Predator cues can influence how aquatic organisms respond to anthropogenic contaminants. This study examined the effects of predator cues on behavior, metabolic rate, and sulfate (as Na2SO4) toxicity in amphipods (Gammarus minus). Predator cues included alarm cue (macerated conspecifics) and kairomone from mosquitofish (Gambusia affinis). Amphipods decreased activity and increased time in refuge when exposed to alarm cue, and increased time in refuge when exposed to kairomone. While median lethal concentrations (96-h LC50) were not influenced by predator cues, analysis of dose response curves indicated that kairomone exposure increased amphipod sensitivity to mid-range concentrations of sulfate (500-1,000 mg/L). Amphipods increased oxygen consumption in response to kairomone but not alarm cue. The influence of predator cues on contaminant lethality can be dependent on the type of cue, and physiological endpoints such as metabolic rate may help explain the basis of observed interactions.

Autism spectrum disorder (ASD) represents a group of developmental disabilities associated with impairments in social, communicative, and imaginative abilities. Speech impairments associated with ASD can be explained by differences in cognitive processing styles relative to neurotypicals. Previous studies found that individual differences in cognitive processing influence one’s production and perception of prosody. For example, Stewart et al. (2018) found that higher levels of autistic character traits indicated by one’s Autism Spectrum Quotient (AQ) score (Baron-Cohen et al., 2001) correlated significantly with one’s ability to discriminate pitch and time, but no significant correlation between auditory discrimination thresholds for intensity. Additionally, Turnbull (2015; 2019) observed shorter overall word and vowel durations during a task which required participants with varying AQ scores to speak for the benefit of a listener with a hearing impairment. The present study examined whether prosodic cue-trading in production and perception differs when comparing populations with varying levels of autistic traits, as indicated by their AQ score differences. Furthermore, the study investigated whether these differences exist on a continuum, or rather are categorical, with respect to participants’ level of autistic character traits. To achieve this, we analyzed individual variability patterns in 18 participants’ speech production and perception. Results from the perception task showed that participants displayed a significant enhanced perception of pitch and intensity, but not duration, when completing a task where participants listened to sentences manipulating the prosodic parameters f0, intensity, duration. Results from the production task where participants read sentences designed to elicit background, broad, and narrow focus found no significant effect of AQ across any of the acoustic parameters measured, although the results for f0 are near the 5% significance level for the f0 condition, suggesting that participants with higher AQ scores may produce lower f0 ranges, and thus, less prosodic variability compared to low AQ participants. / Thesis / Master of Science (MSc) / Autism spectrum disorder (ASD) represents a group of developmental disabilities associated with impairments in communicative abilities, among others. Theories suggest that individuals with higher levels of autistic traits notice small details in the physical properties of sounds, but have trouble distinguishing the more abstract, intended meaning of the same sound patterns. Previous studies found that individual differences in the degree of autistic traits influence one’s production and perception of prosody (i.e., the relative highness or lowness of a tone),; individuals with higher levels of autistic are better able to detect fine-grained differences in pitch and time, but not loudness. The present study examined the extent to which speakers with varying levels of autistic traits use prosody during speech production and perception. This study observed that (1) individuals with higher levels of autistic traits displayed an enhanced perception of pitch and loudness, but not time, and (2) that these same participants may exhibit less variability in their production of pitch.

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The introduction of nonnative salmonids into Southern Appalachia may pose a threat to resident salamander populations. In recent years, the stocking and encroachment of rainbow trout (Oncorhynchus mykiss) into headwaters where the black-bellied salamander (Desmognathus quadramaculatus) and brook trout (Salvelinus fontinalis) naturally coexist has raised concerns. In aquatic prey, predator-avoidance responses are primarily influenced through the detection of chemical cues released from predators. The objective of this study was to determine how co-occurrence with a predator influences black-bellied salamander predator recognition behavior. To evaluate this, salamander activity metrics (general activity, number of movements, and latency to move) were recorded before and after exposure to either native trout predator cue (brook), introduced trout predator cue (rainbow), or conditioned tap water (control). Larvae were collected from different streams based on their trout predator assemblage with larvae coming from brook, rainbow, rainbow/brook, and no trout stream reaches. Our results show that larvae that co-occur with trout reduced their activity when exposed to brook trout predator cue, but their response to rainbow trout predator cue depended on their previous co-occurrence. Larvae from areas with only brook trout exhibited a weak predator-avoidance when exposed to rainbow trout predator cue. A follow-up test to determine the influence of alarm cue on predator response in these larvae indicated that the alarm cue enhanced the response to the rainbow trout predator.

Introduction: Despite advances in smoking cessation interventions, the majority of smokers who seek treatment will relapse. To better understand nicotine dependence, and relapse risk factors this study tested for potential relationships between social problem-solving, negative affect, and smoking urges during a baseline smoking cue exposure trial. Methods: aA part of a larger cessation study. 51 male and 50 female physically inactive, sedentary smokers with the intention to quit smoking, and bioverified smoking abstinence (CO < 11ppm) completed demographic questionnaires, the Social Problem-Solving Inventory-Revised: Short-Form, and questionnaires related to smoking history and demographic characteristics. In addition, participants completed a baseline 5-minute relaxation session followed by a 5-minute imaginal and in vivo smoking cue exposure trial. Participants completed pre and post cue exposure measures of urge and affect. Analysis: t-tests were used to validate the effect of cue exposure procedures on urge and negative affect. Multivariate linear regression models assessed the strength of possible relationships between social problem-solving, gender, negative affect, and urge to smoke. Results: Smoking urge and negative affect significantly increased from pre to post exposure. Women and men did not differ on any measure of social problem-solving, affect, or smoking urge. In regression models, the social problem-solving composite score was not statistically associated with post-cue exposure urge strength (as measured by the Questionnaire for Smoking Urges-Brief) when controlling for cigarettes per day or level of nicotine dependence. Greater pre-test negative problem orientation was significantly correlated with pre-post increases in negative affect (a predictor of relapse). In models with a gender and negative problem orientation interaction, negative problem orientation became a stronger predictor of negative affect, although the interaction term was non-significant. Impulsive-careless problem-solving styles and negative affect were also found to be significantly associated with post-exposure urge strength. Conclusions: A 5-minute smoking cue exposure trial produced a reliable increase in smoking urge and negative affect among treatment-seeking smokers who were abstinent for at least three hours. Future research of social problem-solving, stress and coping and negative affect within cue reactivity paradigms may provide insights for integrating cue exposure treatments and counseling-based smoking cessation interventions. / Public Health

