Does practice in category learning increase rule use or exemplar use—or both?

Categorization research has demonstrated the use of both rules and remembered exemplars in classification, although there is disagreement over whether learners shift from one to the other or use both strategies simultaneously. Theoretical arguments can motivate predictions for both rule use and exemplar use increasing with more practice. We describe a single large experiment (n = 190) that manipulated the number of training items (category size), the number of presentations of each training item, and the similarity between the training and the transfer stimuli in order to discover when rules and exemplars are most likely to be used. Results showed that rules and exemplars both influenced classification and that exemplars were used more often with smaller categories, with more training on items, and when test items were similar to training items. There was no consistent evidence of a shift from rule-based to exemplar-based categorization with more learning. Importantly, we found a number of conditions in which rules and exemplars were both used, even within individual participants. We discuss our results in terms of hybrid models of classification.     

Does cardiovascular reactivity during speech reflect self-construction processes?

Abstract Substantial empirical research has been undertaken on cardiovascular reactivity (CVR). however interpretation of this research is hampered by a lack of theoretical frameworks. This paper develops a framework initially stimulated by evidence demonstrating that the cardiovascular system increases in activity during communication, and that the extent of this activation depends upon numerous and diverse psychosocial factors. We attempt to account for this phenomenon using merit post-structuralist ideas concerning the constructive nature of language and its centrality to an individual's sense of self. Our theoretical framework proposes that the CVR exhibited during language use is explicable in terms of self-construction - From this analysis we hypothesised that CVR would differ across conversations about private self. public self and non-self topics, and that these differences would depend upon people's speaking histories. We found that the blood pressure and heart rate of 102 women was most reactive when they talked in a laboratory with a stranger about aspects of their private self, and least reactive during non-self talk, whilst their heart rate was most reactive during talk about their public self. Overall the results highlight the inextricable link between our inherent socialness and our cardiovascular systems. SUMMARY The explanatory scheme outlined here is an attempt to provide a social reconceptualisation of a phenomenon that is typically interpreted in individualistic psychophysiological terms, and which is consistent with the notion that repeated exposure to situations which provoke large haemodynamic changes may lead to CHD disease progression. The explanation draws heavily on post-structuralist ideas regarding language, and the social constructionist notion that engaging in language use is central to constructing and maintaining a sense of self. This sense of self is a central theoretical entity in our everyday lives, produced and maintained in our interactions with others. We argue that it is this centrality of self-construction that helps to explain the extraordinary consistency of elevated CVR in conversation. Further, we have noted the striking parallels between those features of conversations that make the self salient, and those that have been associated with elevated CVR. To examine it more explicitly, it needs to be tested empirically with new data, using explicitly derived operationalisations and hypotheses.     

Does cardiovascular reactivity during speech reflect self-construction processes?

Abstract

Substantial empirical research has been undertaken on cardiovascular reactivity (CVR). however interpretation of this research is hampered by a lack of theoretical frameworks. This paper develops a framework initially stimulated by evidence demonstrating that the cardiovascular system increases in activity during communication, and that the extent of this activation depends upon numerous and diverse psychosocial factors. We attempt to account for this phenomenon using merit post-structuralist ideas concerning the constructive nature of language and its centrality to an individual's sense of self. Our theoretical framework proposes that the CVR exhibited during language use is explicable in terms of self-construction - From this analysis we hypothesised that CVR would differ across conversations about private self. public self and non-self topics, and that these differences would depend upon people's speaking histories. We found that the blood pressure and heart rate of 102 women was most reactive when they talked in a laboratory with a stranger about aspects of their private self, and least reactive during non-self talk, whilst their heart rate was most reactive during talk about their public self. Overall the results highlight the inextricable link between our inherent socialness and our cardiovascular systems.

