Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Denna uppsats skrevs i syfte att undersöka den påverkan som visualisering har på riskbedömning och affekt, samt sambandet mellan affekt och riskbedömning. Fyra hypoteser testades: 1. Riskskattning vid visualisering förväntades ge högre riskskattningar än utan visualisering.  2. De som visualiserade förväntades ha mer negativ sinnesstämning än de som inte visualiserade. 3. Det förväntades finnas ett samband mellan negativ sinnesstämning och hög riskskattning. 4. Kvinnor förväntades skatta risk högre än män. Beräkningarna baseras på 347 enkäter insamlade bland studenter inom beteendevetenskapliga ämnen. Skillnaderna i riskskattning visade sig finnas i enlighet med hypotes mellan de som instruerades att visualisera och de som enbart skattade riskerna utan specifika instruktioner. Dock fanns ingen signifikant skillnad mellan visualiserings- och resoneringsinstruktioner eller mellan resoneringsinstruktioner och de utan specifika instruktioner. Ingen signifikant skillnad fanns gällande sinnesstämning. En svag korrelation fanns mellan negativ sinnesstämning och riskskattning. Riskskattningen visade sig vara högre bland kvinnorna än männen. Visualiseringsinstruktioner verkar påverka riskbedömningar i negativ riktning. Dock så fanns inte den skillnad mellan visualisering och resonerande som funnits i en tidigare studie. Angående könsskillnader vid riskbedömning ligger denna studie i linje med tidigare forskning. Det svaga sambandet mellan sinnesstämning och riskskattning pekar på att måendet och riskbedömning hänger ihop men att visualisering inte leder till ett rent användande av affektheuristik. Fler studier behövs för att förstå sambandet mellan visualisering, sinnesstämning och riskbedömning. / The purpose of this paper is to examine risk judgement and affect when using mental imagery. Four hypotheses were tested; 1. Risk judgement was expected to be higher when using mental imagery than without using mental imagery. 2. Participants who used mental imagery were expected to have a more negative mood than the ones who didn’t use mental imagery. 3. A negative correlation between mood and risk judgement was expected. 4. Women were hypothesized to give higher risk ratings than men. Calculations were made using 347 surveys from students of behavioral sciences. The hypothesized difference in risk judgement when using mental imagery was found between participants instructed to use mental imagery and those without specific instructions. However no difference was found between mental imagery instructions and reasoning instructions, or between reasoning and no instructions. No significant difference was found for mood.  A weak correlation was found between negative mood and risk judgement. Women rated risks higher than men. Both risk judgement and mood seem to be influenced negatively by mental imagery. However the difference between instructions of mental imagery and reasoning that was found in an earlier study was not present here. The sex differences were consistent with earlier studies. The weak correlation between risk judgement and mood found in this study tells us that the two are connected but mental imagery doesn’t seem to lead to usage of affect heuristics. More studies are needed to understand the connection between mental imagery, mood and risk judgement.

This thesis is written as a collection of research papers through which the cognitive and motivational effects of imagery on sports performance were investigated. A number of research methodologies, ranging from a quasi-experimental design to a multiple-baseline across participants design, were employed to explore the effects of imagery. The first section of this thesis explored the cognitive effects of imagery. Specifically, study I examined the effects of different visual imagery perspectives and kinaesthetic imagery on the acquisition and retention of a simple gymnastics routine. External visual imagery was shown to have superior effects over internal visual imagery for this form-based task. A significant interaction was found in the retention phase; however, follow up tests failed to clarify the nature of the interaction. Study 2 and study 3 further investigated the imagery perspective issue by exploring the strength of relationship between external visual imagery and kinaesthetic imagery, and between internal visual imagery and kinaestlictic imagery. Results indicated that when the participant is the object of the image, kinaesthetic imagery has a greater association with external visual imagery than with internal visual imagery. However, because the tasks that participants imaged were essentially form-based, the results may not generalise to other types of tasks. The second section of the thesis examined the motivational effects of imagery. Study 4 employed a multiple-baseline across participants design to establish the effect of a mastery imagery intervention on sport confidence. Consistent with Paivio's (1985) proposals, the results suggested that imagery has a motivational function as the imagery intervention was found to increase confidence. Study 5 further considered the imagery confidence relationship and two factors which may moderate this relationship, that is skill level and sport-type. The results suggest that in team sport players the type of imagery associated with confidence depends on the skill level of the player.

