ABSTRACT
The subjective complexity of a computer-generated bitmap image can be measured by magnitude estimation scaling, and its objective complexity can be measured by its compressed file size. There is a high correlation between these measures of subjective and objective complexity over a large set of marine electronic chart and radar images. The subjective dissimilarity of a pair of bitmap images can be predicted from subjective and objective measures of the complexity of each image, and from the subjective and objective complexity of the image produced by overlaying the two simple images. In addition, the subjective complexity of the image produced by overlaying two simple images can be predicted from the subjective complexity of the simple images and the subjective dissimilarity of the image pair. The results of the experiments that generated these complexity and dissimilarity judgments are consistent with a theory, outlined here, that treats objective and subjective measures of image complexity and dissimilarity as vectors in Euclidean space.
Subject(s)
Information Theory , Visual Perception , Computer Simulation , Humans , Judgment , Models, Theoretical , Photic Stimulation , Visual FieldsABSTRACT
Nightmares are usually defined as frightening dreams that awaken the sleeper. This study uses the waking criterion to distinguish between nightmares and bad dreams and investigated the variety and intensity of emotions reported in each form of disturbing dream. Ninety participants recorded their dreams for 4 consecutive weeks and, for each dream recalled, noted the emotions present and their intensities on a 9-point scale. Thirty-six participants reported at least one nightmare and one bad dream over the 4 weeks covered by the log, while 29 reported having had at least one bad dream but no nightmares. Nightmares were rated as being significantly (p < 0.001) more intense than bad dreams. Thirty percent of nightmares and 51% of bad dreams contained primary emotions other than fear. The findings support the claim that awakening can serve as an indirect measure of nightmare intensity and raise important implications for the operational definition of nightmares.
Subject(s)
Dreams/classification , Dreams/psychology , Emotions/classification , Night Terrors/classification , Adult , Diagnosis, Differential , Fear/psychology , Female , Humans , Male , Mental Recall , Models, Psychological , Night Terrors/diagnosis , Night Terrors/psychology , Records , Surveys and Questionnaires , Terminology as Topic , WakefulnessABSTRACT
The idea of visual complexity, the history of its measurement, and its implications for behavior are reviewed, starting with structuralism and Gestalt psychology at the beginning of the 20th century and ending with visual complexity theory, perceptual learning theory, and neural circuit theory at the beginning of the 21st. Evidence is drawn from research on single forms, form and texture arrays and visual displays. Form complexity and form probability are shown to be linked through their reciprocal relationship in complexity theory, which is in turn shown to be consistent with recent developments in perceptual learning and neural circuit theory. Directions for further research are suggested.
