Marginally perceptible outcome feedback, motor learning and implicit processes

Participants struck 500 golf balls to a concealed target. Outcome feedback was presented at the subjective or objective threshold of awareness of each participant or at a supraliminal threshold. Participants who received fully perceptible (supraliminal) feedback learned to strike the ball onto the target, as did participants who received feedback that was only marginally perceptible (subjective threshold). Participants who received feedback that was not perceptible (objective threshold) showed no learning. Upon transfer to a condition in which the target was unconcealed, performance increased in both the subjective and the objective threshold condition, but decreased in the supraliminal condition. In all three conditions, participants reported minimal declarative knowledge of their movements, suggesting that deliberate hypothesis testing about how best to move in order to perform the motor task successfully was disrupted by the impoverished disposition of the visual outcome feedback. It was concluded that sub-optimally perceptible visual feedback evokes implicit processes.     

Replies to commentators on <Emphasis Type="Italic">A Virtue Epistemology</Emphasis> (Oxford University Press, 2007)

Paul Boghossian discusses critically my account of intuition as a source of epistemic status. Stewart Cohen takes up my views on skepticism, on dreams, and on epistemic competence and competences and their relation to human knowledge. Hilary Kornblith focuses on my animal/reflective distinction, and, along with Cohen, on my comparison between how dreams might mislead us and how other bad epistemic contexts can do so. In this paper I offer replies to my three critics.

Lexical restructuring in the absence of literacy

Vocabulary growth was suggested to prompt the implementation of increasingly finer-grained lexical representations of spoken words in children (e.g., [Metsala, J. L., & Walley, A. C. (1998). Spoken vocabulary growth and the segmental restructuring of lexical representations: precursors to phonemic awareness and early reading ability. In J. L. Metsala & L. C. Ehri (Eds.), Word recognition in beginning literacy (pp. 89-120). Hillsdale, NJ: Erlbaum.]). Although literacy was not explicitly mentioned in this lexical restructuring hypothesis, the process of learning to read and spell might also have a significant impact on the specification of lexical representations (e.g., [Carroll, J. M., & Snowling, M. J. (2001). The effects of global similarity between stimuli on children’s judgments of rime and alliteration. Applied Psycholinguistics, 22, 327-342.]; [Goswami, U. (2000). Phonological representations, reading development and dyslexia: Towards a cross-linguistic theoretical framework. Dyslexia, 6, 133-151.]). This is what we checked in the present study. We manipulated word frequency and neighborhood density in a gating task (Experiment 1) and a word-identification-in-noise task (Experiment 2) presented to Portuguese literate and illiterate adults. Ex-illiterates were also tested in Experiment 2 in order to disentangle the effects of vocabulary size and literacy. There was an interaction between word frequency and neighborhood density, which was similar in the three groups. These did not differ even for the words that are supposed to undergo lexical restructuring the latest (low frequency words from sparse neighborhoods). Thus, segmental lexical representations seem to develop independently of literacy. While segmental restructuring is not affected by literacy, it constrains the development of phoneme awareness as shown by the fact that, in Experiment 3, neighborhood density modulated the phoneme deletion performance of both illiterates and ex-illiterates.     

Infants perceive human point-light displays as solid forms

While five-month-old infants show orientation-specific sensitivity to changes in the motion and occlusion patterns of human point-light displays, it is not known whether infants are capable of binding a human representation to these displays. Furthermore, it has been suggested that infants do not encode the same physical properties for humans and material objects. To explore these issues we tested whether infants would selectively apply the principle of solidity to upright human displays. In the first experiment infants aged six and nine months were repeatedly shown a human point-light display walking across a computer screen up to 10 times or until habituated. Next, they were repeatedly shown the walking display passing behind an in-depth representation of a table, and finally they were shown the human display appearing to pass through the table top in violation of the solidity of the hidden human form. Both six- and nine-month-old infants showed significantly greater recovery of attention to this final phase. This suggests that infants are able to bind a solid vertical form to human motion. In two further control experiments we presented displays that contained similar patterns of motion but were not perceived by adults as human. Six- and nine-month-old infants did not show recovery of attention when a scrambled display or an inverted human display passed through the table. Thus, the binding of a solid human form to a display in only seems to occur for upright human motion. The paper considers the implications of these findings in relation to theories of infants' developing conceptions of objects, humans and animals.     

