Syntactic Content Research Articles

Carrell et al. Respond to "Observational Research and the EHR"

We appreciate Dr. Chute's thoughtful comments and perspectives on the broader landscape of clinical informatics (1). Three points he makes regarding clinical natural language processing (NLP) of electronic health record (EHR) data have important implications for future research. First, the availability of clinical text for secondary use is a critical first step toward realizing its potential. As Dr. Chute notes, we are witnessing a transition from a past constrained by data to a future that may be overwhelmed by it. Yet in most institutions, researcher access to EHR text lags far behind access to structured data. Barriers to accessing clinical text tend to be less about technical challenges than about perceptions—we would argue, misperceptions—of risks to patient privacy once text is made available outside the EHR. Correcting potential misperceptions is a critical first step in improving access. Difficulties in accessing EHR text across multiple institutions is an additional challenge. Health information exchange addresses this issue from the perspective of care delivery but does not necessarily address aggregating the clinical narrative for research. Longitudinally incomplete records, as Dr. Chute points out, retard algorithm performance. Our own work illustrates this. Four of our NLP algorithm's 5 case identification failures were due to the absence of electronic versions of relevant chart notes. Overcoming access challenges would benefit observational investigations from small to large. Consider, for example, the potential impact on postmarket drug safety surveillance through the Food and Drug Administration's Sentinel Initiative (2, 3) if structured data from the more than 130 million covered lives from 18 organizations could be augmented with text-based EHR information. Second, advancing clinical NLP methods will benefit from open source, sharable resources and software. Dr. Chute mentions the important contributions made by the Strategic Health IT [information technology] Advanced Research Projects (SHARP). Like others, we have benefitted from SHARP-produced tools, including software modules that detect when concepts of interest are qualified by negation or uncertainty—essential details for interpreting cancer screening and diagnosis narratives. Indeed, in the spirit of advancing portability and reproducibility, we have contributed to the Apache cTAKES (4) NLP system. Also essential are sharable samples of clinical text that have been annotated for syntactic and semantic content. Availability of such annotated text in the general domain since the 1990s (5) propelled NLP far beyond the current state of clinical NLP. Achieving parity in the clinical domain, particularly in the application of powerful machine learning approaches, will require additional sharable resources. To accelerate the broad use of clinical NLP technologies, developers should also strive to make their systems more easily portable, including to settings where informatics expertise is limited, thereby extending their potential impact. Third, protecting patient privacy is critically important when using EHR data for research. We agree with Dr. Chute that text deidentification will play an important role in facilitating access while protecting patient privacy. Methods to address the trace amounts of residual identifiers that automated deidentification tools overlook are needed (6). That said, machine processing has inherent advantages over manual abstraction. Though automated systems may “touch” far greater quantities of clinical text, they entail substantially less exposure of patient information than manual abstraction because relatively little human review is needed. Institutional review boards appreciate this. Indeed, the Group Health (Seattle, Washington) institutional review board welcomed the adoption of NLP methods and the construction of a research database for EHR text because they were convinced this would reduce threats to patient privacy. We also point out that, once text-based information has been locally extracted, it can be normalized to standardized coding schemes, free of direct patient identifiers, allowing it to be more easily sharable.

The selfish signifier: meaning, virulence and transmissibility in a management fashion

PurposeManagement fashions can be, and have been, conceptualized as narrative elements competing for replication and resources in the wider managerial discourse. Most wax and wane through a life cycle. Some achieve an extended place and even a transition to quasi‐ permanent institutions. Facilities/Facility Management (FM) is one such example, the purpose of this paper is to explore this.Design/methodology/approachThe case draws FM's history since 1968 and asks whether it is compatible with recent and classic Darwin, thoughts on cultural evolution as a selection process between competing discourses.FindingsSeveral properties of that history are argued as compatible with the theoretical stance taken particularly the mutation of the syntactic content to suit local circumstances and the dilution of the term's intent. Success attributes in the selective competition include contingency, securing an organizational home and mutability (what was represented became, more operational, less virulent but in the process more transmissible). In spreading globally the signifier/meme FM also proved mutatable to local managerial discourses.Originality/valueThe study supports a developing paradigm that it is possible to view organizations as ecologies of variously, memes, signifiers, narratives, representations or discourses. All five terms are shown to have been used to make similar significations by different authors. It shows how a natural history of narrative memes can be constructed.

