Posture based motor planning in a sequential grasping task

Movement planning in sequential tasks is revealed by grasping postures. We explored aspects of planning a sequential drawer opening and object manipulation task with regard to arm and torso postures. We conducted a detailed kinematic analysis of joint postures at the wrist, elbow, and shoulder for a one-grasp and a two-grasp sequence of movement. The second of the two-grasp sequence was constrained (uncomfortable). We predicted that planning for the second grasp in a two-grasp sequence would influence arm, torso, and whole-body postures at the first grasp. Participants prepared for the second grasp by adjusting the posture of the elbow and shoulder and the distance they stepped to the drawer. The joint postures at the elbow and shoulder changed in the direction of the intended object grasp. These findings show that anticipatory adjustments are revealed at postures other than the end-effector and lend insight into the mechanisms of sequential movement planning.     

Intentional suppression of unwanted memories grows more difficult as we age

People often encounter reminders to memories that they would prefer not to think about. When this happens, they often try to exclude the unwanted memory from awareness, a process that relies upon inhibitory control. We propose that the ability to regulate awareness of unwanted memories through inhibition declines with advancing age. In two experiments, we examined younger and older adults' ability to intentionally suppress retrieval when repeatedly confronted with reminders to an experience they were instructed to not think about. Older adults exhibited significantly less forgetting of the suppressed items compared to younger adults on a later independent probe test of recall, indicating that older adults failed to inhibit the to-be-avoided memories. These findings demonstrate that the ability to intentionally regulate conscious awareness of unwanted memories through inhibitory control declines with age, highlighting differences in memory control that may be of clinical relevance in the aftermath of unpleasant life events.     

Reevaluation of Piaget’s concept of egocentrism: New perspectives on a misunderstood idea

The paper states the goal of this special issue and briefly summarizes the topics of the papers addressed in this issue.     

Compatibility between tones, head movements, and facial expressions

The study tests the hypothesis of an embodied associative triangle among relative tone pitch (i.e., high or low tones), vertical movement, and facial emotion. In particular, it is tested whether relative pitch automatically activates facial expressions of happiness and anger as well as vertical head movements. Results show robust congruency effects: happiness expressions and upward head tilts are imitated faster when paired with high rather than low tones, while anger expressions and downward head tilts are imitated faster when paired with low rather than high tones. The results add to the growing evidence favoring an embodiment account that emphasizes multimodal representations as the basis of cognition, emotion, and action.     

Signal detection and threshold models of source memory

Recently, several authors claimed that the curvilinear shape of rating-based source memory receiver operating characteristics (ROCs) refutes threshold models. However, rating-based ROCs are not diagnostic to disprove threshold models. Furthermore, source memory ROC-analyses ignore influences of other processes like old-new-detection and old-new-response-tendencies, so direct estimation of parameters is preferable. Five source monitoring experiments with different response bias manipulations and materials were conducted. We fitted the Two High Threshold Multinomial Model of Source Monitoring by Bayen, Murnane, and Erdfelder (1996) and the Multivariate Signal Detection Model for Selection DeCarlo (2003). We also included rating-based ROCs. The results suggest that both models are at least equally valid as measurement tools which capture bias processes in the corresponding parameters, and they can perhaps be integrated theoretically.     

Sensitivity to initial values in full non‐parametric maximum‐likelihood estimation of the two‐parameter logistic model

Parameters of the two‐parameter logistic model are generally estimated via the expectation–maximization (EM) algorithm by the maximum‐likelihood (ML) method. In so doing, it is beneficial to estimate the common prior distribution of the latent ability from data. Full non‐parametric ML (FNPML) estimation allows estimation of the latent distribution with maximum flexibility, as the distribution is modelled non‐parametrically on a number of (freely moving) support points. It is generally assumed that EM estimation of the two‐parameter logistic model is not influenced by initial values, but studies on this topic are unavailable. Therefore, the present study investigates the sensitivity to initial values in FNPML estimation. In contrast to the common assumption, initial values are found to have notable influence: for a standard convergence criterion, item discrimination and difficulty parameter estimates as well as item characteristic curve (ICC) recovery were influenced by initial values. For more stringent criteria, item parameter estimates were mainly influenced by the initial latent distribution, whilst ICC recovery was unaffected. The reason for this might be a flat surface of the log‐likelihood function, which would necessitate setting a sufficiently tight convergence criterion for accurate recovery of item parameters.     

Disentangling the adult attention-deficit hyperactivity disorder endophenotype: parametric measurement of attention

Attention deficit hyperactivity disorder (ADHD) persists frequently into adulthood. The decomposition of endophenotypes by means of experimental neuro-cognitive assessment has the potential to improve diagnostic assessment, evaluation of treatment response, and disentanglement of genetic and environmental influences. We assessed four parameters of attentional capacity and selectivity derived from simple psychophysical tasks (verbal report of briefly presented letter displays) and based on a "theory of visual attention." These parameters are mathematically independent, quantitative measures, and previous studies have shown that they are highly sensitive for subtle attention deficits. Potential reductions of attentional capacity, that is, of perceptual processing speed and working memory storage capacity, were assessed with a whole report paradigm. Furthermore, possible pathologies of attentional selectivity, that is, selection of task-relevant information and bias in the spatial distribution of attention, were measured with a partial report paradigm. A group of 30 unmedicated adult ADHD patients and a group of 30 demographically matched healthy controls were tested. ADHD patients showed significant reductions of working memory storage capacity of a moderate to large effect size. Perceptual processing speed, task-based, and spatial selection were unaffected. The results imply a working memory deficit as an important source of behavioral impairments. The theory of visual attention parameter working memory storage capacity might constitute a quantifiable and testable endophenotype of ADHD.     

Achievement incentives determine the effects of achievement-motive incongruence on flow experience

Previous research has shown that incongruence between implicit and explicit achievement motives impairs flow experience. We examined this relationship in a more differentiated manner by arguing that achievement-motive incongruence only exerts negative effects when individuals act in situations in which achievement incentives are present and arouse conflict between the two motives. In non-achievement situations, no negative effects of achievement-motive incongruence on flow experience are expected. Study 1 and Study 2 showed that participants with incongruent implicit and explicit achievement motives reported less flow in achievement- as compared to non-achievement-oriented sport situations. In Study 3, we experimentally manipulated achievement and non-achievement situations. Again, motive incongruence impaired the experience of flow in achievement but not in non-achievement situations.     

Predicting academic success with the Big 5 rated from different points of view: Self‐rated,other rated and faked

Self‐ratings of personality predict academic success above general intelligence. The present study replicated these findings and investigated the increment of other‐ratings or intentionally distorted self‐ratings. Participants (N = 145) had to compile a personality questionnaire twice. First they were given neutral instructions. The second time they were asked to imagine a specific applicant setting. Furthermore, two peers rated each participant. Additionally, verbal, numerical and figural reasoning scores were obtained. Grades on a statistics exam obtained 2 months later served as the criterion. Results replicated prior findings and showed incremental validity for self‐ and other‐rated personality, which was stable after controlling for intelligence. Faking had no impact on the domain‐score level, but results on the facet‐score level were less encouraging. Copyright © 2010 John Wiley & Sons, Ltd.