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PubMed1996

Effects of age on state of awareness following implicit and explicit word-association tasks.

Younger and older participants did word-association tasks after implicit and explicit instructions and a read-generate study manipulation. No age differences were shown in the implicit version of the test. A generation effect for both age groups suggested that word-association priming can be classified as a conceptually driven task and a new task at which older adults show a relatively preserved memory function. However, the younger group did better on the explicit test in the generate condition. Participants were asked to examine their implicitly produced responses to make them accessible to conscious retrieval. Remember (R) and Know (K) measures of conscious awareness were applied to both postimplicit and postexplicit word-association responses. Age and awareness showed opposite effects in postimplicit retrieval. Younger participants tended to make more R responses than did the older adults, and K responses did not vary with age, but the older group was unaware of more primed items as study list members. Age differences were also shown in R but not K responses after word-association cued recall.

Adult↗
PubMed1982

Voluntary alteration of visual evoked potentials.

Fifteen normal adults had pattern-shift visual evoked potentials (PSVEPs) using monocular checkerboard pattern reversal. Subjects were instructed to concentrate on the pattern in the first set of trials and then to avoid perceiving it in the second set. Direct, continuous visual observation ensured that the eye remained open and fixed on the pattern. Nonetheless, a third of the subjects could spontaneously alter or obliterate the PSVEP using several maneuvers, including meditation, daydreaming, and convergence. Several could produce shifts in apparent PSVEP latency. With explicit instruction, most subjects could learn to alter their PSVEP by maneuvers that are inapparent even to an observent technician.

Adult↗
PubMed2006

An investigation of false memory in perceptual implicit tasks.

Reports of critical lure priming in perceptual implicit tasks [e.g., McKone, E., & Murphy, B. (2000). Implicit false memory: Effects of modality and multiple study presentations on long-lived semantic priming. Journal of Memory and Language, 43, 89-109] using the Deese-Roediger-McDermott [Roediger, H. L., III, & McDermott, K. B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, and Cognition, 21, 803-814] procedure have suggested availability of the lexical form of lure items at study. Three experiments were conducted to further explore "false" implicit priming in perceptual tests. In Experiments 1 and 3, implicit and explicit stem completion tests were given in the DRM procedure with semantic lists; in Experiment 2, a graphemic response test was used in a similar design. For all experiments, explicit instructions resulted in reliable false memory, while implicit instructions resulted in priming for list items and no priming for lure items. Priming for lure items was evident for "test-aware" subjects only in Experiment 1 and in a combined analysis for all three experiments. These results establish boundary conditions for priming for critical lures and indicate that access to the lexical form of critical lures may not occur under incidental learning conditions when strong controls against explicit retrieval are implemented.

Adult↗
PubMed1991

Effects of self-management training and reinforcement on the transfer of improved conduct in the absence of supervision.

The instruction, maintenance, and transfer of training of social skills of 3 seriously emotionally disturbed adolescents were accomplished by a self-management training and reinforcement package. During baseline sessions these students, who were covertly filmed in their classroom, averaged over 90% off-task or socially inappropriate behavior while their teacher was out of the room. They showed similar behaviors when walking between classes, unattended by their teacher. Treatment was introduced in the classroom and consisted of social skills and self-management training and reinforcement. Treatment procedures included instruction, modeling, and role playing of social skills, as well as self-assessment, self-recording, and self-reinforcement for correct approximations of these skills. After 5 weeks of training, all subjects demonstrated substantial improvements in the classroom during the teacher's absence and when distracted by other students; however, transfer of social skills did not occur to the between-class setting until students were given explicit instruction to initiate self-managing procedures in this setting.

Adolescent↗
PubMed1989

Rules and exemplars in categorization, identification, and recognition.