In recent years, computational neuroscientists have suggested that human behaviour, including perception, occurs in a manner consistent with Bayesian inference. According to the Bayesian ideal observer model, the observer combines cues from multiple sensory streams as a weighted average based on each cue’s reliability. Most cue-combination research has focused on integration of cues between sensory modalities or within the visual modality. Cue combination within the tactile modality has been relatively rarely studied, and it is still not known whether cues from individual digits combine optimally. In this thesis, we use the ideal observer model to determine whether cues from three different digits are combined optimally. We predicted that cues from multiple digits would be combined according to the optimal cue combination model. To test our hypothesis, we devised a two-interval forced choice (2IFC) task where participants had to discriminate the distal/proximal location of a 1-mm thick edge across the fingerpad(s) of the index (D2), middle (D3), and ring (D4) fingers. We used a Bayesian adaptive method, the ψ method, to compute participants’ psychometric functions for single-digit (D2, D3, and D4) and multiple-digit (D23, D24, D34, and D234) conditions. We determined the stimulus level ∆x, the distance (mm) between the distal and proximal stimuli locations, at 76% correct probability. This distance corresponds to a sensitivity index d'=1 and is the σ value of the participant’s stimulus measurement distribution. We then used the single-digit σ values to predict optimal cue combination for the multiple-digits combinations. We did not observer optimal cue-combination between the digits in this study. We outline potential implications the results of this experimental have on determining how the nervous system combines cues between digits, focusing on theoretical and experimental updates to the experiment that might result in the observation of optimal cue combination between digits. / Thesis / Master of Science (MSc)

面為基階段在視覺處理歷程中扮演重要角色，面表徵是高於視網膜影像的視覺表徵，本研究目的在於探討以「面表徵」為選擇基礎之注意力運作。參考過去研究者所採用的面材料，本研究改為同時呈現二個交叉斜面並進行線索提示作業，以同面優勢效果作為面為基注意力運作之指標。 本研究分成四項實驗，每項實驗皆由兩個子實驗構成，此二個子實驗分別使用「外因性線索提示作業」與「內因性線索提示作業」探討面為基注意力的運作。實驗一利用上述「面」的設計及兩種提示作業，得同面優勢效果，反映面為基注意力的運作參與其中。實驗二目的在於排除注意力根據「可能目標的斜度」進行選擇之混淆，因此將面改為擁有相同斜度且互相平行的二個斜面。注意力若根據可能目標的斜度進行選擇，則無法得同面優勢效果。結果顯示在實驗二的兩種提示作業中，仍得同面優勢效果。實驗三目的在於排除可能目標因空間排列而形成簡單的知覺組織，繼而影響注意力分配之可能性。結果顯示在外因性線索提示作業下，仍得同面優勢效果；在內因性線索提示作業下，SOA需延長至500毫秒，才展現同面優勢效果。實驗四則進一步確認在不同SOA下，面為基注意力的運作情況，結果發現：在外因性線索提示作業下，SOA為500毫秒展現同面優勢效果；內因性線索提示作業下， SOA為1000毫秒下展現同面優勢效果。 綜合而言，在外因性線索提示作業與內因性線索提示作業下皆得到同面優勢效果。當可能目標難以群聚後，在長SOA時距下，依然展現同面優勢效果。因此本研究的結果，對於面為基注意力提供了直接的支持證據。 / Surface-based stage plays an important role in visual information process. Surface representation means the representation that goes beyond 2-D image representation. The purpose of this study is on the exploration of attentional selection which is based on surface representation. Referring to the surface material used before, this study adopted two interlacing slant surfaces structured by random-dot stereogram to test the effect of “same-surface advantage”. There are four experiments and each experiment includes two sub-experiments which are exogenous cuing task and endogenous cuing task, respectively. In Experiment 1, the same-surface advantage was revealed. In Experiment 2, the confounding of “slant” was ruled out and the same-surface advantage was still kept. In Experiment 3, we reduced the possibility that candidate targets group together to form simple perceptual organization and then influence the allocation of attention. After rearrange the spatial positions of candidate targets, attention cannot select the simple perceptual organization easily. In exogenous cuing task, same-surface advantage was still revealed. In endogenous cuing task, SOA should be prolonged to 500ms, and it shows same-surface advantage. Furthermore, in Experiment 4, we manipulate three kinds of SOA and confirm the operation of surface-based attention. We found that in exogenous cuing task, SOA should be prolonged to 500ms, and it shows same-surface advantage.In endogenous cuing task, SOA should be prolonged to 1000ms, and it shows same-surface advantage. In conclusion, it shows same-surface advantage in exogenous cuing task and endogenous cuing task. When candidate cannot group together to be selected easily, SOA should be prolonged to longer, and it still shows same-surface advantage. The results provide the direct support evidences of surface-based attention.