Groups perform better than the best individuals on letters-to-numbers problems: effects of group size

Individuals and groups of 2, 3, 4, or 5 people solved 2 letters-to-numbers problems that required participants, on each trial, to identify the coding of 10 letters to 10 numbers by proposing an equation in letters, receiving the answer in letters, proposing a hypothesis, and receiving feedback on the correctness of the hypothesis. Groups of 3, 4, and 5 people proposed more complex equations and had fewer trials to solution than the best of an equivalent number of individuals. Groups of 3, 4, and 5 people had fewer trials to solution than 2-person groups but did not differ from each other. These results suggest that 3-person groups are necessary and sufficient to perform better than the best individuals on highly intellective problems.     

Groups perform better than the best individuals on Letters-to-Numbers problems

Eighty-two four-person cooperative groups and 328 independent individuals solved a random coding of the letters A–J to the numbers 0–9. On each trial the group or individual proposed an equation in letters (e.g., A + D=?), received the answer in letters (e.g., A + D=B), proposed one specific mapping (e.g., A=3), received the answer (e.g., True, A=3), and proposed the full mapping of the 10 letters to the 10 numbers. As predicted, the groups had fewer trials to solution, proposed more complex equations, and identified more letters per equation than each of the best, second-best, third-best, and fourth-best individuals. We interpret the group superiority as due to the highly intellective nature of Letters-to-Numbers problems, which entail demonstrable recognition of correct answers, demonstrable rejection of erroneous answers, and multiple insights into effective collective information processing strategies.     

Nonselective read-out from iconic memory in normal, borderline and retarded adolescents

The hypothesis that retarded individuals read-out information from iconic memory at a slower rate, relative to their CA matched peers, was tested. Three IQ groups (normal, borderline and retarded) were selected with 10 subjects in each group. A tachistoscope presented a stimulus array and a post-stimulus cue for 100 msec. each, separated by a variable interstimulus interval (ISI). This stimulus array consisted of 10 letters arranged on two horizontal rows. The post-stimulus cue was a circle which surrounded the position of the correct letter. Nine ISIs were used and ranged from −100 (cue before array) to 500 msec. A 3 × 9 repeated-measures analysis of variance revealed non-significant effects for IQ and the IQ × ISI interaction. A significant effect was found for ISIs (p < .01) which reflected reduced performance at the intermediate ISIs for all intelligence groups. The hypothesis of a read-out deficit in the retarded was not supported. The present findings were discussed in relation to previous research which supported a read-out deficit in the retarded.     

Automatization through Practice: The Opportunistic-Stopping Phenomenon Called into Question

As a theory of skill acquisition, the instance theory of automatization posits that, after a period of training, algorithm-based performance is replaced by retrieval-based performance. This theory has been tested using alphabet-arithmetic verification tasks (e.g., is A + 4  = E?), in which the equations are necessarily solved by counting at the beginning of practice but can be solved by memory retrieval after practice. A way to infer individuals’ strategies in this task was supposedly provided by the opportunistic-stopping phenomenon, according to which, if individuals use counting, they can take the opportunity to stop counting when a false equation associated with a letter preceding the true answer has to be verified (e.g., A + 4  = D). In this case, such within-count equations would be rejected faster than false equations associated with letters following the true answers (e.g., A + 4  = F, i.e., outside-of-count equations). Conversely, the absence of opportunistic stopping would be the sign of retrieval. However, through a training experiment involving 19 adults, we show that opportunistic stopping is not a phenomenon that can be observed in the context of an alphabet-arithmetic verification task. Moreover, we provide an explanation of how and why it was wrongly inferred in the past. These results and conclusions have important implications for learning theories because they demonstrate that a shift from counting to retrieval over training cannot be deduced from verification time differences between outside and within-count equations in an alphabet-arithmetic task.     