Subjects learned to classify perceptual stimuli varying along continuous, separable dimensions into rule-described categories. The categories were designed to contrast the predictions of a selective-attention exemplar model and a simple rule-based model formalizing an economy-of-description view. Converging evidence about categorization strategies was obtained by also collecting identification and recognition data and by manipulating strategies via instructions. In free-strategy conditions, the exemplar model generally provided an accurate quantitative account of identification, categorization, and recognition performance, and it allowed for the interrelationship of these paradigms within a unified framework. Analyses of individual subject data also provided some evidence for the use of rules, but in general, the rules seemed to have a great deal in common with exemplar storage processes. Classification and recognition performance for subjects given explicit instructions to use specific rules contrasted dramatically with performance in the free-strategy conditions and could not be predicted by the exemplar model.

Adult↗
PubMed2001

The role of the speech-language pathologist in improving decoding skills.

In this article, we consider the processes and knowledge involved in decoding and present some instructional guidelines and suggestions for teaching students the skills necessary for proficient and fluent word reading. The roles and responsibilities of speech-language pathologists (SLPs) are also considered. It may have been enough several years ago for SLPs to focus solely on early literacy skills and phonological awareness. This is not the case today. SLPs not only need to collaborate with teachers to develop a comprehensive approach to literacy, but also should be providing direct, explicit instruction of decoding skills for students with language and learning disabilities.

Awareness↗
PubMed2006

Implicit learning -- explicit knowing: a role for sleep in memory system interaction.

There is evidence that sleep supports the enhancement of implicit as well as explicit memories (i.e., two memory systems that during learning normally appear to act together). Here, employing a serial reaction time task (SRTT) paradigm, we examined the question whether sleep can provide explicit knowledge on an implicitly acquired skill. At learning, young healthy subjects (n = 20) were first trained on the SRTT. Then, implicit knowledge was assessed on two test blocks, in which grammatically incorrect target positions were occasionally interspersed by the difference in reaction times between grammatically correct and incorrect target positions. To assess explicit sequence knowledge, thereafter subjects performed on a generation task in which they were explicitly instructed to predict the sequential target positions. In half the subjects, learning took place before a 9-hour retention interval filled with nocturnal sleep (sleep group), in the other half, the retention interval covered a 9-hour period of daytime wakefulness (wake group). At subsequent retesting, both testing on the generation task and the SRTT test blocks was repeated. At learning before the retention interval, subjects displayed significant implicit sequence knowledge which was comparable for the sleep and wake groups. Moreover, both groups did not display any explicit sequence knowledge as indicated by a prediction performance not differing from chance on the generation task. However, at retesting, there was a distinct gain in explicit knowledge in the subjects who had slept in the retention interval, whereas generation task performance in the wake group remained at chance level. SRTT performance in the test blocks at retesting did not indicate any further gain in skill (i.e., unchanged reaction time differences between grammatically correct and incorrect target positions) independently of whether subjects had slept or remained awake after learning. Our results indicate a selective enhancement of explicit memory formation during sleep. Because before sleep subjects only had implicit knowledge on the sequence of target transitions, these data point to an interaction between implicit and explicit memory systems during sleep-dependent off-line learning.

Adolescent↗
PubMed1991

Tactile attention and the perception of moving tactile stimuli.

Three experiments investigated the ability of subjects to identify the direction of movement of a pattern across the skin. In Experiments 1 and 2, subjects were required to identify the direction of movement of a pattern presented to one fingerpad while another moving pattern was being presented to an adjacent fingerpad. Subjects were instructed to attend only to the target location. The results showed that accuracy was consistently higher and reaction times were consistently faster when the two patterns moved in the same direction than when they moved in opposite directions. Both effects were largest when the two patterns were presented simultaneously. In Experiment 3, the nontarget location was the contralateral hand. In this case, performance was not affected by the presentation of the nontarget. Combined, the results suggest that movement information is processed across adjacent fingers even when subjects are explicitly instructed to attend only to one finger. Subjects do appear to be able to restrict attention to a single hand.

Attention↗
PubMed2006

Theoretical analysis of a synaptotropic dendrite growth mechanism.

