In four experiments on insight problem solving, we investigated the time course of the development of solution knowledge prior to response, as well as the impact of stimulus familiarity on task performance and eye movement measures. In each experiment, participants solved anagram problems while their eye movements were monitored. In Experiments 1a and 1b, each anagram problem consisted of a circular array of letters: a scrambled four-letter solution word containing three consonants and one vowel, and an additional randomly-placed distractor consonant. Viewing times on the distractor consonant compared to the solution consonants provided an online measure of knowledge of the solution. Viewing times on the distractor consonant and the solution consonants were indistinguishable early in the trial. In contrast, several seconds prior to the response, viewing times on the distractor consonant decreased in a gradual manner compared to viewing times on the solution consonants. Importantly, this pattern was obtained across both trials in which participants reported the subjective experience of insight and trials in which they did not. These findings are consistent with the availability of partial knowledge of the solution prior to such information being accessible to subjective phenomenal awareness. In Experiments 2 and 3, each anagram problem consisted of a centrally located three-letter string plus three additional individual letters located above and to the side of the central letter string. All the letters in the central letter string were members of the five-letter solution word, while one of the individual letters was a randomly placed distractor. In Experiment 2, we replicated our findings of the gradual development of solution knowledge using this more complex stimulus display. In Experiment 3, we manipulated the familiarity of the central letter string by presenting it either in the form of a three-letter word, or as a meaningless string of letters. Behavioural measures showed an overall negative impact of familiarity on task performance, while eye movement measures revealed a more complex pattern of effects, including both interference and facilitation. Critically, the effects of familiarity on problem solving did not interact with the development of solution knowledge prior to response.

Personality, motives, and self-efficacy have all been recognized as factors contributing to relapse, and the interaction among these factors has been outlined in Witkiewitz and Marlatt’s contemporary relapse model. However, there is limited empirical research examining the mechanisms involved in this theory. This study aimed to better understand the relationship between personality risk, drinking motives, and confidence to resist drinking during high-risk situations among adults who have changed their drinking. Results indicate that prior to participants’ change in drinking, introversion/hopelessness was associated with coping motives and confidence in situations involving unpleasant emotions, anxiety sensitivity was associated with coping motives, and impulsivity was associated with conformity motives. Following participants’ change, two specific motives (i.e., coping and conformity) were found to moderate the association between two of the personality profiles (i.e., introversion/hopelessness and anxiety sensitivity) and confidence to resist drinking during specific high-risk situations (i.e., negative emotional and social pressure to use).

We examined the spatiotemporal dynamics underlying the processing of a false belief task using magnetoencephalography (MEG). Twenty adults performed a false belief task adapted for MEG. Regions of interest were selected based on source analyses on the contrast between false and true belief, and MEG source time-course reconstructions were generated and analyzed to determine the temporal architecture of neural activations specific to false belief reasoning. We found frontal, temporal and parietal regions to activate during false belief processing, confirming prior findings. We also extend previous findings by adding information about the temporal profile of neural activity during theory of mind processing, an area lacking in the literature. We found that increased frontal activity began at 100 ms bilaterally, followed by parietal regions from 200 to 330 ms and temporal regions at 350 ms, at which point frontal activity became lateralized to the right hemisphere.

When the eye rotates, switching from one fixation point to another, the perception of motion is strongly suppressed and rarely perceived. During these quick ‘saccadic’ eye movements, other aspects of visual perception become suppressed or compressed as well, with certain effects being stronger or weaker along the plane of the saccade - such differences can help identify the underlying neuronal pathways, since some exhibit directional tuning (e.g. neurons projecting from primate V1 to middle temporal area (MT)), and others do not (e.g. relay neurons linking the superior colliculus to area MT). A briefly presented motion probe was placed at a number of points relative to saccade to plot sensitivity to motion along different planes and directions. The results suggest that saccadic motion is suppressed before the eye begins to move, and is applied evenly across planes and directions.

Personality, motives, and self-efficacy have all been recognized as factors contributing to relapse, and the interaction among these factors has been outlined in Witkiewitz and Marlatt’s contemporary relapse model. However, there is limited empirical research examining the mechanisms involved in this theory. This study aimed to better understand the relationship between personality risk, drinking motives, and confidence to resist drinking during high-risk situations among adults who have changed their drinking. Results indicate that prior to participants’ change in drinking, introversion/hopelessness was associated with coping motives and confidence in situations involving unpleasant emotions, anxiety sensitivity was associated with coping motives, and impulsivity was associated with conformity motives. Following participants’ change, two specific motives (i.e., coping and conformity) were found to moderate the association between two of the personality profiles (i.e., introversion/hopelessness and anxiety sensitivity) and confidence to resist drinking during specific high-risk situations (i.e., negative emotional and social pressure to use).

We examined the spatiotemporal dynamics underlying the processing of a false belief task using magnetoencephalography (MEG). Twenty adults performed a false belief task adapted for MEG. Regions of interest were selected based on source analyses on the contrast between false and true belief, and MEG source time-course reconstructions were generated and analyzed to determine the temporal architecture of neural activations specific to false belief reasoning. We found frontal, temporal and parietal regions to activate during false belief processing, confirming prior findings. We also extend previous findings by adding information about the temporal profile of neural activity during theory of mind processing, an area lacking in the literature. We found that increased frontal activity began at 100 ms bilaterally, followed by parietal regions from 200 to 330 ms and temporal regions at 350 ms, at which point frontal activity became lateralized to the right hemisphere.

