Mountain Scholar :: Browsing by Author "Seger, Carol, advisor"

Browsing by Author "Seger, Carol, advisor"

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Open Access
An investigation into the formation of representational associations in visual category learning
(Colorado State University. Libraries, 2017) Jentink, Kade Garrett, author; Seger, Carol, advisor; Rojas, Don, committee member; Burzynska, Agnieszka, committee member
Category learning allows us to use previous information we have accumulated, and extend it to new situations. Multiple systems are proposed to underlie learning, including: an explicit, rule-based system, and an implicit, procedural system. Information integration tasks are thought to load heavily onto the latter. In these tasks, a high degree of accuracy is reached only if participants can integrate incommensurable dimensions, often without being able to verbally describe how they are categorizing each stimulus. Learning in this type of task is thought to occur as participants associate a given stimulus with a category label, and then that label to a motor response. The present study sought to examine whether there may be an additional associative stage in which a stimulus is first associated with a "category representation" – a representation of the critical characteristics of a given category – which is then associated with a category label. Two experiments were conducted which attempted to determine whether this form of category representation is learned in information integration tasks. Both experiments reversed the category representation – category label association for a subset of stimuli and tested if subjects would transfer this reversal to the remaining stimuli, as should happen if they learned to associate each label with a single abstract category representation. Experiment 1 trained subjects with two sets of labels, each of which was associated with the same abstract category representation, to see if reversing one set of labels would alter the other. Experiment 2 trained subjects with 1 set of labels and tested if learning to reverse half of the stimulus space would transfer to the remaining half. In addition, the consistency of category label and motor response associations were manipulated in Experiment 2, with the hypothesis that subjects learning under inconsistent mappings would be forced to learn category labels and be more likely form an abstract category representation, whereas subjects learning under consistent conditions might only learn basic stimulus – response associations. Subjects in Experiment 1 did not transfer the reversal to the second set of category labels, inconsistent with the hypothesis that subjects would form an abstract category representation. However, over half the subjects in Experiment 2 did transfer reversed category label associations to untrained stimuli. Furthermore, a greater number of subjects transferred the reversals in the Inconsistent mapping condition. This is the first study to present evidence suggesting the existence of an abstract category representation and to provide a unique dissociation between consistent and inconsistent mappings for an information-integration task.
Open Access
Assessment of sensation seeking personality type using behavioral and functional neuroimaging measures
(Colorado State University. Libraries, 2020) DiCecco, Samuel M., author; Seger, Carol, advisor; Conner, Brad, advisor; Davies, Patricia, committee member
Sensation seeking personality type, in which an individual has the propensity to engage in risky behaviors while searching for an optimal level of stimulation, is associated with a variety of negative health outcomes, such as higher rates of substance misuse, gambling, and self-harm. It is important to develop methods to identify those at higher risk of engaging in such health risk behaviors. Historically, sensation seeking has been primarily measured using self-report surveys. Providing additional measures of sensation seeking, such as through behavioral assessment or biomarkers, would aid our measurement of the sensation seeking personality type. The present work sought to create a new behavioral measure of sensation seeking personality type, the Sensation Seeking Dot Probe Task (SSDP), that measures an individual's attentional bias towards sensation seeking imagery. Further, the SSDP task was combined with functional Near Infrared Spectroscopy, which utilizes the spectral differences of hemoglobin in the brain to measure neural activity, to identify neural correlates of attention to sensation seeking imagery and relate them to the Sensation Seeking Personality Type scale. I hypothesized that the SSDP would be as effective in identifying sensation seeking as the self-report scale, and that attention to sensation seeking images would correlate with changes in neural activity in the prefrontal cortex and orbitofrontal cortex (regions associated with executive control and decision making) that would be greater in high sensation seeking individuals. While the SSDP did not find significant differences in accuracy or reaction time, the typical measures used in attentional bias dot-probe tasks, there was a significant difference in selection of sensation seeking imagery when paired with neutral control imagery. There were also significantly different changes in activity during sensation seeking congruent tasks in areas of the lateral prefrontal cortex for high sensation seeking individuals. These results suggest functional and behavioral differences measurable in high sensation seekers, and future tasks can use these findings to lead to a greater understanding of the personality type.