It is generally believed that the genome cannot encode explicit instructions to form each synaptic connection in the nervous system, but may provide general neurite growth mechanisms which will result in proper connectivity. Recent in vivo imaging has provided evidence for a synaptotropic growth mechanism, wherein synapses could influence dendrite growth by selectively stabilizing filopodia upon which they form. We undertook a theoretical investigation into the consequences of such a growth process. Discrete stochastic simulations demonstrate that the synaptotropic mechanism can result in decreased dendritic wiring length, is capable of searching for regions of high density pre-synaptic partners, and can recapitulate specific patterns of dendrite growth and connectivity. A mean-field analysis shows that growth by selective stabilization of filopodia can be approximated as a reaction-diffusion system, with a spatially varying diffusion constant that depends on the probability of synapse formation. Thus, growth will occur faster in regions of appropriate synaptic connections, and the net growth can be shown to climb a gradient of synaptic partner density. Synaptotropic growth thus presents a mechanism for the emergent development of connectivity based on local properties of the circuit elements, rather than explicit dependence on global guidance molecules or innate predetermined branching programs.

Animals↗
PubMedDate not supplied

[Inhibition and resource capacity during normal aging: a confrontation of the dorsal-ventral and frontal models in a modified version of negative priming].

BACKGROUND: Over the past decades, cognitive psychology contribution to our understanding of aging relies on two major perspectives, focusing on the selective impact of age on either cognitive multiple-systems or global factors of cognition: slowing, working memory and inhibition. In the latter, reduction in inhibitory control during aging (in its access, deletion or restraint functions) is associated with poorer performance on a variety of tasks referring to memory, comprehension or language [Hasher, Zacks and May (16)]. The attractiveness of inhibition as an explanatory factor results in part in the absence of negative priming during aging. Negative priming refers to the slow down of latencies when individuals have to respond to recently ignored informations, compared to unrelated informations. The dissociation, between a preserved location negative priming and an absence of identity negative priming during aging, supports the dorsal-ventral model of inhibition which suggests that spatial and identity inhibition are supported by different and independent visual pathways. An alternative model, directly at odds, is that inhibitory mechanisms are supported by the frontal lobe. In this perspective, inhibition is not a central process responsible for the control of working memory contents, but an automatic and local mechanism whose triggering depends on controlled attention. Therefore, working memory drives efficient inhibition by sustaining task instructions and appropriate responses throughout task execution. This hypothesis is consistent with Houghton and Tipper's (17) architecture of selective attention. According to the authors, the presence or absence of automatic inhibition is very closely linked to a Match/Mismatch field whose function is to compare the present stimulus to an internal self-generated internal template. When an information fails to match the subject's current goals, the match/mismatch field causes an automatic inhibitory imbalance which reduces the to-be-ignored properties' responsiveness. In contrast, information matching subjects' goal is enhanced through an automatic excitatory imbalance. The accurate functioning of the Match/Mismatch field requires efficient executive functioning responsible for the uphold of goals and correct responses. In the case of negative priming, manipulating the efficiency of working memory is of interest as it should affect the triggering of slowing, ie, an indirect inhibitory deficit, when the task is resource demanding [Conwayet al. (6)]. Moreover, if inhibition, as reflected by negative priming, is mediated by individual resource capacity, then NP should disappear during aging only when individuals are engaged in a resource-demanding task. OBJECTIVES: To address this issue, we examine whether cognitive control load in a gender decision task contributed to the presence or absence of NP during aging. According to the dorsal-ventral model, task complexity should not have any impact on performance, since gender decision task relies on a conceptual analysis of information. In turn, the frontal model predicts that age differences in performance profile will only differ when individual resource capacity is overloaded. DESIGN OF THE STUDY: Sixty-four participants (32 young and 32 older adults) performed a gender categorisation task through two experiments. Trials involved two stimuli presented successively at the same location. A word served as a prime and a word as a target. Both prime and target could be male or female. When prime and target matched on gender, we talked about VALID pairs (or compatible). When prime and target mismatched on the manipulated features, we talked about INVALID pairs (or incompatible). Participants' task was to identify the gender of the target. They were explicitly instructed not to respond to primes but to read them silently. Our interest was in response latencies for valid versus invalid pairs. We manipulated task complexity by the absence (experiment 1) or presence (experiment 2) of a distractor during probe trials. RESULTS: For younger adults, primes presented before targets gave rise to behavioural costs when pairs were mapped to the same response compared to pairs that were mapped to opposite ones. This slowing, called Negative Compatibility Effect (NCE), was independent of the presence or absence of a distractor. NCE was reliable for the elderly patients only under condition of no interfering information during the probe trial: pattern of performance of older participants was identical to that of young adults (experiment 1). This effect disappeared as task complexity increased (experiment 2). DISCUSSION: This result suggests that NCE triggering is dependant on the amount of cognitive control engaged by the task, and therefore that the ability to inhibit irrelevant information is secondary to a general capacity of the working memory. CONCLUSION: The implications of our data are consistent with the level of processing account, as well as the recent neuroimaging contributions which suggest, for example, the involvement of the dorso-lateral prefrontal cortex (sensitive to aging) when task demands are high, and a ventro-lateral prefrontal implication when demands are low [see Eenshuistra et al. for a review (10)].

