Master of Science

thesisThe focus of this research was to investigate the possible existence of an indirect inhibitory mechanism working on activated yet unattended information in long-term memory (LTM). There exists evidence in the cognition and memory literature, specifically the retrieval-induced forgetting and negative priming literature, as well as others, that suggests indirect inhibition may be acting to moderate activation levels in conjunction with semantic activation. Participants (n=120) were given a memory load of different category exemplars and were then instructed to either recall a given dominant category membership or a novel subordinate category membership. The novel category recall instruction required a reorganization of exemplar category associations and the hypothesized inhibition of dominant categories. Following recall, a series of category comparison frames presented new exemplars from the dominant categories of the memory load. Indirect inhibition of the dominant categories would be evidenced by longer response time (RT) on subordinate relative to dominant recall trials. RTs for the category comparisons associated with subordinate recall were not significantly different from the comparisons associated with dominant category recall. These data are incongruent with the hypothesis of an indirect inhibitory mechanism acting on activated yet unattended information in LTM. Instead, they are consistent with Cowan's (1999) model of working memory (WM) that posited active-but-unattended information in WM is subject to tome-based decay but not interference

Doctor of Philosophy

dissertationThe effects of the independent influences of emotional reactivity and cognitive processing on pupil diameter within the same experimental task were investigated. Pupil measurements included pupil diameter level, rate of recovery, and blink rate. All measurements were taken using both eyes to address possible effects of eye dominance. In the experiment, 40 participants (20% male) completed a modified Reading Span Task consisting of neutral and emotionally arousing stimuli, varied orthogonally. The stimuli were administered aurally to maximize pupil dilation differentials with memory loads ranging from one to three words. Participants were instructed to answer yes or no to factual statements along with remembering the last word of each statement. After one to three sentences, the participants were prompted to recall a specific word from the memory load, responses were given verbally. Main effects for cognitive load and emotional reactivity were observed during both the stimuli sentence processing phases and memory load recall phase. A main effect of load was observed for blink rate differences along with a main effect of content for differences in recovery rate. The findings also suggest an over-additive relationship between emotional reactivity (sympathetic) and cognitive processing (parasympathetic) influences on pupil diameter change, which was contrary to the predicted outcome. The evidence for this relationship was observed during trials of greatest cognitive demands, specifically the data for PD level during memory load recall