Browsing by Subject "Cognitive psychology"

"Cognitive control" describes endogenous guidance of behavior in situations where routine stimulus-response associations are suboptimal for achieving a desired goal. The computational and neural mechanisms underlying this capacity remain poorly understood. The present dissertation examines recent advances stemming from the application of a statistical, Bayesian learner perspective on control processes. An important limitation in current models consists of a lack of a plausible mechanism for the flexible adjustment of control over variable environments. I propose that flexible cognitive control can be achieved by a Bayesian model with a self-adapting, volatility-driven learning scheme, which modulates dynamically the relative dependence on recent (short-term) and remote (long-term) experiences in its prediction of future control demand. Using simulation data, human behavioral data and human brain imaging data, I demonstrate that this Bayesian model does not only account for several classic behavioral phenomena observed from the cognitive control literature, but also facilitates a principled, model-guided investigation of the neural substrates underlying the flexible adjustment of cognitive control. Based on the results, I conclude that the proposed Bayesian model provides a feasible solution for modeling the flexible adjustment of cognitive control.

Consumers often lack objective information about product acquisition costs. In such cases, consumers must rely on estimates of acquisition costs in making their choices. The current work examines the influence of mental simulations of product acquisition on estimates of acquisition costs. We suggest that simulations of product acquisition lead estimates to reflect the influence of consumers' current physical states on the experience of a particular cost. Specifically, carrying a heavy burden leads consumers to estimate higher distances to targets when they engage in simulation of walking to targets, but not when they do not engage in such simulation.

Simulation can be either deliberate or spontaneous. Deliberate simulation is engaged when consumers intentionally simulate an action. Spontaneous simulation requires particular conditions for its occurrence, but does not require conscious intent. The specific conditions for the occurrence of spontaneous simulation are the availability of situational inputs and that action be possible in the given situation. We support these ideas in a series of studies.

Study 1 demonstrates preference shifts that occur as a consequence of participants carrying heavy burdens. Participants in this study shifted their preference from an option located a visible but undefined distance away towards one that was available at their current location. Study 2 supports the theory that this shift occurs as a consequence of alterations in estimates of acquisition costs by showing that burdened participants estimate distances as greater than do unburdened participants.

Study 3 provides evidence for the role of mental simulation in producing such changes in estimated acquisition costs by showing that the distance expansion first demonstrated in study 2 occurs when targets are visible, but not when targets are not visible. This result is consistent with the central contention of this dissertation that visibility is critical for spontaneous simulation. Together, the studies support the role of spontaneous simulation in burden leading to distance expansion. Study 4 provides further support for the role of simulation in producing the effects of physical state on estimated acquisition costs by showing deliberate simulation results in similar distance to that of spontaneous simulation.

Studies 5 and 6 further demonstrate the dual roles of spontaneous and deliberate simulation on distance expansion. They show that expansion does not occur when targets are not reachable because they are up in the air (study 5). However, deliberate simulation of realistic (climbing - study 5) or unrealistic (flying - study 6) action restores distance expansion in those circumstances, supporting the role of simulation in leading to consideration of physical state in estimated acquisition costs.

The final study ties together these results by demonstrating the effects of both spontaneous and deliberate simulation in a single setting. Varying both the availability of conditions supporting spontaneous simulation and instructions for deliberate simulation the study allows an examination of the comparative effects of the two types of simulation and of their potential interaction. The study finds that deliberate simulation may produce effects that are larger than those of spontaneous simulation, but spontaneous simulation does not seem to enhance the effects of deliberate simulation.