Neural correlates of the perception of contrastive prosodic focus in French: A functional magnetic resonance imaging study

This functional magnetic resonance imaging (fMRI) study aimed at examining the cerebral regions involved in the auditory perception of prosodic focus using a natural focus detection task. Two conditions testing the processing of simple utterances in French were explored, narrow-focused versus broad-focused. Participants performed a correction detection task. The utterances in both conditions had exactly the same segmental, lexical, and syntactic contents, and only differed in their prosodic realization. The comparison between the two conditions therefore allowed us to examine processes strictly associated with prosodic focus processing. To assess the specific effect of pitch on hemispheric specialization, a parametric analysis was conducted using a parameter reflecting pitch variations specifically related to focus. The comparison between the two conditions reveals that brain regions recruited during the detection of contrastive prosodic focus can be described as a right-hemisphere dominant dual network consisting of (a) ventral regions which include the right posterosuperior temporal and bilateral middle temporal gyri and (b) dorsal regions including the bilateral inferior frontal, inferior parietal and left superior parietal gyri. Our results argue for a dual stream model of focus perception compatible with the asymmetric sampling in time hypothesis. They suggest that the detection of prosodic focus involves an interplay between the right and left hemispheres, in which the computation of slowly changing prosodic cues in the right hemisphere dynamically feeds an internal model concurrently used by the left hemisphere, which carries out computations over shorter temporal windows.

Development of syntactic subject matter knowledge and pedagogical content knowledge for science by a generalist elementary teacher

The nature of knowledge needed for teaching elementary science and the development of such knowledge is a focus of ongoing research in science education. Internationally, there is a move to include scientific literacy as an aim of science education curricula. In order to teach such curricula teachers need two types of subject matter knowledge (SMK): knowledge of science and knowledge about science. Knowledge of science refers to the knowledge produced by science (substantive knowledge). Knowledge about science refers to the nature of science (NOS): the principles and means by which scientific knowledge develops and becomes accepted (syntactic or epistemic knowledge). In addition, teachers need to know how to teach both these kinds of SMK effectively (pedagogical content knowledge [PCK]). This case study analyses the practice of a New Zealand generalist elementary teacher using a framework developed from the literature based on Shulman’s conceptualisation of teacher knowledge. It describes the nature and development of syntactic aspects of her SMK and PCK as she planned and taught a unit on science investigation. Analysis of student learning indicates some success in transfer of syntactic knowledge. The teacher used the limited connections she had with scientific communities of practice and documentation of scientific practice to develop her syntactic science knowledge. She applied strategies used in her general practice to teach syntactic aspects of science. Reflection on the effectiveness of these learning experiences built new PCK, supporting theories about the transformative development of PCK from other knowledge domains. Access to knowledge about the NOS is raised as a possible problem for generalist elementary teachers implementing curriculum with scientific literacy as a goal.

On the functional architecture of DP and the feature content of pronominal quantifiers in Low German

The article investigates the functional architecture of complex pronominal quantifying expressions (PQEs) in Low German, such as jeder-een ‘everyone’ and keen-een ‘no-one’, which provide overt evidence for a Num-projection, situated between the NP- and DP-layer. The feature specification of Num as [+lattice] or [−lattice] is responsible for whether the DP denotes into the domain of atomic or mass/plural entities, respectively. In the case of complex PQEs, the syntactic Num-head hosts the overt element een ‘a, one’, which carries a [−lattice] feature, thus ensuring that the PQE ranges exclusively over the domain of atomic entities, but not mass or plural entities. The Num-head een differs from its simplex counterpart wat ‘something’, which is analyzed as an NP-proform with an underspecified [lattice]-feature. As a result, wat can range over atomic and mass domains alike. In the final part of the article, it is argued that wat is also underspecified for the operator feature [rel/wh], for which reason it can also function as an interrogative expression (what) and as a relative pronoun (which), respectively, depending on the syntactic context. Throughout the article, the Low German data are compared with relevant data from other German dialects and Germanic and Romance languages, pointing out similarities and differences in the syntactic structure and feature content of PQEs across these languages and dialects.

