Harnad, S. (Ed.) (1987). Categorical perception: The groundwork of cognition. Cambridge, UK: Cambridge University Press.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... as view invariant RBF units [20, 68] we in this section only discuss how prior training on categorization tasks can provide additional information to the discrimination process, without regard to how the latter might be implemented computationally) This phenomenon, called Categorical Perception [33], where linear changes in a stimulus dimension are associated with nonlinear perceptual effects, has been observed in numerous experiments, for instance in color or phoneme discrimination. A recent experiment by Goldstone [31] investigated Categorical Perception (CP) in a task involving training ....

Harnad, S. (1987). Categorical perception: The groundwork of cognition. Cambridge University Press, Cambridge, UK.

....of a Peircean model for semantics can be justified by the fact that semantic rules are typically more complex than, for example, the rules of syntax. 2 The cognitive model of signs In this section we recapitulate the basics of our cognitive model of signs ( 3] Following cognition theory ([6]) the recognition of any sign begins with the sensation of the physical input which is processed by the brain in percepts. The generation of a percept is typically triggered by a change in the input. By comparing the current percept with the previous one, the brain can distinguish between two ....

Harnad, S.: Categorical perception: the groundwork of cognition. Cambridge University Press, Cambridge (1987)

....activity of baseball hitting does not affect the activity of the tennis game. However, if the two movements become more similar, in the case of playing squash and tennis, carry over is more likely to occur. This may in fact be evidential of categorical perception effects in sensorimotor learning [33]. Given these considerations we have assigned context a substantial role in our to be described network. Contextual cues can help the network in learning to separate two similar sequences. To maintain a sequence in memory while processing a new one, however, requires resolving the ....

S. Harnad (ed.), Categorical Perception: The Groundwork of Cognition, (Cambridge University Press, NY, 1987).

....contrast in the real world. Because sign and object are the primary representation of such contrast, sign and object must be di er from each other. How can we know about signs We have discussed this problem in [3] and here we will only recapitulate the main results. Following cognition theory ([4]) the recognition of any sign must begin with the sensation of the physical input. Physical stimuli enter the human receiver via the senses which transform the raw data into internal sensation continuously. The output of the senses, a bioelectric signal, is processed by the brain in percepts. The ....

Harnad, S.: Categorical perception: the groundwork of cognition. Cambridge University Press, Cambridge (1987)

....in the real world. How is such a contrast cognitively observed mentary previous percept current percept matching continuants occurrents stimuli observed complementary observed compleFig. 2: Cognitive model of sign recognition 2. 1 Cognitive Basis Following cognition theory ([Har87]) the recognition of any sign must begin with the sensation of the physical input. Physical stimuli enter the human receiver via the senses which continuously transform the raw data into internal sensation. The output of the senses, a bio electric signal, is processed by the brain in percepts. ....

S. Harnad. Categorical perception: the groundwork of cognition. Cambridge University Press, Cambridge, 1987.

.... if the activation of such a cat dog unit was used in a discrimination task along with the activity pattern over the relevant object tuned cells, discrimination of stimulus pairs straddling the boundary would be expected to be facilitated [38] the classical Categorical Perception effect [17]. 7 5.4 Some key predictions We label some of the predictions as critical ( if their falsification will show that the whole class of models described here (and summarized in figure 1) is a nogo . Experimental evidence against others would falsify specific models ( 1 ) Several ....

Harnad, S. (1987). Categorical perception: The groundwork of cognition. Cambridge University Press, Cambridge, UK.

....between two prototypes. The studies have consistently reported categorical transitions in these sequences. Categorical perception typically involves demonstrating a boundary region where responses by subjects change rapidly and show a correspondingly greater ability to discriminate the stimuli [36, 30]. There is a large body of evidence showing that many low level perceptual tasks, such as color discernment [12] or auditory classification of phonemes [36] exhibit this property. In color perception for instance, cross boundary distinctions between blue and green are made more consistently and ....

....Sad Happy Surprised Happy Sad Angry Figure VI.1: Typical dissolve examples. The original expressions are at the extremes of the sequences while the interior images are linear interpolations of the two images. certain stimuli, such as phonemes, are perceived categorically by human subjects [36, 30]. Categorical perception is said to occur when stimuli can be discriminated no better than they can be labeled, although in practice somewhat more relaxed criteria are often taken as evidence of categorical perception. Although the evidence for certain low level categorical perception is strong ....

