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Wednesday 10 April 2002, 18.30 - 19.30
9th EPS Prize Lecture
The Role of the Prefrontal Cortex in Actions and Habits
Cardiff University, UK
The development of behavioural autonomy, or habits, has long been recognised as an effect that appears to result from extended experience of a particular sequence of events in the world. Research in rats has suggested that habit performance results from the enhanced influence of stimulus-response (S-R) associations over performance as a result of a decline in the importance of goal-directed response-outcome (R-O) associations. Experiments presented will examine the role of selective sub-regions of the prefrontal cortex in the development and maintenance of S-R performance in rats. This work indicates that two discrete regions of the medial prefrontal cortex - the infralimbic and prelimbic cortices - are involved in the control of behaviour by S-R and R-O associations, and suggests that there may be a mutually inhibitory relationship between the two. Implications of these findings for the development of behavioural autonomy and the nature of habit performance will be discussed.
Thursday 11-04-02, 9:00 - 11:00,
Symposium 6 Memory and Attention in Timing
Manchester University, UK
Operating the timing system: from automatic to controlled processes
Manchester University, UK
The present paper discusses some operations of the human timing system in terms of automatic and controlled processing. Perhaps the best-known recently-discovered "automatic" effect is that of click trains on the subjective duration of events they precede. Another comes from an experiment where auditory and visual stimuli were present at thesame time. Here, a completely irrelevant auditory stimulus made a visual one increase insubjective duration, but not vice versa, presumably the result of an automatic process. Inanother experiment, the auditory stimulus required processing, but was irrelevant toduration judgements of visual stimuli. This time, the auditory stimulus made the visualone seem shorter. This is consistent with the well-known effects of diversion of attentionfrom temporal to non-temporal processing, but might be considered semi-automatic (i.e.the subject "voluntarily" shifted attention to the tone, but the effect on temporaljudgements was uncontrolled by the subject). Examples of fully controlled processingcome from experiments in which subjects must make judgements of tone duration, wheresome tones have randomly-placed 200 ms gaps in them. Different groups were requiredto include the gap as part of the total tone duration or exclude it. People were able toperform this task almost perfectly, thus demonstrating a high degree of precise voluntarycontrol over their temporal processing. Understanding the ways in which the internalclock might be influenced, automatically, semi-automatically, or in a controlled way,may help us develop a more complete model of the factors which determine timejudgements in humans, while maintaining a consistent internal clock model.
From behavioural data to underlying temporal processes: methodological considerations
University of Liège, Belgium
What is the real nature of the temporal information-processing model? To address thisquestion, experimental methods derived from the peak procedure were used. One aimwas to learn something about the temporal representations used by the subject, theformalization of the decision rules used, as well as the localization of variance within thetiming system. In addition, models derived from the work of Gibbon and Church wereused to compare simulated results with experimental data. Results from analyses ofbehavioural data obtained from rats in peak procedure variants with both single andmultiple times of reinforcement were discussed. One conclusion is that the individual-trials analysis algorithm used may strongly influence the theoretical conclusions thatmight be drawn. A second aim was to analyse data obtained in transition situations (whenthe time of reinforcement is abruptly changed). I describe the dynamics of the adaptationto changes in reinforcement time which could be compatible with the temporalinformation processing models like scalar expectancy theory, initially designed to explainsteady-state behaviours.
Temporal interval production and short-term memory
David T. Field and John A. Groeger
University of Surrey, UK
Interference with time estimation from concurrent nontemporal processing has beenshown to depend on the short-term memory requirements of the concurrent task (Fortin,Rousseau, Bourque & Kirouac, 1993; Fortin & Breton, 1995). In particular, it has beenclaimed that active processing of information in short-term memory producesinterference, whereas retaining information does not. Here, four experiments are reportedin which subjects are trained to produce a 2500 ms interval, and then perform concurrentmemory tasks. Interference with timing is demonstrated for concurrent memory tasksinvolving only maintenance. In one experiment, increasing set size in a pitch memorytask systematically lengthens temporal production. Two further experiments suggest thatthis is due to a specific interaction between the short-term memory requirements of thepitch task and those of temporal production. A final experiment directly investigated theshort-term memory requirements of time estimation by requiring subjects to perform aconcurrent memory task that itself required temporal processing. Interference withinterval production was comparable to that produced by the pitch memory task. Resultsare discussed in terms of a pacemaker-counter model of temporal processing, in whichthe counter component is supported by short-term memory.