Automating modular model construction using JSim

Modular modeling of physiological processes over orders of magnitude of spatial and time scales requires the merging of semantic content with the syntactic content of mathematical formulas. Using JSim's Mathematical Modeling Language (MML), we have designed simple processes which allow us to extract the mathematics from existing models, relabel the parameters and variables with names reflecting semantic content, and combine algebraic, ordinary differential and partial differential equations in an automated fashion to generate more powerful, biologically realistic models. An example is constructing a model for three regions (plasma, interstitial fluid region, and parenchymal cell) using partial differential equations. It includes two metabolites competing for a transporter on the cellular membrane with enzyme conversion of the first metabolite to a second metabolite in the cell. The method uses basic models for diffusion in one region, flow in one region, exchange between two regions, two state conformational change, and an enzyme on‐off model. The method supports taking archived models (CellML, SBML, JSim) and combining them in aggregated or hierarchical forms. Grant support NIH T15HL88516 EB08407.

OS CONSTITUINTES DE SN DO KATUKINA

In our study we discuss the NP internal disponsition in the Katukina language, questioning the nature of its lexical itens - dissylabics and oxitones - which can be formed by syntactic contents sequence. So this leads us to suspect that Katukina is agluting languages.

Rules and Heuristics during Sentence Comprehension: Evidence from a Dual-task Brain Potential Study

Whether syntactic and semantic processes during sentence comprehension follow strict sets of rules or succumb to context-dependent heuristics was studied by recording event-related potentials in a dual-task design. In one condition, sentence-extraneous acoustic material was either semantically congruent or incongruent relative to an adjective in the visually presented sentence, the latter being either semantically correct or incorrect within the sentence context. Homologous syntactic (gender) manipulations were performed in another condition. Syntactic processing within the sentence appeared to be blind to the syntactic content of the second task. In contrast, semantically incongruous material of the second task induced fluctuations typically associated with the detection of within-sentence semantic anomalies (N400) even in semantically correct sentences. Subtle but extant differences in topography between this N400 and that obtained with within-sentence semantic violations add to recent proposals of separate semantic subsystems differing in their specificity for sentence structure and computational procedures. Semantically incongruous material of the second task also influenced later stages of the processing of semantically incorrect adjectives (P600 component), which are traditionally assumed to pertain to the syntactic domain. This result is discussed in the light of current proposals of a third combinatorial stream in sentence comprehension.

A rich semantic model of track as a foundation for sharing beliefs regarding dynamic objects and events

Many defense, homeland security, and commercial security objectives require continuous tracking of mobile entities such as aircraft. The systems that perform these functions produce information products called tracks. A track associates observations with the mobile entity and typically includes position, velocity, and other similar attributes. Military systems have sophisticated tracking and track fusion processes, but lack uniformity in syntactic and semantic content, preventing effective sharing of the information. In other domains of interest, such as seagoing surface ships, dangerous cargo and persons of interest, tracking systems are less mature and have marginal performance. It is now essential that we be able to share information across different tracking systems working in related domains. To combine information from different sources, we need a flexible framework that can tolerate and exploit data products from those systems, even though these systems employ different representations and embody different assumptions. The most basic assumptions concern what the information is intended to mean semantics and how it is intended to be used by a recipient pragmatics. In accordance with best practices in the technology areas of the semantic web and knowledge representation, we seek to reduce the barriers to efficient sharing of information. Our approach is to identify a rich semantic model of tracks that can support multiple important functions: 1 represent a wide variety of meanings and support a broad array of pragmatic goals; 2 reduce the time and cost required to implement capabilities to reason about a new, specialized type of track; 3 simplify the understanding and importation of external sources of track information; 4 help operators describe what attributes of tracks they value in performing their tasks; 5 significantly improve our ability to combine multiple sources of track information; 6 provide a stable and evolvable base for key standards and best practices that support information sharing; and 7 improve bandwidth utilization, raising the proportion of communicated information that recipients consider significant, by delivering valued information at the right time VIRT. This paper describes the proposed rich semantic track model and ongoing efforts to share it widely with appropriate communities of interest.

