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Biomedical subjects

C Plug

Publications and source records attributed to C Plug.

6 recordsLinked to original sources
PubMed1994

The natural moon illusion: a multifactor angular account.

It is argued that the failure to explain the celestial illusion results from conceptual confusion about perceived size and from disregard of the observational evidence relating to the natural moon illusion. The evidence shows that the illusion consists of a perceived angular size enlargement of horizon objects, by a factor of about 1.5-2.0 in diameter in comparison with elevated objects. Most measurements of the illusion have been made in terms of angular size, although in some proposed explanations an illusion of linear size is assumed. The magnitude of the illusion varies, particularly with the detail of the horizon scene. The illusion can be explained as the sum of several factors that affect perceived angular size: size contrast, vergence commands and eye or head position, aerial perspective, and colour. The relative contributions of these factors are assessed.

Color Perception↗
PubMed1992

Weskoppies Hospital, founded 1892--the early years.

The Krankzinnigengesticht te Pretoria (Pretoria Lunatic Asylum) was established in 1892 as the first and only psychiatric institution in the Zuid-Afrikaansche Republiek (now the Transvaal). The asylum was later renamed Weskoppies Hospital. The first 10 years of the hospital's history, including the turbulent years of the Anglo-Boer War, are described. Attention is given to the institution's management, the diagnosis and treatment of patients and the effectiveness of such treatment. The hospital's medical director followed an enlightened approach to caring for the mentally ill, in line with the policies of psychiatric hospitals in contemporary Europe. However, his ideals of no restraint and minimal confinement of patients could not be maintained during the war years owing to insufficient accommodation and a lack of suitably trained attendants. It is concluded that the humane care of the institutionalised psychiatric patient was (and is) not guaranteed by enlightened policies, but depends on sufficient resources to put such policies into practice.

History, 19th Century↗
PubMed1989

The registered distance of the celestial sphere: some historical cross-cultural data.

Estimates of the diameters of the sun and moon expressed in centimetres have been reported by several authors in the past. These estimates imply that the sizes of the sun and moon are perceived as if these bodies are only some tens of metres distant. In this study five units of length that were used by ancient astronomers to estimate arcs on the celestial sphere were investigated. The purpose was to determine whether the lengths and angles represented by these units imply a specific registered distance of the star sphere. The sizes of the Babylonian cubit, Arab fitr and shibr, Greek eclipse digit, and Chinese chang support the conclusion that the registered distance of the stars was about 10 to 40 metres in these four cultures over the last two millennia.

Astronomy↗
PubMed1980

The golden section hypothesis.

The golden section hypothesis states that a visual form is most aesthetically pleasing when the ratio of the dimensions (x,y) equals the ratio of the larger dimension to the sum of the two, i.e. x/y = y/(x + y). The ratio of larger to smaller is then 1.618....A review of studies of the golden section hypothesis indicates that the attempt to determine preferences for certain ratios by asking subjects to rank a fixed series of stimuli does not lead to meaningful results. A simple experiment shows that about half of the subject rank the stimuli in order of increasing or decreasing ratio. The study of preferred ratios from drawings is subject to fewer methodological problems. The modal length-to-breadth ratio of 515 drawn ellipses was found to be 1.60-1.79, close to the golden section. However, a similar "preference" was found for the length of the drawings, indicating that such group preferences are probably of little aesthetic or psychological importance.

Adolescent↗
PubMed1977

Subjective and objective symmetry in perception of form.

A new quantitative measure of the physical symmetry of 2-dimensional shapes is proposed which relates it to the proportion of translational and rotational (TR) overlap between a figure and its mirror image. Category ratings of the apparent vertical symmetry of distorted diamond figures correlate highly with this measure while it is also an important contributor in the prediction of the apparent symmetry and geometricity of random polygons.

Choice Behavior↗