Spatial and non-spatial visual discrimination learning in zebrafish (Danio rerio)

Zebrafish (Danio rerio) provide an excellent model for assessment of molecular processes of neurodevelopment. To determine the functional importance of molecular events during neurodevelopment, we have developed methods for assessing learning in zebrafish in a three-chambered fish tank. In the first study, simple escape response was assessed. Zebrafish tested with a moving net learned to escape to another chamber more rapidly over the six sessions of training than the fish with the still net which did not learn. Upon reversal of the contingencies, the fish switched to the inactive net rapidly learned to suppress the escape response and fish formerly in the inactive net condition learned to avoid the moving net. In the second study, spatial discrimination learning was assessed. Zebrafish were trained on a right-left position discrimination to avoid the active net. Zebrafish showed significant improvement in escape responses over six sessions of training with three trials per session. In the third study, red-blue non-spatial discrimination learning was assessed. There was a significant improvement over the first six training sessions. With the reversal of contingencies, there was a significant decline of performance. With continued training, the fish again significantly improved avoidance. These studies found an effective motivational stimulus and procedure for studying escape behavior in zebrafish; a procedure whereby zebrafish would learn both spatial and non-spatial discrimination. These methods are being developed to help determine the functional importance of molecular events during zebrafish neurodevelopment. Accepted after revision: 20 August 2001 Electronic Publication     

Philosophy and language learning

In this paper, I explore different ways of picturing language learning in philosophy, all of them inspired by Wittgenstein and all of them concerned about scepticism of meaning. I start by outlining the two pictures of children and language learning that emerge from Kripke’s famous reading of Wittgenstein. Next, I explore how social-pragmatic readings, represented by Meredith Williams, attempt to answer the sceptical anxieties. Finally, drawing somewhat on Stanley Cavell, I try to resolve these issues by investigating what characteristically happens to our view of language learning when we do philosophy. The focus throughout is on the relation between the individual (the learning child) and the community (usually represented by the parents), and how that relation is deformed when we operate with a certain philosophical notion of ground.     

Achievement Goals in Social Interactions: Learning with Mastery vs. Performance Goals

Little work has studied achievement goals in social interaction situations. The present experiment aimed at contributing to this matter by showing the potential of social interaction (in particular disagreement) to moderate the effects of achievement goals on learning. Participants were led to think they interacted with a partner, sharing opinions about a text that they were studying. Mastery and performance goals were manipulated. During the “interaction,” they received either disagreement or agreement from this bogus partner. Results showed that a condition in which mastery goals were induced led to better learning than a performance goal condition only when the partner disagreed. No differences between goal conditions were observed when the partner agreed. Implications for achievement goal research are discussed. Part of this work was conducted during Céline Darnon’s doctoral dissertation under the supervision of Fabrizio Butera, and was written during Céline Darnon’s post-doctorate at the University of Wisconsin-Madison, USA, thanks to a Fulbright fellowship.     

Error self-correction and spelling: improving the spelling accuracy of secondary students with disabilities in written expression

In order to improve the spelling performance of high school students with deficits in written expression, an error self-correction procedure was implemented. The participants were two tenth-grade students and one twelfth-grade student in a program for individuals with learning disabilities. Using an alternating treatments design, the effect of error self-correction was compared with a more traditional method of spelling practice. The intervention and follow-up phases were implemented over a 6-week period with maintenance checks conducted 4 and 8 weeks after the termination of instruction. Results indicated that the error self-correction procedure was superior to the traditional method of review during the intervention and follow-up phases, but some gains were lost during the maintenance phase.     

Lexical configuration and lexical engagement: when adults learn new words

People know thousands of words in their native language, and each of these words must be learned at some time in the person's lifetime. A large number of these words will be learned when the person is an adult, reflecting the fact that the mental lexicon is continuously changing. We explore how new words get added to the mental lexicon, and provide empirical support for a theoretical distinction between what we call lexical configuration and lexical engagement. Lexical configuration is the set of factual knowledge associated with a word (e.g., the word's sound, spelling, meaning, or syntactic role). Almost all previous research on word learning has focused on this aspect. However, it is also critical to understand the process by which a word becomes capable of lexical engagement--the ways in which a lexical entry dynamically interacts with other lexical entries, and with sublexical representations. For example, lexical entries compete with each other during word recognition (inhibition within the lexical level), and they also support the activation of their constituents (top-down lexical-phonemic facilitation, and lexically-based perceptual learning). We systematically vary the learning conditions for new words, and use separate measures of lexical configuration and engagement. Several surprising dissociations in behavior demonstrate the importance of the theoretical distinction between configuration and engagement.     

