Neuroscientists

"The principal way that cognitive science can contribute to epistemology, I claim, is to identify basic belief-forming, or problem-solving processes. Once identified, these processes would be examined by primary epistemology according to the evaluative dimensions and standards adduced in Part I."

"The attentive synthesis of any particular letter or figure takes an appreciable time, of the order of 100ms...If a whole row of letters is to be identified, they must be synthesized one at a time... To "identify" generally means to name, and hence to synthesize not only a visual object but a linguistic-auditory one... Hence the span of apprehension is limited to what can be synthesized, and then verbally stored."

"Paying attention is not just analyzing carefully; rather, it is a constructive act... What we build has only the dimensions we have given it."

"The perseverating image, or as Neisser (1967) termed it, icon, has generated considerable interest, but an equally if not more interesting characteristic of this experimental technique is the means by which attention can be selectively directed in a matter of milliseconds to the relevant stimulus item."

"Ulrich Neisser's... book Cognitive Psychology did much to ignite the so-called cognitive revolution."

"To cope with this difficulty [of limited capacity], even a mechanical recognition system must have some way to select portions of the incoming information for detailed analysis."

"Cognitive processes surely exist, so it can hardly be unscientific to study them."

"Given such a sweeping definition, it is apparent that cognition is involved in everything a human being might possibly do; that every psychological phenomenon is a cognitive phenomenon. But although cognitive psychology is concerned with all human activity rather than some fraction of it, the concern is from a particular point of view. Other viewpoints are equally legitimate and necessary. Dynamic psychology, which begins with motives rather than with sensory input, is a case in point. Instead of asking how a man's actions and experiences result from what he saw, remembered, or believed, the dynamic psychologist asks how they follow from the subject's goals, needs, or instincts."

"The fact that the span of apprehension averages only four or five... probably results from the high rate of encoding. In a tachistoscopic experiment the subject must read the fading icon as rapidly as possible."

"Bullets are a convenient way to present the separate elements of a list. However, bullets are a bit like salt—often essential to bring out the best, but distasteful if overdone."

"The term "cognition" refers to all processes by which the sensory input is transformed, reduced, elaborated, stored, recovered, and used. It is concerned with these processes even when they operate in the absence of relevant stimulation, as in images and hallucinations. Such terms as sensation, perception, imagery, retention, recall, problem-solving, and thinking, among others, refer to hypothetical stages or aspects of cognition."

"To deal with the whole visual input at once, and make discriminations based on any combination of features in the field, would require too large a brain, or too much "previous experience" to be plausible."

"Physics seems to have done reasonably well in studying electrons, although there is not to this day a precise definition of this term."

"Mr. Magoo Rule: Text and graphics must be easily distinguished and recognized. Don ́t make your audience members feel like the vision challenged Mr. Magoo—viewers of an electronic slideshow should not risk eyestrain!"

"Even if it were clear what was meant, this sort of treatment would seem closer to describing what is taking place than to explaining it. I do not want to deny the value of describing a phenomenon; rich descriptions facilitate theorizing, and there is no more astute observer than Piaget. But in my view explanations of cognitive phenomena should specify the ways in which functional capacities operate. Piaget and Inhelder’s account is more on the level of intentionality, and hence is open to multiple interpretations at the level of the function of the brain. The do not specify how interiorized imitation operates, nor have they specified the format or content of the image. This level of discourse will never produce process adequacy, and hence seems of limited value."

"Resist the temptation to use special effects. Think about science fiction movies with lots of special effects: If you notice that special effects are special effects, they will fail."

"It is hard to define something one knows little about"

"Attention is not a mysterious concentration of psychic energy; it is simply an allotment of analyzing mechanisms to a limited region of the field. To pay attention to a figure is to make certain analyses of, or certain constructions in, the corresponding part of the icon."

"But because of the way in which depictions represent, there is a correspondence between parts and spatial relations of the representation and those of the object; this structural mapping, which confers a type of resemblance, underlies the way images convey specific content. In this respect images are like pictures. Unlike words and symbols, depictions are not arbitrarily paired with what they represent."