Mental imagery presents humans with the opportunity to predict prospective happenings based on own intended actions, to reminisce occurrences from the past and reproduce the perceptual experience. This cognitive capability is mandatory for human survival in this folding and changing world. By means of internal representation, mental imagery offers other cognitive functions (e.g., decision making, planning) the possibility to assess information on objects or events that are not being perceived. Furthermore, there is evidence to suggest that humans are able to employ this ability in the early stages of infancy. Although materialisation of humanoid robot employment in the future appears to be promising, comprehensive research on mental imagery in these robots is lacking. Working within a human environment required more than a set of pre-programmed actions. This thesis aims to investigate the use of mental imagery in humanoid robots, which could be used to serve the demands of their cognitive skills as in humans. Based on empirical data and neuro-imaging studies on mental imagery, the thesis proposes a novel neurorobotic framework which proposes to facilitate humanoid robots to exploit mental imagery. Through conduction of a series of experiments on mental rotation and tool use, the results from this study confirm this potential. Chapters 5 and 6 detail experiments on mental rotation that investigate a bio-constrained neural network framework accounting for mental rotation processes. They are based on neural mechanisms involving not only visual imagery, but also affordance encoding, motor simulation, and the anticipation of the visual consequences of actions. The proposed model is in agreement with the theoretical and empirical research on mental rotation. The models were validated with both a simulated and physical humanoid robot (iCub), engaged in solving a typical mental rotation task. The results show that the model is able to solve a typical mental rotation task and in agreement with data from psychology experiments, they also show response times linearly dependent on the angular disparity between the objects. Furthermore, the experiments in chapter 6 propose a novel neurorobotic model that has a macro-architecture constrained by knowledge on brain, which encompasses a rather general mental rotation mechanism and incorporates a biologically plausible decision making mechanism. The new model is tested within the humanoid robot iCub in tasks requiring to mentally rotate 2D geometrical images appearing on a computer screen. The results show that the robot has an enhanced capacity to generalize mental rotation of new objects and shows the possible effects of overt movements of the wrist on mental rotation. These results indicate that the model represents a further step in the identification of the embodied neural mechanisms that might underlie mental rotation in humans and might also give hints to enhance robots' planning capabilities. In Chapter 7, the primary purpose for conducting the experiment on tool use development through computational modelling refers to the demonstration that developmental characteristics of tool use identified in human infants can be attributed to intrinsic motivations. Through the processes of sensorimotor learning and rewarding mechanisms, intrinsic motivations play a key role as a driving force that drives infants to exhibit exploratory behaviours, i.e., play. Sensorimotor learning permits an emergence of other cognitive functions, i.e., affordances, mental imagery and problem-solving. Two hypotheses on tool use development are also conducted thoroughly. Secondly, the experiment tests two candidate mechanisms that might underlie an ability to use a tool in infants: overt movements and mental imagery. By means of reinforcement learning and sensorimotor learning, knowledge of how to use a tool might emerge through random movements or trial-and-error which might reveal a solution (sequence of actions) of solving a given tool use task accidentally. On the other hand, mental imagery was used to replace the outcome of overt movements in the processes of self-determined rewards. Instead of determining a reward from physical interactions, mental imagery allows the robots to evaluate a consequence of actions, in mind, before performing movements to solve a given tool use task. Therefore, collectively, the case of mental imagery in humanoid robots was systematically addressed by means of a number of neurorobotic models and, furthermore, two categories of spatial problem solving tasks: mental rotation and tool use. Mental rotation evidently involves the employment of mental imagery and this thesis confirms the potential for its exploitation by humanoid robots. Additionally, the studies on tool use demonstrate that the key components assumed and included in the experiments on mental rotation, namely affordances and mental imagery, can be acquired by robots through the processes of sensorimotor learning.

A considerable amount of research exists on the subjective perception of three-dimensional structure from texture gradients. The present set of experiments extends these tests of phenomenal perception by examining the underlying processes used in interpreting slant-from-texture. The first two experiments show that measures of subjective perception predict speeded performance in a visual search task, and that the mediating representation relies on an assumption of projective size (i.e., discriminating the size of the target is difficult when the short target is far or the long target is near). The third experiment shows that sensitivity to apparent depth in the texture display is present even in rapid and parallel search conditions where early vision is known to operate. The fourth experiment assesses the relative contribution of two dominant dimensions of the texture gradient -- "perspective" (i.e., a radial pattern) and "compression" (i.e., a foreshortened pattern). Both dimensions are detected by early vision as signals for apparent depth. The fmal experiment examines how early vision codes these two dimensions. Sternberg's (1969) Additive Factors Method (AFM) is used to assess separability of encoding, and Blalock's path analysis (1962, 1985) is used to examine the order of encoding. AFM shows that perspective and compression have independent influences on search performance in the most rapid search conditions, but that their interaction increases as search slows. The path analysis shows further that when both texture dimensions are available, perspective exerts a more immediate and perhaps even an exclusive influence on performance. These findings support the view that perspective and compression are coded separately at the earliest stages of visual processing and share a common code only later in visual processing. / Arts, Faculty of / Psychology, Department of / Graduate

