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At least 19 recordsLinked to original sources
PubMed2003

Alphabetical knowledge from whole words training: effects of explicit instruction and implicit experience on learning script segmentation.

We investigated the possibility that pattern segmentation skills, specifically, phonological decoding, evolve implicitly in adult readers given training in an artificial script. In this Morse-like script each phoneme was represented by 2-3 discrete symbols. Subjects were trained in five consecutive sessions, on reading six nonsense words using a forced choice task that required translating symbol strings to sound patterns written in Latin letters. Three training conditions were compared within subject in terms of the time-course of learning and the ability to generalize the acquired knowledge (transfer): alphabetical whole words with letter decoding instruction (Explicit); alphabetical whole words (Implicit), and non-alphabetical whole words (Arbitrary). In separate blocks in each training session, a visual-matching task was administered using the same stimuli. Our results show: (a). that while all three training conditions were equally effective in terms of magnitude and time-course of learning accurate translation, each training condition resulted in a different type of knowledge (i.e. differential transfer). (b). Declarative knowledge of letters evolved from training on whole words only in subjects with previous experience in Explicit training. However, even with declarative knowledge of the specific letters subjects did not develop general letter segmentation skills. (c). Contrary to the robust transfer of learning gains to different stimuli within a given task, there was no significant transfer across tasks indicating that the locus of learning was task dependent. Altogether our results suggest that even given explicit letter instruction, training on word decoding may result in letter recognition rather than in alphabetic segmentation skills.

Adolescent↗
PubMed2006

Productivity costs in health-state valuations : does explicit instruction matter?

BACKGROUND: There has been considerable debate on whether productivity costs should be captured in the numerator or the denominator of the cost-effectiveness ratio. That debate cannot be resolved on the basis of theoretical arguments alone because the final choice also depends on what is incorporated in health-state valuations by respondents and how this influences outcomes. At the moment, little is known about whether the effects of ill health on income are included in health-state valuations, and how instructions on including or excluding the effects on income influence health-state valuations. AIM: To conduct an empirical study of health-state valuations to test: (i) whether or not respondents spontaneously include the effect of ill health on income and leisure time; (ii) the impact on the valuation of inclusion (or exclusion) of such effects; and (iii) the influence of explicit instructions on this matter. METHODS: Three questionnaires were developed and administered to the general public. Health-state valuations were conducted by visual analogue scale scoring of three health states of differing severity taken from the EQ-5D. Version 1 had no directions regarding inclusion/exclusion of effects of ill health on income. Those respondents who spontaneously included effects on income were subsequently asked to value the same three health states again, excluding these effects. Version 2 had explicit instructions to incorporate the effects on income. Version 3 stated that income was assumed to not change as a result of ill health. Respondents for versions 2 and 3 were also questioned about inclusion of effects on leisure time. RESULTS: Giving explicit instructions on the incorporation or exclusion of effects of ill health on income did not lead to significant differences in subsequent health-state valuations. In the absence of instruction, 36% of respondents included and 64% excluded effects on income, but the health-state valuations of the two groups were not significantly different. Eighty-four percent of respondents included the effects of ill health on leisure activities, and again this had no significant impact on the resulting health-state valuations. CONCLUSIONS: It appears that neither spontaneous differences in incorporation of effects on income, nor explicit instructions will yield significantly different health-state valuations. This may suggest that QALY measures are insensitive to concerns regarding effects on income even when these are (explicitly) incorporated, and these effects may therefore be best placed on the cost side of the cost-effectiveness ratio.

Adult↗
PubMed2004

Fostering reading comprehension in fifth grade by explicit instruction in reading strategies and peer tutoring.