Humans universally demonstrate intrinsically motivated prosocial behavior towards kin, non-kin ingroup members, and strangers. However, humans struggle to extend the same prosocial behavior to more abstract concepts like future-others and non-human species. The Adaptive Motivation Hypothesis posits that humans evolved intrinsic motivations to act prosocially towards more tangible social partners like those within an individual’s ingroup, but prosocial behavior towards more distant and abstract partners is constrained by ecological certainty. Prosocial behavior towards these more abstract concepts is more variable and more likely motivated by extrinsic reward. This dissertation aims to examine the development of motivations for prosocial behavior towards these more abstract concepts. My studies rely on common goods games as a proxy for examining behavior towards abstract recipients of prosocial behavior. Common goods are any resource like forests or fisheries that are non-excludable to a population, but rivalrous. In-demand common goods require cooperation of humans to ensure sustainable use in order to avoid depletion. Chapter One examined how children in three populations that differed in ecological certainty behaved in a common goods game where they were asked to contribute portions of their personal endowment to the maintenance of a forest. Participants were either provided a high extrinsic motivation, a low extrinsic motivation, or no extrinsic motivation for contributing to the maintenance of the common good. Results show that overall, children of all ages were more motivated to contribute to abstract recipients when extrinsic motivation is high. However, noticeable variation in behavior between populations was driven by ecological and cultural differences. Chapter Two examined whether aggregated extrinsic rewards increased contributions to common goods in a sample of children aged six to fourteen. Results suggest that both information about personal loss and delay in an acquiring resource together dramatically increase children’s contributions to common goods within both experimental and real-world contexts. Chapter Three explores whether making a typically abstract social partner more tangible increases an individual’s prosocial behavior towards said partner. Results for Chapter Three, conducted with a population in the Democratic Republic of the Congo, find that increasingly the tangibility of an abstract population marginally increases prosocial behavior in children but not in adults. Together, the results of these studies have implications improved understanding of the development of prosocial motivations in school age children, as well as applications to understanding motivations for socially conscious behavior in the face of environmental and conservation dilemmas.

Emotions are pervasive in daily life, and a rich literature has documented how emotional stimuli and events disrupt ongoing processing and place heightened demands on control. Yet the executive control mechanisms that subsequently resolve that interference have not been well characterized. Although many failures of executive control have emotion at their core, numerous questions remain in the field regarding interactions between emotion and executive control. How do executive processes act on affective representations? Are emotional representations less amenable to control? Do distinct processes or neural networks govern their control? The present dissertation addresses these questions by investigating the neural systems and cognitive processes that support executive control in the face of interference from affective sources. Whereas previous research has emphasized the bottom-up impact of emotion on cognition, this dissertation will investigate how top-down executive control signals modulate affect's influence on cognition. Combining behavioral techniques with neuroimaging methodologies, this dissertation characterizes the interactive relationship between affective processes and top-down executive control and the ramifications of that interaction for promoting adaptive behavior.

Cognitive and behavioral phenomena related to affective interference resolution are explored in a series of research projects spanning attention and memory. Task-irrelevant affective representations may disrupt performance, but this interference appears to be dependent on top-down factors and can be resolved by executive mechanisms. Interference resolution mechanisms act on representations both of stimuli in the environment and information stored in memory. The findings reported here support emotion's capacity to disrupt executive processing but also highlight the role executive control plays in overcoming that interference in order to promote adaptive behavior.

Preliminary evidence demonstrates that age-related differences in episodic memory performance become greater in tasks that have greater perceptual demands (e.g., task stimuli are visually degraded), but are attenuated in tasks that have greater semantic demands (e.g., task requires utilizing previous knowledge). This work suggests that age-related differences in how perceptual and semantic information are represented in the brain have an impact on episodic memory. Broadly, the goal of this thesis was to investigate this idea. To investigate this goal, while undergoing functional magnetic resonance imaging scanning, samples of younger and older adults studied and later retrieved their memories of pictures of either scenes (Study 1 and 2) or objects (Study 3). The first two studies found that, compared to younger adults, in older adults, (1) in occipitotemporal cortex, the quality of perceptual-related representations was attenuated, but, intriguingly, (2) in anterior temporal lobes and prefrontal cortex, the quality of semantic-related representations was similar and even enhanced; these effects were found to be related to episodic memory. Study 1 demonstrated this pattern in individual brain regions and Study 2 demonstrated that this pattern was also present in how information was distributed across the whole-brain network. In Study 3 it was found that these age-related differences in functional neural representations are the result of age-related visual signal loss and compensatory semantic-enhancing mechanisms. Taken together, the three studies highlight that age-related differences in neural representations have an impact on cognition and especially episodic memory.

