Functional imaging of the semantic system: retrieval of sensory-experienced and verbally learned knowledge

This paper considers how functional neuro-imaging can be used to investigate the organization of the semantic system and the limitations associated with this technique. The majority of the functional imaging studies of the semantic system have looked for divisions by varying stimulus category. These studies have led to divergent results and no clear anatomical hypotheses have emerged to account for the dissociations seen in behavioral studies. Only a few functional imaging studies have used task as a variable to differentiate the neural correlates of semantic features more directly. We extend these findings by presenting a new study that contrasts tasks that differentially weight sensory (color and taste) and verbally learned (origin) semantic features. Irrespective of the type of semantic feature retrieved, a common semantic system was activated as demonstrated in many previous studies. In addition, the retrieval of verbally learned, but not sensory-experienced, features enhanced activation in medial and lateral posterior parietal areas. We attribute these "verbally learned" effects to differences in retrieval strategy and conclude that evidence for segregation of semantic features at an anatomical level remains weak. We believe that functional imaging has the potential to increase our understanding of the neuronal infrastructure that sustains semantic processing but progress may require multiple experiments until a consistent explanatory framework emerges.     

Causality, criticality, and reading words: distinct sources of fractal scaling in behavioral sequences

The finding of fractal scaling (FS) in behavioral sequences has raised a debate on whether FS is a pervasive property of the cognitive system or is the result of specific processes. Inferences about the origins of properties in time sequences are causal. That is, as opposed to correlational inferences reflecting instantaneous symmetrical relations, causal inferences concern asymmetric relations lagged in time. Here, I integrate Granger-causality with inferences about FS. Four simulations illustrate that causal analyses can isolate distinct FS sources, whereas correlational techniques cannot. I then analyze three simultaneous sequences of responses from a database of word-naming trials. I find that two, or perhaps three, distinct sources account for the presence of FS in these sequences, but FS is not a general property of the system. This suggests that FS arises due to the properties of a limited number of identifiable psychological and/or neural processes. Finally, I reanalyze a previously published dataset of acoustic frequency spectra using the new tools. The causality/criticality combination introduced here offers a new important perspective in the study of cognition.     

Mood acknowledgment and correction for the mood-congruency bias in social judgment

Past research has revealed a mood-congruency bias wherein people evaluate other individuals more positively when they are experiencing good moods than when they are experiencing bad moods. At times, however, people may attempt to prevent their transient mood states from biasing their evaluations of other people. It was proposed that the capacity to attend openly to one’s moods is an important precursor to such mood correction efforts. Two studies supported this hypothesis. People who were encouraged to attend to their feelings (Study 1), as well as people who are naturally inclined to acknowledge their feelings (Study 2), were more likely than their counterparts to prevent their positive and negative moods from biasing their judgments of a target person.     

A Community’s Response to Suicide Through Public Art: Stakeholder Perspectives from the Finding the Light Within Project

Suicide is a preventable public health problem and a leading cause of death in the United States. Despite recognized need for community-based strategies for suicide prevention, most suicide prevention programs focus on individual-level change. This article presents seven first person accounts of Finding the Light Within, a community mobilization initiative to reduce the stigma associated with suicide through public arts participation that took place in Philadelphia, Pennsylvania from 2011 through 2012. The stigma associated with suicide is a major challenge to suicide prevention, erecting social barriers to effective prevention and treatment and enhancing risk factors for people struggling with suicidal ideation and recovery after losing a loved one to suicide. This project engaged a large and diverse audience and built a new community around suicide prevention through participatory public art, including community design and production of a large public mural about suicide, storytelling and art workshops, and a storytelling website. We present this project as a model for how arts participation can address suicide on multiple fronts—from raising awareness and reducing stigma, to promoting community recovery, to providing healing for people and communities in need.