SUMMARY

The explanatory scheme outlined here is an attempt to provide a social reconceptualisation of a phenomenon that is typically interpreted in individualistic psychophysiological terms, and which is consistent with the notion that repeated exposure to situations which provoke large haemodynamic changes may lead to CHD disease progression. The explanation draws heavily on post-structuralist ideas regarding language, and the social constructionist notion that engaging in language use is central to constructing and maintaining a sense of self. This sense of self is a central theoretical entity in our everyday lives, produced and maintained in our interactions with others. We argue that it is this centrality of self-construction that helps to explain the extraordinary consistency of elevated CVR in conversation. Further, we have noted the striking parallels between those features of conversations that make the self salient, and those that have been associated with elevated CVR. To examine it more explicitly, it needs to be tested empirically with new data, using explicitly derived operationalisations and hypotheses.     

Does anxiety-linked attentional bias to threatening information reflect bias in the setting of attentional goals,or bias in the execution of attentional goals?

Heightened anxiety vulnerability is characterised by an attentional bias that favours the processing of negative information. However, this anxiety-linked attentional bias is amenable to two quite different explanations. One possibility is that it reflects anxiety-linked bias in the setting of attentional goals that favours setting the goal of attending towards negative information over the alternative goal of attending away from such information. Another possibility is that it reflects anxiety-linked bias in the execution of attentional goals that enhances the execution of the former attentional goal compared to the latter. The present study introduces a novel methodology designed to discriminate the validity of these competing hypotheses, by examining anxiety-linked attentional bias under two conditions. One condition left attentional goals unconstrained. The other condition imposed the attentional goal of either attending towards more negative or more benign emotional stimuli. The finding that anxiety-linked attentional bias was observed only under the former condition supported the hypothesis that anxiety is characterised by a bias favouring the setting attentional goals involving vigilance rather than avoidance of negative information, while giving no support to the hypothesis that anxiety is characterised by a bias reflecting enhanced execution of the former attentional goal compared to the latter.     

Procedural interference in perceptual classification: Implicit learning or cognitive complexity?

Researchers have argued that an implicit procedural-learning system underlies performance for information integration category structures, whereas a separate explicit system underlies performance for rule-based categories. One source of evidence is a dissociation in which procedural interference harms performance in information integration structures, but not in rule-based ones. The present research provides evidence that some form of overall difficulty or category complexity lies at the root of the dissociation. The authors report studies in which procedural interference is observed for even simple rule-based structures under more sensitive testing conditions. Furthermore, the magnitude of the interference is large when the nature of the rule is made more complex. By contrast, the magnitude of interference is greatly reduced for an information integration structure that is cognitively simple. These results challenge the view that a procedural-learning system mediates performance on information integration categories, but not on rule-based ones.     

Directional bias in the mental representation of spatial events: nature or culture?

Previous research has shown a tendency for people to imagine simple sentences as evolving from left to right, with the sentence subject being located to the left of the object. In two cross-cultural studies comparing Italian and Arab participants, we investigated whether this bias is a function of hemispheric specialization or of directionality of written language (left to right in Italian, right to left in Arabic). Both studies found a reversal of directional bias in Arabs. Italians tended to position the subject to the left of the object, and Arabs tended to position the subject to the right of the object (Experiment 1); both groups were facilitated in a sentence-picture matching task when the subject was drawn in the position that it would usually occupy in the written language (left for Italians, right for Arabs; Experiment 2). In Experiment 2, an additional, language-independent facilitation was observed when action evolved from left to right, suggesting that both hemispheric specialization and scanning habit affect visual imaging.     

Two pathways to stimulus encoding in category learning?

Category learning theorists tacitly assume that stimuli are encoded by a single pathway. Motivated by theories of object recognition, we evaluated a dual-pathway account of stimulus encoding. The part-based pathway establishes mappings between sensory input and symbols that encode discrete stimulus features, whereas the image-based pathway applies holistic templates to sensory input. Our experiments used rule-plus-exception structures, in which one exception item in each category violates a salient regularity and must be distinguished from other items. In Experiment 1, we found discrete representations to be crucial for recognition of exceptions following brief training. Experiments 2 and 3 involved multisession training regimens designed to encourage either part- or image-based encoding. We found that both pathways are able to support exception encoding, but have unique characteristics. We speculate that one advantage of the part-based pathway is the ability to generalize across domains, whereas the image-based pathway provides faster and more effortless recognition.     