Return of Genetic Results in the Familial Dilated Cardiomyopathy Research Project

The goal of the Familial Dilated Cardiomyopathy (FDC) Research Project, initiated in 1993, has been to identify and characterize FDC genetic cause. All participating individuals have been consented for the return of genetic results, an important but challenging undertaking. Since the inception of the Project we have enrolled 606 probands, and 269 of these had 1670 family members also enrolled. Each subject was evaluated for idiopathic dilated cardiomyopathy (IDC) and pedigrees were categorized as familial or sporadic. The coding regions of 14 genes were resequenced in 311 to 324 probands in five studies. Ninety-two probands were found to carry nonsynonymous rare variants absent in controls, and with Clinical Laboratory Improvement Amendment of 1988 (CLIA) compliant protocols, relevant genetic results were returned to these probands and their consented relatives by study genetic counselors and physicians in 353 letters. In 10 of the 51 families that received results >1 year ago, at least 23 individuals underwent CLIA confirmation testing for their family’s rare variant. Return of genetic results has been successfully undertaken in the FDC Research Project. This report describes the methods utilized in the process of returning research results. We use this information as a springboard for providing guidance to other genetic research groups and proposing future directions in this arena.     

ACTH 4-9 analog can retard spatial alternation learning in brain damaged and normal rats

Thirty adult male hooded rats (Long-Evans strain) were assigned randomly to one of three lesion groups (n = 10) and prepared with medial frontal, posterior parietal, or sham neocortical injuries. Following a recovery interval of 10-12 days, access to water was limited to 30 min per day and the rats were shaped to traverse a T-maze for a reward of sweetened water. After a pretraining criterion was attained, osmotic minipumps (Alzet 2002) were installed subcutaneously. The minipumps delivered chronically for the next 14 to 15 days either 0 or 1.2 micrograms of ACTH 4-9 dissolved in bacteriostatic saline per day while the rats were trained on a reinforced spatial alternation task. Analysis of the number of errors made to a criterion of at least 80% correct alternations in two consecutive training sessions, or a ceiling of 62 errors (attained by two rats with parietal lesions), revealed that learning was impaired in the rats with parietal injuries. Contrary to our hypothesis, animals receiving ACTH 4-9 committed more errors than their counterparts receiving only saline.     

Connaissance du nom et du son des lettres, habiletés métaphonémiques et capacités de décodage en grande section de maternelle

This study examined the specific implication of letter-name knowledge in reading acquisition on 5-year-old kindergarten children. Several studies underlined the importance of both phonological and orthographic skills (letters and grapho-phonological associations’ knowledge developed during reading acquisition). So, we focused on the link between those different early abilities and on their links with reading acquisition during school year. Thus, at the beginning and at the end of the year, we proposed to 40 children metaphonemic tasks (phoneme identification in initial and final position in the words), letter-sound and letter-name knowledge tasks (naming and identification) and a pseudo-words decoding task. In addition, to access letter-name knowledge, two types of measurements were proposed: an accuracy measure and a speed one. Mean number of correct responses and reaction times were collected by children and analysed too. Results show that letter-name knowledge could play a part in metaphonemic abilities development and in letter-sound associations’ discovery and acquisition, at the beginning of the year. Thanks to those skills improvement, letter-name knowledge could have an indirect impact on later children's decoding skills. Furthermore, the direct link, already observed at the beginning of the year, between letter-name knowledge and decoding skills still exists in April. At last, analyses on letter-name knowledge access time show that the more children name an important number of letters, the more they do it quickly. These results could mean that a certain level of letter-name knowledge have to be reach before children could use this knowledge automatically. All together, results confirm the importance of good letter-name knowledge in the first stages of reading acquisition. We also suggest taking into account some clues of letter-name knowledge's automatic use to better understand reading acquisition processes.     

A review of substance use research among those with mental retardation

This article reviews research conducted on the cigarette, alcohol, and illicit drug use of adolescents and adults with mental retardation (MR). The majority of the research related to substance use conducted on this population has been limited to surveys. Overall, results of these studies suggest that, although substance use is slightly lower among those with MR than among nondisabled comparison groups, it is nonetheless a problem for many individuals. This research is reviewed and a discussion of both the general and specific flaws of these studies follows. Further, the examination of education, prevention, and treatment programs for this population has been overlooked, indicating that individuals with MR are likely not receiving the services most appropriate for them. The article concludes with a discussion of several topics that need to be addressed in future studies, including research on potential best practices in the overlooked areas of substance abuse interventions.     

