1998 Events

Wednesday, January 21, 1998
2:00-3:30 p.m.
280 Park Hall
North Campus

JAMES F. ALLEN

"CONVERSATIONAL PLANNING AGENTS:
THE TRAINS/TRIPS SYSTEMS"

A conversational agent is a system that can engage in natural language conversation in order to further its goals. In our TRAINS project, the goals consist of simple planning and scheduling tasks, and the system supports mixed initiative planning using several modes of communication: spoken and keyboard natural language, mousable map displays, and menus. The project represents a concerted effort to bring work in natural language understanding, dialog modeling, and planning into a single coherent system. The TRAINS system is a specific agent that can support unconstrained dialogue in order to assist the user in solving randomly generated route planning tasks. Significant effort has been made to make the system robust, so that it can perform well even in the face of inevitable speech recognition errors, and can continue the dialogue in a natural way under any circumstances. This talk will discuss the overall project and its accomplishments so far, and then focus on a few specific mechanisms that enable robust dialogue behavior. Because the system can interact in close to real time, it provides a firm basis for experimentation and data collection to study different strategies for human-computer dialogue for collaborative problem solving.

Refreshments will be available
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Wednesday, January 28, 1998
280 Park Hall
2:00-3:30 p.m.
North Campus

ALAN LOCKWOOD

"FUNCTIONAL IMAGING OF THE HUMAN AUDITORY SYSTEM AND AUDITORY PHENOMENA"

We have used positron emission tomography to map the human auditory stimuli. Stimulating the auditory system with unilateral tones at 500 and 4000 Hz elicits a systematic response in brainstem, midbrain, thalamic, and cortical regions. Our study provides evidence for the existence of tonotopic and ampilotopic organization of cortical portions of the central auditory system. Acitvity in the posterior and mid portions of the cingulate gyrus (BA 23) at low but not high intensity levels of stimuli may be evidence that this brain region functions as a gain control center.

In studies of patients with tinnitus, we found evidence for spontaneous neural activity in the central auditory system that is not of cochlear origin. In addition, tinnitus patients have abnormal links between the auditory and limbic system that may account for the emotional impact of tinniuts. Finally, tinnitus patients with hearing loss express evidence for plastic transformations of the central auditory system. We hypothesize that tinnitus may be the auditory system analog of phantom limb sensations and that the nature and severity of tinnitus may be dependent on the extent of the plastic changes.

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Wednesday, February 4, 1998
2:00-3:30 p.m.
280 Park Hall
North Campus

PHIL MERIKLE

"What Experimental Studies of Perception
Without Awareness Reveal About
Conscious vs. Unconscious Cognition"

Perception can occur without the subjective awareness of perceiving. In what ways are perception without awareness and perception with awareness similar or dissimilar? This question has been addressed in several ways. One approach has been to induce conscious people to perceive unconsciously by presenting stimuli under suboptimal conditions (e.g., short durations). A second approach has been to induce conscious people to perceive unconsciously by presenting stimuli outside their focus of attention. A third approach has been to study people in whom unconsciousness has been induced directly through the administration of surgical anesthesia. Regardless of how unconsciousness is induced, stimuli can produce qualitatively different consequences depending on whether they are perceived with or without awareness. The studies reveal that consciously perceived stimuli can guide intentional actions whereas unconsciously perceived stimuli lead to more habitual reactions which may even interfere with on-going intentional actions. These findings provide empirical support for the widely held assumption that being conscious allows us to act on the world and to produce effects on the world.

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Wednesday, February 18, 1998
2:00-3:30 p.m.
280 Park Hall
North Campus

DAVID NOELLE

"Modeling An Interference Effect In Instructed
Category Learning"

Category learning is often seen as a process of inductive generalization from a set of class-labeled exemplars. Human learners, however, often receive direct instruction concerning the structure of a category before being presented with examples. Such explicit knowledge may often be smoothly integrated with knowledge garnered by exposure to instances, but not always. Some interference effects have been observed. Specifically, errors in instructed rule following may sometimes arise after the repeated presentation of correctly labeled exemplars. Despite perfect consistency between instance labels and the provided rule, such inductive training can drive categorization behavior away from rule following and towards a more prototype-based or instance-based pattern. In this talk, I will present a general connectionist model of instructed category learning which captures this kind of interference effect. I model direct instruction as a sequence of inputs to an artificial neural network which transforms such advice into a modulating force on classification behavior. Exemplar-based learning is modeled in the usual way for connectionist networks: as weight modification driven by error feedback. The proposed network architecture allows instruction following and exemplar-based learning to interact in a psychologically plausible manner. Simulation results are provided on a simple instructed category learning task, and these results are compared with human performance on the same task.