Advanced age is associated with substantial changes in the brain. These changes can be attributed to many difference sources, such as detrimental effects of aging, brain’s compensatory responses to such negative effects, and cognitive or neural resources acquired over lifespan. As a result, under the same cognitive task, healthy older adults (OAs) often show recruitment of brain regions that are different from healthy young adults (YAs). These observations have been drawn from functional magnetic resonance imaging (fMRI) studies on aging and cognition, which have been largely based on univariate analysis that relates experimental conditions to activity level in individual brain region. While univariate analysis reveals the age differences in the recruitment of brain regions, much remains unknown regarding how these regions are playing their roles. Meanwhile, recent methodological advances in cognitive neuroscience have provided the opportunities to examine 1) functional communications across brain regions, and 2) information stored in the distributed neural representation in a region. In this dissertation, I described age-related differences in these two novel perspectives in a series of fMRI studies on episodic memory, a domain of cognition that is particularly affected by aging. In these studies, healthy YAs and OAs encoded and later retrieved images of scenes or objects inside the scanner. Analyses on functional brain network and neural representations were conducted on the neuroimaging data. These analyses revealed three main findings. First, neural representation and functional connectivity revealed reduced involvements of the core task regions in OAs. During encoding, early visual cortex (EVC) in OAs exhibited reduced representation of visual information. During retrieval, medial temporal lobe (MTL) in OAs exhibited reduced reconfiguration of functional connectivity associated with successful remembering. Second, enhanced recruitments of additional neural resources in OAs were also observed. During encoding, anterior temporal lobe (ATL) in OAs exhibited enhanced semantic representation. During retrieval, prefrontal cortex (PFC) in OAs showed enhanced functional connectivity and stronger reconfiguration of connectivity associated with successful remembering. Finally, we found that schematic knowledge affected functional communication in PFC and semantic representation in ATL differently in the two age groups, suggesting that schema-related strategies may be preferentially selected by OAs. Taken together, these studies depicted the detrimental effect of aging and brain’s adaptive changes in two novel perspectives: functional communication and information processing, which may contribute to a more comprehensive understanding of episodic memory function in aging populations.

Of the core faculties underlying higher order human cognition, two of the most fundamental are the ability to focus on particular task while avoiding distraction (cognitive stability) and the ability to switch to new tasks in light of changing circumstances (cognitive flexibility). Research into the regulation of stability and flexibility has revealed that they often display an inverse relationship: prioritizing task focus (stability) is associated with an impaired ability to switch to new tasks (flexibility), and vice versa. Such findings have led to the common conception that stability and flexibility are endpoints of a one-dimensional stability-flexibility continuum, a perspective that requires them to reciprocate in all cases. However, many empirical findings seemingly contradict a one-dimensional account, such that stability and flexibility might better be described by two separate dimensions. The relationship between stability and flexibility therefore remains unclear. In the current dissertation, I present three studies that investigated the behavioral and computational mechanisms underlying concurrent stability and flexibility regulation. In the first study, I test the assumption of an obligatory stability-flexibility tradeoff, demonstrating across three behavioral experiments that stability and flexibility can be regulated independently. Next, I explore the putative mechanisms explaining tradeoffs, revealing that tradeoffs can be attributed to cost-of-control calculations seeking to reduce cognitive exertion in contexts where it is not incentivized. Third, I conduct a formal model comparison between a one- and a two-dimensional model of stability and flexibility, demonstrating that only the two-dimensional account can accurately reproduce empirical data patterns. The better-fitting two-dimensional model also reveals the dissociable influences stability and flexibility have on the putative decision process underlying task shielding and switching. Finally, I summarize the results and explore the implications of these studies for translational research.