Open Access
Categorical evidence, confidence and urgency during the integration of multi-feature information
(Colorado State University. Libraries, 2015) Braunlich, Kurt, author; Seger, Carol, advisor; Anderson, Charles, committee member; Rhodes, Matthew, committee member; Troup, Lucy, committee member
The present experiment utilized a temporally-extended categorization task to investigate the neural substrates underlying our ability to integrate information over time and across multiple stimulus features. Importantly, the design allowed differentiation of three important decision functions: 1) categorical evidence, 2) decisional confidence (the choice-independent probability that a decision will lead to a desirable state), and 3) urgency (a hypothetical signal representing a growing pressure to produce a behavioral response within each trial). In conjunction with model-based fMRI, the temporal evolution of these variables were tracked as participants deliberated about impending choices. The approach allowed investigation of the independent effects of urgency across the brain, and also the investigation of how urgency might modulate representations of categorical evidence and confidence. Representations associated with prediction errors during feedback were also investigated. Many cortical and striatal somatomotor regions tracked the dynamical evolution of categorical evidence, while many regions of the dorsal and ventral attention networks (Corbetta and Shulman, 2002) tracked decisional confidence and uncertainty. Urgency influenced activity in regions known to be associated with flexible control of the speed-accuracy trade-off (particularly the pre- SMA and striatum), and additionally modulated representations of categorical evidence and confidence. The results, therefore, link the urgency signal to two hypothetical mechanisms underling flexible control of decision thresholding (Bogacz et al., 2010): gain modulation of the striatal thresholding circuitry, and gain modulation of the integrated categorical evidence.
Open Access
Controlled and automatic processing in implicit learning
(Colorado State University. Libraries, 2012) Mong, Heather Marie Skeba, author; Seger, Carol, advisor; DeLosh, Ed, committee member; Volbrecht, Vicki, committee member; Draper, Bruce, committee member
This dissertation proposes a new approach for measuring the cognitive outcomes of learning from implicit tasks: measure the controlled and automatic processes at use by participants after training, and focus on how controllable the acquired knowledge is under different learning conditions as measured through a process-dissociation procedure. This avoids the uncertainty of any explicit knowledge test's ability to exhaustively measure the contents of consciousness, and provides a different way to view the cognitive changes due to implicit task training. This dissertation includes three experiments using two different implicit learning tasks (serial response reaction time [SRTT] and contextual cuing) to test how controllable the knowledge gained from these tasks is. The first two experiments used the SRTT, in which participants have to make the appropriate corresponding spatial response when presented with a visual stimulus in one of four locations. The trained information is a repeating 12-item response series, which participants are not typically told is repeating. These experiments found use of both controlled and automatic processes by participants. When participants were cued that a sequence was repeating (Experiment 2), there was significantly less use of controlled processes than when participants were not cued into the sequence repetition, suggesting a shift away from controlled processes when explicitly learning the repeating information. The third experiment used the contextual cuing visual search task, which requires participants to rapidly locate a target (T) in a field of distracters (L). Participants become faster at locating the target within repeating spatial configurations across training. Experiment 3 also found use of both controlled and automatic processes after training. However, cuing the repetition did not change either controlled or automatic process estimates, suggesting that control over acquired knowledge is not affected by intent to learn. Altogether, the process dissociation approach provides process estimates congruent with existing theoretical explanations of the two implicit learning tasks, and are a useful addition to the techniques available to study implicit learning.
Open Access
Cue competition and feature representation in a category learning task: an fMRI study
(Colorado State University. Libraries, 2023) Jentink, Kade, author; Seger, Carol, advisor; Burzynska, Agnieszka, committee member; Rojas, Don, committee member; Thomas, Michael, committee member
During learning, attention is limited, and therefore selecting what feature(s) to attend to in the environment is important. Sometimes, attention is captured by a cue or feature in such a way that other cues or features are not attended to, known as overshadowing. This process is not entirely understood in category learning, with some studies suggesting that it enhances learning of other features (Murphy et al., 2017), while others suggest that it inhibits (Lau et al., 2020). Furthermore, the location and organization of the neural representations that develop for category features during overshadowing has not been previously examined in this context. The present experiment used representational similarity analyses (RSA), a method for interrogating representational structure (Kriegeskorte et al., 2008), in order to examine where and how features were represented during overshadowing in a category learning task. Participants completed a category learning task in which categories were defined based on two informative features, one binary and one continuous. The binary feature was easier to learn (i.e., more salient), and it was hypothesized that it would overshadow learning of the more difficult continuous feature. This was demonstrated behaviorally: participants learned to categorize when the binary feature was present, then performed at chance when it was removed in a transfer task. Three different hypothetical models were fit to the neural data to determine underlying representational structure: a binary category model, an effector-specific motor model, and a model representing the degree of perceptual similarity for the continuous feature. During initial learning when the primary binary feature was present, the category model fit data from both early visual and object-specific areas of visual cortex, while the motor model fit data from motor-related regions including primary somatomotor cortex and the cerebellum. The perceptual similarity model for the continuous feature did not fit any task data during either Training or Transfer. However, there was a trend for the category model to fit activity in the basal ganglia and lateral occipital complex (LOC) during the Transfer task when the only information available for categorization was the continuous feature. Taken together, these results suggest that, although overshadowing inhibits use of the overshadowed continuous feature as the basis of categorization behavior, it might still contribute to activation of neural representations of category membership.