Mapping of prosodic structure onto words and phrases in children's and adults' speech production

Direct recordings of lip and jaw movement were obtained to investigate how children and adults differentiate prosodic structure both within iambic and trochaic words and across word boundaries. It was hypothesised that children, especially those with less language skills, would be particularly likely to produce strong-weak (or trochaic) sequences. This experiment examined children's (both normally developing and specifically language impaired, aged 4–6 years) and adults’ productions of prosodic sequences that were controlled for syntactic and phonetic content, but that differed in rhythmic alternations, both within words (i. e., iambs vs. trochees) and across words (i. e., optimal strong-weak vs. stress gap or stress clash). To avoid final position effects, target words were in utterance internal position. Analyses included kinematic measures of prosodic structure (i. e., amplitude and duration of movements in weak vs. strong syllables; ratios of weak-to-strong movements). Consistent with prior work, weak syllables in iambs were produced differentially from those in trochees; though these effects were now observed in utterance position. However, in noun-noun sequences within a phrase, even when the rhythm rule was violated, prosodic foot structure was not reorganised as a function of rhythmic properties of the utterance. Overall, children with the least mature language skills demonstrated poor control of temporal and amplitude aspects of movement, especially in weak syllables. Findings are related to the organisation of speech production units across prosodic levels.

Guest editors' introduction to the special section on energy minimization methods in computer vision and pattern recognition

ENERGY minimization techniques are central to many methods in computer vision and pattern recognition. Stated simply, if a task can be posed as the minimization of an energy measure, which may, for instance, be the negative logarithm of a probability or an entropy, then a variety of optimization methods may be applied to locate the solution. The solution may be a vector of parameters representing the shapes of a curve, a surface, or a volume, it may be a set of symbolic labels representing the semantic or syntactic content of a signal, or it may be a graph representing arrangement or structure. The optimization methods that can be applied to the cost function to recover the solution include gradient descent, simulated annealing, mean-field annealing, evolutionary search, and tabu search, to mention just a few. Many of the classical methods in the fields of computer vision and pattern recognitionmake use of energyminimization techniques. Familiar examples include relaxation labeling, regularization, active contours, and Markov models. More recent examples include the use of graph-cuts, spectral graph theory, and semidefinite programming. Energy minimization techniques have also been pivotal in the development of algorithms for learning, inference, and classification. One of the characteristics of this field is that it draws strongly on recent developments in other disciplines such as mathematics, statistics, operations research, biology, and economics. Moreover, the basic methodology is being developed at a great rate in these related disciplines. In this respect, energy minimization is different from other widely used techniques such as geometry or probability, where the basic methods have been available in the mathematics literature for well over 100 years. It is probably fair to say that the problems of optimization and, in particular, combinatorial optimization, are ones of a computational nature and have hence only emerged over the past few decades. Our own involvement in this field has been, in part, through a biennial series of workshops (EMMVCPR) that commenced in 1997 and which have been aimed at providing a focus for research in this area. From the interest shown in these workshops and the number of papers on the topic appearing in the main conferences (CVPR, ECCV, ICCV), it seemed to us that a special edition of IEEE Transactions on Pattern Analysis and Machine Intelligence would be both timely and valuable to the community. The call for papers was issued in mid-2001 and we received 50 papers by the deadline on 1 May 2002. Each paper was reviewed by at least three reviewers according to the standard TPAMI reviewing procedure. This meant that we needed the assistance of some 150 reviewers. By late October 2002, we had first reviews for all of the papers and met in Venice to make initial decisions. Based on the reviews, and giving authors the chance to revise their papers in the light of reviewers comments, we selected the six papers that appear in the current special section, together with three papers that will appear in a subsequent special section. The papers span a diverse set of methods and applications. The techniques covered include semidefinite programming, Markov models, and simulated annealing, while the problems addressed include deformable models, shape-from-shading, and clustering. The first regular paper in this special section is “Binary Partitioning, Perceptual Grouping, and Restoration with Semidefinite Programming” by J. Keuchel, C. Schnorr, C. Schellewald, and D. Cremers. The authors describe a new optimization method based on semidefinite programming relaxations. The method is applied to the computer vision problems of unsupervised partitioning, figure-ground discrimination, and binary restoration. The interesting feature of the proposed method is that it does not require any parameter tuning. Moreover, apart from the symmetry condition, no assumptions aremade concerning the objective criterion. IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE, VOL. 25, NO. 11, NOVEMBER 2003 1361