BACKGROUND: Research reveals that explicit reading strategies instruction and engaging students in interaction about texts promote students' reading comprehension ability. The present intervention study combines both aspects. AIMS: The study examines the educational benefits of explicit reading strategies instruction, followed by practice in (a) teacher-led whole-class activities (STRAT), (b) reciprocal same-age (STRAT + SA), or (c) cross-age peer tutoring activities (STRAT + CA) on fifth graders' reading comprehension achievement. SAMPLE: Twenty-two fifth-grade teachers and their 454 students from 19 different schools throughout Flanders (Belgium) participated. METHOD: A quasi-experimental pretest post-test retention test design was used with three experimental (STRAT, STRAT + SA, and STRAT + CA) and a matched control group. The experimental interventions were implemented during an entire school year. RESULTS: Multilevel analysis revealed that the STRAT and STRAT + CA condition made a significantly larger pretest to retention test progress than the control group. The significant major progress was especially situated from pretest to post-test, during which the intervention took place. Concerning the STRAT + SA condition no significant differences with regard to the control group were detected. Pairwise comparisons of the experimental conditions indicated that the STRAT + CA condition's progress from pretest to retention test also exceeded the STRAT + SA condition's advancement significantly. CONCLUSION: The study corroborated the efficacy of the STRAT and STRAT + CA conditions' interventions as feasible tools to enhance fifth graders' reading comprehension achievement.

Belgium↗
PubMed1999

Speech volume regulation in Parkinson's disease: effects of implicit cues and explicit instructions.

This study examined the regulation of speech volume in hypophonic subjects with Parkinson's disease (PD) and age- and gender-matched controls. The first two experiments investigated the ability of subjects with PD to automatically regulate speech volume in response to two types of implicit cue: (i) background noise (BGN) and (ii) instantaneous auditory feedback (IAF). Control subjects demonstrated the Lombard effect by automatically speaking louder when competing against increasing levels of background noise. They also showed the reverse effect, decreasing speech volume when increasing levels of facilitative instantaneous auditory feedback were provided. Subjects with PD demonstrated decreased overall speech volume; they were less able than controls to appropriately increase volume as background noise increased, and to decrease volume as IAF increased. Thus, subjects with PD demonstrated over-constancy of speech volume and failed to respond to the implicit cues integral to volumetric scaling. A further experiment (3) was carried out to contrast the regulation of volume in response to implicit cue with an explicit attention-driven cue (i.e. instructions regarding volume level). As in Experiments 1 and 2, subjects with PD exhibited reduced speech volume. Under explicit volume instructions, the ability of subjects with PD to regulate volume was normalised. These findings suggest that subjects with PD have the capacity to speak with normal volume provided they consciously attend to speaking loudly. In subjects with PD, overall speech volume was always lower than for control subjects, suggesting a reduction of cortical motor set in the articulatory system similar to that demonstrated by the reduced amplitude of limb movements (hypokinesia) in the motor system.

Aged↗
PubMed1975

Effects of explicit instructions to "be creative" on the psychological meaning of divergent thinking test scores.

The Alternate Uses Test was administered to 50 undergraduate males instructed to produce creative (i.e., novel and worthwhile) uses and to 55 comparable subjects simply instructed to produce as many uses as possible. All uses were rated for creativity. An index of self-assessed creative thinking ability correlated significantly more strongly (p less than .05) with the number of creative uses produced in the qualitatively-oriented condition than with the number of creative or total uses produced in the standard, quantitatively-oriented condition. The correlation between self-rated creative ability and creative uses production in the qualitatively-oriented condition remained significant (p less than .001) after indices of achievement motivation and general verbal aptitude were partialled out. The results were interpreted as demonstrating the value of coordinating informative divergent thinking test instructions with qualitative scoring criteria.

Achievement↗
PubMed2002

The influence of explicit instructions and stimulus material on lateral frontal responses to an encoding task.

In this functional magnetic resonance imaging study, we explored the effects of both stimulus material and encoding task demands on activation in lateral prefrontal cortex (PFC). Two factors were manipulated: material type and task instructions. Subjects encoded words or abstract figures (factor 1: stimulus type) and were required to make either a meaning-based or a form-based (letter or shape) decision about each stimulus (factor 2: task instructions). Abstract figures engendered significantly higher levels of right PFC activity than did words. This effect was seen for meaning-based and form-based processing tasks and was significantly greater for the former. We did not observe a differential response of left lateral PFC to verbal and pictorial material. A double dissociation, however, was found within left PFC. A ventrolateral region (within left inferior frontal gyrus) showed the highest levels of activity when words were processed according to their meaning whereas activity in a more dorsolateral region (within left middle frontal gyrus) was greatest when words were processed according to their form (constituent letters). We have therefore observed a main effect of material type in producing lateralized activation of frontal lobes, although the strength of this effect is sensitive to the nature of the task that subjects are asked to perform. Left-side lateral PFC activity is also sensitive to task instructions but this effect was specific to verbal material. The complex patterns of frontal effect counsel against any simple dichotomy of frontal function at the level of either material or task type.

