The positional-specificity effect reveals a passive-trace contribution to visual short-term memory.

The positional-specificity effect refers to enhanced performance in visual short-term memory (VSTM) when the recognition probe is presented at the same location as had been the sample, even though location is irrelevant to the match/nonmatch decision. We investigated the mechanisms underlying this effect with behavioral and fMRI studies of object change-detection performance. To test whether the positional-specificity effect is a direct consequence of active storage in VSTM, we varied memory load, reasoning that it should be observed for all objects presented in a sub-span array of items. The results, however, indicated that although robust with a memory load of 1, the positional-specificity effect was restricted to the second of two sequentially presented sample stimuli in a load-of-2 experiment. An additional behavioral experiment showed that this disruption wasn't due to the increased load per se, because actively processing a second object--in the absence of a storage requirement--also eliminated the effect. These behavioral findings suggest that, during tests of object memory, position-related information is not actively stored in VSTM, but may be retained in a passive tag that marks the most recent site of selection. The fMRI data were consistent with this interpretation, failing to find location-specific bias in sustained delay-period activity, but revealing an enhanced response to recognition probes that matched the location of that trial's sample stimulus

Bayesian stochastic blockmodeling

This chapter provides a self-contained introduction to the use of Bayesian inference to extract large-scale modular structures from network data, based on the stochastic blockmodel (SBM), as well as its degree-corrected and overlapping generalizations. We focus on nonparametric formulations that allow their inference in a manner that prevents overfitting, and enables model selection. We discuss aspects of the choice of priors, in particular how to avoid underfitting via increased Bayesian hierarchies, and we contrast the task of sampling network partitions from the posterior distribution with finding the single point estimate that maximizes it, while describing efficient algorithms to perform either one. We also show how inferring the SBM can be used to predict missing and spurious links, and shed light on the fundamental limitations of the detectability of modular structures in networks.Comment: 44 pages, 16 figures. Code is freely available as part of graph-tool at https://graph-tool.skewed.de . See also the HOWTO at https://graph-tool.skewed.de/static/doc/demos/inference/inference.htm

Steady-state responses to concurrent melodies: source distribution, top-down, and bottom-up attention

Humans can direct attentional resources to a single sound occurring simultaneously among others to extract the most behaviourally relevant information present. To investigate this cognitive phenomenon in a precise manner, we used frequency-tagging to separate neural auditory steady-state responses (ASSRs) that can be traced back to each auditory stimulus, from the neural mix elicited by multiple simultaneous sounds. Using a mixture of 2 frequency-tagged melody streams, we instructed participants to selectively attend to one stream or the other while following the development of the pitch contour. Bottom-up attention towards either stream was also manipulated with salient changes in pitch. Distributed source analyses of magnetoencephalography measurements showed that the effect of ASSR enhancement from top-down driven attention was strongest at the left frontal cortex, while that of bottom-up driven attention was dominant at the right temporal cortex. Furthermore, the degree of ASSR suppression from simultaneous stimuli varied across cortical lobes and hemisphere. The ASSR source distribution changes from temporal-dominance during single-stream perception, to proportionally more activity in the frontal and centro-parietal cortical regions when listening to simultaneous streams. These findings are a step forward to studying cognition in more complex and naturalistic soundscapes using frequency-tagging

Discovering the Harmony of Reason and Faith in the Symphony of Eternal Creation

Tensions between the domain of reason and the domain of faith have been one of the most controversial issues in the history of our civilization for over three hundred years. They have contributed to many divisions, conflicts, and even wars. Contributions that have sought to reconcile the two domains have largely used the cultural approach in trying to solve this problem. The approach used in this essay views faith and reason from the perspective of cognitive operations. It shows that viewed from this perspective, faith and reason emerge as two aspects of the process of creation of new levels of organization that takes place in the human mind. The essay correlates faith and reason with such cognitive operations as equilibration and the production of disequilibrium. This approach shows that there is no fundamental ontological contradiction between faith and reason, and that cooperation between them is not only possible but is actually essential for sustaining our mental work and the survival of our civilization

Discovering the Harmony of Reason and Faith in the Symphony of Eternal Creation

Tensions between the domain of reason and the domain of faith have been one of the most controversial issues in the history of our civilization for over three hundred years. They have contributed to many divisions, conflicts, and even wars. Contributions that have sought to reconcile the two domains have largely used the cultural approach in trying to solve this problem. The approach used in this essay views faith and reason from the perspective of cognitive operations. It shows that viewed from this perspective, faith and reason emerge as two aspects of the process of creation of new levels of organization that takes place in the human mind. The essay correlates faith and reason with such cognitive operations as equilibration and the production of disequilibrium. This approach shows that there is no fundamental ontological contradiction between faith and reason, and that cooperation between them is not only possible but is actually essential for sustaining our mental work and the survival of our civilization