Open Access
Development of a behavioral measurement of sensation seeking personality trait and its association with negative health outcomes
(Colorado State University. Libraries, 2024) DiCecco, Samuel M., author; Seger, Carol, advisor; Conner, Brad, advisor; Davies, Patti, committee member; Karoly, Hollis, committee member
Sensation seeking, a personality trait in which an individual has the tendency to pursue novel and highly stimulating experiences and often engages in risky behaviors to do so, is associated with several negative health outcomes when paired with low cognitive control. These outcomes include higher rates of substance misuse, self-harm, problem gambling, risky sexual behavior, engaging in dangerous sports, and criminal activities. It would be beneficial to have valid ways of measuring the trait to address or prevent these negative health outcomes from occurring. The sensation seeking personality trait is typically only measured using self-report surveys, even though it manifests itself behaviorally. Creation of behavioral measurements of sensation seeking may aid in the understanding of the trait and its behavioral effects, as well as aid in prevention of negative health outcomes. Previous attempts to measure sensation seeking behaviorally have not been successful, potentially due to the inherent nature of the trait being difficult to elicit in standard laboratory tasks and environments, and use of extrinsic rather than intrinsic motivators. I developed two novel emergent behavioral tasks to measure observed changes in participant-driven behavior and related these task variables to each individual's measured sensation seeking personality trait. I also assessed whether these new task measures correlated with reported negative health behaviors that have been associated with sensation seeking. This dissertation consists of three studies utilizing these novel emergent behavioral tasks. The first compared task measures to self-report measures of sensation seeking and personality traits, the second served as a replication and looked at relations between task measures and risky behaviors, and the third developed a virtual reality variant of the tasks. Several of the behavioral measurements within the emergent behavior tasks showed significant relations with sensation seeking personality trait, in particular measures of risky or "dangerous" decisions made in Studies 1 and 2 that correlated with the risk seeking subtype of sensation seeking personality trait. Study 3 found that implementing the behavioral tasks in virtual reality resulted in weaker, rather than stronger, relationships between the behavioral measures and self-report measures. Together, these studies found that the emergent tasks implemented using standard computer interfaces, but not virtual reality, show promise as valid behavioral measurements of sensation seeking personality trait.
Open Access
Differentiating associations between tasks and outcomes in the human brain
(Colorado State University. Libraries, 2022) Nelson, Lauren, author; Seger, Carol, advisor; Thomas, Michael, committee member; Anderson, Chuck, committee member; Tompkins, Sara Anne, committee member
In order to successfully achieve their goals in a noisy and changing environment, organisms must continually learn both Pavlovian (stimulus-outcome or S-O) and instrumental (action-outcome or A-O) associations. A wide range of brain regions are implicated in reinforcement learning and decision-making, including the basal ganglia, medial prefrontal cortex, the dorsolateral prefrontal cortex (dlPFC), and the anterior cingulate cortex (ACC). One possible explanation of disparate findings is that activation depends on the nature of the action or response under consideration. To investigate representations of task-reward associations, subjects switched between an emotional judgement task and a spatial judgement task, combined with either a high or low level of reward. A general linear model (GLM) compared activation for different combinations of task and reward. A cluster in the mid-prefrontal cortex was more active for right versus left response, whereas a cluster in the midbrain near the brainstem was more active for left responses. Performance of the spatial task was associated with activation in the ventral occipital cortex and ventral prefrontal cortex. Clusters in the posterior parietal cortex and lateral prefrontal cortex were more active during the emotion task. Receiving a large reward was accompanied by activation in primary somatosensory cortex and auditory cortex, while receiving a low reward appeared to recruit the anterior cingulate cortex. Comparing trials which yielded a reward versus trials with no reward revealed activation in the dorsal prefrontal cortex. A 2-way ANOVA examining independent contributions of response and reward found an effect of response in cuneus and pre-cuneus, an effect of reward in anterior insula and sensorimotor cortex, and an interaction in the post-central gyrus. A 2-way ANOVA of task and reward found a main effect of task in several clusters in the medial occipital cortex, a main effect of reward in somatosensory cortex and anterior insula, and an interaction in the ventral occipital and anterior prefrontal cortex.