Stevan R. Harnad. Categorical perception: the groundwork of cognition. Cambridge University Press, Cambridge, NY, 1987.

....below. FIGURE 1 ABOUT HERE 3.3 Theories of CP Few topics in speech science have generated as much study, debate and controversy as the phenomenon of CP. It would be out of place to say too much about this here: the reader unfamiliar with the background is referred to [8] 9] and [22] for full discussion and original references. It is, however, necessary to outline the bare bones of the debate. 9 Many theories partially explain CP. According to Rosen and Howell [23] writing in 1987, three of the most influential have been: ARTICULATORY: in this theory, categorization is ....

S. Harnad, editor. Categorical Perception: the Groundwork of Cognition. Cambridge University Press, Cambridge, UK, 1987.

....a percept is triggered by a change in the input, typically, or by the duration of some sampling time, e.g. in the case of visual perception. The time necessary for an observation is 35: 50ms, or more, much larger than the time necessary for the perception of an input change 3 which is 1: 10ms ([6]) The brain compares the current percept with the previous one, and this enables it to distinguish between two sorts of input qualities: one, which was there and remained there, something stable, which we will call a continuant ; and another, which, though it was not there, is there now (or the ....

S. Harnad. Categorical perception : the groundwork of cognition. Cambridge University Press, Cambridge, 1987.

....has been performed by researchers in different areas. Studies in art have focused on interpretation and perception [1] 3] aesthetics and formal analysis [2] visual communication [4] levels of meaning in art [5] etc. Studies in cognitive psychology have dealt with issues such as perception [9][10] 16] visual similarity [18] mental categories (i.e. concepts) 6] distinctions between perceptual and conceptual category structure [7] 8] 15] internal category structure (i.e. levels of categorization) 11] 12] 13] 14] 17] etc. In the field of information sciences, work has been ....

....be undertaken, however, it is essential to have an understanding of the nature of the data being categorized. Since this was done in section 3, we can now focus on the types of categories that could be used. In the literature of classification, researchers have identified two kinds of categories [9]: 1) Sensory Perception categories (e.g. texture, color or speech sounds e ) and (2) Generic Knowledge (GK) categories (e.g. natural kinds birds, artifacts cars and events eating) In our structure we can identify Sensory Perception categories such as color and texture. GK categories, ....

S. Harnad, editor. Categorical Perception: the Groundwork of Cognition, Cambridge University Press, New York, 1987.

.... mean that we can now say they are the same 14 Another shortcoming of this experiment is that we did not test the discriminability of the images for the human subjects at the transition points versus near the prototypes, a necessary condition in the standard de#nition of categorical perception #Harnad, 1987#. However, in the next experiment, we do test the networks discrimination of these stimuli and compare it to humans on similar stimuli. We can also compare the human and network responses on particular transitions directly. A #particularly good # sample graph of this sort is shown for one ....

Harnad, S. R. #1987#. Categorical perception: The groundwork of cognition. Cambridge University Press, Cambridge, UK.

.... as view invariant RBF units [4, 9] we in this section only discuss how prior training on categorization tasks can provide additional information to the discrimination process, without regard to how the latter might be implemented computationally) This phenomenon, called Categorical Perception [8], where linear changes in a stimulus dimension are associated y Multi class classification is a challenging and yet unsolved computational problem the scheme employed here was chosen for its simplicity. with nonlinear perceptual effects, has been observed in numerous experiments, for ....

Harnad, S. (1987). Categorical perception: The groundwork of cognition. Cambridge University Press, Cambridge.

....object. Chapter 1: Introduction 9 As demonstrated, by altering an analogy problem just slightly, one might perceive it completely differently. That is, two analogy problems may be superficially very similar, but are perceived very differently. This distinction, related to categorical perception (Harnad, 1987), is the flip side of analogy making (e.g. things may be superficially very different but are perceived the same) In Samples #1 and #2, we did not consider any object s position in the way we perceived the problem or selected an analogous object. However, one might wish to do so. Consider ....

....it is guaranteed that the where component for each object s location is completely orthogonal to that of all other possible objects in the scene. Because the notion of an iconic representation is appealing, researchers have used the term before, although without a specific implementation (see Harnad, 1987; also Barsalou s related notion of a perceptual symbol, 1992) The representation described above captures many of the qualities that an iconic representation should have. It is iconic in that the values representing an object s attributes are localized to particular regions of the ....