An ERP study of continuous speech processing: I. Segmentation, semantics, and syntax in native speakers

Speech segmentation, breaking continuous streams of sound into units that can be recognized, is a necessary step in auditory language processing. To date, most studies of speech segmentation have been limited to behavioral measures that may not index online segmentation as it occurs when listening to natural speech. In the present study, we measured event-related potentials (ERPs) evoked by word-initial and word-medial syllables equated for loudness, length, and phonemic content. This comparison provided an online measure of natural speech segmentation. Word-initial sounds elicited a larger early sensory component (N100). In addition, we measured the effects of semantic and syntactic information on speech segmentation by comparing ERPs to word-initial and word-medial syllables in sentences with varying amounts of semantic and syntactic content. The results indicated that neither semantic nor syntactic information is necessary for the word-onset segmentation effect to be observed. We also identified additional ERP components that index more general semantic and syntactic aspects of natural speech processing.

Where are the minimal trees? Evidence from early Zulu L2 subordination

The Minimal Trees Hypothesis (Vainikka and Young-Scholten 1994; 1996a; 1996b) proposes that second language (L2) initial state grammars lack functional categories because functional categories are not subject to transfer effects. The aim of this article is to argue that, to some extent, functional categories instantiated in the learner's first language (L1) transfer to the initial state of L2 syntactic development. On the basis of Zulu interlanguage (IL) data on the acquisition of the obligatory declarative complementizer ukuthi(‘that’) by English native speakers, it is argued that Comp contains a null complementizer system which has sufficient syntactic content to generate subordination in the learners' initial Zulu IL grammar. Regarding transfer of functional categories, it is suggested that null Comp evident at the Zulu L2 initial state is transferred from English, the subjects' L1.

The Failure of Language Comprehension at Sentence and Phrasal Levels in A Patient Who can Speak Normally

An unexpected dissociation between intact propositional speech and impaired language comprehension was observed in a right handed patient following a right hemisphere stroke. Although CHO's comprehension was intact at the single word level, his ability to comprehend a wide range of sentence structures was profoundly impaired. This deficit was observed in the context of normal sentence production both with regard to semantic and syntactic content. This case provides further evidence for the independence of on-line language input and output systems.

Product modeling within the framework of the World Wide Web

This paper presents an approach to the development of an open collaborative design environment in the Computer Aided Design (CAD) setting of a networked enterprise. Demand for high quality and variety of low to medium quality of products or 'mass customization' has led to the concept of'virtual organizations'. The de-centralized design teams of such an organization require a framework to manage the CAD product information. By integrating the emerging standard for 3D geometry on the World Wide Web with conventional CAD packages, we describe a framework for the development of a product model with various levels of abstractions. The syntactic content of the product model, accessible through any Internet interface such as Netscape Navigator associates itself with a centralized database for embedding technological information at the face and feature levels. The semanlic and syntactic content of the product model can then be accessed and manipulated through the single Internet interface. The system is deployed on a test-bed utilizing both a UNIX box and a machine operating under the Windows NT system, to demonstrate it's open architecture and interoperability.

