Reinflating Logical Consequence

Shapiro (Philos Q 61:320–342, 2011) argues that, if we are deflationists about truth, we should be deflationists about logical consequence. Like the truth predicate, he claims, the logical consequence predicate is merely a device of generalisation and more substantial characterisation, e.g. proof- or model-theoretic, is mistaken. I reject his analogy between truth and logical consequence and argue that, by appreciating how the logical consequence predicate is used as well as the goals of proof theory and model theory, we can be deflationists about truth but not logical consequence.     

Reinflating Truth as an Explanatory Concept

Abstract: Despite his protests, there have been numerous efforts to enroll Davidson in the deflationist program. Michael Williams has recently continued this enterprise, arguing that a truth-theoretic Davidsonian approach to meaning can be harnessed to a deflationary approach to truth. It is our contention that Williams' attempt is unsuccessful.     

Classical population genetics and the semantic approach to scientific theories

In what follows, I argue that the semantic approach to scientific theories fails as a means to present the Wright–Fisher formalism (WFF) of population genetics. I offer an account of what population geneticist understand insofar as they understand the WFF, a variation on Lloyd’s view that population genetics can be understood as a family of models of mid-level generality.     

Organisation and evocation of the semantic knowledge: a non-abstractive approach

The majority of the models which attempt to explain category-specific deficits are based on the assumption that the conceptual knowledge is represented in a permanent way in memory (abstractive view). showed that a non-abstractive view would be more suitable to account for some of these cases. The present study aims to assess the hypotheses on the meaning evocation process as formulated by these authors, using a property verification task conducted on healthy subjects. The data were in agreement with these hypotheses and would be more hardly accounted in the frame of the abstractive view.     

Unique contribution of semantic representations to immediate memory: an individual-differences approach

Studies have reported dissociations between the contributions of semantic and phonological representations to immediate remembering, found through experimental manipulations as well as specific clinical cases. Also, some studies based on the analysis of individual differences reported that a semantic cued recall task has a variance unshared with the immediate memory tasks which tap the contribution of phonological representations. However, another study suggested that cued recall performance could reflect a wider ability to cluster information by category. Furthermore, no studies of individual differences have investigated the unique semantic contribution in the visual domain. Therefore, the present study used specific immediate recognition memory tasks that have been used to investigate the semantic contribution in the verbal and visual domains. The results demonstrate the unshared variance that reflects the semantic contribution in both the verbal and the visual domain, and some commonality in these variances across the domains.     

A common representation for semantic and physical properties: a cognitive-anatomical approach

This is the first report of a mutual interference between luminance and numerical value in magnitude judgments. Instead of manipulating the physical size of compared numbers, which is the traditional approach in size congruity studies, luminance levels were manipulated. The results yielded the classical congruity effect. Participants took more time to process numerically larger numbers when they were brighter than when they were darker, and more time to process a darker number when its numerical value was smaller than when it was larger. On the basis of neurophysiological studies of magnitude comparison and interference between semantic and physical information, it is proposed that the processing of semantic and physical magnitude information is carried out by a shared brain structure. It is suggested that this brain area, the left intraparietal sulcus, subserves various comparison processes by representing various quantities on an amodal magnitude scale.     

CoTO: A novel approach for fuzzy aggregation of semantic similarity measures

Semantic similarity measurement aims to determine the likeness between two text expressions that use different lexicographies for representing the same real object or idea. There are a lot of semantic similarity measures for addressing this problem. However, the best results have been achieved when aggregating a number of simple similarity measures. This means that after the various similarity values have been calculated, the overall similarity for a pair of text expressions is computed using an aggregation function of these individual semantic similarity values. This aggregation is often computed by means of statistical functions. In this work, we present CoTO (Consensus or Trade-Off) a solution based on fuzzy logic that is able to outperform these traditional approaches.     

Structure in semantic memory: A probabilistic approach using a continuous response task

In the continuous response (CR) task, the subject is given the name of a familiar category and must respond with category examples within a fixed time limit. The response sequence and the interresponse times are the measured variables. A general model is proposed for performance in the CR task. The time taken to generate a response is identified with the shortest search time from among a set of simultaneous search processes. Each response has a generation probability that is a function of the parameters governing the search process durations. Data involving the category states in the United States are used to test the model. The model accounts for the performance of nearly all individuals in these data.This article is based on a dissertation completed at the University of California-Berkeley in partial fullfillment of the requirements for the Ph.D. degree in psychology. Portions of the article were presented at the joint meeting of the Psychometric and Classification Societies (June 1984) and at the meeting of the Society for Mathematical Psychology (August 1984). The authors wish to thank Barbara Mellers, Juliet Schaffer, Steve Palmer, and Eleanor Rosch for helpful comments.     