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Wednesday, February 25, 1998
2:00-3:30 p.m.
280 Park Hall
North Campus

EVAN THOMPSON

"FINDING OUT ABOUT FILLING IN"

Abstract-Visual scientists use the terms "filling in" and "perceptual completion" to refer to situations where subjects report that something is present in a particular region of visual space when it is actually absent from that region, but present in the surrounding area. Whether there is neural filling-in, however, is a matter of great debate. I will first present a taxonomy of perceptual completion phenomena to organize the discussion and then argue for the following points: (1) Certain forms of perceptual completion seem to involve spatially propogating neural activity (neural filling in) and so, contrary to Daniel C. Dennett's position, cannot be described as the results of the brain's "ignoring an absence" or "jumping to a conclusion." (2) Nevertheless, neural filling-in does not entail either "analytic isomorphism" or "Cartesian materialism." (3) Most discussions of filling-in have been based on a representational conception of vision. To reject this conception in favour of an "enactive" or "animate" conception reduces the importance of filling-in as a theoretical category in the explanation of vision. (4) The evaluation of perceptual content should not be dictated by "subpersonal" considerations about internal processing, but rather by considerations about the task of vision at the level of the animal or person interacting with the world.

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Wednesday, March 4, 1998
280 Park Hall
2:00 - 3:30 p.m.
North Campus

STUART C. SHAPIRO

A PROCEDURAL SOLUTION TO THE UNEXPECTED HANGING AND SORITES PARADOX

The paradox of the Unexpected Hanging, related prediction paradoxes, and the sorites paradoxes all involve reasoning about ordered collections of entities: days ordered by date in the case of the Unexpected Hanging; men ordered by the number of hairs on their heads in the case of the bald man version of the sorites. The reasoning then assigns each entity a value that depends on the previously assigned value of one of the neighboring entities. The final result is paradoxical because it conflicts with the obviously correct, commonsensical value. The paradox is due to the serial procedure of assigning a value based on the newly assigned value of the neighbor. An alternative procedure is to assign each value based only on the original values of neighbors---a parallel procedure. That procedure does not give paradoxical answers.

This paper was inspired by the paper, ``Treatment of Conflict: The Pragmatic Dimension of Paradox,'' given by Mariam Thalos to the University at Buffalo Center for Cognitive Science on October 22, 1997.

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Wednesday, March 18, 1998
280 Park Hall
2:00 - 3:30 p.m.
North Campus

ROBERT MACLAURY

"Current Anthropological Research
on Color Categorization:
Points of View in Categorization"

After Berlin and Kay (cir. 1975) found neurally determined universals in color categorization, blatant cross-cultural differences remained to be explained. These consisted of different stages of color-cateogry evolution, systems of categorizing color that did not fit the neurally-based model, plasticity and change among color categories, and category-internal semantic relations previously overlooked. Such observations were enhanced by expansion of worldwide and regional surveys and by an improvement of Munsell-chip interviewing methods.

This up-grading of data made it possible to formulate and test explanatory models. Today we shall review one of these results, called vantage theory, which has developed over the last 15 years (MacLaury 1997). Vantage theory offers three levels of argumentation: (1) any person constructs a category as though it were one or more points of view; (2) the analogy is formed between the coordinates of space-time and equivalent fixed and mobile reference points in categorical cognition; (3) the analogy is wholly unconscious and neurally expedited such as to enable people to form many categories in succession as fast as they think and speak. We shall emphasize the evidence for (1), the most accessible of these claims. The evidence consists of statistically significant patterns among certain pairs of color terms that occur commonly in language. Both terms name a single color category from different slants, and the terms show a predictable trajectory of change in their semantic relation as the category divides over time. There are other sources of evidence, at least 100 replicable observations. But the approach here will be to review a few of the major patterns, presenting material slowly while encouraging questions throughout. The objective is to suggest one way that current anthropological resarch on color semantics may contribute to interests of cognitive science, especially the effort to understand the method and process by which people categorize.