From grammatical number to exact numbers: early meanings of 'one', 'two', and 'three' in English, Russian, and Japanese

This study examined whether singular/plural marking in a language helps children learn the meanings of the words 'one,' 'two,' and 'three.' First, CHILDES data in English, Russian (which marks singular/plural), and Japanese (which does not) were compared for frequency, variability, and contexts of number-word use. Then young children in the USA, Russia, and Japan were tested on Counting and Give-N tasks. More English and Russian learners knew the meaning of each number word than Japanese learners, regardless of whether singular/plural cues appeared in the task itself (e.g., "Give two apples" vs. "Give two"). These results suggest that the learning of "one," "two" and "three" is supported by the conceptual framework of grammatical number, rather than that of integers.     

Spoken and gestural production in a naming task by young children with Down syndrome

Lexical production in children with Down syndrome (DS) was investigated by examining spoken naming accuracy and the use of spontaneous gestures in a picture naming task. Fifteen children with DS (range 3.8-8.3 years) were compared to typically developing children (TD), matched for chronological age and developmental age (range 2.6-4.3 years). Relative to TD children, children with DS were less accurate in speech (producing a greater number of unintelligible answers), yet they produced more gestures overall and of these a significantly higher percentage of iconic gestures. Furthermore, the iconic gestures produced by children with DS accompanied by incorrect or no speech often expressed a concept similar to that of the target word, suggesting deeper conceptual knowledge relative to that expressed only in speech.     

Processing of Syllables in Production and Recognition Tasks

Empirical evidence for a functional role of syllables in visual word processing is abundant, however it remains rather heterogeneous. The present study aims to further specify the role of syllables and the cognitive accessibility of syllabic information in word processing. The first experiment compared performance across naming and lexical decision tasks by manipulating the number of syllables in words and non-words. Results showed a syllable number effect in both the naming task and the lexical decision task. The second experiment introduced a stimulus set consisting of isolated syllabic and non-syllabic trigrams. Syllable frequency was manipulated in a naming and in a decision task requiring participants to decide on the syllabic status of letter strings. Results showed faster responses for syllables than for non-syllables in both tasks. Syllable frequency effects were observed in the decision task. In summary, the results from these manipulations of different types of syllable information confirm an important role of syllabic units in both recognition and production.     

The Knowledge Argument and Objectivity

In this paper I argue that Frank Jackson’s Knowledge Argument is better considered not as an argument against physicalism, but as an argument that objective theories must be incomplete. I argue that despite the apparent diversity of responses to the knowledge argument, they all boil down to a response according to which genuine epistemic gains are made when an individual has an experience. I call this the acquaintance response. I then argue that this response violates an intuitive stricture on the objectivity of theories. Therefore, the knowledge argument does show that objective theories cannot provide a complete understanding of the world. The result, however, is that both objective dualism and objective physicalism are refuted by the argument. In the end it is suggested that the notion of “subjective physicalism” is one that should be pursued.     

Moral Expertise and the Credentials Problem

Philosophers have harbored doubts about the possibility of moral expertise since Plato. I argue that irrespective of whether moral experts exist, identifying who those experts are is insurmountable because of the credentials problem: Moral experts have no need to seek out others’ moral expertise, but moral non-experts lack sufficient knowledge to determine whether the advice provided by a putative moral expert in response to complex moral situations is correct and hence whether an individual is a bone fide expert. Traditional accounts of moral expertise require that moral experts give reliably correct moral advice supported by adequate justification, an account which, I argue, is too lean in allowing for the possibility of a moral expert who is motivationally indifferent to her own moral judgments and advice. Yet even if the proposition that a moral expert is an individual who provides reliably correct moral advice supported by adequate justification and is necessarily motivated by that advice exhausts the necessary and sufficient conditions for moral expertise, this proposition cannot function as an applicable criterion for non-experts to use in appraising would-be experts’ claims to expertise. The credentials problem thus remains unanswered.

When is ignorance bliss? The effects of inaccurate self-assessments of knowledge on learning and attrition

Two studies were conducted to examine the implications of inaccurate self-appraisals in online training. Self-assessment of knowledge moderated the effects of trainees’ performance on subsequent performance and attrition. Performance was highest after uniformly positive ratings (i.e., high self-assessment and high performance), followed by underestimation, overestimation, and uniformly negative ratings, respectively. Attrition was lowest after uniformly positive ratings, followed by underestimation, uniformly negative ratings, and overestimation, respectively. Effort had a more positive effect on performance following low than high self-assessments and this interaction fully mediated the self-assessment/performance interaction on subsequent performance. Commitment had a more negative effect on subsequent attrition following low than high self-assessments and this interaction fully mediated the self-assessment/performance interaction on subsequent attrition. Finally, trainee conscientiousness affected their behavior when their performance and self-assessments were inconsistent—overestimating and underestimating performance increased attrition more for trainees low in conscientiousness and impaired performance more for trainees high in conscientiousness.