"A mental image occurs when a representation of the type created during the initial phases of perception is present but the stimulus is not actually being perceived; such representations preserve the perceptible properties of the stimulus and ultimately give rise to the subjective experience of perception."

"These organizational processes result in our perceptions being structured into units corresponding to objects and properties of objects. It is these larger units that may be stored and later assembled into images that are experienced as quasi-pictorial, spatial entities resembling those evoked during perception itself.... It is erroneous to equate image representations with mental photographs, since this would overlook the fact that images are composed from highly processed perceptual encodings."

"We must begin by distinguishing between visual mental imagery and visual perception: Visual perception occurs while a stimulus is being viewed, and includes functions such as visual recognition (i.e., registering that a stimulus is familiar) and identification (i.e., recalling the name, context, or other information associated with the object). Two types of mechanisms are used in visual perception: “bottom-up” mechanisms are driven by the input from the eyes; in contrast, “top-down” mechanisms make use of stored information (such as knowledge, belief, expectations, and goals). Visual mental imagery is a set of representations that gives rise to the experience of viewing a stimulus in the absence of appropriate sensory input. In this case, information in memory underlies the internal events that produce the experience. Unlike afterimages, mental images are relatively prolonged."

"If we allow several figures to appear at once, the number of possible input configurations is so very large that a wholly parallel mechanism, giving a different output for each of them, is inconceivable."

"During the late 1970s and early 1980s there was vigorous debate about the nature of visual mental imagery. One position (championed primarily by Pylyshyn, 1973, 1981) held that representations that underlie the experience of mental imagery are the same type as those used in language; the other position (which my colleagues and I supported, e.g., Kosslyn, 1980, 1994) held that these representations serve to depict, not describe, objects. The debate evolved over time... but always centred on the nature of the internal representations that underlie the experience of visualisation."

"Like pictures, images seem to depict information about interval spatial extents. The scanning experiments support the claim that portions of images depict corresponding portions of the represented objects, and that the spatial relations between portions of the image index the spatial relations between the corresponding portions of the imaged objects."

"The university is a space for would-be adults to explore new ideas, to expand their knowledge, to interrogate power, to learn how to make an argument. A space within which students can be challenged, even upset or shocked or made angry."

"The demand from [identity politics] is that we should respect not just the person qua person but also his or her beliefs. It’s a demand that undermines individual autonomy, both by constraining the right of people to criticise others’ beliefs and by insisting that individuals who hold those beliefs are too weak or vulnerable to stand up to criticism, satire or abuse. Far from according them respect, the politics of identity treats people less as autonomous beings than as vulnerable victims needing special protection."

"In plural societies, it is both inevitable and important that people offend the sensibilities of others. Inevitable, because where different beliefs are deeply held, clashes are unavoidable. Almost by definition such clashes express what it is to live in a diverse society. And so they should be openly resolved [rather] than suppressed in the name of ‘respect’ or ‘tolerance’. And important because any kind of social change or social progress means offending some deeply held sensibilities."

"Free speech – proper, full-blooded free speech – is the lifeblood of any progressive politics and of any progressive transformation of society. If we treasure the one, we must treasure the other."

"To accept that certain things cannot be said is to accept that certain forms of power cannot be challenged. ...This is why free speech is essential not simply to the practice of democracy, but to the aspirations of those groups who may have been failed by the formal democratic processes; to those whose voices may have been silenced by racism, for instance. The real value of free speech, in other words, is not to those who possess power, but to those who want to challenge them. And the real value of censorship is to those who do not wish their authority to be challenged. The right to ‘subject each others’ fundamental beliefs to criticism’ is the bedrock of an open, diverse society. Once we give up such a right in the name of ‘tolerance’ or ‘respect’, we constrain our ability to challenge those in power, and therefore to challenge injustice."