Reading: Maclaury, Robert E. 1997. Color and Cognition in Mesoamerica: Constructing Categories as Vantages. Austin: University of Texas Press.

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Wednesday, March 25, 1998
2:00 - 3:30 p.m.
280 Park Hall
North Campus

GAIL MAUNER

 "HOW DO WE KNOW THAT THE SHIP
WAS SUNK BY SOMEONE?"

Typically, our understanding of a sentence like "The ship was sunk" includes an unexpressed agent who is responsible for sinking the ship. Within the psychological literature, it is commonly assumed that this unexpressed information is derived from stored conceptual knowledge. An alternative view is that unexpressed agents are derived from linguistic sources such as lexical representations and implicit grammatical knowledge. In this talk, I will present recent data from experiments using eye-monitoring, cross-modal naming, and word-by-word reading to argue that (1) the unexpressed agent that is part of our understanding of a sentence like "The ship was sunk" is derived from linguistic sources; and (2) this information is accessed as soon as a reader recognizes the main verb in an agentless passive sentence. I will end by discussing the implications these data hold for theories of modularity in language processing.

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Wednesday, April 1, 1998
280 Park Hall
North Campus
2:00 -3:30 p.m.

BARRY SMITH

Introductory Tutorial on
Searle's Cognitive Theory of Social Ontology

On April 24-25 the Center will co-sponsor a major international conference in Buffalo on the topic of "Applied Ontology: Law and Institutions in Society". The first day of the conference will be devoted to John Searle's book The Construction of Social Reality, and John Searle will himself be present. As part of the preparations for this conference Barry Smith will give an introductory tutorial on Searle's cognitive theory of social ontology.

All are invited to attend
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Wednesday, April 1, 1998
280 Park Hall
North Campus
2:00 -3:30 p.m.

Corinne Jorgensen 

"Image Attributes: An Investigation"

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With the rapid expansion in imaging technologies, access to collections of digital images is a subject of major interest. Indexing systems and computerized retrieval for images both need data concerning typically described image attributes. To date, there is little research upon which to base choices as to which attributes should be included in these systems. This research is investigating attributes typically described in several types of tasks using pictorial images. Participants performed descriptive, categorizing, and searching tasks, and word and phrase data were subjected to content analysis. Forty-two image attributes and nine higher level attribute classes were described. The data suggest that indexing of literal object is of prime significance, as is indexing of the human form and other human characteristics. Content/Story and other abstract attributes are also typically described, suggesting that image indexing may benefit by application of concepts associated with indexing of fiction. Term variability is less than might have been expected, suggesting some constraints may exist on the process of communicating about visually perceived data. The data are of interest in terms of what they suggest about human perception of and communication about complex images.

Time: Pizza and drinks at 5:30; informal talk 6-ish

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Wednesday, April 15, 1998
2:00 - 3:30 p.m.
280 Park Hall
North Campus

JANET DEAN FODOR

"WHAT IS A PARAMETER?"

Recent research in learnability has made it clear that for natural language there can be no instant "automatic" triggering of parameters. This is because the trigger properties in natural languages are often deep properties, not recognizable without parsing the input sentence.

Current approaches such as Gibson and Wexler (LI 1994) therefore use the parsing routines to identify triggers. Unfortunately, the proposed mechanism for doing so if very inefficient. I show that this is because it does not respect the Parametric Principle: it evaluates millions of particular grammars, rather than establishing the values of 20 or 30 parameters.

By tracking out why this is so, I have found a remedy for it. There is a way of using the parser that does implement the Parametric Principle. But it calls for a new conception of parameters and of their triggers: they are one and the same thing, and consist of features of small treelets, made available by UG and adoptable into individual grammars.

This conclusion is in accord with most current theories of syntactic parameterization, including the Minimalist program, HPSG and TAG theory.

All are welcome 
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Wednesday, April 22, 1998
2:00 - 3:30 pm
280 Park Hall
North Campus

ROBERTO CASATI

"WHAT SOUNDS ARE"

The physicalist reduction of sounds seems to be achieved once we identify sounds with sound waves in a medium in which a sounding object (and possibly a hearer) is present. This raises some objections and leaves some questions open. Among other things, the relationship between the sound and the sounding object remains in the dark. I shall suggest that there is another and more promising candidate for the physical identification of sounds, namely processes or events inside (or at the surface of) sounding objects, or in the stuff of the sounding object. Three main issues will be discussed in the talk: the location of sounds, their nature, and the perceptual representation we have of them.

