Dick J. Bierman

Stroop versus Stroop: Comparison of a card format and a single-trial format of the standard color-word Stroop task and the emotional Stroop task

Abstract The card format and the single-trial format of the Stroop task are used alternately for the same purposes in general cognitive studies and in emotion studies. However, no convergent validity or testretest reliability has ever been shown. In the present study, a card format and a single-trial format of a standard color-word Stroop and an emotional Stroop (i.e. spider words) were administered to a normal sample and re-administered after 3 months. Neither for the standard Stroop effect, nor the emotional Stroop effect, was there convergence between the two formats. The test-retest reliability of the standard Stroop effects of both formats was low but significant and the test-retest reliability of the emotional Stroop effects was very low. The results suggest that the two formats measure different underlying mechanisms and that both mechanisms are unstable. It is concluded that the application of cognitive paradigms within emotional research is of value if combined with the appropriate psychometric research.

ANOMALOUS ANTICIPATORY RESPONSE ON RANDOMIZED FUTURE CONDITIONS

Physiological baseline conditions preceding stimulus presentation are shown to depend on emotionality of stimulus content.

The therapeutic effect of clinical trials: understanding placebo response rates in clinical trials – A secondary analysis

Background and purposePlacebo response rates in clinical trials vary considerably and are observed frequently. For new drugs it can be difficult to prove effectiveness superior to placebo. It is unclear what contributes to improvement in the placebo groups. We wanted to clarify, what elements of clinical trials determine placebo variability.MethodsWe analysed a representative sample of 141 published long-term trials (randomized, double-blind, placebo-controlled; duration > 12 weeks) to find out what study characteristics predict placebo response rates in various diseases. Correlational and regression analyses with study characteristics and placebo response rates were carried out.ResultsWe found a high and significant correlation between placebo and treatment response rate across diseases (r = .78; p < .001). A multiple regression model explained 79% of the variance in placebo variability (F = 59.7; p < 0.0001). Significant predictors are, among others, the duration of the study (beta = .31), the quality of the study (beta = .18), the fact whether a study is a prevention trial (beta = .44), whether dropouts have been documented (beta = -.20), or whether additional treatments have been documented (beta = -.17). Healing rates with placebo are lower in the following diagnoses; neoplasms (beta = -.21), nervous diseases (beta = -.10), substance abuse (beta = -.14). Without prevention trials the amount of variance explained is 42%.ConclusionMedication response rates and placebo response rates in clinical trials are highly correlated. Trial characteristics can explain some portion of the variance in placebo healing rates in RCTs. Placebo response in trials is only partially due to methodological artefacts and only partially dependent on the diagnoses treated.

The cognitive and affective alexithymia dimensions in the regulation of sympathetic responses

OBJECTIVE The literature regarding research into alexithymia and sympathetic responses is far from consistent. An explanation might be on the way subjects are classified. Generally, subjects are diagnosed as either alexithymic or non-alexithymic on the basis of questionnaires focusing on the cognitive aspects of alexithymia. However, alexithymia, as originally defined, concerns both emotion-affective and emotion-cognitive deficits. The aim of the present paper is to study the importance of the affective and cognitive alexithymia components in the regulation of sympathetic responses. METHODS Subjects, who scored extremely (either high or low) on both the cognitive and the affective components of alexithymia, were shown neutral and emotional pictures, while their GSR was measured. RESULTS The affective alexithymia component, not the cognitive component, turned out to be an important factor in the regulation of GSR peak amplitude. The results further indicate a significant interaction of type of emotional deficit (cognitive by affective) on GSR latency times. Finally, suggestive evidence indicated that baselines values, defined by the levels during the second preceding the stimulus, are related to the cognitive component of alexithymia, in the sense that higher emotion-cognitive capacities result in higher baseline values. CONCLUSIONS We cautiously conclude that the classification of alexithymics on the basis of both the affective and cognitive components, rather than on the basis of the cognitive component only, might provide more consistent research results, and thus lead to a better understanding of emotional physiological responses in alexithymic subjects.