Are individual or consecutive letters the unit affected by repetition blindness?

When 2 similar words (e.g., react reach) are briefly sequentially displayed, the 2nd word may be omitted from the report, a phenomenon known as repetition blindness (RB). Previous researchers have suggested that consecutive letters are the unit affected by RB. Six experiments provided new data on orthographic RB. Two letters at the beginning or end of words resulted in RB, as did alternating interior letters (tactile earthly) and 3 letters with different relative positions (arid bird). However, no RB was found with a single final letter (show view). Observed RB may reflect pattern completion because RB for pairs like throat theory was reduced when the nonrepeated letters (eory) were consistent with only a single word. The experiments point to a model of orthographic RB in which both individual letters and letter sequences of length 2 or more play a role.     

Positive and Negative Hypothesis Testing by Cooperative Groups

In a rule induction problem positive hypothesis tests select evidence that the tester expects to be an example of the correct rule if the hypothesis is correct, whereas negative hypothesis tests select evidence that the tester expects to be a nonexample if the hypothesis is correct. Previous research indicates the general effectiveness of a positive test strategy for individuals, but there has been very little research with cooperative groups. We extend the analysis of Klayman and Ha (Psychological Review, 1987) of ambiguous verification or conclusive falsification of five possible types of hypotheses by positive and negative tests by emphasizing the importance of further examples following hypothesis tests. In two experiments four-person cooperative groups solved rule induction problems by proposing a hypothesis and selecting evidence to test the hypothesis on each of four arrays on each trial. In different conditions the groups were instructed to use different combinations of positive and negative tests on the four arrays. Positive tests were more likely to lead to further examples than negative tests, and the proportion of correct hypotheses corresponded to the proportion of positive tests, in both experiments. We suggest that positive tests are more effective than negative hypothesis tests in generating further evidence, and thus in inducing the correct rule, in experimental rule induction tasks with a criterion of certainty imposed by the researcher.     

The effects of load variability in short-term memory task

Six groups of Ss viewed briefly exposed arrays of letters, half designated high-valued and half low-valued. Immediately after each exposure Ss wrote down as many of the stimuli as they could remember. For three groups, the number of letters in each exposure was constant from trial to trial; for the remaining three groups, the number of letters in each exposure varied from trial to trial. This tested the hypothesis that load variability influences the development of an efficient response strategy which, in turn, affects the processing of information stored in short-term memory. The data supported this hypothesis. Performance was superior under the constant load condition due to the ability of these Ss to correctly report both high- and low-valued letters. Poor performance was observed under the variable load condition because of a decrease in the number of low valued letters correctly reported.     

Two Trajectories of Depressive Symptom Reduction Throughout Behavioral Activation Teletherapy Among Underserved,Ethnically Diverse,Primary Care Patients: A VitalSign6 Report

While prior research has investigated trajectories of depressive symptom change throughout psychotherapy, such work has not been conducted exclusively among underserved patients receiving brief Behavioral Activation (BA) teletherapy, intervention modifications that should reduce barriers to therapy initiation and engagement. The current project used cluster analysis to determine discrete groups of symptom change among patients receiving an 8-session BA teletherapy intervention, and analyzed whether demographic and clinical characteristics were associated with group membership. Data from 105 patients referred from charity primary care clinics and receiving at least two therapy sessions were analyzed. Patients were predominantly female and Latina. The 9-item Patient Health Questionnaire (PHQ-9) was the outcome. Two categories were determined: a larger group (N = 61) demonstrating initially less severe symptoms and experiencing a gradual recovery, and a smaller group beginning with more severe symptoms, and experiencing a steeper recovery. In both groups, a majority of participants experienced at least a 5-point drop in depressive symptoms, while in the latter group, a majority of patients achieved depressive symptom remission (PHQ-9 < 5). Monolingual Spanish speakers were more likely to be in the former group, but no other demographic or clinical characteristics were associated with group membership. In both groups, a majority of the symptom reduction occurred by sessions 4–6. Therefore, two categories of depressive symptom change, slow responders and rapid responders, occur among patients receiving a brief BA teletherapy intervention. No demographic differences aside from primary language, nor any clinical characteristics, distinguish group membership, suggesting similar patterns of symptom reduction among a primarily underserved sample.     