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Wednesday, April 29, 1998
2:00 - 3:30 p.m.
280 Park Hall
North Campus

INGVAR JOHANSSON

"The Ontology of Patterns"

Most ontologists regard patterns as some kind of easily analyzed subcategory, a mere by-product in need of no special attention. This view I will challenge. I think that, in fact, pattern belongs to the top-level categories, and that a close scrutiny of its specifica differentia may be of interest both for ontologists and for cognitive scientists. I will, as a starting point for discussion, list certain features which accrue to patterns: the feature of fiatness, the feature of non-reducibility to a set or aggregate of properties, parts or relations, the feature of having that kind of objective existence which can be represented cognitively (via language and perception). Reference will also be made to the question whether all patterns can be represented pictorially.

Wednesday, September 9, 1998
2:00-3:30 p.m.
280 Park Hall
North Campus

LEONARD TALMY, Ph.D.
Center for Cognitive Science and Dept. of Lingusitics, UB

"Relating Language to Other Cognitive Systems"

An important research direction in cognitive science consists of cross-comparing the forms of organization exhibited by different cognitive systems, with the long-range aim of ascertaining the overall character of human cognitive organization. Relatively distinct major cognitive systems of this sort would seem to include: language, (different modalities of) perception, reasoning and understanding, affect, attention, memory, and cultural structure. Much of my work, in particular, has sought to relate the conceptual structuring exhibited by language to the structuring that is exhibited by other cognitive systems. The general finding is that each cognitive system has some structural properties that may be uniquely its own; some further structural properties that it shares with only one or a few other cognitive systems; and some fundamental structural properties that it has in common with all the cognitive systems. It appears that each such cognitive system resembles and interacts with other cognitive systems more than is envisaged by the strict modularity notion. I term this view the "overlapping systems" model of cognitive organization. To illustrate, both language and visual perception have in common such structuring factors as the schematization of spatial relations between objects. But some factors with a significant structural role in visual perception -- such as symmetry, rotation, and dilation -- are at best minimally represented in the closed-class forms of languages. And conversely, linguistic closed-class forms express such categories as `reality status' -- e.g., inflections that represent a proposition as factual, conditional, potential, or counterfactual -- that have little part in visual perception. The talk will mainly examine this partial overlap between language and vision. If time permits, it will proceed to comparisons of language with the affect system, the culture system, and the understanding system, and end by examining structuring factors that appear to operate across all the major cognitive systems.

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Wednesday, September 16, 1998
2:00-3:30 p.m.
280 Park Hall
North Campus
BRIAN MACWHINNEY, Ph.D.

Department of Psychology
Carnegie-Mellon University

"The Emergence of Grammar from Perspective-Talking"

We can think of language as a system that allows human beings to assume and enact alternative specifically human perspectives that are grounded on the realities of physical existence. Perspective-taking operates on four distinct levels that correspond to major levels of primate cognition. These four levels are: affordances, spatio-temporal reference frames, causal action chains, and social frames. Affordances allow us to ground our understanding of particular lexical items on sensory and motor realities. Spatio-temporal reference frames allow us to generalize the ego-centered perspective to object-centered and environment-centered reference frames. The linguistic expression of spatio-temporal frames is concentrated on adverbial phrases, but the results affect the whole pattern of accessibility for mental models. Causal action chains allow us to understand the actions of objects in terms of movements and changes of our own bodies. The linguistic expression of these chains strongly influences basic processes in clausal grammar. Social frames allow us to shift between the perspectives of different social actors. The linguistic expression of this level of perspective-taking focuses on discourse structure and the interpretations of socially complex lexical items. Although these four systems are supported by partially separate dynamic neural pathways, the overall control of perspective-taking and perspective shifting is achieved through the interaction of language with prefrontal processes. The full interaction of language with the four embodied systems gives rise to the construction of an internalized homunculus that is then available for the control language comprehension, language production, inner speech, and problem-solving. By tracing through the on-line incremental processing of sentences during production and comprehension, we can observe the operations of perspective-taking as it threads across alternative perspectives on these four levels.

