Peter Sedlmeier

Do studies of statistical power have an effect on the power of studies

The long-term impact of studies of statistical power is investigated using J. Cohens (1962) pioneering work as an example. We argue that the impact is nil; the power of studies in the same journal that Cohen reviewed (now the Journal of Abnormal Psychology) has not increased over the past 24 years. In 1960 the median power (i.e., the probability that a significant result will be obtained if there is a true effect) was .46 for a medium size effect, whereas in 1984 it was only .37. The decline of power is a result of alpha-adjusted procedures. Low power seems to go unnoticed: only 2 out of 64 experiments mentioned power, and it was never estimated. Nonsignificance was generally interpreted as confirmation of the null hypothesis (if this was the research hypothesis), although the median power was as low as .25 in these cases. We discuss reasons for the ongoing neglect of power.

The Psychological Effects of Meditation: A Meta-Analysis.

In this meta-analysis, we give a comprehensive overview of the effects of meditation on psychological variables that can be extracted from empirical studies, concentrating on the effects of meditation on nonclinical groups of adult meditators. Mostly because of methodological problems, almost ¾ of an initially identified 595 studies had to be excluded. Most studies appear to have been conducted without sufficient theoretical background. To put the results into perspective, we briefly summarize the major theoretical approaches from both East and West. The 163 studies that allowed the calculation of effect sizes exhibited medium average effects (r = .28 for all studies and r = .27 for the n = 125 studies from reviewed journals), which cannot be explained by mere relaxation or cognitive restructuring effects. In general, results were strongest (medium to large) for changes in emotionality and relationship issues, less strong (about medium) for measures of attention, and weakest (small to medium) for more cognitive measures. However, specific findings varied across different approaches to meditation (transcendental meditation, mindfulness meditation, and other meditation techniques). Surprisingly, meditation experience only partially covaried with long-term impact on the variables examined. In general, the dependent variables used cover only some of the content areas about which predictions can be made from already existing theories about meditation; still, such predictions lack precision at present. We conclude that to arrive at a comprehensive understanding of why and how meditation works, emphasis should be placed on the development of more precise theories and measurement devices.

Teaching Bayesian Reasoning in Less Than Two Hours

The authors present and test a new method of teaching Bayesian reasoning, something about which previous teaching studies reported little success. Based on G. Gigerenzer and U. Hoffrages (1995) ecological framework, the authors wrote a computerized tutorial program to train people to construct frequency representations (representation training) rather than to insert probabilities into Bayess rule (rule training). Bayesian computations are simpler to perform with natural frequencies than with probabilities, and there are evolutionary reasons for assuming that cognitive algorithms have been developed to deal with natural frequencies. In 2 studies, the authors compared representation training with rule training; the criteria were an immediate learning effect, transfer to new problems, and long-term temporal stability. Rule training was as good in transfer as representation training, but representation training had a higher immediate learning effect and greater temporal stability.

From the functions of music to music preference

To date, not much is known about how the functions of music relate to music preference. This article examines the basic hypothesis that the strength of preference for a given kind of music depends on the degree to which that kind of music serves the needs of the listener; that is, how well the respective functions of music are fulfilled. Study 1, a pilot study, identified the best-known musical styles of the participants, yielding 25 styles that were known by at least 10 percent of them. Study 2 used these 25 styles and found that rock, pop and classical music were liked most. A factor analysis yielded six distinct dimensions of music preference. People showed great variation in the strength of preference for their favourite music. This is explained by the impact of different functions of music. The potential of music to express peoples identity and values and to bring them together was most closely related to the strength of preference. However, the reasons for liking a particular style are not congruent with the functions that people ascribe to their favourite music in general. A theoretical model of the development of music preferences is suggested.

Intuitions about sample size: The empirical law of large numbers

According to Jacob Bernoulli, even the ‘stupidest man’ knows that the larger one’s sample of observations, the more confidence one can have in being close to the truth about the phenomenon observed. Two-and-a-half centuries later, psychologists empirically tested people’s intuitions about sample size. One group of such studies found participants attentive to sample size; another found participants ignoring it. We suggest an explanation for a substantial part of these inconsistent findings. We propose the hypothesis that human intuition conforms to the ‘empirical law of large numbers’ and distinguish between two kinds of tasks — one that can be solved by this intuition (frequency distributions) and one for which it is not suAcient (sampling distributions). A review of the literature reveals that this distinction can explain a substantial part of the apparently inconsistent results. * c 1997 by John Wiley & Sons, Ltd.