'Shooting stars': a review and development of the multiplicative transform K* inexplanations of temporal reference memory in SET
University of Manchester, UK
A common way of positing scalar variance in the SET information-processing model oftiming (Gibbon & Church, 1982/1992; Meck, 1983) is in the form of a multiplicativetransform (K*). This transform operates when the contents of the accumulator/workingmemory are transferred to reference memory, scalar variance being produced uponmultiple presentations of the standard. A brief review of this concept and researchfindings that sheds new light on its validity and the general nature of temporal referencememory is presented. There were two main strands to the empirical studies presented: thefirst examined the effect of manipulating the number of presentations of the standard tonein a modified temporal generalization task. Some conceptualisations of the K* transformpredict an increase in temporal acuity with increased number of presentations. In fact,results suggested that the effect of multiple presentations of a temporal generalizationstandard was small or non-existent, over and above the effect of presenting a singleexample of the standard. The second strand of research examined the encoding oftemporal reference memory. Does the formation of a reference memory require justencoding or is utilisation of that memory also necessary? The capacity of temporalreference memory was also examined by manipulating the number of standards to beencoded. This was achieved by the use of a modified version of the temporalgeneralization procedure called double temporal generalization.
The effect of knowledge of results on time estimation: Is there mediation by thereference memory?
André Vandierendonck & Vicky Franssen
Ghent University , Belgium
This study presents evidence for the role of knowledge of results in the estimation ofmedium time intervals (4 to 12 s durations). A series of experiments is presented. A firstexperiment tested the hypothesis that knowledge of results (KR) operates at the samestage of temporal processing as attention. The absence of an interaction of attention andknowledge of results is taken as evidence against this hypothesis. Next, two experimentsstudied the effects of KR in a reproduction and a production task, respectively. Theeffects of KR were small in the reproduction and substantial in the production task. Theresults are interpreted in terms of a clock-based timing model and the findings takentogether converge on the interpretation that KR affects the reference memory, rather thanthe other components of the model.
Thursday 11-04-02, 9:00 - 10:00, Sessions 10, 11
Session 10: Codes in Memory
Semantic coding in the recall of picture and word lists shown at RSVP and STM rates
Veronika Coltheart, Stephen Mondy and Robyn Langdon
Macquarie University, Sydney, Australia
Short-term memory serial recall provides evidence for the use of phonological codes with little, if any, involvement of semantic coding. However, when sequences of words or pictures are visually presented at high rates (8-12 items/second, termed RSVP - rapid serial visual presentation) there is evidence of early extraction of conceptual and semantic information. Such results led Potter (1993, 1999) to propose a model of Conceptual Short-term Memory. We report experiments which investigated the influence of thematic relationships among items in picture and word list recall when items were shown at RSVP rates (8/second) and low STM rates (1/second). The list items were selected from a large pool, and the nature of the semantic relationship among list items varied from list to list. Semantic relatedness benefited item recall, even when items were phonologically similar, at high and low rates of presentation. This is evidence for early involvement of semantic codes as hypothesized by the theory of Conceptual STM and it also indicates a role for semantic coding in STM.
