Why aggregated learning follows the power law of practice when individual learning does not: comment on Rickard (1997, 1999), Delaney et al. (1998), and Palmeri (1999)

The power law of practice is often considered a benchmark test for theories of cognitive skill acquisition. Recently, P. F. Delaney, L. M. Reder, J. J. Staszewski, and F. E. Ritter (1998), T. J. Palmeri (1999), and T. C. Rickard (1997, 1999) have challenged its validity by showing that empirical data can systematically deviate from power-function fits. The main purpose of the present article is to extend their explanations in two ways. First, the authors empirically show that abrupt changes in performance are not necessarily based on a shift from algorithm to memory-based processing, but rather and more generally, that they occur whenever a more efficient task strategy is generated. Second, the authors show mathematically and per simulation that power functions can perfectly fit aggregated learning curves even when all underlying individual curves are discontinuous. Therefore, the authors question conclusions drawn from fits to aggregated data.     

Examining the Influence of Self-Efficacy on Message-Framing Effects: Reducing Salt Consumption in the General Population

Health-promoting messages can be framed in terms of the gains associated with healthy behavior or the losses associated with unhealthy behavior. Studies show inconsistent results as to which type of framing is more effective. In this study, we investigated whether participants' self-efficacy to decrease salt intake would moderate the effects of gain- and loss-framed messages promoting a low-salt diet on information acceptance, intention, and behavior. We hypothesized that loss-framed messages would more effectively decrease salt intake than gain-framed messages, but only when participants had high self-efficacy. A total of 575 adults, recruited from an Internet panel, took part in the study. Half of the participants received self-efficacy enhancing information, whereas the other half received no such information. After this self-efficacy manipulation, half of the participants received a gain-framed and half of the participants received a loss-framed message promoting a low-salt diet. Information acceptance and intention were assessed at immediate posttest and salt consumption was assessed at a 3-week follow-up. The results revealed the hypothesized effect on behavior. However, the interaction between self-efficacy and framing on salt consumption was not mediated by measures of information acceptance and intention to reduce salt intake. Our results suggest that messages stressing losses may be more effective than messages stressing gains in decreasing salt intake but only in persons with high self-efficacy to do so.     

Modelling the History of Ideas

We propose a new method for the history of ideas that has none of the shortcomings so often ascribed to this approach. We call this method the model approach to the history of ideas. We argue that any adequately developed and implementable method to trace (dis)continuities in the history of human thought, or concept drift, will require that historians use explicit interpretive conceptual frameworks. We call these frameworks models. We argue that models enhance the comprehensibility of historical texts, and provide historians of ideas with a method that, unlike existing approaches, is susceptible neither to common holistic criticisms nor to Skinner's objections that the history of ideas yields arbitrary and biased reconstructions. To illustrate our proposal, we discuss the so-called Classical Model of Science and draw upon work in computer science and cognitive psychology.     

Poor working memory predicts false memories

Two studies investigated whether individual differences in simple span verbal working memory and complex working memory capacity are related to memory accuracy and susceptibility to false memory development. In Study 1, undergraduate students (N=60) were given two simple span working memory tests: forward and backward digit span. They also underwent a memory task that is known to elicit false memories of nonpresented words, the Deese/Roediger-McDermott (DRM) paradigm. Poor simple span working memory (as reflected by suboptimal backward digit span scores) was related to elevated levels of false recognition. Study 2 (N=65) replicated this finding, in that suboptimal backward digit span performance was found to be predictive of false recognition. However, complex working memory capacity (operation span) was not related to false recognition. This pattern suggests that even in a homogenous sample of undergraduates, poor working memory is associated with the susceptibility to recollect words never presented.     

Are smokers interested in genetic testing for smoking addiction? A socio-cognitive approach

Genetic advances have made genetically tailored smoking cessation treatments possible. In this study, we examined whether smokers are interested in undergoing a genetic test to identify their genetic susceptibility to nicotine addiction. In addition, we aimed to identify socio-cognitive determinants of smokers’ intention to undergo genetic testing. Following the protection motivation theory (PMT), we assessed the following constructs using an online survey among 587 smokers: threat appraisal (i.e. susceptibility and severity), fear, coping appraisal (i.e. response efficacy and self-efficacy), response costs and intention. In addition, knowledge, social norms and information-seeking behaviour were measured. Mean intention rates were 2.57 on a 5-point scale. Intention was significantly associated with threat appraisal and coping appraisal, as predicted by the PMT. Fear of the outcome was negatively associated with the intention to undergo genetic testing, but response costs, knowledge and social influence were not. Intention to undergo genetic testing in turn was positively related to seeking information about genetic testing and genetically tailored smoking cessation treatments. Smokers seem ambivalent or ‘on the fence’ with regard to undergoing a genetic test for smoking addiction. Socio-cognitive concepts such as susceptibility, severity, response efficacy and self-efficacy may be used to inform or educate smokers about the value of genetically tailored smoking cessation treatments.     