Adult↗
PubMed2006

Physician communication when prescribing new medications.

BACKGROUND: Communication about taking a new medication is critical to proper use of drug therapy and to patient adherence. Despite ample evidence that medications are not taken as prescribed, few investigations have detailed the elements of communication about new medication therapy. This article describes and assesses the quality of physician communication with patients about newly prescribed medications. METHODS: This was an observational study that combined patient and physician surveys with transcribed audiotaped office visits from 185 outpatient encounters with 16 family physicians, 18 internists, and 11 cardiologists in 2 Sacramento, Calif, health care systems between January and November 1999, in which 243 new medications were prescribed. We measured the quality of physician communication when prescribing new medications. RESULTS: Physicians stated the specific medication name for 74% of new prescriptions and explained the purpose of the medication for 87%. Adverse effects were addressed for 35% of medications and how long to take the medication for 34%. Physicians explicitly instructed 55% of patients about the number of tablets to take and explained the frequency or timing of dosing 58% of the time. Physicians fulfilled a mean of 3.1 of 5 expected elements of communication when initiating new prescriptions. They counseled the most about psychiatric medications, fulfilling a mean of 3.7, 3.5, and 3.4, pulmonary, and cardiovascular elements, respectively. CONCLUSIONS: When initiating new medications, physicians often fail to communicate critical elements of medication use. This might contribute to misunderstandings about medication directions or necessity and, in turn, lead to patient failure to take medications as directed.

Adult↗
PubMed2001

The Mini-Cog: receiver operating characteristics with expert and naïve raters.

BACKGROUND: As elderly populations grow, dementia detection in the community is increasingly needed. Existing screens are largely unused because of time and training requirements. We developed the Mini-Cog, a brief dementia screen with high sensitivity, specificity, and acceptability. Here we describe the development of its scoring algorithm, its receiver operating characteristics (ROC), and the generalizability of its clock drawing scoring system. SAMPLE AND METHODS: A total of 249 multi-lingual older adults were examined. Scores on the three-item recall task and the clock drawing task (CDT-CERAD version) were combined to create an optimal algorithm. Receiver operating characteristics for seven alternatives were compared with those of the MMSE and the CASI using expert raters. To assess the CDT scoring generalizability, 20 naïve raters, without explicit instructions or prior CDT exposure, scored 80 randomly selected clocks as "normal" or "abnormal" (20 from each of four CERAD categories). RESULTS: An algorithm maximizing sensitivity and correct diagnosis was defined. Its ROC compared favorably with those of the MMSE and CASI. CDT concordance between naïve and trained raters was >98% for normal, moderately and severely impaired clocks, but lower (60%) for mildly impaired clocks. Recalculation of the Mini-Cog's performance, assuming that naïve raters would score all mildly impaired CDTs in the full sample as normal, retained high sensitivity (97%) and specificity (95%). CONCLUSION: The Mini-Cog algorithm performs well with simple clock scoring techniques. The results suggest that the Mini-Cog may be used successfully by relatively untrained raters as a first-stage dementia screen. Further research is needed to characterize the Mini-Cog's utility when population dementia prevalences are low.

