found that upright faces receive more efficient attention than inverted faces, and that faces shown with normal contrast receive more efficient attention than faces shown in photographic negative. Moreover, eyes receive greater attention than the mouth. In experiment 2 we studied detection of local changes to the eyes or mouth, and found the same results. It is well known that inversion and negation impair the perception and recognition of faces. The experiments presented here extend previous findings by showing that inversion and negation also impair attention to faces.
Research Interests:
Research Interests:
Flank transparency is the perception of a colored transparent filter evoked by apparent-motion displays containing as few as two colors. Displays of flank transparency contain a random array of line segments placed on a uniform... more
Flank transparency is the perception of a colored transparent filter evoked by apparent-motion displays containing as few as two colors. Displays of flank transparency contain a random array of line segments placed on a uniform background. Small flanks are added to the line segments if the segments fall in the interior of a moving virtual shape, such as a virtual disk. This leads to the perception of a colored transparent disk with well-defined boundaries moving over the array of lines. Current qualitative and quantitative models of luminance and color conditions for perceptual transparency do not account for flank transparency as they require displays containing at least three different colors.
Research Interests:
Research Interests:
Research Interests: Computer Science, Optics, Medical Imaging, Fiber Optics, Telecommunications, and 15 morePattern Recognition, Photonics, Machine Vision, Infinity, Society, Optical, Curvature, Light, Position, Optical physics, Optometry and Ophthalmology, Three Dimensional, Constraint, Electrical And Electronic Engineering, and Silhouette
Research Interests: Computer Science, Game Theory, Perception, Monte Carlo Simulation, Evolution, and 15 moreEvolutionary Game Theory, Medicine, Theoretical biology, Natural Selection, Biological Sciences, Mathematical Sciences, Sensation, Replicator Dynamics, Animals, Biological evolution, Academic, Normal Distribution, Frequency-dependent selection, Environment, and Archaeology of Natural Places
Research Interests:
It is fruitful to think of the representational and the organism-centered approaches as complementary levels of analysis, rather than mutually exclusive alternatives. Claims to the contrary by proponents of the organism-centered approach... more
It is fruitful to think of the representational and the organism-centered approaches as complementary levels of analysis, rather than mutually exclusive alternatives. Claims to the contrary by proponents of the organism-centered approach face what we call the “basketball problem.”
Research Interests:
Research Interests:
Research Interests: Psychology, Cognitive Science, Psychophysics, Computer Science, Artificial Intelligence, and 13 morePerception, Visual perception, Philosophy of Property, Medicine, Image Analysis (Mathematics), Vision, Humans, Human Vision, Mathematical Model, Completion, Optical Illusion, Proposition, and Luminance
Research Interests:
Psychophysical studies of change blindness indicate that, at any instant, human observers are aware of detail in few parts of the visual field. Such results suggest, to some theorists, that human vision reconstructs only a few portions of... more
Psychophysical studies of change blindness indicate that, at any instant, human observers are aware of detail in few parts of the visual field. Such results suggest, to some theorists, that human vision reconstructs only a few portions of the visual scene and that, to bridge the resulting representational gaps, it often lets physical objects serve as their own short-term memory. We propose that human vision reconstructs no portion of the visual scene, and that it never lets physical objects serve as their own short-term memory.