"In developing my account of consciousness, I have tried to obey a number of constraints. The first and most important is to take consciousness seriously. The easiest way to develop a "theory" of consciousness is to deny its exis­tence, or to redefine the phenomenon in need of explanation as something it is not. This usually leads to an elegant theory, but the problem does not go away."

"Conscious experience is at once the most familiar thing in the world and the most mysterious."

"Consciousness can be startlingly intense. It is the most vivid of phenomena; nothing is more real to us. But it can be frustratingly diaphanous: in talking about conscious experience, it is notoriously difficult to pin down the subject matter."

"The easy problems of consciousness are those that seem directly susceptible to the standard methods of cognitive science, whereby a phenomenon is explained in terms of computational or neural mechanisms. The hard problems are those that seem to resist those methods. ...The really hard problem of consciousness is the problem of experience. When we think and perceive, there is a whir of information-processing, but there is also a subjective aspect. ...When we see, for example, we experience visual sensations: the felt quality of redness, the experience of dark and light, the quality of depth in a visual field. Other experiences go along with perception in different modalities: the sound of a clarinet, the smell of mothballs. Then there are bodily sensations, from pains to orgasms; mental images that are conjured up internally; the felt quality of emotion, and the experience of a stream of conscious thought."

"Another useful way to avoid confusion [used by e.g. Allen Newell 1990 Unified Theories of Cognition] is to reserve the term "consciousness" for the phenomena of experience, using the less loaded term "awareness" for the more straightforward phenomena... If such a convention were widely adopted, communication would be much easier; as things stand, those who talk about "consciousness" are frequently talking past each other."

"Consciousness is the biggest mystery. It may be the largest outstanding obstacle in our quest for a scientific understanding of the universe."

"Why doesn't all this information-processing go on "in the dark", free of any inner feel? ...We know that conscious experience does arise when these functions are performed, but the very fact that it arises is the central mystery. There is an explanatory gap [a term due to J. Levine, "Materialism and qualia: The explanatory gap" Pacific Philosophical Quarterly 64:354-61, 1983] between the functions and experience, and we need an explanatory bridge to cross it."

"I am an optimist about consciousness: I think that we will eventually have a theory of it, and in this book I look for one. But consciousness is not just business as usual; if we are to make progress, the first thing we must do is face up to the things that make the problem so difficult. Then we can move forward toward a theory, without blinkers and with a good idea of the task at hand."

"I am not sure that Marr would agree, but I am tempted to add learning as the very top level of understanding, above the computational level. [...] Only then may we be able to build intelligent machines that could learn to see—and think—without the need to be programmed to do it."

"[If] we can experimentally isolate a process and show that it can still work well, then it cannot require complex interaction with other parts of vision and can therefore be understood relatively well on its own."

"When David Marr at MIT moved into computer vision, he generated a lot of excitement, but he hit up against the problem of knowledge representation; he had no good representations for knowledge in his vision systems."

"The critical act in formulating computational theories turns out to be the discovery of valid constraints on the way the world is structured -- constraints that provide sufficient information to allow the processing to succeed."

"The primitives of a representation are the most elementary units of shape information available in a representation."

"Vision is the process of discovering from images what is present in the world, and where it is."

"A representation is a formal system for making explicit certain entities or types of information, together with a specification of how the system does this. And I shall call the result of using a representation to describe a given entity a description of the entity in that representation."

"To understand the relationship between behavior and brain one has to begin by defining the function, or computational goal, of a complete behavior. Only then can a neuroscientist determine how the brain achieves that goal."

"The abstract properties of this mapping are defined precisely, and its appropriateness and adequacy for the task at hand are demonstrated."

"Vision is a process that produces from images of the external world a description that is useful to the viewer and not cluttered with irrelevant information."

"In order to understand bird flight, we have to understand aerodynamics; only then does the structure of feathers and the different shapes of bird's wings make sense."

"Our choices from diet to outlook to emotional state directly alter our neural and gene activity at every moment."