Reply to William R. Ferrell’s paper “A model for realism of confidence judgments: Implications for underconfidence in sensory discrimination”

Ferrell’s decision-variable partition model and our subjective distance model belong to the same family of Thurstonial models. The subjective distance model is limited to sensory discrimination with the method of constant stimuli and rooted in such notions as discriminal dispersion and sense distance. Ferrell’s model is intended to be wider in scope and to apply to both cognitive and sensory tasks. Both models need supplementary assumptions to predict calibration phenomena. The point of departure for us is the fact that the model predicts under-confidence under “guessing” and the empirical finding that people are about 100% correct when they report “absolutely certain.” Ferrell makes assumptions about cutoffs on the decision variable. The respondent is assumed to adjust or not adjust cutoffs according to “cues to difficulty.” We disagree with Ferrell’s claim that the hard-easy effect is explained by the respondent’s failure to adjust cutoffs sufficiently when there is a change in level of difficulty, and argue that this amounts to little more than a translation of the hard-easy effect into the lingua of Ferrell’s decision-variable partition model. Our argument is that the hard-easy effect is a consequence of the post hoc division of items according to solution probability. In addition, error variance may contribute to regression effects that enlarge the hard-easy effect. Finally, in contrast to Ferrell’s position, we regard inference (cognitive uncertainty) and discrimination (sensory uncertainty) as different psychological processes. An understanding of calibration in these two areas requires separate models.     

Post‐conversion experiences of native British converts to Islam

Research¹ has been carried out on native British converts to Islam. It was based on formal interviews with 70 converts to Islam, 50 males and 20 females. Interviews were done in various parts of England. The sample consïsted of 66 English, 3 Irish, and 1 Welsh. Fifty‐one had been Anglicans, 12 Catholics, 3 Methodists, and 4 Jews. The research was designed to find out the pre‐conversion, conversion, and post‐conversion experiences of the converts interviewed. The present article is part of the research, looking at the converts’ post‐conversion experiences with regard to intellectual, moral, and social changes, changes in beliefs and practices, behaviour, and social relations.     

Towards authentic conversations. Authenticity in the patient-professional relationship

The purpose of this paper is to evaluate the significance of the existential notion of authenticity for medical ethics. This is done by analyzing authenticity and examining its implications for the patient-professional relationship and for ethical decision-making in medical situations. It is argued that while authenticity implies important demand for individual responsibility, which has therapeutic significance, it perpetuates ideas which are antithetical both to authentic interaction between patients and professionals and to fruitful deliberation of moral dilemmas. In order to counteract these consequences, an alternative idea of authenticity is introduced. According to this idea, authenticity is not regarded primarily as individual sovereignty, but as an ability to participate in a dialogue in which the subjectivity of both partners is respected. Such practice, based on mutual trust and responsibility, would enhance common decision-making and overcome the alienation between patients and professionals.     

Sensorimotor synchronization: Motor responses to pseudoregular auditory patterns

Musically trained and untrained subjects (N=30) were asked to synchronize their finger tapping with stimuli in auditory patterns. Each pattern comprised six successive tonal stimuli of the same duration, the first of which was accented by a different frequency. The duration of interstimulus onset intervals (ISIs) gradually increased or decreased in constant steps toward the end of the patterns. Four values of such steps were used in different trials: 20, 30, 45, and 60 msec. Various time-control mechanisms are hypothesized as being simultaneously responsible for subjects’ incorrect reproduction of the internal temporal ratios of the stimulus patterns. The mechanism of assimilation (of a central tendency) led subjects to enforce a regular (isochronous) structure on the patterns. The influence of other time-control mechanisms (distinction, subjective expression of an accent, sequential transfer) was expressed mainly in differences between intertap onset intervals (ITIs) and the corresponding ISIs at the beginning of the patterns. The duration of the first two ITIs was in the majority of the trials in an inverse ratio to the ratio of the respective ISIs. The distortions resulting from the timing mechanisms concerned were more pronounced in the performance of nonmusicians than in that of musicians.     

On the scaling of visual space from motion—in response to Pizlo and Salacfa-Golyska

Pizlo and Salack-Golyska (1994) have raised an important question about the validity of the interpretation of experiments reported by Lappin and Love (1992)—based on the fact that alternative cues in the image plane might have supported the shape discriminations in those experiments. The meaning of the hypothesis that visual space may be scaled by congruence under motion is clarified, pertinent evidence is reviewed, and new experimental evidence is reported We conclude that visual space can be metrically scaled by congruence of moving shapes.     

Classical geometric illusion effects with nonclassical stimuli: Angular induction from decomposing lines into point arrays

Angular induction is the process by which one line segment can bias judgment of orientation and/or collinearity of another segment, and it has been established that the magnitude of error is a determinate function of the relative angle between the two. We examined how these known relationships are affected by decomposing the induction segment into an array of scattered points. The bias that was produced by such arrays was found to be consistent with a formal model of angular induction, with the strength of the effect decreasing as the scatter among the points was increased. This decline in strength was almost linear with a logarithmic transform of the dimensions of the stimulus array. We also evaluated the hypothesis that the induction stimulus is detected by one or more channels—for example, neurons—for which the sensitivity profiles are modeled as Gabor wavelets. The change in induction strength with increasing point scatter was not predicted by a single width of channel. However, the combined activity of an ensemble of channels that differed in width did match the perceptual effects if one also stipulated that each channel would respond maximally to a fine-line stimulus.     

Detachment and defeasibility in deontic logic

The purpose of the paper is to present a logical framework that allow to formalize a kind of prima facie duties, defeasible conditional duties, indefeasible conditional duties and actual (indefeasible) duties, as well as to show their logical interconnections.     

Developing the matrix representation grid (MRG): A method for observing group processes. Findings from time-limited group psychotherapy for alcohol-dependent patients

The MRG was published 1988 in order to support developments in group psychotherapy methods as one of the all too few process observation research methods for studying group-as-a-whole. After 9 years of what pilot studies have labeled successful clinical trials, this study aims at validating the MRG against the established SAVI: Structural Analysis of Verbal Interaction (Agazarian & Simon 1989). Videotaped group sessions from short-term groups for alcohol dependent patients conducted along two therapy methods, one behaviorally oriented and the other group analytic, are used as material. The MRG is validated in the study, confirmed to be clinically valuable, and some interesting comparisons between the two treatment modalities are also made.     

An injection olfactometer for humans and a new method for the measurement of the shape of the olfactory pulse

An injection olfactometer for human psychophysical experiments is described. The olfactometer is capable of presenting, either mono- or birhinally, single odorants and binary mixtures. The pulse form of the olfactory stimulus at the exit of the olfactometer approaches a rectangular form, which makes the olfactometer well suited for olfactory reaction time measurements. Since stimulation periods are independent of the subject’s inhalation, time-intensity measurements over prolonged periods of time are possible as well. In the second part of this paper, a new technique is described for the measurement of the stimulus pulse form at the exit of the olfactometer.