Estimating the average need of semantic knowledge from distributional semantic models

Continuous bag of words (CBOW) and skip-gram are two recently developed models of lexical semantics (Mikolov, Chen, Corrado, & Dean, Advances in Neural Information Processing Systems, 26, 3111–3119, 2013). Each has been demonstrated to perform markedly better at capturing human judgments about semantic relatedness than competing models (e.g., latent semantic analysis; Landauer & Dumais, Psychological Review, 104(2), 1997 211; hyperspace analogue to language; Lund & Burgess, Behavior Research Methods, Instruments, & Computers, 28(2), 203–208, 1996). The new models were largely developed to address practical problems of meaning representation in natural language processing. Consequently, very little attention has been paid to the psychological implications of the performance of these models. We describe the relationship between the learning algorithms employed by these models and Anderson’s rational theory of memory (J. R. Anderson & Milson, Psychological Review, 96(4), 703, 1989) and argue that CBOW is learning word meanings according to Anderson’s concept of needs probability. We also demonstrate that CBOW can account for nearly all of the variation in lexical access measures typically attributable to word frequency and contextual diversity—two measures that are conceptually related to needs probability. These results suggest two conclusions: One, CBOW is a psychologically plausible model of lexical semantics. Two, word frequency and contextual diversity do not capture learning effects but rather memory retrieval effects.     

Motivated semantic control: Exploring the effects of extrinsic reward and self-reference on semantic retrieval in semantic aphasia

Recent insights show that increased motivation can benefit executive control, but this effect has not been explored in relation to semantic cognition. Patients with deficits of controlled semantic retrieval in the context of semantic aphasia (SA) after stroke may benefit from this approach since ‘semantic control’ is considered an executive process. Deficits in this domain are partially distinct from the domain-general deficits of cognitive control. We assessed the effect of both extrinsic and intrinsic motivation in healthy controls and SA patients. Experiment 1 manipulated extrinsic reward using high or low levels of points for correct responses during a semantic association task. Experiment 2 manipulated the intrinsic value of items using self-reference, allocating pictures of items to the participant (‘self’) or researcher (‘other’) in a shopping game before participants retrieved their semantic associations. These experiments revealed that patients, but not controls, showed better performance when given an extrinsic reward, consistent with the view that increased external motivation may help ameliorate patients’ semantic control deficits. However, while self-reference was associated with better episodic memory, there was no effect on semantic retrieval. We conclude that semantic control deficits can be reduced when extrinsic rewards are anticipated; this enhanced motivational state is expected to support proactive control, for example, through the maintenance of task representations. It may be possible to harness this modulatory impact of reward to combat the control demands of semantic tasks in SA patients.     

Charting the progression in semantic dementia: Implications for the organisation of semantic memory

Abstract

A patient, JL, with the syndrome of semantic dementia was assessed longitudinally over a two-year period. The data presented here address the controversy concerning the hierarchical organisation of semantic memory. On a range of category fluency tests, when first tested JL was just within the normal range on the broadest categories of animals and household items, but was virtually unable to produce any instances of specific categories such as breeds of dog or musical instruments. Longitudinal fluency data for the animal category demonstrate that while JL continued to produce the most prototypical responses (cat, dog, horse), other animal labels dropped out early from his vocabulary. On the picture-sorting tests from our semantic memory test battery, JL's discrimination between living things and man-made objects was preserved for a substantial time in conjunction with a marked decline in his sorting ability for more specific categories, particularly features or attributes (e.g. size, foreign-ness, or ferocity of animals).

An analysis of naming responses to the 260 Snodgrass and Vanderwart pictures on four occasions suggests a progressive loss of the features of semantic representations that enable discrimination between specific category instances. There was a progressive decline in circumlocutory and category co-ordinate responses with a rise in broad superordinate and cross-category errors. The latter are of particular theoretical interest; on session I, all cross-category errors respected the living/man-made distinction, but by session IV almost half of such errors failed to respect this distinction. The emergence of category prototypes was another notable feature, particularly in the living domain: at one stage, land (or four-legged) animals were all named either cat, dog, or horse. By contrast, within the man-made domain, items were frequently described in terms of their broad use or function, until eventually no defining features were produced. These findings are discussed in the context of competing theories of semantic organisation.     