Intuitive decision making in complex situations: Somatic markers in an artificial grammar learning task

In this article, we explore the extent to which implicit learning is subtended by somatic markers, as evidenced by skin conductance measures. On each trial, subjects were asked to decide which “word” from a pair of “words” was the “correct” one. Unknown to the subjects, each “word” of a pair was constructed using a different set of rules (Grammar Aand Grammar B). A (monetary) reward was given if the subject chose the “word” from Grammar A. Choosing the Grammar B word resulted in (monetary) punishment. Skin conductance was measured during each of 100 trials. After each set of 10 trials, the subjects were asked how they selected the “correct word.” Task performance increased long before the subjects could even formulate a single relevant rule. In this preconceptual phase of the experiment, skin conductance was larger before incorrect than before correct choices. Thus, it was shown that artificial grammar learning is accompanied by a somatic marker, possibly “warning” the subject of the incorrect decision.

Empirical research on the radical subjective solution of the measurement problem. Does time get its direction through conscious observation

In a number of experimental studies we explored the so‐called ‘radical subjective’, and rather controversial, solution of the measurement problem. This solution posits that an interaction with a conscious entity is required to complete the measurement. Thus the collapse of the wave packet is assumed to be causally linked to a conscious observation. Under the assumption that the brain is sensitive for the difference between observing a quantum (superposition) state and a classical state this radical solution can be tested. A radioactive source was used to trigger beeps that first were delayed for 1 second and then were observed by a (final) observer from whom a continuous recording of brain activity was made. In about 50% of the events, another (pre) observer got feedback of this quantum event before the final observer. In those cases, presumably the pre‐observer’s observation resulted in collapse of the wave‐packet while in the other half of the cases the final observer was ‘producing’ the collapse. The brain signals of the final observer for the two types of events were compared. The ambiguous results of the studies will be discussed. If consciousness is the crucial ingredient for ‘collapse’ to occur, then this might also give a new anthropocentric hypothesis with regard to the ‘arrow of time’. The projection postulate implies a irreversible process of reduction and hence can be seen as one of the few non time‐symmetric processes in physics. If consciousness is required to have a collapse then it might follow that consciousness introduces time asymmetry into physics. New neuro‐cognitive models of consciousness suggest that the neural correlate of conscious experience (rather than non conscious processing) is the occurrence of massive parallel recurrent (i.e. non linear) neural activation. Thus the collapse of the wave packet would become associated with a strong non‐linear process. This fits, at least in a metaphorical sense, with the theoretical results where an introduction on a non linear term in the Schrodinger equation results in an ‘objective’ reduction of the wave packet.In a number of experimental studies we explored the so‐called ‘radical subjective’, and rather controversial, solution of the measurement problem. This solution posits that an interaction with a conscious entity is required to complete the measurement. Thus the collapse of the wave packet is assumed to be causally linked to a conscious observation. Under the assumption that the brain is sensitive for the difference between observing a quantum (superposition) state and a classical state this radical solution can be tested. A radioactive source was used to trigger beeps that first were delayed for 1 second and then were observed by a (final) observer from whom a continuous recording of brain activity was made. In about 50% of the events, another (pre) observer got feedback of this quantum event before the final observer. In those cases, presumably the pre‐observer’s observation resulted in collapse of the wave‐packet while in the other half of the cases the final observer was ‘producing’ the collapse. The b...

Testing for Questionable Research Practices in a Meta-Analysis: An Example from Experimental Parapsychology.