Harnad, S. (1987). (Ed.) Categorical perception: the groundwork of cognition. Press Syndicate, University of Cambridge, Australia.

....a listener into the discrete percept of a linguistic message 2. How does each individual listener acquire the particular form of sound system, morphology, grammar, etc. appropriate to the language of his her social community The first of these is the classical problem of categorical perception (Harnad 1987) and the second is that of language acquisition (Wexler and Culicover 1980; Pinker 1984) Both have been intensively studied, and have given rise to intense debate and controversy, as befits their key status in the field. They are generally held to be rather different problems and are ....

Harnad, S. (Ed.) (1987). Categorical Perception: the Groundwork of Cognition. Cambridge, UK: Cambridge University Press.

....consonants. The role of the auditory periphery in this case seems to be to emphasize the region of first formant information around the time of voicing onset. INTRODUCTION The categorization of speech sounds by the auditory system has been a subject of intense attention over several decades e.g. [1, 2], reflecting its importance to the scientific study of speech perception and the technological development of more human like capabilities in automatic speech recognition. In previous work [3, 4, 5, 6, 7] we have firmly established that a two stage computational model can mimic important aspects ....

S. Harnad (ed.), Categorical Perception: The Groundwork of Cognition, Cambridge, UK: Cambridge University Press, 1987.

....in its iconic representations, the features that make them icons of that particular object (or kind of object) rather than another; the rest of the features must be ignored. The more abstract representations that this feature filtering of the icons generates are categorical representations (Harnad 1987). Categorical representations are still only sensory rather than symbolic, because they continue to preserve some of the shape of the sensory projections, but this shape has been warped in the service of categorization: The feature filtering has compressed within category differences and ....

....of categorization: The feature filtering has compressed within category differences and expanded between category distances in similarity space so as to allow a reliable category boundary to separate members from nonmembers. This compression expansion effect is called categorical perception (Harnad 1987) and has been shown to occur in both human subjects (Goldstone 1994; Andrews et al. 1998; Pevtzow Harnad 1998) and neural nets (Harnad et al. 1991, 1995; Tijsseling Harnad 1997; Csato et al. submitted) during the course of category learning. Categorical representations can be connected to ....

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Harnad, S (Ed.) (1987). Categorical Perception: The Groundwork of Cognition. New York, Cambridge University Press.

....in turn allows an all or none (categorical) boundary to be placed between the regions of similarity space occupied by members of different categories, thereby allowing them to be assigned distinct symbolic names. These compression separation effect has come to be called categorical perception (CP) (Harnad 1987) and has been observed with both inborn categories and learnt ones, in human subjects as well as in animals and in neural nets (Harnad, Hanson Lubin 1991; 1995; Tijsseling Harnad 1978) The neural nets offer the advantage that they give us an idea of what the functional role of CP might be, ....

....by Theft. Categorical perception induced by language can thus be seen as an instance of the Whorfian Hypothesis (Whorf 1964) according to which our language influences the way the world looks to us. 2. The mushroom world Our simulations take place in a mushroom world (Cangelosi Parisi, 1998; Harnad 1987) in which little virtual organisms forage among the mushrooms, learning what to do with them (eat or don t eat, mark or don t mark, return or don t return) The foragers feed, reproduce and die. Mushrooms with feature A (i.e. those with black spots on their tops, as illustrated in Figure 1) are to ....

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Harnad, S. (Ed.) 1987. Categorical Perception: The groundwork of cognition. New York: Cambridge University Press.

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Harnad, S. (Ed.) (1987). Categorical perception: The groundwork of cognition. Cambridge, UK: Cambridge University Press.

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S. Harnad. Categorical perception: The groundwork of cognition. New York NY: Cambridge University Press, 1987.

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Harnad S. Categorical Perception: The groundwork of cognition. Cambridge University Press, 1987

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S. Harnad. Categorical perception: the groundwork of cognition. Cambridge University Press, Cambridge, 1987.

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S. Harnad. Categorical perception: the groundwork of cognition. Cambridge University Press, Cambridge, 1987.

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S. Harnad. Categorical perception: The groundwork of cognition. New York NY: Cambridge University Press, 1987.

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Harnad, S.: Categorical perception: the groundwork of cognition. Cambridge University Press, Cambridge (1987)

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Harnad, S. (1987). (Ed.) Categorical perception: the groundwork of cognition. Press Syndicate, University of Cambridge, Australia.

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