Associations between abstainer,moderate and heavy drinker prototypes and drinking behaviour in young adults

Objective: Previous research has focused mostly on abstainer and/or general drinker prototypes. The present studies examined an abstainer, moderate drinker and heavy drinker prototype in relation to drinking behaviour.

Design: Two studies among young adults aged 18–25 (paper-and-pencil, cross-sectional, N?=?140; online, prospective, N?=?451) assessed prototype favourability and participants’ perceived similarity to the prototypes. Participants were also categorised into abstainers, moderate, and heavy drinkers.

Results: Similarity and favourability had similar sequences in both studies: the moderate drinker and abstainer prototypes were evaluated most favourable and felt similar to; the heavy drinker prototype was rated the least favourable and felt similar to. Importantly, heavy drinking participants felt most similar to the moderate drinker prototype and rated the heavy drinker least desirable. The results suggest a need for research to include other prototypes, such as the moderate drinker, besides the abstainer and heavy drinker.

Conclusion: The studies provide insights into the contribution of alternative prototypes (i.e. moderate drinker) into the relationship between prototype perceptions and drinking behaviour. The results suggest tailoring prototype-based interventions according to drinking behaviour. Importantly, realistic perceived similarity to the more favourable moderate drinker prototype may therefore need to be encouraged only after appropriate reductions in heavy drinkers’ alcohol consumption.     

Changing fit and fat bias using an implicit retraining task

Objective: To change implicit and explicit bias so that active obese people are regarded as more fit and normal weight sedentary people as less fit.

Design: Study one created a questionnaire that measured perceptions of active obese persons and sedentary normal weight persons on fitness-related items. Study two used a modified visual probe task to retrain perceptions regarding active obese persons and sedentary normal weight persons.

Main outcome measures: Self-reported explicit bias was measured with a questionnaire and implicit bias was measured with response times collected during a visual probe task.

Results: The questionnaire reliably measured ‘fitness and fatness’ perceptions. In study two, pairing images of active obese persons with positive activity-related words resulted in active obese persons being explicitly rated more fit; pairing images of normal weight sedentary persons with negative words associated with sedentary lifestyles increased endorsement of normal weight people as unfit. There were no changes in implicit bias.

Conclusions: Bias regarding how body weight is thought of relative to fitness can be altered by pairing images of obese persons being active with words such as ‘health’ and ‘fit’. This is evidence that representations of persons of all body weight should be used when promoting physical activity.     

Improving Parental Competencies: Subjectively Perceived Usefulness of a Parent Training Matters

As parental competencies are of importance for the development of children, these competencies are often fostered in parent training programs. Research suggests that a lack of fit between training contents and parental perceptions and expectations might result in a lower effectiveness of a parent training. Consequently, parents’ subjective perceptions of trainings should be in the focus of research on the effects of parent trainings. The present study evaluated the effectiveness of a parent training (MonteBaRo-Training) and analyzed pre-post-test changes. Parents who participated in the program (N = 117) and a waiting list control group (N = 88) were surveyed about children’s behavior problems, parenting sense of competence and dysfunctional parenting at two measurement occasions. Results indicated that the training was effective in improving parenting sense of competence, the perceptions of child problem behavior and dysfunctional parenting. Subjectively perceived usefulness of the training was associated with a change in children’s behavior problems and the parenting sense of competence after the completion of the course.     

A shortened version of Raven’s standard progressive matrices for children and adolescents

Numerous developmental studies assess general cognitive ability, not as the primary variable of interest, but rather as a background variable. Raven’s Progressive Matrices is an easy to administer non-verbal test that is widely used to measure general cognitive ability. However, the relatively long administration time (up to 45 min) is still a drawback for developmental studies as it often leaves little time to assess the primary variable of interest. Therefore, we used a machine learning approach – regularized regression in combination with cross-validation – to develop a short 15-item version. We did so for two age groups, namely 9 to 12 years and 13 to 16 years. The short versions predicted the scores on the standard full 60-item versions to a very high degree r = 0.89 (9–12 years) and r = 0.93 (13–16 years). We, therefore, recommend using the short version to measure general cognitive ability as a background variable in developmental studies.     

An old problem: how can we distinguish between conscious and unconscious knowledge acquired in an implicit learning task?

A long lasting debate in the field of implicit learning is whether participants can learn without acquiring conscious knowledge. One crucial problem is that no clear criterion exists allowing to identify participants who possess explicit knowledge. Here, we propose a method to diagnose during a serial reaction time task those participants who acquire conscious knowledge. We first validated this method by using Stroop-like material during training. Then we assessed participants’ knowledge with the Inclusion/Exclusion task (Experiment 1) and the wagering task (Experiment 2). Both experiments confirmed that for participants diagnosed as having acquired conscious knowledge about the underlying sequence the Stroop congruency effect disappeared, whereas for participants not diagnosed as possessing conscious knowledge it only slightly decreased. In addition, both experiments revealed that only participants diagnosed as conscious were able to strategically use their acquired knowledge. Thus, our method allows to reliably distinguish between participants with and without conscious knowledge.