Adult↗
PubMed2004

Procedural and declarative knowledge of word recognition and letter decoding in reading an artificial script.

In a previous study [Cogn. Brain Res. 16 (2003) 325], we found that letter knowledge did not evolve from implicit training on whole-word recognition in an artificial Morse-like script, although the participants were adults, experienced in alphabetical reading. Here we show minimal conditions in which letter knowledge may evolve in some individuals from training on whole-word recognition. Participants received multi-session training in reading nonsense words, written in an artificial script, in which each phoneme was represented by two discrete symbols. Three training conditions were compared: alphabetical whole words with letter decoding instruction (Explicit), alphabetical whole words (Implicit), and non-alphabetical whole words (Arbitrary). Subjects were assigned to training either on the explicit and arbitrary or on the implicit and arbitrary conditions. Our results show that: (a) Letter-decoding knowledge evolved implicitly from training on alphabetical whole-word recognition, in some individuals. However, (b) a clear double dissociation was found between effectively applied implicit letter knowledge and declarative letter knowledge. (c) There was no advantage of the implicitly derived over the explicitly instructed letter knowledge. (d) Long-term retention was more effective in the explicit compared to the arbitrary condition. (e) Word-specific recognition contributed significantly to performance in all three training conditions, i.e. even under conditions that presumably afford advantage for word segmentation. Altogether, our results suggest that both declarative and procedural knowledge contributed to letter decoding as well as to word-specific recognition performance. Moreover, a greater dependency on declarative knowledge may not be an inherent characteristic of word-specific recognition, but rather that both letter decoding and word-recognition routines can become proceduralized given sufficient practice.

Adolescent↗
PubMed1993

An investigation of attention allocation deficits in aphasia.

Nine aphasic and 18 normal adults participated in a dual task with components of phoneme monitoring and semantic judgment. Subjects listened to lists of recorded spoken words and were required to detect semantic and phonetic targets. Two within-subject variables were manipulated: the probability of target occurrence for each dual-task component (.2, .5, and .8) and the explicitness of instruction (explicit vs. implicit). Only in the explicit condition were subjects told about the probability structure and given the attention allocation strategy congruent with that structure. Reaction times were recorded on-line for analysis by an IBM-AT. The results showed that normal subjects' overall latencies in detecting phonetic targets decreased as the target occurrence probability increased in both implicit and explicit instruction conditions. The detection latencies for semantic targets showed a similar probability effect but only in the explicit condition. By contrast, the aphasic subjects did not show the probability effect in any condition, although they performed above the chance level on both semantic and phonetic tasks. The presence of the probability effects for the normal subjects indicated that an efficient attention allocation mechanism was operating so as to optimize the performance level. On the other hand, the absence of probability effects for the aphasic subjects suggests that their attention control system might be inefficient so that task-demand cues (probability and attention allocation instruction) were not utilized properly.

Adult↗
PubMed2000

A connectionist approach to making the predictability of English orthography explicit to at-risk beginning readers: evidence for alternative, effective strategies.

A case is made (and illustrated with empirical data with children) for connectionist models that are not only computationally explicit but also instructionally explicit. First-graders (N = 128) at the bottom of their classes in reading (average 11.5 percentile on nationally normed tests) participated in a 3-layer intervention. In the first layer, kept constant for all treatment groups, the alphabet principle was taught, making functional spelling units and alternations explicit. In the second layer, which varied systematically across treatment groups, children received different kinds of tutor modeling in learning a set of words of varying spelling-sound predictability, using different connections between printed and spoken words, singly or in combination. In the third layer, also kept constant, children read and discussed illustrated books. Over the 4-month, 24-lesson intervention, all 7 treatment groups in the second layer improved more in word-specific learning than a contact control group that received phonological and orthographic awareness training without explicit instruction on orthographic-phonological connections. Of these 7, only 3 kinds of explicit modeling (whole word, letter-phoneme, and combined whole word and letter-phoneme) resulted in greater transfer to untrained words than the contact control or the other 4 kinds of explicit modeling. Results are discussed in reference to the controversy over whether dual route or connectionist models best account for the acquisition of reading.

