Adaptive threshold estimation with unforced-choice tasks

This paper evaluates an adaptive staircase procedure for threshold estimation that is suitable for unforced-choice tasks—ones with the additional response alternativedon’t know. Within the framework of a theory of indecision, evidence is developed that fluctuations of the response criterion are much less detrimental to unforced-choice tasks than to yes/no tasks. An adaptive staircase procedure for unforced-choice tasks is presented. Computer simulations show a slight gain in efficiency ifdon’t know responses are allowed, even if response criteria vary. A behavioral comparison with forcedchoice and yes/no procedures shows that the new procedure outdoes the other two with respect to reliability. This is especially true for naive participants. For well-trained participants it is also slightly more efficient than the forced-choice procedure, and it produces a smaller systematic error than the yes/no procedure. Moreover, informal observations suggest that participants are more comfortable with unforced tasks than with forced ones.     

Slope bias of psychometric functions derived from adaptive data

Several investigators have fit psychometric functions to data from adaptive procedures for threshold estimation. Although the threshold estimates are in general quite correct, one encounters a slope bias that has not been explained up to now. The present paper demonstrates slope bias for parametric and nonparametric maximum-likelihood fits and for Spearman-Kärber analysis of adaptive data. The examples include staircase and stochastic approximation procedures. The paper then presents an explanation of slope bias based on serial data dependency in adaptive procedures. Data dependency is first illustrated with simple two-trial examples and then extended to realistic adaptive procedures. Finally, the paper presents an adaptive staircase procedure designed to measure threshold and slope directly. In contrast to classical adaptive threshold-only procedures, this procedure varies both a threshold and a spread parameter in response to double trials.     

Five-factor model of personality and organizational commitment: The mediating role of positive and negative affective states

Using a one-year longitudinal study of four components of organizational commitment (affective, normative, continuance–sacrifices, and continuance–alternatives) on a sample of employees from multiple organizations (N = 220), we examined the relationships of employee Big-Five personality traits to employee commitment components, and the mediating role of positive and negative affective states. Personality was measured at Time 1 while affective states and commitment components were measured at Time 2, while controlling for Time 1 commitment. Extraversion and agreeableness were positively related to affective, normative, and continuance–sacrifices commitments via enhanced positive affect. Agreeableness was also positively linked to affective commitment and negatively associated with continuance–alternatives commitment through reduced negative affect. Finally, neuroticism was negatively linked to affective commitment, and positively related to continuance–alternatives commitment, through increased negative affect. The implications of these findings for our understanding of personality–commitment linkages are discussed.     

Relationship maintenance and biases on the line bisection task: Attractive alternatives,asymmetrical cortical activity,and approach–avoidance motivation

People in long-term romantic relationships possess relationship maintenance mechanisms designed to protect against the temptation of desirable relationship alternatives. The current research examined the link between relationship maintenance mechanisms and an index of neurologically based approach/avoidance motivation. Participants completed a line bisection task that yields measures of asymmetric activity in the right and left frontal cortices; such activity is thought to reflect people's level of approach/avoidance motivation. Compared to single participants, participants in committed relationships displayed relatively less left visual field bias on the line bisection task (indicative of greater left frontal cortical activation and greater cognitive avoidance motivation) in response to available, attractive opposite-sex targets. Decreased left visual field bias was particularly pronounced among individuals with moderate levels of relationship commitment — those expected to display the highest levels of relationship maintenance. These findings provide insight into perceptual, motivational, and neurological processes that may help people avoid tempting relationship alternatives.