Does incidental training increase the prevalence of overall similarity classification? A re-examination of Kemler Nelson (1984)

Kemler Nelson (1984) reported that incidental training, relative to intentional training, increased the prevalence of overall similarity classification, supporting a non-deliberative account of overall similarity sorting. However, the analysis conducted by Kemler Nelson (1984) does not adequately distinguish between usage of an overall similarity classification strategy and single-attribute strategies. The current study replicates Kemler Nelson’s (1984) experiment, seeking to test the original conclusions using a more rigorous analysis. The current study approximates the original experimental procedure, using almost identical stimuli and a longer, modified test phase. Results replicate those found by Kemler Nelson (1984) when the original analysis is applied; however the model-based analysis suggest an overall similarity classification strategy is used rarely and that incidental training increases the prevalence of suboptimal single-attribute strategies. These results imply that overall similarity classification may be more deliberative than previously thought

Combination or Differentiation? Two theories of processing order in classification

ArticleCopyright © 2015 Elsevier Inc. All rights reserved.Does cognition begin with an undifferentiated stimulus whole, which can be divided into distinct attributes if time and cognitive resources allow (Differentiation Theory)? Or does it begin with the attributes, which are combined if time and cognitive resources allow (Combination Theory)? Across psychology, use of the terms analytic and non-analytic imply that Differentiation Theory is correct—if cognition begins with the attributes, then synthesis, rather than analysis, is the more appropriate chemical analogy. We re-examined four classic studies of the effects of time pressure, incidental training, and concurrent load on classification and category learning (Kemler Nelson, 1984; Smith & Kemler Nelson, 1984; Smith & Shapiro, 1989; Ward, 1983). These studies are typically interpreted as supporting Differentiation Theory over Combination Theory, while more recent work in classification (Milton et al., 2008, et seq.) supports the opposite conclusion. Across seven experiments, replication and re-analysis of the four classic studies revealed that they do not support Differentiation Theory over Combination Theory—two experiments support Combination Theory over Differentiation Theory, and the remainder are compatible with both accounts. We conclude that Combination Theory provides a parsimonious account of both classic and more recent work in this area. The presented data do not require Differentiation Theory, nor a Combination–Differentiation hybrid account

Unsupervised categorisation and cross-classification in humans and rats

This thesis examines how stimulus similarity structure and the statistical properties of the environment influence human and nonhuman animal categorisation. Two aspects of categorisation behaviour are explored: unsupervised (spontaneous) categorisation and stimulus cross-classification. In my General Introduction, I raise the issue of the respective roles of similarity and the classifier in determining categorisation behaviour. In Chapter 1, I review previous laboratory-based unsupervised categorisation research, which shows an overwhelming bias for unsupervised classification based on a single feature. Given the prominent role of overall similarity (family resemblance) in theories of human conceptual structure, I argue that this bias for unidimensional classification is likely an artefact. One factor in producing this artefact, I suggest, are the biases that exist within the similarity structure of laboratory stimuli. Consequently, Chapter 2 examines if it is possible to predict unidimensional versus multidimensional classification based solely on abstract similarity structure. Results show that abstract similarity structure commands a strong influence over participants' unsupervised classification behaviour (although not always in the manner predicted), and a bias for multidimensional unsupervised classification is reported. In Chapter 3, I examine unsupervised categorisation more broadly, by investigating how stimulus similarity structure influences spontaneous classification in both humans and rats. In this way, evidence is sought for human-like spontaneous classification behaviour in rats. Results show that humans and rats show qualitatively different patterns of behaviour following incidental stimulus exposure that should encourage spontaneous classification. In Chapter 4,1 investigate whether rats exhibit another important aspect of human categorisation namely, stimulus cross-classification. Results show that the statistical properties of the environment can engender such cognitively flexible behaviour in rats. Overall, the results of this thesis document the important influence of stimulus similarity structure and the statistical properties of the environment on human and nonhuman animal behaviour

