Vague Expectation Value Loss

Vague subjective probability may be modeled by means of a set of probability functions, so that the represented opinion has only a lower and upper bound. The standard rule of conditionalization can be straightforwardly adapted to this. But this combination has difficulties which, though well known in the technical literature, have not been given sufficient attention in probabilist or Bayesian epistemology. Specifically, updating on apparently irrelevant bits of news can be destructive of one’s explicitly prior expectations. Stability of vague subjective opinion appears to need a more complex model.     

Measuring implementation intentions in the context of the theory of planned behavior

The usefulness of measuring implementation intentions in the context of the theory of planned behavior (TPB) was explored among 112 Norwegian college students. They responded to a questionnaire measuring past behavior, perceived behavioral control, behavioral intentions, implementation intentions, and actual performance of regular exercising and recycling of drinking cartons. Implementation intentions were measured using five items relating to recycling and four items relating to exercise, which showed satisfactory internal consistencies. Consistent with the main prediction, the presence of implementation intentions was related to performing the two behaviors, although behavioral intentions were the strongest determinant for both behaviors. The results suggest that the TPB may benefit from inclusion of the concept of implementation intentions to provide a more complete understanding of the psychological process in which motivation is translated into action.     

Determining the bias and variance of a deterministic finger-tracking algorithm

Finger tracking has the potential to expand haptic research and applications, as eye tracking has done in vision research. In research applications, it is desirable to know the bias and variance associated with a finger-tracking method. However, assessing the bias and variance of a deterministic method is not straightforward. Multiple measurements of the same finger position data will not produce different results, implying zero variance. Here, we present a method of assessing deterministic finger-tracking variance and bias through comparison to a non-deterministic measure. A proof-of-concept is presented using a video-based finger-tracking algorithm developed for the specific purpose of tracking participant fingers during a psychological research study. The algorithm uses ridge detection on videos of the participant’s hand, and estimates the location of the right index fingertip. The algorithm was evaluated using data from four participants, who explored tactile maps using only their right index finger and all right-hand fingers. The algorithm identified the index fingertip in 99.78 % of one-finger video frames and 97.55 % of five-finger video frames. Although the algorithm produced slightly biased and more dispersed estimates relative to a human coder, these differences (x=0.08 cm, y=0.04 cm) and standard deviations (σ_x=0.16 cm, σ_y=0.21 cm) were small compared to the size of a fingertip (1.5–2.0 cm). Some example finger-tracking results are provided where corrections are made using the bias and variance estimates.     

Accessibility of affective versus cognitive components of attitudes

Four studies investigated differences in accessibility of affective and cognitive components of attitudes. Accessibility was measured by response times on bipolar semantic differential evaluative adjectives (e.g. ‘positive–negative’) in response to how one felt and thought, respectively, about an attitude object. The evaluative items were accompanied by affective and cognitive context items, which were not analysed, but were meant to promote the retrieval of affective and cognitive evaluations respectively. Responses to affective evaluations were given faster than responses to cognitive evaluations, suggesting that affect-based evaluations are more accessible in memory than cognition-based evaluations. The results were obtained in two attitude domains, i.e. brand names and countries. The results support the validity of a two-component affect–cognition model of attitude. © 1998 John Wiley & Sons, Ltd.     

On measurement properties of continuation ratio models

Three classes of polytomous IRT models are distinguished. These classes are the adjacent category models, the cumulative probability models, and the continuation ratio models. So far, the latter class has received relatively little attention. The class of continuation ratio models includes logistic models, such as the sequential model (Tutz, 1990), and nonlogistic models, such as the acceleration model (Samejima, 1995) and the nonparametric sequential model (Hemker, 1996). Four measurement properties are discussed. These are monotone likelihood ratio of the total score, stochastic ordering of the latent trait by the total score, stochastic ordering of the total score by the latent trait, and invariant item ordering. These properties have been investigated previously for the adjacent category models and the cumulative probability models, and for the continuation ratio models this is done here. It is shown that stochastic ordering of the total score by the latent trait is implied by all continuation ratio models, while monotone likelihood ratio of the total score and stochastic ordering on the latent trait by the total score are not implied by any of the continuation ratio models. Only the sequential rating scale model implies the property of invariant item ordering. Also, we present a Venn-diagram showing the relationships between all known polytomous IRT models from all three classes.     

Constructive Empiricism Now

Philosophical Studies -     

Antecedents of self identity and consequences for action control: An application of the theory of planned behaviour in the exercise domain

ObjectivesTo study whether exercise action control profiles should be usefully extended to include exercise identity. Further, this study investigated theory of planned behaviour antecedents of exercise identity.DesignProspective data from 413 undergraduate students (M age = 21.4; 73.5% females).MethodValidated questionnaires were used at baseline and follow-up two weeks later to assess exercise behaviour, intention, self-identity, and theory of planned behaviour concepts. Research questions were analysed using chi-square analysis, discriminant function analysis and structural equation modelling. Results were interpreted using p-values and effect sizes.ResultsThere was a higher proportion of exercise intenders in the strong exercise identity group than in the weak exercise identity group (81.9% vs. 14.5%) and a higher proportion of successful intenders in the high exercise identity group than in the low exercise identity group (45.5% vs. 18.2%). Affective attitude and perceived behavioural control (PBC) were the most important predictors of exercise action control. Regarding the antecedents of identity, results showed significant and small-sized associations for baseline affective attitude and perceived behavioural control and large-sized association for baseline self-identity.ConclusionExercise identity should be usefully employed to understand exercise motivation and action control. Affective attitude and perceived behavioural control facilitate action control and exercise identity development and are suggested to be taken into account when developing exercise interventions.