Much of our real-life decision making is bounded by uncertain information, limitations in cognitive resources, and a lack of time to allocate to the decision process. To mitigate these pressures, people satisfice, foregoing a full evaluation of all available evidence to focus on a subset of cues that allow for fast and “good-enough” decisions. Although this form of decision-making likely mediates many of our everyday choices, very little is known about the manner in which satisficing is spontaneously triggered and accomplished. The aim of this dissertation, therefore, is to characterize cognitive and neural mechanisms underlying human satisficing behavior via tasks that closely model real-life challenges in decision making. Specifically, the empirical studies presented here examine how people solve a novel multi-cue probabilistic classification task under various external and internal pressures, using a set of strategy analyses based on variational Bayesian inference, which can track and quantify shifts in strategies. Results from these behavioral and computational approaches are then applied to model human functional magnetic resonance imaging (fMRI) data to investigate neural correlates of satisficing. The findings indicate that the human cognitive apparatus copes with uncertainty and various pressures by adaptively employing a “Drop-the-Worst” heuristic that minimizes cognitive time and effort investment while preserving the consideration of the most diagnostic cue information.

There is a long-standing claim that humans and nonhuman primates share an evolutionarily ancient system of nonverbal number representation. By and large, the focus in the field has been on providing existence proofs of numerical competence in wide-ranging taxa or using individual species as models for comparisons with humans. Recent findings in numerical cognition have suggested that evidence for approximate numerical abilities in nonhuman species may indicate that humans and animals share a cognitive system for representing numerosities nonverbally. To date, little is known about the contextual and quantitative limits of that system, or how those limits differ between species. The studies presented here take a comparative, behavioral approach to characterizing species differences and similarities in the approximate number system, and the contexts that affect that system. Collectively, this set of studies provides evidence that the approximate number system evolved in primates as a malleable system in which numerical representations are accessed spontaneously and improved through training. Despite the sensitivity of the system to experience and context individual differences in sensitivity are greater than species differences suggesting that the selective pressures that constrained its evolution were early and general and that species variation in social group size and diet have less influence on the ANS. Finally my studies indicate that the ANS supports approximate arithmetic and is consistent with the idea that ANS representations evolved to allow animals to calculate the world around them.

The stability-flexibility dilemma describes the challenge of balancing the antagonistic goals of focusing on the current task-set (cognitive stability) and updating that task-set in response to changes in the environment (cognitive flexibility). Dynamic adjustments of cognitive flexibility are observed in cued task-switching paradigms, wherein switch costs, or the performance costs associated with switching between tasks, have been shown to decrease as the proportion of switch trials within a block increase. This effect is referred to as the list-wide proportion switch (LWPS) effect, and presents evidence of meta-flexibility, or people’s ability to find an optimal level of flexibility based on contextual demands. While context-sensitive control adaptations have been extensively researched in the conflict literature, fewer studies have been dedicated to investigating such flexibility adaptations. Consequently, the underlying mechanisms of meta-flexibility remain unknown. Across four behavioral experiments, Chapter 2 teases apart the different levels of learning that may contribute to list-wide flexibility adaptations, controlling for stimulus- and task-level associations. Chapter 3 investigates the EEG neural signatures of meta-flexibility. In Chapter 4, we test for whether learned flexibility adjustments benefit from memory consolidation, like other forms of associative learning. Lastly, Chapter 5 utilized three novel behavioral paradigms to investigate different conditions under which flexibility learning transfers or fails to transfer. Collectively, the results in this dissertation suggest that flexibility adjustments to contextual demands occurs rapidly and transfers reliably across novel stimuli, such that, in high switch frequency blocks, participants could perform more rapid task switches even on trials involving items never seen before. However, both behavioral and neural evidence suggest that flexibility learning is also task specific, such that switch performance boosts to tasks that appear more often as switch trials do not generalize to other tasks that occur in the same temporal contexts.