Perceptual strategies of experts and novices in a fast ball sport

This thesis examined the perceptual strategies of expert and novice badminton players in an attempt to test notions of visual selective attention within applied, ecologically valid, sport settings. In keeping with established premises from information-processing theory it was hypothesized that the expert players would be characterized by a greater ability to extract advance information from the display (to facilitate anticipation), by the allocation of attention to the most pertinent cues available in the display (to promote search efficiency and to avoid distractions) and by the utilization of a relatively low visual search rate (as indicative of processing efficiency). In Experiment 1 the perceptual strategies of 20 elite and 35 novice badminton players were compared using a series of tasks in which the perceptual display of a badminton player was simulated using film. When the film display was manipulated using variable temporal occlusion points it was found that experts showed a consistently greater ability to predict the landing position of the shuttle from early advance cues than did novices, with the time period between 170 and 85 msec prior to racquet-shuttle contact being a critical one for the establishment of skill group differences. For both skill groups greatest improvements in prediction accuracy arose in the subsequent time period from 85 msec prior to contact to 85 msec after contact implying the criticality of cues arising in this period to the normal decision-making process. When specific spatial cues were selectively occluded from the film display the racquet and the playing side arm were found to be the principal cues upon which experts based their anticipatory prediction of shuttle direction whereas novices appeared to rely only upon racquet cues. These proficiency-related differences in cue usage were capable of explaining, in part, the differences ln anticipatory performance observed on the temporal occlusion task. Eye movements recorded during the performance of the film task (Experiment 2) were consistent with the notion of the racquet region containing the anticipatory cues of highest informational content with over 70% of all fixations occurring on that section of the display. The visual search sequence was found to normally progress from an early orientation of fixations upon gross bodily features of the opponent (such as trunk, head or lower body) to a later, more precise orientation to the region of the racquet with this apparent proximal-to-distal shift of the fixation distributions matching closely the emergent biomechanical characteristics of the stroke. Both the location and sequence of the fixations however, appeared relatively uninfluenced by the task conditions suggesting that the search patterns adopted were relatively inflexible as if pre-determined by some over-riding perceptual framework. Contrary to some earlier sport-specific investigations of the visual search process no significant differences In fixation location, duration or sequence were observed between experts and novices suggesting that the differences In anticipatory performance observed on the film task were not a consequence of differences In overt visual search characteristics. Advantages of the film task approach over the eye movement recording approach in terms of assessing actual information extraction rather than merely visual orientation were therefore apparent. Experiments 3 to 7 sought to establish the validity and reliability of the paradigm tor the assessment of individual differences in perceptual strategy used in Experiments 1 and 2. The film task was shown, using dual task methods, to provide comparable attention demands to actually playing and it was shown that concurrent eye movement recording could take place without interference with the subject's response to the film task. Prediction error measures derived from the film task were found to have high reliability with identical conclusions being reached regarding individual subject's perceptual strategies on each occasion the test was administered. Visual search parameters appeared somewhat less reliable with the same anticipatory performance being apparently possible through the use of different search rates, although fixation location and order characteristics remained consistent over time. When the ski II group distinction was reduced and an alternative form of error analysis was adopted the characteristic earlier extraction of information and greater utilization of arm cues by experts again emerged, suggesting that the proficiency-related differences observed in Experiment 1 were robust ones

Forest Pathology and Plant Health

Every year, a number of new forest pathosystems are discovered as the result of introduction of alien pathogens, host shifts and jumps, hybridization and recombination among pathogens, etc. Disease outbreaks may also be favored by climate change and forest management. The mechanisms driving the resurgence of native pathogens and the invasion of alien ones need to be better understood in order to draft sustainable control strategies. For this Special Issue, we welcome population biology studies providing insights on the epidemiology and invasiveness of emergent forest pathogens possibly by contrasting different scenarios varying in pathogen and host populations size, genetics, phenotype and phenology, landscape fragmentation, occurrence of disturbances, management practices, etc. Both experimental and monitoring approaches are welcome. In summary, this special issue focuses on how variability in hosts, pathogens, or ecology may affect the emergence of new threats to plant species

Proceedings of the 5th International Conference on Molluscan Shellfish Safety

The aim of the global series of ICMSS Conferences has been well defined by our colleagues in Santiago de Compostela (Spain) who hosted the previous Conference in June 2002: “To establish a forum where useful, enriching debate and interchange of knowledge flow easily on a broad spectrum in the area of Shellfish Safety”. The ICMSS 04 Programme followed on the tradition and patterns which were set in Santiago de Compostela (2002); Southampton, New York, USA (2000) and in The Philippines (1998) of thematic sessions on a multi-disciplinary basis. Our session topics included: • Microbiological Status of Shellfish • Shellfish Viruses and Pathogens • Harmful Algal Blooms (HAB) and Biotoxin Contamination • HAB Mitigation and Depuration • Toxicology of Shellfish Toxins • Current and Emerging Analytical Methods • Quality Assurance and Consumer Safety • Regulation and Management of Shellfish Safety • Role of Industry in Risk Management and Innovatio