Visual Search and Task-irrelevant Shape Information in Autism Spectrum Disorder

Visual processing in autism has become a popular topic of research in the past two decades. However, many findings in the reported visual processing abnormalities in autism remain contradictory (Greenaway & Plaisted-Grant, 2013; Simmons et al., 2009). Theories of autism divide into those that favor an explanation of symptoms based on differences in social cognition and orienting on the one hand, and on perception, including vision, on the other. This thesis explores potential differences in visual attentional processing in autism spectrum disorder independently of social cognition factors. The focus lies on visual search as a task by which shifts of attention can be measured and inferences drawn as to underlying perceptual and cognitive processes. It reviews previous work on visual search in autism. The only recently published review on this topic lacked scrutiny (Kaldy et al., 2013). Reviewing the studies with respect to task designs and demographic features of the participants reveals a pattern of results consistent with a previously reported pattern (O’Riordan et al., 2001) but which is distinct from the common notion of “superior search abilities in autism in general”. While children with autism are faster in conjunction and only inefficient feature searches, findings are mixed with regard to adults and feature search and are largely lacking for conjunction search in adults with autism. This thesis also presents an experiment which makes use of the combination of eye-tracking techniques and a visual orientation-feature search task under interference from higher level shape recognition (Zhaoping & Guyader, 2007). Moreover, relevant studies addressing what may be called “task-irrelevant higher-level visual processing” in autism are reviewed. Finally, a more complete characterization of the disorder in terms of its symptomatology with regard to visual attention and visual perception might lead to a better understanding of its cause

Molecular and morphometric phylogenetics of Dryinidae and Bethylidae (Hymenoptera, Chrysidoidea)

ix, 166 pages : illustrations (chiefly color)Aculeata (Hymenoptera) is largely known for its bees, ants, and social wasps, from which most people would immediately recognize honey bees and paper wasps. However, sister to the clade of Apoidea and Vespoidea is the much smaller, and infinitely more enigmatic Chrysidoidea, which contains seven extant families that are relatively understudied. Unlike the other superfamilies, Chrysidoidea is exclusively parasitic -- although this behavior ranges from ectoparasitoidism to endoparasitoidism to cleptoparasitism (targeting solitary wasps and bees), as seen in Chrysididae (the cuckoo wasps). Dryinidae, which contains about 1700 species worldwide in 16 subfamilies, are parasitoids of Auchenorrhyncha (leafhoppers, planthoppers, and their allies) and are known to attack major rice and fruit crop pests. In Chapters II and III, the relationships within the family were investigated at the subfamily level. In Chapter II, a phylogeny reconstructed from 18S, 28S, Cytochrome Oxidase I (COI) and Cytochrome b (CytB) resulted in the resurrection of Thaumatodryinus to Thaumatodryininae to preserve the monophyly of Dryininae. Chapter III examined the utility of landmark analysis in parsimony using the methods implemented by Catalano et al. (2010) and subsequent publications. The trees constructed from the landmark analyses were incongruent with the combined molecular and morphological phylogeny, but landmark analyses could be utilized effectively to reconstruct species-level phylogenies for Dryinus and Gonatopus, both of which were found as nonmonophyletic in Chapters II and III. Chapters IV and V focused on Epyris, the largest genus within the subfamily Epyrinae, and Bethylidae as a whole. Epyris has long been suspected of being a taxonomic wastebasket, but the molecular phylogeny reconstructed from 16S, 18S, 28S, COI, and CytB is the first phylogeny to sample the worldwide breadth of its species diversity. Epyris was shown to be nonmonophyletic, although the type specimen, Epyris niger Westwood, was recovered in a clade with a distinct synapomorphy of large, nearly touching, scutellar pits. In Chapter V, five new species from Epyris sensu stricto were described from Western Australia and Queensland, and a key was provided to the known female Epyris of Australia.Richard Gilder Graduate School at the American Museum of Natural History