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Wednesday, September 23, 1998
2:00-3:30 p.m.
280 Park Hall
North Campus
DAVID MARK, Ph.D.

Department of Geogrpahy,
National Center for Geographic Information and Analysis (NCGIA),
and Center for Cognitive Science

BARRY SMITH

Department of Philosophy and Center for Cognitive Science

"Cognition, Ontology and Geographic Information Science"

Geographic categories are structured differently from categories for closed, portable objects at table-top scales. Geographic objects are not merely located in space, they are tied to space intrinsically, in a manner that implies that they inherit from space many of its structural (part/whole, topological, geometrical) properties. In addition, to a much greater extent than in the world of table-top objects, the realization that a thing or type of thing exists at all may have individual or cultural variability. Moreover, the boundaries of geographic objects are themselves salient phenomena for purposes of categorization. Such boundaries may be crisp or graded, open or closed, and they may be subject to dispute.

Mark and Smith will describe their current work on geographic categories and its relation to the work of Rosch and others. They will also outline plans for the empirical testing of a general ontological theory of geographic objects and categories, and set these plans in relation to other cognitively oriented research in the NCGIA, including the recently approved interdisciplinary training grant under the NSF's IGERT scheme.

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Wednesday, October 7, 1998
2:00-3:30 p.m. 
280 Park Hall
North Campus

PAUL THAGARD, Ph.D.

University of Waterloo
Department of Psychology

Emotional Analogies: How People Use Analogies in Persuasion,Empathy, and Humor

People frequently use analogies when they are trying to persuade others to agree with them, when they are trying to understand each other, and when they are making jokes. This talk will present a cognitive theory of the role of emotions in such analogies. The theory extends previous computational accounts of coherence and analogy to encompass emotion, and proposes a novel understanding of analogical inference.

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Wednesday, October 21, 1998
2:00-3:30 p.m.
280 Park Hall
North Campus

JONATHAN DOSTROVSKY, Ph.D.

University of Toronto
Deprtments of Physiology and Speech
Language Pathology
Director, Program in Neuroscience

BRAIN MAPS AND PHANTOM LIMBS

It is now well known from animal studies that the representation of the body's surface, at least at the cortical level, is quite plastic. In particular, following removal of input from a given body region, the representations of the surrounding regions expand into the deafferented region. However the functional/perceptual consequences of these alterations are not known. Furthermore, following amputation of a limb most people retain an image of the amputated limb and can experience sensations in the phantom. The underlying mechanisms are not well understood. I will describe studies involving recordings of sensory neurons and the perceptual effects of electrical stimulation at such sites in the thalamus of awake patients undergoing stereotactic surgery for relief of pain following amputation. The findings provide new insights regarding plasticity and phantoms.

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Wednesday, October 28, 1998 
280 Park Hall
2:00-3:30 p.m.
North Campus

DAVID HUNTER, Ph.D.

Department of Philosophy
Buffalo State College

States and Identity

The Identity Thesis in the philosophy of mind holds that a person's mental states are identical with physical states, typically brain states. Proponents of this view have claimed that the identities in question are empirical and contingent truths, and that a given mental state might, in different species or different members of one species, be identical with physical states of different types. This thesis raises important questions about the nature of states, and about the logic of identity claims involving states. Just what is a state, and what does it mean to say that a mental state is identical with a brain state? I begin by proposing an account of the nature and logic of states, according to which states are simply property instantiations. I distinguish several versions of the Identity Thesis and argue that, given this account, the Identity Thesis does not support the claims made by its proponents. I suggest that some of these are best viewed as concerning the claim that mental states supervene on physical states. I then argue that rejecting the account of the logic and ontology of states yields identity statements that are but a stylistic variant on statements about the supervenience of the mental on the physical. My tentative conclusion is that physicalists about the mind are better served by defending a supervenience claim, than an identity claim.

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Wednesday, November 4, 1998

280 Park Hall
2:00-3:30 p.m.
North Campus

DANA H. BALLARD, Ph.D.

Department of Computer Science
University of Rochester

Deictic Behaviors

We argue that a computational theory of the brain will have to address the issue of computational hierarchies, wherein the brain can be seen as using different instruction sets at different spatio-temporal scales. As examples, we describe two such abstraction levels.