Interactions between long- and short-term phonological memory: Evidence from an implicit phonological learning paradigm
Steve Majerus1, Martial Van der Linden2, Thierry Meulemans3, Ludivine Mulder3
1 Research Fellow-FNRS, Neuropsychology Unit, University of Liège, Belgium
2 Cognitive Psychopathology Unit, University of Geneva, Switzerland
3 Neuropsychology Unit, University of Liège, Belgium
Verbal short-term memory (STM) is influenced by phonological and lexico-semantic knowledge stored in long-term memory (LTM), as evidenced by better STM for words than nonwords. This knowledge is highly over-learned and acquired early during development. In this study we show that STM can also be supported by very recently and implicitly acquired phonological information. In experiment 1, 20 adult and 20 eight-year-old participants passively listened to a thirty-minute sequence of CV syllables while they were performing a picture drawing task. The succession of the consonants and vowels and the CV syllables was governed by an artificial grammar, which the participants were unaware of. After this implicit phonological learning phase, a nonword repetition task was presented comprising nonwords of increasing length, which were either legal or illegal relative to the artificial grammar. STM performance was significantly better for legal than for illegal nonwords, in adults and children. In experiment 2, STM performance was similar for legal and illegal nonword lists when not preceded by a phonological learning phase. Our results suggest that STM can be supported by recently and implicitly acquired phonological information and directly reflects subtle changes in phonological LTM. Implications for current models of STM and LTM are discussed.
Session 11: Shape, Space, and Language
The cultural relativity of shape categories: Goodness had nothing to do with it.
Debi Roberson1, Jules Davidoff2 and Laura Shapiro2
1 University of Essex, UK
2 Goldsmiths College, University of London, UK
The Gestalt theorists of the early twentieth century proposed a psychological primacy for circles, squares and triangles over other shapes. They described them as ‘good' shapes and the Gestalt premise has been widely accepted. Rosch (1973), for example, found that speakers of a language lacking terms for any geometric shape nevertheless learnt paired-associates to these ‘good' shapes more easily than to asymmetric variants. A cross-cultural investigation sought to replicate Rosch's findings with the Himba of Northern Namibia who also have no terms in their language for the supposedly basic shapes of circle, square and triangle. We found no advantage for these ‘good' shapes in the organization of categories. It was concluded that there is no necessary salience for circles, squares and triangles. Indeed, we argue for the opposite because the general absence of straight lines and symmetry in the perceptual environment should rather make circles, squares and triangles unusual and, therefore, less likely to be used as prototypes in categorization tasks. We place shape as one of the types of perceptual input, like colour, that is readily susceptible to effects of language variation in categorisation tasks.
Spatial discourse: Processing, memorizing, and using navigational instructions
Groupe Cognition Humaine, LIMSI-CNRS, Université de Paris-Sud, Orsay, France
Spatial discourse takes place in a variety of environmental contexts. The value of analyzing the cognitive processes involved in the processing of this type of discourse is to reflect the mind's capacity to translate verbal information into visuo-spatial knowledge, and reciprocally its capacity to express non-linguistic spatial representations in a linguistic format. The studies that we have conducted in the past years have focused on the processing, memory, and use of navigational discourse, in both laboratory and field settings. These studies provide information on the cognitive resources called upon during the processing of the descriptive and the procedural parts of spatial discourse. Because of the visuo-spatial nature of navigational information, the hypothesis that individual imagery capacities affect the processing of this type of discourse has been examined and has received substantial empirical support.
Thursday 11 April 2002, 10:00 - 12:30
The Relationship Between the Lexical and Semantic Systems in Word Processing
Royal Holloway, University of London, UK
Meanignful models of word recognition
Lorraine K. Tyler
University of Cambridge, UK
Models of word recognition aim to understand processes involved in mapping from form onto meaning. However, standard models of word recognition tend to ignore semantics, even though semantic information is clearly activated early in the process of recognising a word. I will describe some of the studies which show this early activation of semantic information and then go on to discuss a variety of experiments which show how meaning influences form-based lexical processing.
While the results of these studies do not dictate a specific model of word recognition, they are most consistent with those models in which form-based and meaning-based constraints are integrated to achieve lexical recognition. I will argue that to make progress in developing models of work recognition we need to develop more specific theories of semantic representation. To this end, I will describe one distributed model of sematics - the conceptual structure account - which focuses on the internal structure of concepts, and show how the structure of concepts affects word recognition processes. Taken together these studies suggest that theories of word recognition will remain incomplete until they take semantics seriously.
