The Schedule for Affective Disorders and Schizophrenia-Change Version (SADS-C), the Social Adjustment Scale-Patient Version II (SAS-PATII) and the Command Hallucination Questionnaire (CAQ) were administered to 86 psychotic inpatients to investigate the relationship between command hallucinations, aggressive behavior, and compliance. Two SADS-C items ("severity of hallucinations" and "depersonalization") were useful as indicators of command hallucinations. Ninety-two percent had complied with their command at least once in the past month. Three SADS-C variables related to compliance with command hallucinations were identified: middle insomnia, the belief that the voice was acting in your best interest, and overt irritability. The patients' level of distortion of reality did not appear to influence compliance rates. Results also indicated that patients who experience command hallucinations were not significantly more or less dangerous than other psychotic inpatients.

This experiment was designed to examine aspects of human visual perception during approaches to a runway. The runway width illusion has commonly been reported to contribute to the dangerous tendency of pilots to fly low approaches to runways that are wide and high approaches to runways that are narrow. Attempts to prevent the runway width illusion have not attempted to identify the ideal location for an indicator of altitude. Thus the present experiment examined the effect of varying runway width and manipulated scenes in order to determine whether the runway width illusion was present and where participants were focusing their attention in the scenes. Thirty-two non-pilot participants and 3 pilots took part in the experiment and viewed static and dynamic scenes of runways that were narrow (30.48m), medium (60.96m) or wide (91.44m) at one of three viewing heights low (30.48m), medium (45.72m) or high (60.96m). After viewing scenes, participants were required to estimate their altitude and aim-point. The results of this experiment revealed that participants were fairly inaccurate at estimating altitude and were inclined to overestimate aim-point, however the data also indicated that there was a robust runway width illusion that was present across static and dynamic trials and in both altitude and aim-point data. The standard marking on the runway in an attempt to prevent the runway width illusion was not effective at preventing incorrect altitude estimations but did assist participants to estimate aim-point. It was also found that the objects that participants' most commonly reported using to estimate altitude in the visual scene were located in the lower segment of the scenes.

In this text I am investigating the relationship between craft, fine art and kitsch/popular culture through the making of a three-dimensional pattern in patchwork technique. I apply the investigation to my working technique by comparing certain examples of fine art pieces with kitsch items. A method that during the process was named Versus Associations. I have connected the art pieces and kitsch items through this method of associations based on their similarities in colors and composition. The aim of the pattern is to mediate color interactions that make up a visual illusion. I want to make the beholders curious of what is happening in the pattern and show that it can affect them physically. / <p>Due to copyright some pictures has been removed. Numbers, representing these pictures, with attached web links can be found in references.</p>

Thesis (Ph. D.)--Columbia University, 1933. / Vita. Published also as Archives of psychology, no. 153. Bibliography: p. 81-83.

Thesis (M.F.A.)--Rochester Institute of Technology, 2006. / Typescript. Includes bibliographical references (leaves 42-43).

Thesis (M.A. in Psychology)--Vanderbilt University, Dec. 2007. / Title from title screen. Includes bibliographical references.

It has been long hypothesized that due to the inherent ambiguities of visual input and the limitations of the visual system, vision is a form of “unconscious inference” whereby the brain relies on assumptions (aka expectations) to interpret the external world. This hypothesis has been recently formalized into Bayesian models of perception (the “Bayesian brain”) that represent these expectations as prior probabilities. In this thesis, I focus on a particular kind of expectation that humans are thought to possess – that objects in the world tend to be still or move slowly – known as the “slow speed prior”. Through a combination of experimental and theoretical work, I investigate how the speed prior is acquired and how it impacts motion perception. The first part of my work consists of an experiment where subjects are exposed to simple "training" stimuli moving more often at high speeds than at low speeds. By subsequently testing the subjects with slow-moving stimuli of high uncertainty (low contrast), I find that their perception gradually changes in a manner consistent with the progressive acquisition of an expectation that favours progressively higher speeds. Thus subjects appear to gradually internalize the speed statistics of the stimulus ensemble over the duration of the experiment. I model these results using an existing Bayesian model of motion perception that incorporates a speed prior with a peak at zero, extending the model so that the mean gradually shifts away from zero. Although the first experiment presents evidence for the plasticity of the speed prior, the experimental paradigm and the constraints of the model limit the accuracy and precision in the reconstruction of observers’ priors. To address these limitations, I perform a different experiment where subjects compare the speed of moving gratings of different contrasts. The new paradigm allows more precise measurements of the contrast-dependent biases in perceived speed. Using a less constrained Bayesian model, I extract the priors of subjects and find considerable interindividual variability. Furthermore, noting that the Bayesian model cannot account for certain subtleties in the data, I combine the model with a non-Bayesian, physiologically motivated model of speed tuning of cortical neurons and show that the combination offers an improved description of the data. Using the paradigm of the second experiment, I then explore the role of visual experience on the form of the speed prior. By recruiting avid video gamers (who are routinely exposed to high speeds) and nongamers of both sexes, I study the differences in the prior among groups and find, surprisingly, that subjects’ speed priors depend more on gender than on gaming experience. In a final series of experiments similar to the first, I also test subjects on variations of the trained stimulus configuration – namely different orientations and motion directions. Subjects’ responses suggest that they are able to apply the changed prior to different orientations and, furthermore, that the changed prior persists for at least a week after the end of the experiment. These results provide further support for the plasticity of the speed prior but also suggest that the learned prior may be used only across similar stimulus configurations, whereas in sufficiently different configurations or contexts a “default” prior may be used instead.

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Optical illusions are inseparably part of our lives. We are influenced by illusions on daily base, in commercials, various tests or fun web pages. But we must ask a questions about background of illusions, about their history. What was the original meaning of illusions? When we are confronted with illusion, what's happend? Do we understood illusions? How should be our attitude to illusions? These are only few questions, that this work try to answer. Due to history we try to understand illusions, their evolution and find some kind of classification. We used semiotic analysis to an illusions in commercial use. Actually semiotic analysis combined with optical illusions is a challenge. How we can interpret multi- significant or ambiguous objects? Semiotic analysis help us understand and recognized illusions in common world. Powered by TCPDF (www.tcpdf.org)

Current explanations for the Ames Trapezoid Illusion are based upon the the absence of cues: the illusion is said to occur at chance. A review of recent literature showed that: (a) the illusion varies in frequency as a function of target shape (b) that the dominant cue to reduce the frequency of the illusion is the variant in retinal height. Based upon the dominance of this cue a new model was presented. Following this model it was hypothesized that observers viewing partial rotation when the target produces the greatest difference in the retinal height of the ends would determine the true direction more accurately than observers viewing the same target when the differences in the retinal height was least. The results confirmed the hypothesis.