At a timescale of one-third of a second, a language is needed to address the way the brain directs the physical resources of its body. An example of these kinds of instructions would be those used to direct saccadic eye- movements. Interpreting experimental data from this perspective implies that subjects select eye-movements in a special strategy to avoid loading short-term memory. This constraint has implications for the organization of high- level behavior.

At a timescale of 50 milliseconds we consider a model of instructions which capture the details of programming the individual eye-movements themselves. This model makes extensive use of feedback. The implications of this are that brain circuitry may be far more dependent on the context of a task than traditionally proposed.

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Wednesday, November 11, 1998

280 Park Hall
2:00-3:30 p.m.
North Campus

ELLEN BIALYSTOK, Ph.D.

Department of Psychology
York University

Languages, Scripts, and Bilingualism:
Learning the Meaning of Print

In order to read, children must understand that the relationship between the written forms and the meanings they represent is symbolic. Thus, children's mental representation of the nature and function of print needs to be represented symbolically as well. This symbolic relationship between print and meaning includes two insights. The first is the general principle that the written forms wholly determine the meaning; the second is the specific principle that determines how the forms signify meaning in that script. In alphabetic languages, for example, letters stand for sounds. Both insights come after children appear to have learned the written forms. Several studies are reviewed that show that children know the forms (e.g., letters) before they know that they are symbols and that bilingual children come to understand aspects of the symbolic function of these forms earlier than monolingual children do. Further, the writing systems used in the two languages of the bilingual determine how the development of each of these insights will proceed. Finally, the pattern performance demonstrated by the bilinguals is discussed in terms of different processes of representation and attention established by bilingual children from a very early age.

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Wednesday, November 18, 1998

280 Park Hall
2:00-3:30 p.m.
North Campus

RALPH H. BENEDICT, Ph.D.

Department of Neurology
University at Buffalo

Functional Neuroimaging of Auditory Attention
Using a Continuous Performance Test

The general emphasis of this colloquium is the relationship between cognition and cerebral function. While no unitary model of attention has gained wide acceptance in the cognitive science literature, scientists have repeatedly emphasized three aspects or components of attention: (1) capacity demand, (2) vigilance, and (3) selection. Functional neuroimaging methods provide a means of determining the cerebral correlates of theses constructs. Neuropsychological models have been proposed (eg Posner) which account for attention task performance in humans, but these models have emphasized the visual modality. The degree to which Posner's model accounts for attention in a different modality (eg audition) is not known. The results of a preliminary study on auditory attention using positron emission tomography (PET) will be presented. It is concluded that an area of the brain, the anterior cingulate gyrus, can be identified which is active during high-capacity demand attention, across sensory modalities. This anterior brain region is distinguishable from posterior regions which appear to be involved in the sensory aspects of cognitive processing, but not in attention, per se. An intriguing area for future research concerns the overlap (anatomically speaking) between regions concerned with high- capacity demand attention and motor function. An experiment designed to isolate these functions will be presented.

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Wednesday, November 25, 1998 
280 Park Hall
2:00-3:30 p.m.
North Campus

SIDNEY SEGALOWITZ, Ph.D.

Department of Psychology
Brock University

Pushing around the P300 event-related potential:
Attentional control and allocation

Scalp EEG can be used to reflect some aspects of information processing in the brain, especially when segments of EEG are time-locked to stimulus presentation and then averaged, forming an averaged event-related potential (ERP). One of the major components of the ERP is the P300 (or P3) peak, which is traditionally thought to reflect the updating of stimulus information in working memory. I will present a series of studies that show that the P300 reflects attentional allocation rather than memory per se; I will then apply present results from our studies using this paradigm to see the effects of alcohol, caffeine, and mild head injury on the allocation of attention.

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Wednesday, December 9, 1998 
280 Park Hall
2:00-3:30 p.m.
North Campus

STUART SHAPIRO, Ph.D.

Department of Computer Science and Engineering and 
Center for Cognitive Science, UB

Embodied Cassie

We have enhanced a computational cognitive agent by embodying it with real and simulated bodies operating in real and simulated worlds. This has allowed us to experiment with various ways that embodiment influences the creation and meaning of the agent's beliefs and other terms in its knowledge base, including: symbol-grounding by perception and action; first-person privileged knowledge; the representation and use of indexicals; having a personal sense of time; and low-level bodily awareness.