Neuroimaging studies of episodic memory, or memory of events from our personal past, have predominantly focused their attention on medial temporal lobe (MTL). There is growing acknowledgement however, from the cognitive neuroscience of memory literature, that regions outside the MTL can support episodic memory processes. The medial prefrontal cortex is one such region garnering increasing interest from researchers. Using behavioral and functional magnetic resonance imaging measures, over two studies, this thesis provides evidence of a mnemonic role of the medial PFC. In the first study, participants were scanned while judging the extent to which they agreed or disagreed with the sociopolitical views of unfamiliar individuals. Behavioral tests of associative recognition revealed that participants remembered with high confidence viewpoints previously linked with judgments of strong agreement/disagreement. Neurally, the medial PFC mediated the interaction between high-confidence associative recognition memory and beliefs associated with strong agree/disagree judgments. In an effort to generalize this finding to well-established associative information, in the second study, we investigated associative recognition memory for real-world concepts. Object-scene pairs congruent or incongruent with a preexisting schema were presented to participants in a cued-recall paradigm. Behavioral tests of conceptual and perceptual recognition revealed memory enhancements arising from strong resonance between presented pairs and preexisting schemas. Neurally, the medial PFC tracked increases in visual recall of schema-congruent pairs whereas the MTL tracked increases in visual recall of schema-incongruent pairs. Additionally, ventral areas of the medial PFC tracked conceptual components of visual recall specifically for schema-congruent pairs. These findings are consistent with a recent theoretical proposal of medial PFC contributions to memory for schema-related content. Collectively, these studies provide evidence of a role for the medial PFC in associative recognition memory persisting for associative information deployed in our daily social interactions and for those associations formed over multiple learning episodes. Additionally, this set of findings advance our understanding of the cognitive contributions of the medial PFC beyond its canonical role in processes underlying social cognition.

Disgust features prominently in many facets of human life, from dining etiquette to spider phobia to genocide. For some applications, such as public health campaigns, it might be desirable to know how to increase disgust, whereas for things like legal and political decision-making it might be desirable to know how to suppress disgust. However, interventions in neither direction can take place until the basic structure of disgust is better understood. Disgust is notoriously difficult to model, largely due to the fact that it is a highly individually variable, multifactorial construct, with a great breadth of eliciting stimuli and contexts. As such, many of the theories which attempt to comprehensively describe disgust come into conflict with each other, impeding progress towards more efficient and effective ways of predicting disgust-related outcomes. The aim of this dissertation is to explore the possible contribution of data-driven methods to resolving theoretical questions, evaluating extant theories, and the generation of novel conceptual structures from bottom-up insights. Data were collected to sample subjective experience as well as psychophysiological reactivity. Through the use of techniques such as factor analysis and support vector machine classification, several insights about the approaching the study of disgust emerged. In one study, results indicated that the level of abstraction across subdivisions of disgust is not necessarily constant, in spite of a priori theoretical expectations: in other words, some domains of disgust are more general than others, and recognizing as much will improve the predictive validity of a model. Another study highlighted the importance of recognizing one particular category of disgust elicitors (mutilation) as a separate entity from the superordinate domains into which extant theories placed it. Finally, another study investigated the influence of concurrent emotions on variability in disgust physiology, and demonstrated the difference in the representations of the structure of disgust between the level of subjective experience and the level of autonomic activity. In total, the studies conducted as part of this dissertation suggest that for constructs as complex as disgust, data-driven approaches investigations can be a boon to scientists looking to evaluate the quality of the theoretical tools at their disposal.