Aged↗
PubMed1991

A comparison of occupational data from death certificates and interviews.

A comparison was made of the occupational data reported on the death certificates of 586 men with their employment history obtained by interviews. Agreement was assessed for 19 occupational and 14 industrial categories of usual employment, with the highest levels of concordance (greater than or equal to 80%) found for agricultural, medical, and public administration activities. Between the two sources of information, there was overall agreement of 56% for usual occupation and 51% for usual industry of employment. Concordance was highest among the 68 self-respondents (usual occupation 66%; usual industry 53%). Among the 518 surrogates, spousal agreement was highest (58% for occupation and 51% for industry). For other surrogate types, agreement was 49% for both industry and occupation. Agreement varied by duration of employment and by level of education, with concordance tending to increase as length of employment and educational attainment rose. These relationships remained when examined by respondent type. Evaluation of agreement levels by age and other study subject characteristics showed little effect on concordance. Review of verbatim data from the interviews and death certificates revealed that most disagreements could be attributed to coding problems caused by vague or misleading information on the death certificates, although some disconcordance was due to uncodable and missing information in the interview history. Based on results from this and prior studies, the value of occupational data derived from death certificates in epidemiologic studies may be limited, although the addition of explicit instructions on the death certificate itself may aid in providing more useful and complete information for usual employment.

Death Certificates↗
PubMed2006

Processing of emotionally toned pictures in dementia.

BACKGROUND: Apathy is a common symptom in dementia and is often associated with reduced emotional reactivity. This study examined whether reduced emotional reactivity can be demonstrated in dementia patients using a picture viewing task. METHODS: The viewing time of three different types of visual stimuli was measured in 24 elderly participants, half of which suffered from dementia. The participants had to make a target response to an emotionally neutral target stimulus that was intermixed with a frequently occurring non-target or 'background' stimulus and infrequently presented emotional stimuli. All participants could control the presentation time of each stimulus, but one half of the participants were explicitly instructed to perform the task quickly. RESULTS: The main measure was a ratio score in which the viewing time for emotional stimuli was expressed relative to the viewing time for the neutral non-target stimulus. Using this measure, the instigation of a time-pressure condition proved to significantly reduce the viewing time for emotional stimuli in the healthy subjects. Irrespective of time-pressure condition, the dementia patients showed a similar short viewing time for emotional stimuli as did the healthy subjects in the time-pressure condition. However, both dementia patients and healthy controls displayed longer viewing times for unpleasant than for pleasant stimuli. CONCLUSION: These results suggest the ability of the present task to reveal the simultaneous occurrence of an overall reduced interest for novel stimuli and an intact differential emotional reactivity to stimuli with a negative versus positive valence in the dementia patients.

Aged↗
PubMed1998

Awareness of remembering achieved through automatic and conscious processes in multiple sclerosis.

Fifty multiple sclerosis (MS) and forty-one matched control subjects were administered a word stem completion task and the California Verbal Learning. Test (CVLT). As predicted, priming in a conventional "implicit" task did not differ for MS and control groups, and under "explicit" instructions verbal list recall was significantly lower in the MS group with recognition intact. Application of the process dissociation procedure (Jacoby, Toth, & Yonelinas, 1993) to the word stem task demonstrated that conscious and unconscious processes both contribute to remembering in MS. Exploratory analyses found no group differences in words remembered under inclusion nor exclusion conditions, though preliminary estimates for MS automatic processing exceeded those for controls. As predicted, prospective metamemory judgments reflected subsequent performance for both groups in the inclusion but not the exclusion condition. By contrast, retrospective monitoring for both groups reflected memory performance in both conditions. However post hoc analyses demonstrated that those MS subjects who employed more automatic processing were less aware retrospectively of their successful remembering under exclusion than MS subjects who used less automatic processing.