The impact of background music on adult listeners: A meta-analysis

Background music has been found to have beneficial, detrimental, or no effect on a variety of behavioral and psychological outcome measures. This article reports a meta-analysis that attempts to summarize the impact of background music. A global analysis shows a null effect, but a detailed examination of the studies that allow the calculation of effects sizes reveals that this null effect is most probably due to averaging out specific effects. In our analysis, the probability of detecting such specific effects was not very high as a result of the scarcity of studies that allowed the calculation of respective effect sizes. Nonetheless, we could identify several such cases: a comparison of studies that examined background music compared to no music indicates that background music disturbs the reading process, has some small detrimental effects on memory, but has a positive impact on emotional reactions and improves achievements in sports. A comparison of different types of background music reveals that the tempo of the music influences the tempo of activities that are performed while being exposed to background music. It is suggested that effort should be made to develop more specific theories about the impact of background music and to increase the methodological quality of relevant studies.

The psychological functions of music listening

Why do people listen to music? Over the past several decades, scholars have proposed numerous functions that listening to music might fulfill. However, different theoretical approaches, different methods, and different samples have left a heterogeneous picture regarding the number and nature of musical functions. Moreover, there remains no agreement about the underlying dimensions of these functions. Part one of the paper reviews the research contributions that have explicitly referred to musical functions. It is concluded that a comprehensive investigation addressing the basic dimensions underlying the plethora of functions of music listening is warranted. Part two of the paper presents an empirical investigation of hundreds of functions that could be extracted from the reviewed contributions. These functions were distilled to 129 non-redundant functions that were then rated by 834 respondents. Principal component analysis suggested three distinct underlying dimensions: People listen to music to regulate arousal and mood, to achieve self-awareness, and as an expression of social relatedness. The first and second dimensions were judged to be much more important than the third—a result that contrasts with the idea that music has evolved primarily as a means for social cohesion and communication. The implications of these results are discussed in light of theories on the origin and the functionality of music listening and also for the application of musical stimuli in all areas of psychology and for research in music cognition.

Functional neuroanatomy of meditation: A review and meta-analysis of 78 functional neuroimaging investigations

Meditation is a family of mental practices that encompasses a wide array of techniques employing distinctive mental strategies. We systematically reviewed 78 functional neuroimaging (fMRI and PET) studies of meditation, and used activation likelihood estimation to meta-analyze 257 peak foci from 31 experiments involving 527 participants. We found reliably dissociable patterns of brain activation and deactivation for four common styles of meditation (focused attention, mantra recitation, open monitoring, and compassion/loving-kindness), and suggestive differences for three others (visualization, sense-withdrawal, and non-dual awareness practices). Overall, dissociable activation patterns are congruent with the psychological and behavioral aims of each practice. Some brain areas are recruited consistently across multiple techniques-including insula, pre/supplementary motor cortices, dorsal anterior cingulate cortex, and frontopolar cortex-but convergence is the exception rather than the rule. A preliminary effect-size meta-analysis found medium effects for both activations (d=0.59) and deactivations (d=-0.74), suggesting potential practical significance. Our meta-analysis supports the neurophysiological dissociability of meditation practices, but also raises many methodological concerns and suggests avenues for future research.

Are judgments of the positional frequencies of letters systematically biased due to availability

How do people estimate whether a particular letter is more frequent in the 1st versus in a later position? The authors tested 2 precise versions of the availability hypothesis, a hypothesis that assumes that frequency processing occurs on the level of the phonological classes of vowels and consonants, and the regressed-frequencies hypothesis, which assumes monitoring of individual letters. Across 3 studies, it was found that (a) judgments of whether a letter is more frequent in the 1st or the 2rid position generally followed the actual proportions and (b) the estimated relative frequencies in the 1st versus the 2rid position closely agreed with the actual rank ordering, except for an overestimation of low and underestimation of high values. These results favor the regressed-frequencies hypothesis and challenge the conclusions about frequency judgments in the heuristics and biases literature.

Free Word Associations Correspond to Contiguities Between Words in Texts

A free associative response is the first word a person comes up with after perceiving another word, the so-called associative stimulus. People commonly associate hot to cold, church to priest, and hard to work. According to traditional association theory this behaviour is the result of learning by contiguity: “Objects once experienced together tend to become associated in the imagination, so that when any one of them is thought of, the others are likely to be thought of also, in the same order of sequence or coexistence as before” (James, 1890). This explanation has been rejected by cognitive psychologists who explain the production of associations as the result of symbolic processes which make use of complex semantic structures (Clark, 1970). We will show, however, that human associative responses can be predicted from contiguities between words in language use. This finding supports the hypothesis that the behaviour of participants in the free association task can be explained by associative learning.