Self-modeling (SM) involves an observer viewing oneself on an edited video showing desired behaviors (Dowrick, & Dove, 1990). The impact of a SM video on skill acquisition has been frequently explored (e.g., Clark & Ste-Marie, 2006), however, few researchers have investigated SM in competition (Ste-Marie, Rymal, Vertes, & Martini, 2009). Also of limited study has been the underlying self-regulatory mechanisms engaged in alongside a SM video (e.g., Rymal, Martini, & Ste-Marie, 2010). To date, research has not investigated the effects of SM on gymnasts competitive bar performance or how it is used to self-regulate, nor whether SM increases self-regulation. Thus, the purpose here was to investigate the effects of a SM video on gymnasts’ physical performance and self-regulation. Of further interest was to explore the combination of SM and psychological skills training (PST) on competitive performance. Eighteen gymnasts were divided into two groups; SM+PST (n = 10) and SM (n =8). The SM+PST group took part in workshops one month prior to the competitions wherein links between SM and psychological skills were made. The SM group did not do the workshops. Gymnasts competed at four competitions; two received the SM video and two did not. For the video competitions, participants viewed their video three times prior to warm-up and once before competing. After one video competition and one competition that gymnasts did not receive the video, interview sessions were conducted with ten gymnasts. The results of the physical performance data did not show any significant group or condition main effects (all F’s < 1). Imagery ability, however, was a moderating variable. Gymnasts low in visual imagery ability benefitted from the use of the self-modeling video later in the season F(1, 16) = 5.976, p = .026, η2 = .27, (1 – β) = .63, but not early in the season. Through the qualitative analysis of interview questions, it can be said that gymnasts used the SM video as a task analysis strategy before, during, and after their competitive event. Analysis of transcripts also suggested that the SM video encouraged the use of certain self-regulatory processes and beliefs related to the forethought (i.e., before) and self-reflection (i.e., after) phases above and beyond that typically used when competing.

The ability to mentally represent actions is suggested to have a role in the online control of movement in healthy adults. Children’s movement imagery ability and online control have been shown to develop at similar non-linear rates. The current study investigated the relationship between movement imagery and online control in children by comparing implicit and explicit movement imagery measures with the ability to make online trajectory corrections. Imagery ability was a significant predictor of children’s online control of reaching once age and general reaching efficiency were controlled for. These findings extend the proposed relationship between movement imagery and online control.

The objective of this dissertation is to investigate all the necessary components in spectral mixture analysis (SMA) for hyperspectral imagery under an unsupervised circumstance. When SMA is linear, referred to as linear spectral mixture analysis (LSMA), these components include estimation of the number of endmembers, extraction of endmember signatures, and calculation of endmember abundances that can automatically satisfy the sum-to-one and non-negativity constraints. A simple approach for nonlinear spectral mixture analysis (NLSMA) is also investigated. After SMA is completed, a color display is generated to present endmember distribution in the image scene. It is expected that this research will result in an analytic system that can yield optimal or suboptimal SMA output without prior information. Specifically, the uniqueness in each component is described as follow. 1)A new signal subspace-based approach is developed to determine the number of endmembers with relatively robust performance and the least parameter requirement. 2)The best implementation strategy is determined for endmember extraction algorithms using simplex volume maximization and pixel spectral similarity; and algorithm with the special consideration for anomalous pixels is developed to improve the quality of extracted endmembers. 3)A new linear mixture model (LMM) is deployed where the number of endmembers and their types can be changed from pixel to pixel such that the resulting endmember abundances are sum-to-one and nonnegative as required; and fast algorithms are developed to search for a sub-optimal endmember set for each pixel. 4)A simple approach for NLSMA based on LMM is investigated and an automated approach is developed to determine either linear or nonlinear mixing is actually experienced. 5)A color display strategy is developed to present SMA results with high class/endmember separability.

The Urban Heat Island (UHI) effect is a function of excess heating of man-made impermeable surfaces and structures. Using Landsat satellite imagery along with its Thermal-Infrared (TIR) band, the UHI of Starkville, MS; Birmingham, AL; and Atlanta, GA were analyzed. Unsupervised classification of the Landsat imagery and temperature extraction from the TIR band revealed city size and amount of high-density urban land use are directly related to UHI intensity and higher than average surface temperatures. Vegetation analysis within the three study area cities, however, revealed an average surface temperature reduction of 2 °C with only 15% forest coverage within a 1km2 area. Results obtained can be useful as a potential monitoring tool that can characterize relationships between amount and percentage of urban tree cover and surface temperature. The information can be utilized by city planners and others who are interested in mitigating UHI effects in the ever- increasing urban America.

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