Automatic activation of phonology in silent reading is parallel: evidence from beginning and skilled readers

The picture-word interference paradigm was used to shed new light on the debate concerning slow serial versus fast parallel activation of phonology in silent reading. Prereaders, beginning readers (Grades 1-4), and adults named pictures that had words printed on them. Words and pictures shared phonology either at the beginnings of words (e.g., DOLL-DOG) or at the ends of words (e.g., FOG-DOG). The results showed that phonological overlap between primes and targets facilitated picture naming. This facilitatory effect was present even in beginning readers. More important, from Grade 1 onward, end-related facilitation always was as strong as beginning-related facilitation. This result suggests that, from the beginning of reading, the implicit and automatic activation of phonological codes during silent reading is not serial but rather parallel.     

Correlates of Canadian native children's reading performance: From cognitive styles to cognitive processes

Individual differences in reading and cognitive processing among a sample of generally poor readers were studied in order to answer two major questions: Do they have a specific cognitive style that favors global-simultaneous strategies and a weak sequential strategy? If they do not have a distinct cognitive style or strategy, but are merely poor in using sequential (Successive) strategies, then, would the same processes that influence reading performance in the general population determine their performance as well? A sample of 84 Canadian First Nations (FN) children were assessed in word and pseudoword reading, rapid naming speed, and ability to process information using the Planning, Attention, Successive, and Simultaneous (PASS) theory of intelligence. Results confirmed that this sample of children did not exhibit a specific cognitive style. Rather, there was evidence of a weakness in Successive processing only in the subgroup of poor readers. The importance of understanding the role of Successive processing and rapid naming speed relative to reading is further discussed.     

Combining versus analyzing multiple causes: how domain assumptions and task context affect integration rules

In everyday life, people typically observe fragments of causal networks. From this knowledge, people infer how novel combinations of causes they may never have observed together might behave. I report on 4 experiments that address the question of how people intuitively integrate multiple causes to predict a continuously varying effect. Most theories of causal induction in psychology and statistics assume a bias toward linearity and additivity. In contrast, these experiments show that people are sensitive to cues biasing various integration rules. Causes that refer to intensive quantities (e.g., taste) or to preferences (e.g., liking) bias people toward averaging the causal influences, whereas extensive quantities (e.g., strength of a drug) lead to a tendency to add. However, the knowledge underlying these processes is fallible and unstable. Therefore, people are easily influenced by additional task-related context factors. These additional factors include the way data are presented, the difficulty of the inference task, and transfer from previous tasks. The results of the experiments provide evidence for causal model and related theories, which postulate that domain-general representations of causal knowledge are influenced by abstract domain knowledge, data-driven task factors, and processing difficulty.     

Confidence–accuracy resolution in the misinformation paradigm is influenced by the availability of source cues

After witnessing an event, people often report having seen details that were merely suggested to them. Evidence is mixed regarding how well participants can use confidence judgments to discriminate between their correct and misled memory reports. We tested the prediction that the confidence–accuracy relationship for misled details depends upon the availability of source cues at retrieval. In Experiment 1, participants (N = 77) viewed a videotaped staged crime before reading a misleading narrative. After seven minutes or one week, the participants completed a cued recall test for the details of the original event. Prior to completing the test, all participants were warned that the narrative contained misleading details to encourage source monitoring. The results showed that the strength of the confidence–accuracy relationship declined significantly over the delay. We interpret our results in the source monitoring framework. After an extended delay, fewer diagnostic source details were available to participants, increasing reliance on retrieval fluency as a basis for memory and metamemory decisions. We tested this interpretation in a second experiment, in which participants (N = 42) completed a source monitoring test instead of a cued recall test. We observed a large effect of retention interval on source monitoring, and no significant effect on item memory. This research emphasizes the importance of securing eyewitness statements as soon as possible after an event, when witnesses are most able to discriminate between information that was personally seen and information obtained from secondary sources.