Child↗
PubMed2006

Chunking in task sequences modulates task inhibition.

In a study of the formation of representations of task sequences and its influence on task inhibition, participants first performed tasks in a predictable sequence (e.g., ABACBC) and then performed the tasks in a random sequence. Half of the participants were explicitly instructed about the predictable sequence, whereas the other participants did not receive these instructions. Task-sequence learning was inferred from shorter reaction times (RTs) in predictable relative to random sequences. Persisting inhibition of competing tasks was indicated by increased RTs in n- 2 task repetitions (e.g., ABA) compared with n- 2 nonrepetitions (e.g., CBA). The results show task-sequence learning for both groups. However, task inhibition was reduced in predictable relative to random sequences among instructed-learning participants who formed an explicit representation of the task sequence, whereas sequence learning and task inhibition were independent in the noninstructed group. We hypothesize that the explicit instructions led to chunking of the task sequence, and that n- 2 repetitions served as chunk points (ABA-CBC), so that within-chunk facilitation modulated the inhibition effect.

Adult↗
PubMed2002

Web-based experiments controlled by JavaScript: an example from probability learning.

JavaScript programs can be used to control Web experiments. This technique is illustrated by an experiment that tested the effects of advice on performance in the classic probability-learning paradigm. Previous research reported that people tested via the Web or in the lab tended to match the probabilities of their responses to the probabilities that those responses would be reinforced. The optimal strategy, however, is to consistently choose the more frequent event; probability matching produces suboptimal performance. We investigated manipulations we reasoned should improve performance. A horse race scenario in which participants predicted the winner in each of a series of races between two horses was compared with an abstract scenario used previously. Ten groups of learners received different amounts of advice, including all combinations of (1) explicit instructions concerning the optimal strategy, (2) explicit instructions concerning a monetary sum to maximize, and (3) accurate information concerning the probabilities of events. The results showed minimal effects of horse race versus abstract scenario. Both advice concerning the optimal strategy and probability information contributed significantly to performance in the task. This paper includes a brief tutorial on JavaScript, explaining with simple examples how to assemble a browser-based experiment.

Computer-Assisted Instruction↗
PubMed2001

Human locognosic acuity on the arm varies with explicit and implicit manipulations of attention: implications for interpreting elevated tactile acuity on an amputation stump.

In Experiment 1, normal subjects' ability to localize tactile stimuli (locognosia) delivered to the upper arm was significantly higher when they were instructed explicitly to direct their attention selectively to that segment than when they were instructed explicitly to distribute their attention across the whole arm. This elevation of acuity was eliminated when subjects' attentional resources were divided by superimposition of an effortful, secondary task during stimulation. In Experiment 2, in the absence of explicit attentional instruction, subjects' locognosic acuity on one of three arm segments was significantly higher when stimulation of that segment was 2.5 times more probable than that of stimulation of the other two segments. We surmise that the attentional mechanisms responsible for such modulations of locognosic acuity in normal subjects may contribute to the elevated sensory acuity observed on the stumps of amputees.

Adolescent↗
PubMed2002

Interactions between human explicit and implicit perceptual motor learning shown by kinematic variables.

The goal of this study was to investigate in non-impaired humans the interaction between explicit and implicit learning in a catching task. The situation presented probabilistic contingencies between visual signals and various final pathways of the target. Subjects were asked to practice the interception task for 320 trials. Explicit instructions describing the probabilistic rules were given prior to (11 subjects), or in the middle of (11 subjects), physical practice. Eleven subjects not provided with verbal instructions served as control subjects. We measured the combination between explicit verbal instructions and implicit learning via kinematics of the end-effector and an outcome measure (i.e. spatial error). The time when explicit instructions were given resulted in systematic changes in the spatio-temporal ordering of the action. These data suggested that analyzing the way the task is executed with scrutiny allows a new understanding of how the aforementioned learning systems interact.

Adult↗
PubMed2006

Dissociable contributions of the mid-ventrolateral frontal cortex and the medial temporal lobe system to human memory.

