Cognitive and Visual Speech Contributions to Speech Perception in Challenging Listening Conditions

Speech perception routinely takes place in noisy or degraded listening environments, leading to ambiguity in the identity of the speech token. Here, I present one review paper and two experimental papers that highlight cognitive and visual speech contributions to the listening process, particularly in challenging listening environments. First, I survey the literature linking audiometric age-related hearing loss and cognitive decline and review the four proposed causal mechanisms underlying this link. I argue that future research in this area requires greater consideration of the functional overlap between hearing and cognition. I also present an alternative framework for understanding causal relationships between age-related declines in hearing and cognition, with emphasis on the interconnected nature of hearing and cognition and likely contributions from multiple causal mechanisms. I also provide a number of testable hypotheses to examine how impairments in one domain may affect the other. In my first experimental study, I examine the direct contribution of working memory (through a cognitive training manipulation) on speech in noise comprehension in older adults. My results challenge the efficacy of cognitive training more generally, and also provide support for the contribution of sentence context in reducing working memory load. My findings also challenge the ubiquitous use of the Reading Span test as a pure test of working memory. In a second experimental (fMRI) study, I examine the role of attention in audiovisual speech integration, particularly when the acoustic signal is degraded. I demonstrate that attentional processes support audiovisual speech integration in the middle and superior temporal gyri, as well as the fusiform gyrus. My results also suggest that the superior temporal sulcus is sensitive to intelligibility enhancement, regardless of how this benefit is obtained (i.e., whether it is obtained through visual speech information or speech clarity). In addition, I also demonstrate that both the cingulo-opercular network and motor speech areas are recruited in difficult listening conditions. Taken together, these findings augment our understanding of cognitive contributions to the listening process and demonstrate that memory, working memory, and executive control networks may flexibly be recruited in order to meet listening demands in challenging environments.

Trade relations between the Mycenaean Greeks and the civilizations of the Eastern Mediterranean in the Late Bronze Age

The Mycenaean Greeks are often assumed to have been in contact with the civilizations of the Mediterranean throughout the Late Bronze Age. The extent of this contact however is not as clearly understood, and the archaeological evidence that has survived provides a sample of what must have exchanged hands. This thesis will examine the archaeological, textual and iconographic evidence from a number of sites and sources, from the Anatolian plains to the Kingdom of Egypt and major settlements in-between during the Late Bronze Age to examine what trade may have looked like for the Mycenaeans. Due to the extensive finds in some regions and a lack of evidence in others, this paper will also try to understand the relationship between the Mycenaeans and other cultures to determine whether a trade embargo was enacted on the Mycenaeans by the Central Anatolian Hittites during this period, or whether other factors contributed to the paucity of objects in Central Anatolia.