Open Access
Disambiguating ambiguity: influence of various levels of uncertainty on neural systems mediating choice
(Colorado State University. Libraries, 2011) Lopez Paniagua, Dan, author; Seger, Carol, advisor; Cleary, Anne, committee member; Draper, Bruce, committee member; Troup, Lucy, committee member
Previous studies have dissociated two types of uncertainty in decision making: risk and ambiguity. However, many of these studies have categorically defined ambiguity as a complete lack of information regarding outcome probabilities, thereby precluding the study of how various neural substrates may acknowledge and track levels of ambiguity. The present study provided a novel paradigm designed to address how decisions are made under varying states of uncertainty, ranging from risk to ambiguity. More important, the present study was designed to address limitations of previous studies looking at decision making under uncertainty: explore neural regions sensitive to hidden but searchable information by parametrically controlling the amount of information hidden from the subject by using different levels of ambiguity manipulations instead of just the one, as used in previous studies, and allowed subjects to freely choose the best option. Participants were asked to play one of two lotteries, one uncertain and one certain. Throughout the task, the certain lottery offered to participants was always a 100% chance of winning $1. This was contrasted by the uncertain lottery in which various probabilities of winning (20%, 33%, 50 % or 80%) were combined with different potential gains (2$, 3$, 5$, or 8$) so that expected values ranged from being better, equal or worse than the expected value of the certain lottery. In our lotteries, the probability of winning or losing any given amount of money was indicated along the borders of the wheel, increasing from 0% to 100% in a clockwise direction starting at the 12 o'clock position. For some uncertain lotteries and all certain lotteries, a "dial" explicitly indicated the probability of winning. For some uncertain lotteries, there was no dial to indicate a specific probability. Instead, a blinder that covered a portion of the wheel occluded the dial. This occlusion represented the possible range of percentages in which the actual probability of winning lay. Finally, the blinder covered 15%, 33%, 66%, 80% or 100% of the wheel in order to vary the level of ambiguity. By manipulating the level of ambiguity, we were able to explore neural responses to different types of uncertainty ranging from risk to full ambiguity. Participants completed this task while BOLD contrast images were collected using a 3T MR scanner. Here, we show that both risk and ambiguity share a common network devoted to uncertainty processing in general. Moreover, we found support for the hypothesis that regions of the DLPFC might subserve contextual analysis when search of hidden information is both necessary and meaningful in order to optimize behavior in a decision making task; activation in the DLPFC peaked when the degraded information could be resolved by additional cognitive processing. Our results help to underscore the importance of studying varying degrees of uncertainty, as we found evidence for different neural responses for intermediate and high levels of ambiguity that are easy to ignore depending on how ambiguity is defined. Additionally, our results help reconcile two different accounts of brain activity during ambiguous decision making, one suggesting that uncertainty increases linearly and another suggesting ambiguity processing is greater at intermediate levels. The graded coding of uncertainty we reported may reflect a unified neural treatment of risk and ambiguity as limiting cases of a general system evaluating uncertainty mediated by the DLPFC which then recruits different regions of the prefrontal cortex as well as other valuation and learning systems according to the inherent difficulty of a decision.
Open Access
Intrinsic motivation to learn: can individual differences decrease susceptibility to undermining effects?