Is desynchrony tolerance adaptable in the perceptual organization of speech?

Speech signal components that are desynchronized from the veridical temporal pattern lose intelligibility. In contrast, audiovisual presentations with large desynchrony in visible and audible speech streams are perceived without loss of integration. Under such conditions, the limit of desynchrony that permits audiovisual integration is also adaptable. A new project directly investigated the potential for adaptation to consistent desynchrony with unimodal auditory sine-wave speech. Listeners transcribed sentences that are highly intelligible, with veridical temporal properties. Desynchronized variants were created by leading or lagging the tone analog of the second formant relative to the rest of the tones composing the sentences, in 50-msec steps, ranging from 250-msec lead to 250-msec lag. In blocked trials, listeners only tolerated desynchronies <50 msec, and exhibited no gain in intelligibility to consistent desynchrony. Unimodal auditory and bimodal audiovisual forms of perceptual integration evidently exhibit different temporal characteristics, an indication of distinct perceptual functions.     

Adaptation to sensory-motor temporal misalignment: instrumental or perceptual learning?

Sensory-motor delays vary over the course of development and under different environmental conditions. Previous research has shown that humans can compensate for the resulting temporal misalignment while performing sensory-motor tasks (e.g., Cunningham, Billock, & Tsou, 2001a), but remains silent on the question of whether perceptual learning-similar to that involved in adaptation to spatial misalignment (e.g., Redding & Wallace, 1993) and in adaptation to purely intersensory misalignment (e.g., Fujisaki, Shimojo, Kashino, & Nishida, 2004)-is also involved in this adaptive response. Following an attempted replication of Cunningham et al.'s (2001a) study in a preliminary experiment, we present in this paper two experiments that demonstrate that after-effects of adaptation to temporal misalignment do not spontaneously decay. The literature on adaptation to spatial misalignment suggests that, while instrumental learning spontaneously decays in the absence of reinforcement, perceptual learning persists. Therefore our results are consistent with adaptation being effected through perceptual learning.     

Artificial grammar learning in children: abstraction of rules or sensitivity to perceptual features?

We examined sensitivity to grammatical sequences of colors in an artificial grammar learning task in a sample of 120 children aged between 5 and 8 years. The aim of the experiment was to test whether the children would preferentially learn the specific salient features of the items they were exposed to or the rules that generated these items. The children were divided into two experimental groups (identical grammar but training items differing in their surface features) and a control group (random items). The results showed that regardless of age, participants learned the most frequent salient features of the items, as well as some kind of abstract relational information. However, the 8-year-olds presented a more complex result profile, with one of the experimental groups apparently developing sensitivity to grammatical rules. These results are discussed with reference to the main current models of implicit learning. Overall, the results provided more support for stimulus-specific processing models than for rule-based models.     

Distinctiveness and the salience of social category memberships: Is there an automatic perceptual bias towards novelty?

It was hypothesized that the effects of novelty on social category membership salience may be mediated by perceivers' current tasks, rather than by an automatic perceptual bias (Taylor and Fiske, 1978). Subjects viewed tape-slide portrayals of mixed-sex groups (1 male—5 females, 2M—4F, 3M—3F, 4M—2F, 5M—1F) under ‘individual’ (focus on one target person) or ‘collective’ (focus on entire stimulus group) task conditions. Results on measures of sex stereotyping strongly supported the hypothesis, indicating that ‘individual’ task subjects tended to maximize stereotyping in the 1M—5F and 5M—1F conditions whilst ‘collective’ subjects did so in the 3M-3F condition. It is concluded that novel category memberships are not automatically prepotent in social perception, and the results are discussed in the context of a functional approach to the salience problem.     

Does bilingualism hamper lexical access in speech production?

In the present study, we tested the hypothesis that bilingualism may cause a linguistic disadvantage in lexical access even for bilinguals' first and dominant language. To this purpose, we conducted a picture naming experiment comparing the performance of monolinguals and highly-proficient, L1-dominant bilinguals. The results revealed that monolinguals name pictures faster than bilinguals, both when bilinguals perform picture naming in their first and dominant language and when they do so in their weaker second language. This is the first time it has been demonstrated that bilinguals show a naming disadvantage in their L1 in comparison to monolingual speakers.     