Letter encoding in visual word identification: more evidence for a word-integration explanation for parafoveal preview effects in reading.

A letter string presented briefly in the parafovea facilitates naming a foveally presented word provided that the two stimuli are orthographically similar. The facilitation (called priming) is asymmetrical in that to obtain it, both letter strings must have the first letters in common. One possible explanation, a letter-integration hypothesis, proposes that readers only identify the letters at the beginning of the parafoveal stimulus, an action that facilitates processing the target. Another explanation, a word-integration hypothesis, postulates that all the letters of the parafoveal stimulus are identified and that the asymmetry occurs because the first letters of the parafoveal stimulus are weighted more heavily than the later ones. The two accounts differ in the way the position of the first letter is determined: The first postulates that readers know the side to identify first without reference to the stimulus; the second postulates that readers establish an order on the stimuli postcategorically. To distinguish the views, we presented English and Hebrew stimuli to bilingual readers. Readers could not anticipate the position of the first letters; hence, if the letter-integration explanation is correct, the asymmetry in the priming should be attenuated. Consistent with the word-integration explanation, however, priming occurred when the target shared the beginning letters with the prime in both languages.     

Reexamining the word length effect in visual word recognition: New evidence from the English Lexicon Project

In the present study, we reexamined the effect of word length (number of letters in a word) on lexical decision. Using the English Lexicon Project, which is based on a large data set of over 40,481 words (Balota et al., 2002), we performed simultaneous multiple regression analyses on a selection of 33,006 English words (ranging from 3 to 13 letters in length). Our analyses revealed an unexpected pattern of results taking the form of a U-shaped curve. The effect of number of letters was facilitatory for words of 3–5 letters, null for words of 5–8 letters, and inhibitory for words of 8–13 letters. We also showed that printed frequency, number of syllables, and number of orthographic neighbors all made independent contributions. The length effects were replicated in a new analysis of a subset of 3,833 monomorphemic nouns (ranging from 3 to 10 letters), and also in another analysis based on 12,987 bisyllabic items (ranging from 3 to 9 letters). These effects were independent of printed frequency, number of syllables, and number of orthographic neighbors. Furthermore, we also observed robust linear inhibitory effects of number of syllables. Implications for models of visual word recognition are discussed.     

Structural complexity of motor patterns: A study on reaction times and movement times of handwritten letters

This study investigates the effects of psychomotor complexity on latencies for beginning to write single letters and numerals, and on times taken to complete the first strokes of letters and numerals. An experiment measured simple and choice reaction times for writing homogeneous graphemes (i.e., letters or numerals made up of similar strokes) and for writing heterogeneous graphemes (i.e., characters made up of dissimilar strokes). It was assumed that the motor programme for writing a letter is retrieved from long-term memory and briefly held, until it is used, in a short-term buffer store. The experiment examined the hypothesis that it is more difficult to read out homogeneous than heterogeneous stroke-structures from this store. For three out of four allographic grapheme pairs, homogeneous graphemes required longer initiation times or longer movement times for completion of the first stroke than did heterogeneous graphemes. These results are discussed in relation to recent findings on motor programming based on the use of reaction-time paradigms.     

Human performance on the traveling salesman problem

Two experiments on performance on the traveling salesman problem (TSP) are reported. The TSP consists of finding the shortest path through a set of points, returning to the origin. It appears to be an intransigent mathematical problem, and heuristics have been developed to find approximate solutions. The first experiment used 10-point, the second, 20-point problems. The experiments tested the hypothesis that complexity of TSPs is a function of number of nonboundary points, not total number of points. Both experiments supported the hypothesis. The experiments provided information on the quality of subjects’ solutions. Their solutions clustered close to the best known solutions, were an order of magnitude better than solutions produced by three well-known heuristics, and on average fell beyond the 99.9th percentile in the distribution of random solutions. The solution process appeared to be perceptually based.     