When the eye rotates, switching from one fixation point to another, the perception of motion is strongly suppressed and rarely perceived. During these quick ‘saccadic’ eye movements, other aspects of visual perception become suppressed or compressed as well, with certain effects being stronger or weaker along the plane of the saccade - such differences can help identify the underlying neuronal pathways, since some exhibit directional tuning (e.g. neurons projecting from primate V1 to middle temporal area (MT)), and others do not (e.g. relay neurons linking the superior colliculus to area MT). A briefly presented motion probe was placed at a number of points relative to saccade to plot sensitivity to motion along different planes and directions. The results suggest that saccadic motion is suppressed before the eye begins to move, and is applied evenly across planes and directions.

Competing speech seems to pose a greater challenge to spoken language comprehension than does competing noise, especially for older adults. The difficulties of older adults may be due to declines in auditory and cognitive processing. However, evidence suggests that the use of top-down information processing to overcome this interference may be preserved in aging. This research investigated the effect of speech- and noise masking on language comprehension, as well as age-related differences in the use of top-down processing to overcome masking. Topic I examined whether younger and older adults gain the same release from masking given a partial preview of a target sentence in quiet (auditory prime) prior to hearing the full sentence in noise, and investigated the auditory factors contributing to the advantage provided by the primes. Results showed that despite age-related declines in overall performance, younger and older listeners benefited similarly from priming. This benefit was not attributable to cues about the target talker’s voice or fluctuations in the amplitude envelope of the target sentences. Topics II and III examined the effect of speech- and noise masking on the time-course of stream segregation. The analyses revealed that stream segregation takes time to build up when a speech target is masked by other speech, but not when it is masked by noise. Subsequent analyses showed that in younger adults, the delay in segregation under speech masking was primarily due to the vocal similarities between the talkers, with interference from the semantic content of the masker playing a secondary role in impeding performance. The results also showed that older listeners were less efficient than younger listeners in segregating speech from speech-like maskers. Furthermore, older listeners benefited less than younger listeners when the amplitude envelope modulations of maskers were limited. Overall, the findings indicate that some of the language comprehension difficulties experienced by older listeners in noisy environments may be due to age-related declines in stream segregation and a decreased ability to benefit from fluctuations in the amplitude envelopes of maskers. However, benefit from priming may help offset some of these age-related declines in auditory scene analysis.

Competing models of eye movement control during reading disagree over the extent to which eye movements reflect ongoing linguistic and lexical processing, as opposed to visual/oculomotor factors (for reviews, see Rayner, 1998, 2009a). To address this controversy, participants’ eye movements were monitored in four experiments that manipulated a wide range of lexical variables. Specifically, Experiment 1 manipulated contextual predictability by presenting target words (e.g., teeth) in a high-predictability prior context (e.g. “The dentist told me to brush my teeth to prevent cavities.”) versus a low-predictability prior context (e.g., “I'm planning to take better care of my teeth to prevent cavities.”), Experiment 2 manipulated lexical ambiguity by presenting biased homographs (e.g., bank, crown, dough) in a subordinate-instantiating versus a dominant-instantiating prior context, and Experiments 3A and 3B manipulated word frequency by contrasting high frequency target words (e.g., table) and low frequency target words (e.g., banjo). In all four experiments, I used distributional analyses to examine the time-course of lexical influences on fixation times. Ex-Gaussian fitting (Staub, White, Drieghe, Hollway, & Rayner, 2010) revealed that all three lexical variables (i.e., predictability, lexical ambiguity, word frequency) were fast-acting enough to shift the entire distribution of fixation times, and a survival analysis technique (Reingold, Reichle, Glaholt, & Sheridan, 2012) revealed rapid lexical effects that emerged as early as 112 ms from the start of the fixation. Building on these findings, Experiments 3A and 3B provided evidence that lexical processing is delayed in an unsegmented text condition that contained numbers instead of spaces (e.g., “John4decided8to5sell9the7table2in3the9garage6sale”), relative to a normal text condition (e.g., “John decided to sell the table in the garage sale”). These findings have implications for ongoing theoretical debates concerning eye movement control, lexical ambiguity resolution, and the role of interword spaces during reading. In particular, the present findings provide strong support for models of eye movement control that assume that lexical influences can have a rapid influence on the majority of fixation durations, and are inconsistent with models that assume that fixation times are primarily determined by visual/oculomotor constraints.

This project investigated the statistical learning of musical expectancy. As a secondary goal, the effects of the perceptual properties of tone set familiarity (Western vs. Bohlen-Pierce) and textural complexity (melody vs. harmony) on the robustness of that learning process were assessed. A series of five experiments was conducted, varying in terms of these perceptual properties, the grammatical structure used to generate musical sequences, and the methods used to measure musical expectancy. Results indicated that expectancies can indeed be developed following statistical learning, particularly for materials composed from familiar tone sets. Moreover, some expectancy effects were observed in the absence of the ability to successfully discriminate between grammatical and ungrammatical items. The effect of these results on our current understanding of expectancy formation is discussed, as is the appropriateness of the behavioural methods used in this research.