Creating and effacing differences in speeches on unemployment

In this article, what makes politicians' talk political' is examined. It is suggested that the political refers to actions that involve disputes and struggles over competing ideas, interests, and goals. In order to examine the political quality of politicians' talk, the thematic, syntactic, and lexical content of three speeches given by politicians of the European Commission on the topic of unemployment was analyzed. It was found that the speakers used a variety of discursive resources to portray a struggle between the competing perspectives of the European Commission and those in opposition to the Commission's policies. The struggle consisted of the speakers' discursive practices that emphasized (politicization) and minimized differences (depoliticization) between opposing groups. It is argued that this interplay between the emphasis and effacement of differences played a major role in making these texts political. Of particular importance was the speakers' use of confidence terms to create consensus and block alternatives.

Product modeling within the framework of the World Wide Web

This paper presents an approach to the development of an open collaborative design environment in the Computer Aided Design (CAD) setting of a networked enterprise. Demand for high quality and variety of low to medium quality of products or 'mass customization’ has led to the concept of 'virtual organizations’. The de-centralized design teams of such an organization require a framework to manage the CAD product information. By integrating the emerging standard for 3D geometry on the World Wide Web with conventional CAD packages, we describe a framework for the development of a product model with various levels of abstractions. The syntactic content of the product model, accessible through any Internet interface such as Netscape Navigator associates itself with a centralized database for embedding technological information at the face and feature levels. The semantic and syntactic content of the product model can then be accessed and manipulated through the single Internet interface. The system is deployed on a test-bed utilizing both a UNIX box and a machine operating under the Windows NT system, to demonstrate it's open architecture and interoperability.

The Knowledge of Christ Jesus my Lord: The High Christology of Philippians 3:7-11

Employing the traditional tools of historical-critical methodology as well as a selected mix of techniques from newer literary criticism, this book provides a close analysis of the syntactic and semantic content of Phil 3:7-11 in its immediate and broader context, concluding that this passage represents a very high christological statement on the part of Paul, and discusses some of the implications of these findings in regard to the interpretation of Phil 2:5-11, the wisdom ambience of the letters of Paul, and relevance for modern christologies. In Philippians 3:7-11, Paul makes a very strong statement about how much Christ Jesus means to him. This study seeks to demonstrate how the passage within its context gives expression to a high christological statement which is frequently disregarded in treatments of Pauline christology. Chapter One presents a concise summary of the history of exegesis of Phil 3:7-11 and identifies the elements present within that history which indicated the desirability of a more in-depth treatment. Chapter Two focuses on the entire letter to the Philippians as the context of interpretation of Phil 3:7-11, beginning with a discussion of the methodology employed in the remainder of the work. Chapter Three focuses on Phil 3:7-11, first considering the textual variants within these verses, then describing in detail the relation of the complex sentence consisting of vv. 8-11. Chapters Four and Five deal with those issues of semantics in vv. 8-11 which require more extensive treatment. Chapter Six returns to a consideration of the meaning of knowledge of Christ, concluding with a consideration of the results of this study for current discussions of New Testament Christology.

Processing distinctions between stems and affixes: Evidence from a non-fluent aphasic patient

In this paper, we study the ability of a non-fluent aphasic patient, BN, to comprehend morphologically complex words when they appear in utterance contexts. We first establish that he is insensitive to the contextual appropriateness of both derived and inflected words. In a further experiment we show that he has no difficulty processing the stems of complex words and conclude that his problem is with the bound morphemes themselves. We then ask whether this problem is due to his inability to access either the phonological form of a morphologically complex word or its semantic and/or syntactic content. We find that only the access of semantic and syntactic content is impaired. We conclude from these six studies that: (a) BN presents a counter-example to the claim that non-fluent patients have particular difficulty with those aspects of morphology which have a syntactic function; (b) BN processes both derived and inflected words by mapping the sensory input onto the entire full-form of a complex word, but the semantic and syntactic content of the stem alone is accessed and integrated into the context. The semantic and syntactic implications of the suffix are never evaluated. This implies separate representation of the stems and suffixes of some types of morphologically complex words.