Adult↗
PubMed2000

Attentional bias toward low-intensity stimuli: an explanation for the intensity dissociation between reaction time and temporal order judgment?

If two stimuli need different times to be processed, this difference should in principle be reflected both by response times (RT) and by judgments of their temporal order (TOJ). However, several dissociations have been reported between RT and TOJ, e.g., RT is more affected than TOJ when stimulus intensity decreases. One account for these dissociations is to assume differences in the allocation of attention induced by the two tasks. To test this hypothesis, different distributions of attention were induced in the present study between two stimulus positions (above and below fixation). Only bright stimuli appeared in one position and either bright or dim stimuli in the other. In the two RT experiments, participants had to respond to every stimulus appearing in one of the two positions. Reaction times to bright stimuli were faster when they appeared in the position where dim stimuli were likely to occur. This finding suggests that the allocation of attention was adapted to the asymmetrical arrangement of stimuli, not suggested by explicit instruction. In the two TOJ experiments, the temporal order of stimuli appearing in the two positions had to be judged. Although bright stimuli appearing at the bright-and-dim location were judged to be earlier, this effect was small and insignificant. Further, the intensity dissociation between RT and TOJ was insensitive to random vs blockwise presentations of intensities, therefore was not modified by attentional preferences. Thus, asymmetrical arrangement of stimuli has an impact on the allocation of attention, but only in the RT task. Therefore dissociations between TOJ and response times cannot be accounted for by an attentional bias in the TOJ task but probably by different use of temporal information in the two tasks.

Adult↗
PubMed1996

Neural activation during covert processing of positive emotional facial expressions.

Lesion studies indicate distinct neural systems for recognition of facial identity and emotion. Split-brain experiments also suggest that emotional evaluation of a stimulus can occur without conscious identification. The present study tested a hypothesis of a differential neural response, independent of explicit conscious mediation, to emotional compared to nonemotional faces. The experimental paradigm involved holding in mind an image of a face across a 45-s delay while regional cerebral blood flow was measured using positron emission tomography. Prior to the delay, a single face was presented with an explicit instruction to match it to one of two faces, photographed at different angles from the target face, presented at the end of the delay. Repeated blood flow measures were obtained while subjects held happy or neutral faces in mind or during a neutral control fixation condition without initial face presentation. The representation of emotional faces over a delay period, compared to either the nonemotional or the fixation condition, was associated with significant activation in the left ventral prefrontal cortex, the left anterior cingulate cortex, and the right fusiform gyrus. The findings support our hypothesis of a differential neural response to facial emotion, independent of conscious mediation, in regions implicated in the processing of faces and of emotions.

Adult↗
PubMed1993

The effects of alphabetic-reading competence on language representation in bilingual Chinese subjects.

The metaphonological abilities of two groups of bilingual Chinese adults residing in the Netherlands were examined. All subjects were able to read Chinese logograms, but those in the alphabetic group had, unlike those in the non-alphabetic group, also acquired some competence in reading Dutch. In Experiment 1, strong, significant differences between the two groups were obtained in the task of deleting the initial consonant of a Dutch spoken pseudo-word and also in a task consisting of segmenting a sentence into progressively smaller fragments, but there was no difference in a rhyme--nonrhyme classification task with pairs of Dutch words. In the latter task, the subjects in the two groups performed at a near-ceiling level. In Experiment 2, a significant difference was obtained again for the consonant-deletion task and no difference with an initial syllabic-vowel-deletion task, but the non-alphabetic subjects performed at a significantly lower level than the alphabetic subjects in the rhyme-judgement task. Taken together, these results are consistent with the earlier evidence that learning a non-alphabetic orthography does not promote awareness of the segmental structure of utterances. On the other hand, they confirm, for a population of Chinese readers, the conclusion drawn earlier from work with illiterate subjects that explicit instruction is more critical for the development of segmental representations of language than of representations of higher levels such as those of rhymes and syllables.

Adolescent↗