Genetic studies of stuttering in a founder population

Genome-wide linkage and association analyses were conducted to identify genetic determinants of stuttering in a founder population in which 48 individuals affected with stuttering are connected in a single 232-person genealogy. A novel approach was devised to account for all necessary relationships to enable multipoint linkage analysis. Regions with nominal evidence for linkage were found on chromosomes 3 (P=0.013, 208.8 centiMorgans (cM)), 13 (P=0.012, 52.6 cM), and 15 (P=0.02, 100 cM). Regions with nominal evidence for association with stuttering that overlapped with a linkage signal are located on chromosomes 3 (P=0.0047, 195 cM), 9 (P=0.0067, 46.5 cM), and 13 (P=0.0055, 52.6 cM). We also conducted the first meta-analysis for stuttering using results from linkage studies in the Hutterites and The Illinois International Genetics of Stuttering Project and identified regions with nominal evidence for linkage on chromosomes 2 (P=0.013, 180-195 cM) and 5 (P=0.0051, 105-120 cM; P=0.015, 120-135 cM). None of the linkage signals detected in the Hutterite sample alone, or in the meta-analysis, meet genome-wide criteria for significance, although some of the stronger signals overlap linkage mapping signals previously reported for other speech and language disorders. EDUCATIONAL OBJECTIVES: After reading this article, the reader will be able to: (1) summarize information about the background of common disorders and methodology of genetic studies; (2) evaluate the role of genetics in stuttering; (3) discuss the value of using founder populations in genetic studies; (4) articulate the importance of combining several studies in a meta-analysis; (5) discuss the overlap of genetic signals identified in stuttering with other speech and language disorders.     

Adaptation and communicative design.

Two theoretical frameworks that examine the nature of adaptability and mutual influence in interaction, interpersonal deception theory and interaction adaptation theory, were used to derive hypotheses concerning patterns of interaction that occur across time in truthful and deceptive conversations. Two studies were conducted in which senders were either truthful or deceptive in their interactions with a partner who increased or decreased involvement during the latter half of the conversation. Results revealed that deceivers felt more anxious and were more concerned about self‐presentation than truthtellers prior to the interaction and displayed less initial involvement than truthtellers. Patterns of interaction were also moderated by deception. Deceivers increased involvement over time but also reciprocated increases or decreases in receiver involvement. However, deceivers were less responsive than truthtellers to changes in receiver behavior. Finally, partner involvement served as feedback to senders regarding their own performance.     

The impact of violations on uncertainty and the consequences for attractiveness

This investigation aimed at extending past research on expectation violations by arguing that violations vary both in valance and in their influence on uncertainty and that the combination of valence and uncertainty states conjointly influences judgments of a violator's social attractiveness. In explaining the predicted variance in uncertainty following violations, a distinction is proposed between congruent violations (i.e., behaviors that are more intense instantiations of a previously displayed message) and incongruent violations (i.e., behaviors that are opposite in meaning from previously displayed messages). Five models for explaining violation effects are contrasted. Results (a) confirm that violations differ in their impact on uncertainty, (b) generally support the validity of the proposed distinction between congruent and incongruent violations, and show that the inclusion of uncertainty and valence in models of violation outcomes accounts for greater variance in social attraction than either one separately.