Public health data show that many everyday reckless behaviors reach a developmental peak in adolescence, with adolescents engaging in more reckless behaviors than both children and adults. In contrast, most studies of decision-making across development do not find laboratory risk-taking to peak in adolescence. Here, I focus on two factors that contribute to the discrepancy between public health and laboratory findings: ambiguity and social context. Everyday decisions tend to involve ambiguous decisions (choices with unknown probabilities), while previous laboratory studies have largely focused on risky decisions (choices with known probabilities). Consequently, little is known about the ambiguity preferences of young children. Across three behavioral studies, I show that ambiguity aversion is absent in 5-year-old children (Chapter 2) and 8- and 9-year-old children (Chapter 3) but present in 15- to 18-year-old adolescents (Chapter 4) and adults (Chapters 2 to 4). The results of Chapters 2 through 4 indicate that the willingness to take ambiguous gambles, like the willingness to take risky gambles, does not peak in adolescence. Everyday decisions also often occur in social contexts when friends are present and outcomes can be shared, whereas most laboratory studies occur in social isolation. In Chapter 5, I use functional magnetic resonance imaging to show that neural response to reward for self and for friend are similar in a sample of young adults (ages 18 to 28), and that neural response to reward linearly decreases with age when participants are watched by their friends but not when they are alone. In Chapter 6, I use behavioral modeling to show that adults value rewards similarly for themselves and for their friend. Adolescents, in contrast, value their own rewards more than those of their friend, but the presence of their friend reduces this valuation difference. The results of Chapters 5 and 6 indicate that the presence of friends prompts adolescents and young adults to engage in behavior that benefits both themselves and their friends. Collectively, the results in this dissertation demonstrate the need to consider contextual influences on decision-making in order to better capture everyday decision behavior in the laboratory.

Decision-making under risk has been of interest to philosophers for centuries. in Only in recent years through interdisciplinary approaches has knowledge concerning the descriptive nature of decision-making under risk increased. Although we know that risk-preference proceeds from a risk-seeking trend in childhood to risk-aversion in adulthood, little is known about the factors that contribute this development. The studies presented here take an interdisciplinary approach to identifying the factors that contribute to age-related changes in risk preference, where in the decision-making process these factors have influence, and changes in neural circuitry that could be responsible. The work presented herein finds that risk-preference is differentially modulated across development by risk level, the values of choice options, and the domain (gains or loss) in which options are presented. During valuation, many brain regions that have previously been associated with decision-making and risk were found to increase in activation with age, suggesting the maturation of a decision-making network. Activation in a few key areas were associated with greater risk-aversion in children, suggesting that maturation of the decision-making network leads to more adult-like behavior. The cognitive component of children's greater risk-seeking was not found to be a deficiency in probabilistic reasoning, the ability to learn from negative feedback, or a general optimism for winning. Rather, children's valuation of a gamble may be exaggerated by a disproportionate amount of attention given to the winning outcome of a gamble. It is further speculated that a lack of regret during outcome evaluation may also contribute to differences in children's risk preference compared to adults.

The visual system is thought to represent the trajectory of moving objects in the activity of large populations of cortical neurons that respond preferentially to the direction of stimulus motion. Here I employed in vivo voltage sensitive dye (VSD) imaging to explore how abrupt changes in the trajectory of a moving stimulus impact the population coding of motion direction in ferret primary visual cortex (V1). For motion in a constant direction, the peak of the cortical population response reliably signaled the stimulus trajectory; but for abrupt changes in motion direction, the peak of the population response departed significantly from the stimulus trajectory in a fashion that depended on the size of the direction deviation. For small direction deviation angles, the peak of the active population shifted from values consistent with the initial direction of motion to those consistent with the final direction of motion by progressing smoothly through intermediate directions not present in the stimulus. In contrast, for large direction deviation angles, peak values consistent with the initial motion direction were followed by: a small deviation away from the final motion direction, a rapid 180° jump, and a gradual shift to the final direction. These departures of the population response from the actual trajectory of the stimulus predict specific misperceptions of motion direction that were confirmed by human psychophysical experiments. I conclude that cortical dynamics and population coding mechanisms combine to place constraints on the accuracy with which abrupt changes in direction of motion can be represented by cortical circuits.

