On the relation between skilled performance of simple division and multiplication.

Are corresponding multiplication and division facts (e.g., 7?×?8, 56?÷?7) based on common or on independent memory processes? University students received division problems alternated with multiplication problems under instructions for speeded responses. Response times were highly correlated for corresponding division and multiplication problems, and error characteristics indicated parallel retrieval structures. Specifically, division errors were constrained by the distance between the dividend and the product implied by the error, rather than by distance from the correct quotient. This suggests that division memory is organized in terms of multiplicative relationships. Multiplication errors (e.g., 7?×?9?=?56) were primed by previous division trials (56?÷?7?=?8), but division errors were not primed by previous multiplications. The error priming results suggest that multiplication is often used at least to check division. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context effects: The proportional difference model and the reflection of preference.

The reflection effect (D. Kahneman & A. Tversky, 1979) was investigated using the stochastic model of choice developed by C. Gonzalez-Vallejo (2002). The model assumes that individuals make trade-offs among attribute values by relying on a difference variable. The model also specifies a threshold representing individual proclivities to reach to attribute differences. Two experiments demonstrated that changes in risk attitudes, from a gain to a loss situation, depended on the stimuli as well as on individuals' thresholds. Thresholds were generally lower in losses than in gains, indicating a risk-taking tendency. Thresholds were also lower when participants were endowed with greater savings. Model testing revealed better fits for the stochastic model than cumulative prospect theory (A. Tversky &. D. Kahneman, 1992). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A shift in task routines during the learning of a motor skill: Group-averaged data may mask critical phases in the individuals' acquisition of skilled performance.

The authors describe a transient phase during training on a movement sequence wherein, after an initial improvement in speed and decrease in variability, individual participants' performance showed a significant increase in variability without change in mean performance speed. Subsequent to this phase, as practice continued, variability again decreased, performance significantly exceeded the gains predicted by extrapolation of the initial learning curve, the type of errors committed changed, and performance became more coherent. The transient phase of increased variability may reflect a mixture of 2 (or more) performance routines before the more effective one is set and mastered, presumably the setting up of a sequence-specific representation. Both group and individual analyses indicated a departure from the single process (e.g., power-law) model of learning. However, although similar phases appeared in the mean group data, there was little correspondence to individual participants' time courses, and the individuals' gains in the second low-variability phase were masked. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stability of skilled performance across time: Some generalizations and limitations on utilities.

We review two closely related phenomena in the study of ability and performance: (a) decreasing predictive validity in ability–performance relations when studied longitudinally and (b) the superdiagonal stability matrices (i.e., simplex-like matrices) found in the correlations between repeated trials on a variety of tasks. We discuss briefly two models that explain these phenomena, a changing-task model and a changing-subject model, and report an empirical study in which (a) the generality of the simplex phenomenon in an area of human performance not previously studied and (b) whether the decrease in correlations across time would eventually stabilize (a hypothesis of the changing-task model) were investigated. Intercorrelation matrices of major league baseball performance across 10 years (four measures) indicate that the correlations systematically decrease over time, with no evidence of stabilizing. We discuss the implications of these empirical findings and conceptual developments for utilities of selection programs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and individual differences in the development of skilled memory search performance.

We examined individual differences in measures of multiple intellectual abilities and performance on a pure memory search task over 5 experimental sessions. Old (n?=?104) and young (n?=?97) participants showed expected patterns of substantial improvement in memory search intercepts and slopes in consistently mapped (CM) conditions, relative to varied mapping (VM) conditions. Initial (unskilled) CM and VM memory search was highly correlated with a Semantic Memory Access Speed factor and moderately correlated with General Intelligence. Structural equation models showed that measures of Semantic Memory Access remained a strong predictor of skilled CM search performance in both age groups despite individual differences in CM memory search performance changes. These results indicate qualitative differences in the nature of automaticity between memory search and visual search and suggest age invariance in the mechanisms determining automaticity in memory search. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relative task difficulty and transfer of training in skilled performance.

Summarized and analyzed critically are recent studies dealing directly or indirectly with the influence of the relative difficulty of initial and final tasks on transfer of training in skilled performance. Methods used to vary task difficulty are discussed under stimulus variations, response variations, and variations in control-display linkage. Task difficulty is examined in terms of the isolation and control of task variables, of task difficulty and performance standards, and of the U (shaped curve) hypothesis. 23 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reaction time measures of spelling: Testing a two-strategy model of skilled spelling.

Two strategies have been suggested to be important in skilled English spelling: a lexical strategy, which relies on word-specific graphemic information, and a rule strategy, which relies on phoneme-to-grapheme correspondences. Limitations in the usefulness of spelling accuracy as a dependent variable make it difficult to test claims about how the strategies might work together. Two experimental paradigms that measure both spelling accuracy and time are suggested to be useful. Results produced with the paradigms were consistent with the claims that skilled spellers make use of both strategies and that the lexical strategy is more useful than the rule strategy. Working memory may be important in combining products of both strategies. Results were inconsistent with the claim that the rule strategy is invoked only when the lexical strategy fails to produce a complete spelling. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the fragility of skilled performance: What governs choking under pressure?