We describe a method of quantifying the effect of Questionable Research Practices (QRPs) on the results of meta-analyses. As an example we simulated a meta-analysis of a controversial telepathy protocol to assess the extent to which these experimental results could be explained by QRPs. Our simulations used the same numbers of studies and trials as the original meta-analysis and the frequencies with which various QRPs were applied in the simulated experiments were based on surveys of experimental psychologists. Results of both the meta-analysis and simulations were characterized by 4 metrics, two describing the trial and mean experiment hit rates (HR) of around 31%, where 25% is expected by chance, one the correlation between sample-size and hit-rate, and one the complete P-value distribution of the database. A genetic algorithm optimized the parameters describing the QRPs, and the fitness of the simulated meta-analysis was defined as the sum of the squares of Z-scores for the 4 metrics. Assuming no anomalous effect a good fit to the empirical meta-analysis was found only by using QRPs with unrealistic parameter-values. Restricting the parameter space to ranges observed in studies of QRP occurrence, under the untested assumption that parapsychologists use comparable QRPs, the fit to the published Ganzfeld meta-analysis with no anomalous effect was poor. We allowed for a real anomalous effect, be it unidentified QRPs or a paranormal effect, where the HR ranged from 25% (chance) to 31%. With an anomalous HR of 27% the fitness became F = 1.8 (p = 0.47 where F = 0 is a perfect fit). We conclude that the very significant probability cited by the Ganzfeld meta-analysis is likely inflated by QRPs, though results are still significant (p = 0.003) with QRPs. Our study demonstrates that quantitative simulations of QRPs can assess their impact. Since meta-analyses in general might be polluted by QRPs, this method has wide applicability outside the domain of experimental parapsychology.

Student Models, Scratch.Pads, and Simulation

The paper discusses the status of student models and it is proposed that in order to infer more subtle and complex student models from student’s behaviour, an electronic scratchpad or note-pad might be a valuable tool. A design methodology for these scratch-pads is explored. The method consists of a primary task analysis followed by a analysis of natural notes according to a scoring scheme based upon this task analysis. Special attention is given to notes that can not be classified. It is concluded that the task-analysis covers about 98% of the natural notes but that from the remaining 2% useful design criteria can be extracted. It is proposed that the point of view that for specific domains simulation can be seen as ‘runnable1 scratch-pads, might add futher design-criteria.

Consciousness and Quantum Physics: Empirical Research on the Subjective Reduction of the Statevector

There are two major theoretical perspectives on the relation between quantum physics and consciousness. The first one is the proposal by Hameroff and Penrose CHEXX[16] that consciousness arises from the collapse of the statevector describing nonconscious brainstates. The second perspective is the proposition that consciousness acts as the ultimate measurement device, i. e. a measurement is defined as the collapse of the statevector describing the external physical system, due to interaction with a conscious observer. The latter (dualistic) proposition has resulted in the thought experiment with Schrodinger’s cat and is generally considered as extremely unlikely. However, that proposition is, under certain assumptions, open to empirical verification. This was originally done by Hall et al. CHEXX[15]. A refined experiment to test the “subjective” reduction’ interpretation of the measurement problem in quantum physics was reported by Bierman CHEXX[3]. In the latter experiment, auditory evoked potentials (AEPs) of subjects observing (previously unobserved) radioactive decay were recorded. These were compared with AEPs from events that were already observed and thus supposedly already collapsed into a singular state. Significant differences in brain signals of the observer were found. In this chapter we report a further replication that is improved upon the previous experiments by adding a nonquantum event as control. Differential effects of preobservation were expected not to appear in this classical condition since the quantum character of the event is presumed crucial. No differential effects were found in either condition, however. Marginal differences were found between the quantum and classical conditions. Possible explanations for the inability to replicate the previous findings are given as well as suggestions for further research.

Structure of Learning Environments and Individual Differences as Predictors of Learning

The relation between intellectual ability, working method and learning was investigated in two different simulation-based learning environments. By conducting experiments, students had to discover principles of physics theory. A structured condition offered the students guided experimentation and a structured learning sequence. An unstructured condition allowed for unguided discovery learning. Think-aloud protocols of high and low intelligent subjects were analysed on quality of working method: orientation, systematical orderliness, evaluation and elaboration. The results indicated that both intellectual ability and working method are predictors of learning, but that their mutual relation is an intricate one. No learning effects due to structure of learning could be detected.