Social influence on predictions of simulated stock prices

Herding in financial markets refers to that investors are influenced by others. This study addresses the importance of consistency for herding. It is suggested that, in financial markets perceptions of consistency are based on repeated observations over time. Consistency may then be perceived as the agreement across time between investors' predictions. In addition, consistency may be related to variance over time in each investor's predictions. In an experiment using a Multiple Cue Probability Learning paradigm, 96 undergraduates made multi‐trial predictions of future stock prices given information about the current price and the predictions made by five fictitious others. Consistency was varied between the others' predictions (correlation) and within the others' predictions (variance). The results showed that the predictions were significantly influenced by the others' predictions when these were correlated. No effect of variance was observed. Hence, participants were influenced by the others when they were in agreement, regardless of whether they varied their predictions over trials or not. Copyright © 2008 John Wiley & Sons, Ltd.     

Heart-Rate responses (HRR) to lateralized visual stimuli

Direction of changes in heart-rate responses (HRR) were investigated in three separate experiments as a measure of differential cognitive and emotional specialization of the cerebral hemispheres. Visual stimuli were presented via the visual half-field technique in all three experiments. Slides with different contents were flashed for 200 msec on each trial either to the left or right of a center LED fixation point. The LED went on 5 seconds prior to slide onset. HR changes were scored as second-by-second deviations during 10 seconds after LED onset from pre-LED base line. In the first experiment it was hypothesized that emotionally relevant stimuli initially projected to only the right hemisphere would result in more anticipatory acceleration than when the same stimulus was initially projected to the left hemisphere. A picture of a snake and of a geometric figure were repeatedly briefly flashed to the right of the LED for half of the subjects, and to the left for the other half. There were 25 trials with an intertriai interval of 25–40 seconds. Results showed significant effects of deceleration as a function of the slide stimulus in all groups on seconds 5, 6, or 7 after onset of the center LED. Furthermore, an anticipatory acceleration was observed during the first trial-block on seconds 3 and 4 in the right hemisphere groups only with no differences between the neutral and emotional stimuli. In Experiments 2 and 3, a letter-string of six letters and a complex symmetric pattern were used as stimuli. These stimuli were chosen because previous research has clearly implicated the hemispheres to be differentially specialized in their ability to process verbal and visuo-spatial stimuli. The set-up was identical to Experiment 1, with the exception that differences in response to the two types of stimuli were evaluated on a within-subjects basis. The results from Experiments 2 and 3 showed stimulus-related deceleration, peaking on seconds 5–7 in all groups and an anticipatory acceleration peaking on seconds 3 and 4 in the right hemisphere groups, with decelerations during the corresponding seconds in the left hemisphere groups. The results are discussed in relation to recent findings by Walker and Sandman (1982) about the possibility of hemispheric specialization in psychologic influences on heart rate changes in response to environmental demands.     

Phonological representation and speech understanding with cochlear implants in deafened adults

In the present study cognitive performance in 15 deafened adult cochlear implant candidates was examined and related to level of speech understanding after 12 months of experience with the implant. The implant group performed on par with normal hearing controls in all cognitive tasks used in the study with one exception: Performance was significantly lower in cognitive tasks where use of a phonological representation of sound is a key task-demand. Observations of the implanted individuals’ level of speech understanding indicate that only those individuals who, pre-operatively, were in possession of phonological representations comparable to that of normal hearing could follow and understand a speaker that was out of sight. The results are discussed with respect to (a) deterioration in the phonological representation of sounds as a function of absence of external auditory stimulation, and (b) the role of cognitive factors in predicting success in speech understanding with the implant.     

Toward a dialectic theory of concepts

The article spells out some guidelines for a dialectic theory of concepts. Concept formation is treated in terms of polemic and polar reference. The main thesis is that opposite references structure concepts by way of advocacy. On polar dimensions of comparison, (e. g., light versus dark), people select and advocate objects of comparison in agreement with the context of comparison (i.e., what is light depends on what is dark, and vice versa). In principle, any concept is subject to polemics because polarity enables opposite comparisons, (e.g., an object as dark and light with reference to lighter and darker objects, respectively). When opposite comparisons apply to the same object, reference becomes anomalous which will motivate conceptual change, (e.g., twilight accounts for a reference in between). Consequently, meaning is not secured by general rules but concepts presuppose advocated references; concepts are intentional constructs. The dialectic theory is illustrated by a case study of the environmental discourse on forest management. Conflicting references fuelled by industrial and environmental values demonstrate how opposite comparisons motivate revisions.Dialectic is a convenient technical name for the kind of thinking which takes place when human beings enter into dispute, or when they carry on in reflection the polemical consideration of some theory or idea. Adler, 1927, p. V     

CHANGE IN AFTERIMAGE AND SPIRAL AFTEREFFECT SERIALS DUE TO ANXIETY CAUSED BY SUBLIMINAL THREAT

Experiments with projected negative afterimages and with the aftereffects of a rotating spiral were performed serially (repeated stimulus presentation). In the middle of the sequences the experimental groups were subjected to subliminal threat by means of a metacontrast technique. The effects of threat on the latter part of the sequences were according to predictions and differed markedly from the results in control groups.     

Retrospective Frequency Formats Promote Consistent Experience‐Based Bayesian Judgments

On the basis of their experiences with pregnant patients in their practice, obstetrician/gynecologists estimated the posterior probability of Down syndrome given a positive screening result. They also estimated the base rate of Down syndrome in their practice, along with the hit and false alarm rates for the screening test; for each subject, these numbers were combined to calculate a posterior probability to which the initial estimated posterior probability could be compared. Physicians gave highly consistent estimates when asked to think about their past experiences in terms of event frequencies. However, those told to respond using single event probabilities or to use past experiences to predict prospective frequencies gave inconsistent Bayesian estimates. Thus, when making Bayesian judgments based on real life experience, natural frequency formats only lead to better judgments, compared with single event probability formats, if people think retrospectively, not when using past experiences to make prospective predictions. Copyright © 2011 John Wiley & Sons, Ltd.