(Colorado State University. Libraries, 2013) Wehe, Hillary S., author; Seger, Carol, advisor; Rhodes, Matthew, committee member; Conner, Bradley, committee member; Hoke, Kimberly, committee member
This study extended the theory of the undermining effect on motivation to a learning context and examined the interaction with individual goals for learning. The undermining effect suggests that the removal of external rewards can decrease levels of internal motivation. Students possessing a desire to improve, or learning goal individuals, often appear to be more internally motivated to engage in challenging tasks, whereas, performance goal individuals tend to engage in tasks that confirm their intelligence. Students were assigned to either a reward or non-reward condition and completed a word-learning task. They were allowed to engage in studying the words during a free period. An undermining effect was found: A greater amount of time was spent studying by individuals in the non-reward group, no matter the personal goals for learning. Learning goal subjects were hypothesized to show little difference in study time between groups, whereas performance goal subjects were predicted to be more sensitive to motivational undermining and therefore engage in the task more in the non-reward group; however, the interaction between undermining and goal orientation was not significant and these hypotheses were not supported. These results have significant implications for verifying the impact of motivation on learning behaviors and provide support for the encouragement of intrinsic motivation and contribute to the current literature exploring the cause for differences in performance success among students.
Open Access
Undermining learning: the impact of rewards on learning behavior
(Colorado State University. Libraries, 2016) Wehe, Hillary, author; Seger, Carol, advisor; Rhodes, Matthew, committee member; Conner, Bradley, committee member; Hoke, Kim, committee member
The undermining effect suggests that external rewards can decrease levels of internal motivation. Research exploring student motivation shows that internally motivated students appear to engage longer and in more challenging tasks compared to students focused on external rewards or performance feedback. The current study tested variables that may decrease susceptibility to motivational undermining for learning behaviors. In all studies, students were assigned to either a reward or non-reward condition and completed a word-learning task followed by a final test. Subjects were given the option to choose to re-study the words at two times during the task—pre- (while reward is still achievable) and post-test (after reward is given and no further extrinsic reward is achievable). Across all studies, an undermining effect was expected: Non-reward subjects would spend a greater amount of time reviewing the words during the post-test interval compared to the reward group. Study 1 directly tested the hypothesis by observing whether or not the reward groups behaved differentially at the pre- and post-test choice. Reward subjects spent significantly less time engaging in the task during the post-test review phase, supporting the presence of the undermining effect (t (1,60)=2.06, p = .02, 1-tailed) but a 2 (group: reward x non-reward) x 2 (study time: pre-test x post-test) repeated measures ANOVA comparing the mean study times for the reward and non-reward subjects’ pre-test study and post-test review time revealed that the interaction between group and study time did not reach significance (F (1,60) = 3.52, p = .065). Study 2 was identical to the first study but with the addition of a surprise, 24-hour delayed memory test to examine whether the extra post-test study had beneficial effects on long-term retrieval. Non-reward subjects were hypothesized to recall more items on a delayed memory test compared to reward subjects due to increased study time. A 2 (group: reward x non-reward) x 2 (study time: pre-test x post-test) repeated measures ANOVA was conducted to compare the mean study times for the reward and non-reward subjects’ pre-test study and post-test review times. The interaction between group and time spent on task was significant (F (1,241) = 4.24, p < .05) but there was not a significant main effect for the between subjects variable of reward on the amount of time spent engaging in the task during the pre- and post-test phases (F (1)= .63, p = .44). A 2 (group: reward vs. non-reward group) x 2 (test performance: immediate x delayed) repeated measures ANOVA was conducted to compare the average accuracy between groups on the delayed memory test. There was not a main effect of group on performance (F (1, 110) = .82, p = .38) and the interaction between reward group and immediate or delayed test was not significant (F (1,156) = .201, p = .65). Study 3 was similar to the first study but subjects were allowed to choose the material they were learning (i.e., Swahili or Lithuanian words). The element of choice was expected to increase the degree of control and internal motivation students experienced and consequently decrease the effect of undermining between the reward and non-reward group. Specifically, study times between the reward and non-reward group were hypothesized to be equal between groups and higher than then a forced choice condition. A 2 (group: reward x non-reward) x 2 (choice: self-determined x forced-choice) x 2 (study time: pre-test x post-test) x 2 (language: Swahili x Lithuanian) repeated measures ANOVA was conducted. The main effect of choice condition was not significant (F (1,60) = .140, p = .71). The main effect of reward was also not significant (F (1,60) = .920, p = .34) but the interaction between choice and reward on time spent on task was significant (F (1,60) =4.11, p < .05). A 2 (group: reward x non-reward) x 2 (choice: self-determined x forced-choice) repeated measures ANOVA was conducted to compare performance on an immediate memory test for the self-determined and forced choice group but the effect was non-significant (F (1,60) = .67, p = .16); in addition, there was not a significant main effect of reward (p =.32) nor was there an interaction (p = .16).

Browsing by Author "Seger, Carol, advisor"

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