Everyday, animals make decisions that require balancing tradeoffs like time delays, uncertainty, and physical effort demands with the prospect of rewards like food or money. The tendency to devalue rewards according to these tradeoffs is also known as discounting and depends on how much subjective value an animal places on a reward. These discounting decisions are supported by different neural systems. The influence of dopamine signaling is well-characterized as a modulator of motivation and decision making. However, the role of dopamine as a marker of interindividual differences of reward sensitivity and valuation is less clearly understood. Using a combination of neuroimaging techniques (functional magnetic resonance imaging and positron emission tomography), behavioral experiments, and meta-analyses, this dissertation identifies how trait-like variation in dopamine function explains the way people differ in their preferences and neural computations of value. Overall, the findings indicate that while dopamine may exert acute influence over reward discounting behavior, these associations may not extend to trait-like differences. Specifically, individual differences in dopamine receptor availability are related to discounting behavior in clinical populations but not healthy adults. Nevertheless, individual differences in dopamine are related to functional brain activation associated with the subjective valuation of rewards—the input to choice behavior. These results highlight that interindividual variation in dopamine is more directly linked to neural computations than observed behaviors and that dopamine-mediated psychopathology does not precisely map on to acute pharmacodynamics.

Background: The role of grandparents has changed in response to social, economic and demographic factors, which may operate both in favour of or against the relationship between grandparents and their grandchildren. The potential positive impact of the grandparent-grandchild relationship on the development of adolescent grandchildren has been increasingly recognized, although relatively few studies have directly related this relationship to measures of child well-being. This study aims to examine the association between grandparent-grandchild interactions and socio-emotional and cognitive outcomes among adolescent grandchildren in Sri Lanka. Methods: This cross-sectional study was conducted within schools, temples, homes and community buildings in Galle District. An interviewer-assisted survey was used to collect data about the adolescent participants’ demographics, family and household information, grandparent relationships, empathy, and socio-emotional development. A cognitive test was used to assess the adolescents’ cognitive development. Univariate, bivariate and multivariate analyses were used to examine the association between the grandparent-grandchild relationship and adolescent outcomes. Results: Our results indicate that grandparent-grandchild relationships are significantly associated with adolescent socio-emotional and cognitive development. Conclusions: This study underlines the importance of the grandparent-grandchild relationship.

A pervasive aspect of daily life is searching for a specific target amongst an array of distracting items. Studying such visual searches offers a useful and powerful tool for revealing the underlying aspects of visual attention. Understanding how factors influence accurate target detection serves to both enhance real-world search tasks and inform basic cognitive psychology. The goal of the research presented herein is to examine the effects of expectation, experience, and environment on search behavior. The experiments are conducted in controlled laboratory environments, but are designed to simulate real-world searches, with the express goal of informing the implementation of search tasks in everyday life. First, expectation is explored by manipulating target prevalence and measuring the resultant change in behavior as participants' biases shift. Second, experience is tested by comparing individuals with and without extensive video game exposure, specifically on their susceptibility to the pressures of rare target search. Lastly, environment is examined by utilizing multiple simultaneous targets. This manipulation has been shown to induce errors in radiology, and here the generality of this effect is explored to establish the various pressures to which it is sensitive. Collectively, these data serve to inform how different influences modulate visual search performance, and the results can directly inform the training, recruitment, and execution of real-world search tasks such as those in radiology, cytology, and airport security.

Distancing is a type of emotion regulation that involves simulating a new perspective to alter the psychological distance and emotional impact of a stimulus. The effectiveness and versatility of distancing make it a promising skill for clinical applications. However, the specific neurocognitive mechanisms of this emotion regulation tactic are poorly defined relative to the broader strategy of reappraisal. More focused investigation of these mechanisms would promote further understanding of the processes underlying distancing and potentially improve its applications. Therefore, I first synthesized literature on the component processes of distancing to propose a preliminary neurocognitive model. I tested the neural architecture of this model through a meta-analysis of fMRI literature, and then further validated and refined it by comparing three forms of distancing in an fMRI study. Finally, I investigated self-projection and its relation to the left temporoparietal junction using transcranial magnetic stimulation. The results of this work supported the neural architecture of the proposed model and suggested subtle differences in the recruitment of parietal regions across forms of distancing. No conclusions could be drawn regarding the specific functional contribution of the left temporoparietal junction, but I found that distancing performance was facilitated by repeated use, reinforcing the utility of this tactic for applied contexts. This model contributes new insights into the neurocognitive mechanisms of distancing, informs the optimal use of this tactic, and provides a framework for future research and interventions.