Although the prefrontal cortex and regions of the medial temporal lobe are commonly co-activated in neuroimaging studies, their precise respective contributions to human memory remain unclear. In this event-related fMRI study, conditions requiring volunteers to simply look at pictures of abstract art were compared with conditions in which they were explicitly instructed to remember similar stimuli for later recognition. Looking, with no explicit instruction to remember, was associated with significant increases in signal intensity in the medial temporal lobe in 19 of the 20 volunteers scanned, but not in a region of the mid-ventrolateral prefrontal cortex that has previously been implicated in memory encoding and retrieval. Behavioral data collected outside the scanner on the same task revealed that recognition of these stimuli was, however, above chance. When the task instructions were changed to encourage the volunteers to remember the stimuli, significant increases in signal intensity were observed bilaterally, in the mid-ventrolateral frontal cortex, but there was no concomitant increase within the medial temporal lobe region. Moreover, behavioral data collected outside the scanner confirmed that recognition of these stimuli was significantly improved relative to the 'just look' trials. These results suggest that the mid-ventrolateral frontal cortex and the medial temporal lobe region make dissociable contributions to human memory that correspond closely to 'top-down' and 'bottom-up' notions of cognitive control, respectively.

Adolescent↗
PubMed1998

The role of strategic visual attention in children's drawing development.

The many variables that affect the production of visually realistic drawings in children (such as instructions and contrasting models), have been widely documented in the research literature. The experiments reported here assess one variable that has been largely ignored, namely the attention that the child pays towards the drawing model. First, it was shown that the progression from intellectual to visual realism occurred between six and eight years of age, and was accompanied by a spontaneous increase in attention towards the drawing models. A second experiment showed that the drawing performance of the 6-year-olds was enhanced by contrasting tasks and explicit instructions. At all ages, explicit instructions increased attention towards the model, and the use of an efficient attentional strategy was associated with visually realistic drawings. These studies provide further evidence that intellectual and visual realism are not distinct developmental stages, but may instead reflect the use of different attentional strategies by children.

Age Factors↗
PubMed1997

Associative priming in word fragment completion: a dissociation between explicit and implicit retrieval processes.

Three experiments investigated associative priming in word fragment completion. In associative priming, the study word that acts as a prime is semantically related in some way to the response word that the subject must produce or respond to at test. For example, a prime might be semantically related to the solution to its paired word fragment (e.g. study "VANILLA", solve fragment "-H-C--A-E" at test, solution is "CHOCOLATE"). Associative priming therefore differs from both repetition and conceptual priming, in which the studied primes are themselves the words that must be produced or responded to at test. In Experiment 1, associative primes were found to influence word fragment completion performance on an explicit test, but not on an implicit test. Experiment 2 demonstrated that the effects of associative primes on explicitly instructed fragment completion cannot be attributed to the specific information about cue-prime relationships that is included in the explicit instructions. Experiment 3 demonstrated that a manipulation of modality, a variable known to disrupt implicit retrieval processes, disrupts repetition priming on an explicit test, but not associative priming. The results of these three experiments suggest that whereas repetition primes are retrieved from memory by both explicit and implicit retrieval processes, associative primes are retrieved by only explicit processes. These data suggest that implicit retrieval processes are cue-dependent processes which automatically retrieve memory information that provides a good match to retrieval cues. Explicit retrieval processes are cue-independent, functioning as an intentional retrieval set to access particular categories or types of memory information.

Association↗
PubMed2005

Priming and false memories from Deese-Roediger-McDermott lists on a fragment completion test with children.

This study examined priming and false memories with children on a word fragment completion task using the Deese-Roediger-McDermott (DRM) paradigm. Forty-five 4th- and 5th-grade children were shown lists of words and instructed to fill in fragments with the first word that came to mind (implicit instructions) or with the words that were presented during study (explicit instructions). Reliable priming to critical lure words was found under implicit retrieval instructions, and false memory to critical lure words was found under explicit retrieval instructions. However, priming under implicit retrieval instructions did not depend on whether the critical lure word was in the study list. In addition, greater false memory was observed under explicit test instructions. The results replicate and extend research on DRM false memory illusion with children to include implicit retrieval and word fragment completion. Explanations of false memory including gist failure (Brainerd, Reyna, & Forrest, 2002) and implicit associative response (Underwood, 1965) are considered.

Age Factors↗