Subjective estimates of total processing time in dual-tasking: (some) good news for bad introspection

Previous studies have shown severe distortions of introspection about dual-task interference in the Psychological Refractory Period (PRP) paradigm. The present study investigated participants’ ability to introspect about the total trial time in this paradigm, as this temporal information may arguably be more relevant for strategic task scheduling than subjective estimates of each task within the dual task. To this end, participants provided estimates of their reaction times (IRTs) for the two subtasks in one half of the experiment, and estimates of the total trial time (ITTs) in the other half of the experiment. Although the IRT results showed the typical unawareness of the PRP effect, ITTs reflected the effects of SOA and Task 2 difficulty on objective total trial time. Additional analyses showed that IRTs were influenced by the introspective task order; that is, the ITT pattern carried over to IRTs when IRTs were assessed in the second half of the experiment. Overall, the present results show that people are able to accurately introspect about total trial time in the PRP paradigm and thus provide some good news for bad introspection in the PRP paradigm

The Cognitive Representation of Time and Duration

How do people represent the duration of an event in memory and which mechanisms except timing are involved in processing and maintaining temporal information within the cognitive system? The speakers of this symposium will address this and related questions. Anne-Claire Rattat focuses on long-term retention of durations in children and adults. Ruth Ogden discusses executive functions that are involved in timing and time perception. Hedderik van Rijn and Niels Taagten show how general principles of memory and attention can be connected with theories about time perception. Finally, Daniel Bratzke reviews prominent ideas about how temporal information is coded within and across sensory modalities. The titles and abstracts of the four talks are given below

Automatic Segmentation of Human Cortical Layer-Complexes and Architectural Areas Using Ex vivo Diffusion MRI and Its Validation

Recently, several magnetic resonance imaging contrast mechanisms have been shown to distinguish cortical substructure corresponding to selected cortical layers. Here, we investigate cortical layer and area differentiation by automatized unsupervised clustering of high-resolution diffusion MRI data. Several groups of adjacent layers could be distinguished in human primary motor and premotor cortex. We then used the signature of diffusion MRI signals along cortical depth as a criterion to detect area boundaries and find borders at which the signature changes abruptly. We validate our clustering results by histological analysis of the same tissue. These results confirm earlier studies which show that diffusion MRI can probe layer-specific intracortical fiber organization and, moreover, suggests that it contains enough information to automatically classify architecturally distinct cortical areas. We discuss the strengths and weaknesses of the automatic clustering approach and its appeal for MR-based cortical histology