On the existence of semantic working memory: evidence for direct semantic maintenance

Despite widespread acknowledgment of the importance of online semantic maintenance, there has been astonishingly little work that clearly establishes this construct. We review the extant work relevant to short-term retention of meaning and show that, although consistent with semantic working memory, most data can be accommodated in other ways. Using a new concurrent probe paradigm, we then report experiments that implicate a semantic maintenance capacity that is independent of phonological or visual maintenance that may build on a mechanism of direct semantic maintenance. Experiments 1 through 5 established that while subjects maintain the meaning of a word, a novel delay-period marker of semantic retention, the semantic relatedness effect, is observed on a concurrent lexical decision task. The semantic relatedness effect refers to slowed response times when subjects make a lexical decision to a probe that is associatively related to the idea they are maintaining, compared to when the probe is unrelated. The semantic relatedness effect occurred for semantic but not for phonological or visual word-form maintenance, dissipated quickly after maintenance ends, and survived concurrent articulatory suppression. The effect disappeared when subjects performed our immediate memory task with a long-term memory strategy rather than with active maintenance. Experiment 6 demonstrated a parallel phonological relatedness effect that occurs for phonological but not semantic maintenance, establishing a full double dissociation between the effects of semantic and phonological maintenance. These findings support a distinct semantic maintenance capacity and provide a behavioral marker through which semantic working memory can be studied.     

How semantic memory structure and intelligence contribute to creative thought: a network science approach

The associative theory of creativity states that creativity is associated with differences in the structure of semantic memory, whereas the executive theory of creativity emphasises the role of top-down control for creative thought. For a powerful test of these accounts, individual semantic memory structure was modelled with a novel method based on semantic relatedness judgements and different criteria for network filtering were compared. The executive account was supported by a correlation between creative ability and broad retrieval ability. The associative account was independently supported, when network filtering was based on a relatedness threshold, but not when it was based on a fixed edge number or on the analysis of weighted networks. In the former case, creative ability was associated with shorter average path lengths and higher clustering of the network, suggesting that the semantic networks of creative people show higher small-worldness.     

Cognitive load and semantic analogies: Searching semantic space

The aim of the present study is to investigate the performance of children of different ages on an analogymaking task involving semantic analogies in which there are competing semantic matches. We suggest that this can best be studied in terms of developmental changes in executive functioning. We hypothesize that the selection of common relational structure requires the inhibition of other salient features, in particular semantically related matches. Our results show that children's performance in classic A ∶ B ∶∶ C ∶ D analogy-making tasks seems to depend crucially on the nature of the distractors and the association strength between both the A and B terms and the C and D terms. These results agree with an analogy-making account (Richland, Morrison, & Holyoak, 2006) based on different limitations in executive functioning at different ages.     

On the spread of semantic excitation

Summary Access to word-representations in memory was studied in two experiments. A lexical decision paradigm was used in both: Ss had to decide whether a string of letters shown to them was a word or a nonword. Decision time was the main dependent variable. Independent variables were context-similarity and context-intensity. The former is defined in terms of the categorical relationship that holds between a set of context-words and a subsequently presented test-word. The latter is defined by the number of highly related context-words, all sampled from a small semantic subcategory, that preceded the test-stimulus. In theory, the presentation of the context-words generates semantic excitation that spreads over memory and activates other memory representations. Differences in mean decision time, as a function of experimental conditions, are attributed to differences in the activation of test-words. Two hypotheses about the course or gradient of excitation-spread in lexical memory were studied. The results indicate that a simple spread-of-excitation hypothesis as proposed by Meyer, Schvaneveldt and Ruddy (1972, 1974) is sufficient to account for the data. For the conditions studied in the experiments, there was no reliable evidence of inhibitory processes that confine spread of excitation to a small region of lexical memory.This paper reports work that was conceived and begun at Stanford University, Calif., USA, where the author spent a year as a postdoctoral fellow. The fellowship was made possible by the Deutsche Forschungsgemeinschaft, Bad Godesberg, West Germany, Grant Schm 350/1. I thank Prof. Richard G. Atkinson and Dr. Stephan Monsell for discussing aspects of this work with me. I further thank Paul Matthews for introducing me to the art of running computerized experiments.     

Connectionist semantic systematicity

Fodor and Pylyshyn [Fodor, J. A., & Pylyshyn, Z. W. (1988). Connectionism and cognitive architecture: A critical analysis. Cognition, 28, 3–71] argue that connectionist models are not able to display systematicity other than by implementing a classical symbol system. This claim entails that connectionism cannot compete with the classical approach as an alternative architectural framework for human cognition. We present a connectionist model of sentence comprehension that does not implement a symbol system yet behaves systematically. It consists in a recurrent neural network that maps sentences describing situations in a microworld, onto representations of these situations. After being trained on particular sentence–situation pairs, the model can comprehend new sentences, even if these describe new situations. We argue that this systematicity arises robustly and in a psychologically plausible manner because it depends on structure inherent in the world.