Experiments 1-2 examined generic knowledge and episodic memories of putting in novice and expert golfers. Impoverished episodic recollection of specific putts among experts indicated that skilled putting is encoded in a procedural form that supports performance without the need for step-by-step attentional control. According to explicit monitoring theories of choking, such proceduralization makes putting vulnerable to decrements under pressure. Experiments 3-4 examined choking and the ability of training conditions to ameliorate it in putting and a nonproceduralized alphabet arithmetic skill analogous to mental arithmetic. Choking occurred in putting but not alphabet arithmetic. In putting, choking was unchanged by dual-task training but eliminated by self-consciousness training. These findings support explicit monitoring theories of choking and the popular but infrequently tested belief that attending to proceduralized skills hurts performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The perfectionism model of binge eating: Tests of an integrative model.

This study proposes, tests, and supports the perfectionism model of binge eating (PMOBE), a model aimed at explaining why perfectionism is related to binge eating. According to this model, socially prescribed perfectionism (SPP) confers risk for binge eating by generating exposure to 4 triggers of binge episodes: interpersonal discrepancies, low interpersonal esteem, depressive affect, and dietary restraint. In testing the PMOBE, a daily diary was completed by 566 women for 7 days. Predictions derived from the PMOBE were supported, with tests of mediation suggesting that the indirect effect of SPP on binge eating through triggers of binge episodes was significant. Reciprocal relations were also observed, with certain triggers of binge episodes predicting binge eating (and vice versa). Results supported the incremental validity of the PMOBE over and above self-oriented perfectionism and neuroticism and the generalizability of this model across Asian and European Canadian participants. The PMOBE offers a novel view of individuals with high levels of SPP as active agents who raise their risk of binge eating by generating conditions in their daily lives that are conducive to binge episodes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Allocating visual attention: Tests of a two-process model.

Observers require less time to identify a visual target when its location is cued in advance than when it is not cued, and the magnitude of the improvement depends on the validity of the cue. According to J. Jonides's (1983) 2-process model, there exist 2 possible modes of attentional readiness: a focused-attention mode and a diffuse-attention mode. Observers are assumed to enter the focused-attention mode on a proportion of trials that matches the validity of the cue and to enter the diffuse-attention mode on the remaining trials. The present experiment tested and rejected the response time mixture prediction of the 2-process model. An instance of the class of 1-process models in which perceptual objects are sampled in parallel according to the validity of the cue was evaluated. A stochastic simulation of the model yielded results that paralleled those of the experiment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reconceptualizing arousal: Psychobiological states in motor performance.

This review of research dealing with psychologically induced arousal and motor performance focuses on the hypothesized inverted-U function relating arousal to performance. The inverted-U hypothesis is supported only in a weak and psychologically trivial fashion. More useful research in human motor performance would investigate discrete psychobiological states, which include affect and cognition as well as physiology. Examination of profound individual differences in response to incentive and threat suggests that psychobiological states have their genesis in response expectancies and hypnotic-like self-inductions. The cognitive and affective components of these states are highly interactive and perhaps not profitably separated. Because performance anxiety is a central problem in the motor realm, it is carefully delineated and the test anxiety literature is scrutinized. Psychophysiological test batteries and other investigations in the area are described, and guidelines for future research are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbalizable knowledge and skilled task performance: Association, dissociation, and mental models.

Dissociations have often been found between skilled task performance and verbalizable knowledge about those tasks. Four experiments were designed to determine when associations and dissociations occur and how they should be interpreted. The experimental task involved the trial-and-error solution of equations whose form was unknown. Initially, the task was analyzed to determine the knowledge that might be expected of an expert, and different possible mental models that subjects might have were identified. Associations between task performance and verbalizable knowledge (measured by questionnaire) occurred when subjects had a moderate amount of practice at finding precise solutions (Experiment 1). A graphical display format improved performance but did not diminish false beliefs (Experiment 2). Even when the equations matched the cover story exactly, verbalizable knowledge still improved with practice (Experiment 3). When the cover story was discarded, subjects still showed an improvement in overall questionnaire score and had different, yet correct, beliefs at the end of the session (Experiment 4). In contrast to some previous work, these experiments show that verbal knowledge can increase with practice but that learning occurs at a different pace for different measures of performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Urn sampling and the proportional hazard model

This paper investigates the urn sampling analogue for the score statistic relating survival to covariates assuming a proportional hazard model. The exact permutation distribution can be calculated as well as the exact low order moments for arbitrary censoring patterns. The asymptotic distribution of the score statistic is an easy consequence. The method is naturally extended to deal with the multivariate case, time varying covariates and interval censoring. Finally the relationship between the censoring process, the survival times and covariates are studied considering different reference sets for the distribution of the score statistic. Some assumptions about the censoring process are investigated and as a consequence the effect of censoring is clarified.     