The relationship between the lexical and semantic systems in word and object processing
Macquarie University, Australia
Research on patients with impairments of comprehension for pictures or environmental sounds or spoken words or printed words will be reviewed so as to demonstrate that lexical processing can be intact when semantic processing is severely impaired. It will be argued that these data indicate not only that the lexical and semantic systems are distinct but also that a phonological lexicon, an orthographic lexicon, and a lexicon of pictorial forms all exist as components of our cognitive architectures.
Thursday 11 April 2002, 13:30 - 15:30,
Symposium 7 -Category-specificity in Mind and Brain
Glyn W. Humphreys
Univerisity of Birmingham, UK
Domain Differences in Semantic Dementia: Implications for Theories of Category-Specific Deficits
Timothy T. Rogers, Matthew A. Lambon-Ralph, David C. Plaut, John R. Hodges and Karalyn Patterson
MRC- Cognition and Brain Sciences Unit, Cambridge, UK
Semantic dementia (SD) is a syndrome marked by progressive and profound deterioration of semantic knowledge, consequent upon bilateral atrophy of the antero-lateral temporal lobes. This deficit is rarely characterized by significant category- or modality-specific effects: the great majority of SD patients are impaired for all semantic categories and all varieties of both input to and output from the semantic system, suggesting disruption to a unitary and a modal system of conceptual knowledge. Such patients do, however, show interesting differences in the kinds of errors they make indifferent semantic domains. We have attempted to explain these differences with reference to a computational model in which central semantic representations emerge in a system that must learn the mappings among structured perceptual representations indifferent modalities. Domain effects arise as a consequence of differences in the degree to which objects in a given domain share structure in different modalities. We will consider the implications of this idea for theories of category-specific deficits, and will propose an extension of the unitary-semantics model that may account for different patterns of impairment in generalised semantic dementia vs category-specific cases.
A case of impaired conceptual knowledge for fruit and vegetables
Dana Samson & Agnesa Pillon
Université Catholique de Louvain, Belgium
We report the case of a patient, RS, whose conceptual knowledge about fruit and vegetables appeared to be disproportionately impaired as compared to animals and nonliving things. RS was impaired when asked to retrieve semantic knowledge about fruit and vegetables whatever the modality of input (a picture or a word). The patient was also impaired when asked to retrieve colour knowledge about fruit and vegetables when the items were presented as word stimuli but not when the items were presented as picture stimuli. These findings suggest that (1) for a visually presented object, colour knowledge can be retrieved directly from the object's structural description (2) semantic knowledge about animals at the one hand and fruit and vegetables at the other hand can be damaged independently of each other and (3) impaired retrieval of object-colour knowledge is not at the origin of a category-specific deficit for fruit and vegetables.
Semantic category dissociation in Alzheimer's disease : a longitudinal study.
V. Cornil & A. Pillon
Université Catholique de Louvain, Belgium
Several cross-sectional studies on picture naming in Alzheimer's disease have reported inconsistent findings regarding dissociations in the recognition of specific semantic categories. To clarify this point, 15 patients suffering from dementia of Alzheimer's type(DAT) were examined four times, across a period of two years. These patients were given a naming task and a word-picture matching task based 120 colour photographs, which allowed us to take in account several variables ( notably word frequency and stimulus familiarity) that might influence performance . The 120 target words, were drawn from 3 categories: animals, plants and objects. The findings are discussed in the context of two competing theories of semantic breakdown in DAT. One differentiates between domains of knowledge in terms of the structure of semantic representations within a single distributed network; the other emphasizes the importance of different brain regions in the category distinction.
The diversity of category-specific deficits for living things.