Handwriting process and product characteristics of children diagnosed with developmental coordination disorder

Deficits in handwriting performance limit the school participation of children with developmental coordination disorder (DCD). The aim of this study was to compare the handwriting process and product characteristics of children with DCD to those of typically developing (TD) children in order to determine the best means of differentiation between the groups. Participants were 40 children, from 7 to 10 years old. The experimental group consisted of 20 children who met the criteria of DCD, and the control group consisted of 20 age- and gender-matched controls. The children were asked to perform three graded writing tasks on an electronic tablet, which was part of a computerized handwriting evaluation system (ComPET), in order to obtain measures of their handwriting process. The children's handwriting product was then evaluated by the Hebrew Handwriting Evaluation (HHE). Results showed significant differences between the groups for the handwriting process measures (on-paper and in-air time, mean pressure) and for the handwriting product characteristics (global legibility, number of letters erased or overwritten, spatial arrangement, and number of letters written in the first minute). The discriminant analysis yielded a high significant discrimination (80-90%), with the 'number of letters erased or overwritten' variable as the most differentiating variable (-.67). We concluded that an evaluation of both handwriting process and product characteristics among children with DCD provides a more comprehensive picture of their deficits. Using this method may enable practitioners to focus on children's main deficits and to tailor intervention methods so as to prevent academic underachievement and its consequences on their emotional well-being.     

The word-detection effect: Sophisticated guessing or perceptual enhancement?

Subjects discriminate letters in words better than letters in nonwords. The sophisticated guessing hypothesis attributes this word advantage to a guessing strategy. In words, the possible letters at each letter position are constrained by letters at other positions, whereas letters in nonwords are not restricted in this manner. A critical test of this hypothesis is that if subjects are givenexplicit knowledge of the letters in nonwords before the trial, the word advantage would disappear. We investigated the effect of preknowledge of the alternatives in the word-detection effect. In the word-detection effect, subjects decide which of two character strings contains letters and which contains pseudoletters. In four experiments, subjects were more accurate with words than with nonwords, and subjects were more accurate when they were told the word or nonword before the trial. However, even with foreknowledge of the alternatives, subjects were more accurate with words than with nonwords.     

Impact of cognitive-behavioral therapy for panic disorder on comorbidity: a controlled investigation

This study examined the effects of cognitive-behavioral therapy (CBT) for principal panic disorder with or without agoraphobia, on comorbidity in 30 individuals (16 female). To test the hypothesis that improvements in co-existing conditions were not due to spontaneous fluctuations across time, patients receiving immediate CBT were compared to those assigned to wait list (n = 11). Results indicated clinician-rated severity of comorbid specific phobia declined significantly following immediate CBT compared to no change after wait list. The number of patients without comorbidity of any severity increased after immediate CBT, with no such increase following wait list. However, the groups did not differ in the frequency of additional diagnoses or overall severity of comorbidity. In the total sample, results indicated reductions in comorbidity by 9-month follow-up, with marked declines in the severity of comorbid generalized anxiety disorder (GAD), social and specific phobia. Our findings suggest that targeted CBT for panic disorder has beneficial effects on comorbidity over the longer term and that some of its immediate effects exceed those due to the passage of time alone.     

Detecting phonemes and letters in text: Interactions between different types and levels of processes

In six experiments, subjects detected phonemes or letters in text presented auditorily or visually. Experiments 1 and 2 provided support for the hypothesis that a mismatch between the phoneme and letter representations of a target leads to detection errors. In addition, visual word unitization processes were implicated. Experiments 3 and 4 provided support for the hypothesis that the Gestalt goodness of pattern affected detection errors when subjects searched for letters. Experiments 5 and 6 demonstrated that the effects of unitization on the detection of letters in common words were decreased by altering the familiar configuration of the test words. The combined results of all six experiments lead to the conclusion that both visual and phonetic processes influence letter detection, that these processes communicate through a type of cross-checking, and that there are at least two levels of visual (and perhaps of phonetic) processing involved in the letter detection task.