Psychometric schizotypy and motor performance.

Motor abnormalities have long been a focus in discussions of schizophrenia. The present study used a newly developed line drawing task to examine fine motor performance and psychometrically assessed schizotypy in a large, randomly ascertained sample of young adults (N = 120) with no history of psychosis. Poor motor performance on the line drawing task, indexed by root-mean-square error (RMS), was significantly related to 4 separate psychometric measures of schizotypy in the overall sample. The psychometric schizotypy-RMS association remained significant for 2 of the schizotypy measures even when the effects of intellectual functioning, mental state factors, and sustained attention were statistically controlled in a regression analysis. The status of the line drawing index as a schizophrenia liability measure is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of temporal position, proportional variance, and proportional duration on decision weights in temporal pattern discrimination

Two experiments investigated how listeners allocate their attention to different segments of a temporal pattern. The experiments allowed a direct test of the predictions of the Proportion of Total Duration (PTD) rule and the Component Relative Entropy (CoRE) model. Listeners had to decide whether two sequences of nine tones had the same or different temporal patterns (tone duration = 25 ms, tone frequency = 1000 Hz). A sequence's temporal pattern was determined by the time intervals between each tone's offset and the next tone's onset. On same trials, the time intervals at corresponding temporal positions in the two sequences were identical. On different trials, the corresponding time intervals were randomly varied. Listener attention to different temporal positions within a sequence was assessed by calculating the decision weights at each position. The results supported the CoRE model and were inconsistent with the PTD rule. Manipulating the mean of the time intervals within the sequence had no consistent effect on the pattern of weights (or on overall performance), indicating that listener attention was not affected by either the proportion of total duration or the perceptual salience of a longer or shorter time interval. However, manipulating the variance of the time intervals had a significant effect: the highest weight was given to the highest variance segment. This weighting strategy leads to better performance because higher variance segments are more diagnostic of whether the sequences are the same or different.     

Visual motor performance of psychotic children.

Explored visual motor deviations by means of a Childhood Psychosis Scale applied to the Primary Visual-Motor Test protocols of 130 psychotic children (6–12 yrs), and 507 normal and retarded (IQ range 35–79) controls. 45.4% of the psychotic sample achieved critical scores on the scale as compared to 1.7% of the normal Ss and 12.9% of the retarded Ss. It was possible to match 94 of the psychotic children with nonpsychotic controls on the basis of CA and MA. Significantly more psychotics than matched controls were high scorers. Correlations with MA were moderately significant for each group. In IQ comparisons, significantly more psychotics who were retarded had critical scores than did normal-IQ psychotics. Age at diagnosis, type and length of treatment, recency of diagnosis, and degree of organicity did not discriminate between high- and low-responding psychotics. Base rate problems and theoretical aspects of the scale items are discussed. The scale appears useful as a screening device for normal and retarded children under the age of 13 yrs, with particular utility in detecting psychotic aspects of functioning among the retarded. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of surface friction on skilled performance with bare and gloved hands.

"The major purpose of this study was to assess the effects of surface friction upon three criterion measures of manipulatory performance: (a) prehension force, (b) time per transport, (c) total number of transports. These measurements were considered as indices of the following aspects of performance: (a) effort, (b) speed, (c) output rate." Results: a close relation of decreased surface friction and increased prehension force, obscured data on performance speed, and less output rate only at very low friction values. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tests of a model of informational persistence.

Evaluated a model of informational persistence, the memory underlying performance in partial-report experiments, proposed by the 1st author and J. M. Yeomans (see record 1986-26361-001). This model consisted of 2 components: (1) a visual analog representation that briefly maintains form and location information about the contents of a visual display and (2) a durable, abstract identity representation that codes location information poorly. Results of pattern mask and row vs category partial-report performance experiments involving the authors and 11 undergraduates were consistent with the model, but indicate that the abstract identity representation may actually code location information quite well. An expanded version of the model is proposed in which the abstract identity representation is viewed as a location-specific, limited capacity memory. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tests of a model of binocular brightness.

Tested a model of binocular brightness mixing which describes binocular brightness as the vector sum of the 2 monocular brightnesses where each monocular brightness is weighted according to an autocorrelation function that measures the relative amounts of contour and contrast in the 2 monocular views. 3 experiments were carried out with 2 Os, and show that binocular brightness interactions depend on the size and shape of the monocular stimuli in ways predicted by the model. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Series effects in motor performance studies.

It was hypothesized that a series effect would operate in a study designed to determine the optimal work surface height for the performance of a simple motor task. Under Condition A, Ss performed the task at each of 6 work surface hieghts, comprising the lower ? of the range of heights used in an earlier study. Under Condition B, Ss performed at 6 heights comprising the upper ? of the range. Systematic differences were observed in the performance of the 2 groups at the 4 heights they had in common. The differences in motor performance were attributed to a series effect stemming from differences in judgments Ss made concerning what the optimal height should be. (PsycINFO Database Record (c) 2010 APA, all rights reserved)