Glyn W. Humphreys
Behavioural Brain Sciences, School of Psychology,. University of Birmingham, UK
Over the past twenty years there has been an increasing interest in 'category-specific deficits' in object recognition and naming, and several conflicting accounts of these deficits have been offered (see Humphreys & Forde, 2001, for a recent summary). One problem with the literature, however, is that the tests used to assess the recognition and naming deficits have differed across patients, and the terms applied to particular tests have differed across investigators (e.g., for tests of 'functional' knowledge). In the present paper, I report results from a group of six patients, all with category-specific problems for living things. The results indicate that the nature of the deficits can differ across patients; using the same materials, patients can have impairments at different levels within the systems supporting object recognition and naming. In addition, the nature of the deficits appear to take a graded form, with visual factors modulating performance from small to large amounts, dependent on the particular patient. I discuss the data in terms of current accounts of category-specific deficits in the literature.
Humphreys, G.W. & Forde, E.M.E. (2001). Hierarchies, similarity and interactivity in object recognition: On the multiplicity of 'category specific' deficits in neuropsychological populations. Behavioural and Brain Sciences, 24, 453-509.
Category-specific representations for numbers and animals, commonly activated in two different semantic tasks
Marc Thioux, Xavier Seron, and Mauro Pesenti
Université Catholique de Louvain, Belgium
Recent functional neuroimaging studies suggest that specific brain regions may be differentially involved in processing certain semantic categories such as living things or artefacts. In this study, we used PET to test the hypothesis of a segregation between the brain regions involved in the semantic processing of numerals and those involved in the semantic processing of another category of words (animals). Our experiment capitalized on the use of two different semantic tasks (classification and comparison) across two categories of words (animals and number words) in order to determine the brain regions more active for one category of words than for the other irrespective of the semantic task.
A first conjunction analysis revealed bilateral intra parietal activation during the semantic processing of numerals irrespective of the semantic task. On the other hand, the reverse conjunction showed significant activation on the ventral aspect of the left inferior temporal cortex for animals irrespective of the semantic task. Our results support the hypothesis of a segregation between numbers and the other semantic categories at the semantic level.
Thursday 11-04-02, 13:30 - 15:30,
Symposium 8 - The Perception of Biological Motion
Karl Verfaillie and Jan Vanrie
Laboratory of Experimental Psychology, University of Leuven, Belgium
Recognising the Style of Human Movement
Frank E. Pollick
University of Glasgow, UK
The ability to perceptually organise point-light displays into the percept of a specific human action has long served as a demonstration that humans are adept at recognising the actions of their conspecifics. While much research has been directed at gaining an understanding of the processes involved in the perception of human movement, there has been little work directed towards quantifying the general limits of our abilities to recognise different styles of human movement. Moreover, there has been a general trend to conflate our remarkable abilities to perceptually organise point light displays with our sometime mediocre abilities to identify movement style. My research examines the recognition of movement style from a variety of approaches that relate the information available in human movements to their categorisation. These approaches include exaggeration, automatic pattern recognition, obtaining estimates of human efficiency and finally, designing algorithms for stylistic movement generation on a humanoid robot. Using psychological experiments on humans I have examined the recognition of gender, identity, affect and style of tennis serves from human movement. Taken together results from these experiments reveal complex interactions between information available and human classification performance. For example, in the case of identifying affect it appears that movement velocity and phase relations among the limbs act independently to support a 2-dimensional circumplex model of affect. It is argued that a more complete understanding of the recognition of movement style will not only contribute to understanding the mechanisms of human movement perception but also facilitate the design of humanoid robots.
Is biological motion perception modular?
Winand H Dittrich
University of Hertfordshire, UK
The perception of biological motion seems effortless. Biological motion refers to Johansson's point-light technique to investigate whether perceivers could recognise others from walking displays, solely on the kinematic pattern produced when walking, independent of form information. Motion and form information are commonly seen as being processed separately, especially in computational vision. Two basic assumptions have been prominent when investigating biological motion perception: a) modularity of vision and, specifically, b) form versus motion modularity. Examples of both, a low-level and a high-level approach to the perception of biological motion will be contrasted and evaluated in connection with the modularity assumptions. Furthermore, own studies on the role of kinematic patterns in the recognition of emotions will be discussed. Finally, it is argued that the new notion of 'motion integrators' seems valuable in trying to understand the effortlessness of recognising human movement.