What Is Computational Psychology?

ly-defined information-processing tasks. With respect to virtually all matters normally studied by psychologists, we cannot identify the basic task. The one possible exception is language-or, rather, parsing. The task of a parsing system is to map the input word-string onto structural descriptions couched in syntactic terms. Syntactic structure enters into our definition of what language is. So whether chimps can learn language is now taken to depend, not on their producing humanoid speech-sounds or new meaningful symbol-strings, but on their ability to make syntactic disThis content downloaded from 157.55.39.254 on Sun, 04 Sep 2016 04:48:29 UTC All use subject to http://about.jstor.org/terms WHAT IS COMPUTATIONAL PSYCHOLOGY? 27 criminations. We already have some candidate syntactic descriptions, and (controversial) abstract arguments about the relative power of transformational versus context-free grammars to effect the mapping. We even have one example of an abstract task-identification and a computerized mapping-algorithm based on it, where these are clearly conceived by their authors at distinct explanatory levels. Noam Chomsky's formal grammatical rules do not describe actual psychological processes, but abstract structural relationships. It is often said that Chomsky ignored process because he is a linguist, not a psychologist: psychologists are interested in how language happens in the mind, whereas linguists are concerned only with language in itself. This is true, so far as it goes. But it is sometimes taken to imply that if Chomsky had been really interested in psychology, he would have concentrated on specifying the mental processes involved. This is the typical reaction of computational psychologists (in the broad sense). In Marr's sense, however, Chomsky was doing psychology all along. Indeed, he was attempting the mathematical groundwork on which any scientific process-oriented (second-level) explanation must be based. He was right to ignore process, leaving it to others (such as Mitchell Marcus3) to think about the specific algorithms that could exploit the structural constraints discovered by him. Syntax is a relatively simple case (which is not to deny that it is both difficult and controversial). What of semantics? Attempts to formalise semantics have been made, but are also controversial. We cannot, in general, specify the task involved in mapping a word-string onto a semantic representation. As for mapping an extended text onto its thematic representation, we are even more in the dark. And what structural regularities underlie language-use in conversations? In all these cases, there are scattered insights and a variety of computer-models supposedly directed to the problem. But, in the strong sense discussed within this section, we do not have even the beginnings of a computational understanding of these matters. We are in the same position with respect to most topics S M. P. Marcus, A Theory of Syntactic Recognition for Natural Language (Cambridge, Mass.: MIT Press, 1980). This content downloaded from 157.55.39.254 on Sun, 04 Sep 2016 04:48:29 UTC All use subject to http://about.jstor.org/terms 28 I-MARGARET A. BODEN studied by psychologists. Even where it is intuitively plausible that a psychological category rests on an identifiable task, we have little idea of what this might be. As Marr put it, when criticizing explanations of problem-solving based on computer simulations of people doing cryptarithmetic: no doubt something computational is going on when we do mental arithmetic, but it almost certainly is not mental arithmetic. Moreover, there may not be one task for each category. Social psychologists offer 'theories' of attitude-change, but it is not obvious that attitudechange is a natural kind. And what of learning, social interaction, or personality development: is it even plausible that an abstract information-processing definition could be given for these phenomena? General arguments of a 'transcendental' character are needed in each case, specifying a generic information-processing task and identifying computational constraints to be exploited by creatures enjoying psychological powers of the relevant class. Philosophical study of the necessary conditions of (for example) conversation, personal interaction, and intentional action in general might be useful, and comparable discussions are to be found in the literature of psychology and AI. But even where such insights exist, they do not have the degree of precision which enabled Marr to prove that his representational system is in principle capable of computing various sorts of 2D-to-3D mapping whereas others are not. He had physics to help him, and physics might allow abstract computational analysis of other low-level sensory systems. It is not obvious, however, that high-level psychological abilities (even including high-level vision) can helpfully be thought of in this way. If they can, then we may hope for a computational psychology that will explain why mental abilities are as they are, by grounding them in general conditions of experience which constrain all psychological beings. But if they cannot, then (nonsensory) computational psychology is possible-if at all-only in a sense weaker than that defined by Marr.