Does the compatibility effect in the race Implicit Association Test reflect familiarity or affect?

In the Implicit Association Test (IAT; Greenwald, McGhee, & Schwartz, 1998) involving race classification (white vs. black), an apparent compatibility effect is found between the “pleasant” attribute and the “white” category. This race IAT effect has been interpreted in terms of “implicit prejudice”—that is, more positive evaluation of whites than of blacks that is not open to consciousness. We suggested instead that the race IAT effect is better interpreted in terms of the salience asymmetry account proposed by Rothermund and Wentura (2004), whereby greater familiarity with the white category makes it more salient. Evidence that has been presented against the familiarity interpretation is considered, and alternative interpretations of findings related to the race IAT effect are discussed.     

Monitoring in clinical trials: benefit or bias?

Monitoring ongoing clinical trials for early signs of effectiveness is an option for improving cost-effectiveness of trials that is becoming increasingly common. Alongside the obvious advantages made possible by monitoring, however, there are some downsides. In particular, there is growing concern in the medical community that trials stopped early for benefit tend to overestimate treatment effect. In this paper, I examine this problem from the point of view of statistical methodology, starting from the observation that the overestimation is caused by the statistical method adopted. Consequently, I argue that some modifications can and should be made to the present statistical framework in order not to miss the advantages the possibility of monitoring can grant.     

Does word frequency affect lexical selection in speech production?

We evaluated whether lexical selection in speech production is affected by word frequency by means of two experiments. In Experiment 1 participants named pictures using utterances with the structure “pronoun + verb + adjective”. In Experiment 2 participants had to perform a gender decision task on the same pictures. Access to the noun's grammatical gender is needed in both tasks, and therefore lexical selection (lemma retrieval) is required. However, retrieval of the phonological properties (lexeme retrieval) of the referent noun is not needed to perform the tasks. In both experiments we observed faster latencies for high-frequency pictures than for low-frequency pictures. This frequency effect was stable over four repetitions of the stimuli. Our results suggest that lexical selection (lemma retrieval) is sensitive to word frequency. This interpretation runs against the hypothesis that a word's frequency exerts its effects only at the level at which the phonological properties of words are retrieved.     

Does word frequency affect lexical selection in speech production?

We evaluated whether lexical selection in speech production is affected by word frequency by means of two experiments. In Experiment 1 participants named pictures using utterances with the structure “pronoun + verb + adjective”. In Experiment 2 participants had to perform a gender decision task on the same pictures. Access to the noun's grammatical gender is needed in both tasks, and therefore lexical selection (lemma retrieval) is required. However, retrieval of the phonological properties (lexeme retrieval) of the referent noun is not needed to perform the tasks. In both experiments we observed faster latencies for high-frequency pictures than for low-frequency pictures. This frequency effect was stable over four repetitions of the stimuli. Our results suggest that lexical selection (lemma retrieval) is sensitive to word frequency. This interpretation runs against the hypothesis that a word's frequency exerts its effects only at the level at which the phonological properties of words are retrieved.     

Do priming effects in perceptual identification and word judgment reflect different underlying mechanisms?

We examined priming of orthographically illegal nonwords in a perceptual identification task and a word judgment task in undergraduate participants. In perceptual identification, priming was significant and equivalent after structural or phonological encoding. In word judgment, priming was significant after phonological encoding but not structural encoding. In a follow-up experiment in older control participants and amnesic participants, priming in word judgment was not significant. Older control participants found the stimuli more difficult to pronounce than did undergraduate participants, and word judgment priming in undergaduate participants was significant only for the stimuli that were judged easy to pronounce. These findings demonstrate that priming in perceptual identification and word judgment extends to novel stimuli that are not linked to preexisting lexical or sublexical representations but that priming occurs at different levels in the two tasks: at a featural or orthographic level in perceptual identification and at a phonological level in word judgment.