THE VISUAL SYSTEM'S MEASUREMENT OF INVARIANTS NEED NOT ITSELF BE INVARIANT

Abstract— When two shapes that differ in orientation or size have to be compared or objects have to be recognized from different viewpoints, the response time and error rate art systematically affected by the size of the geometric difference. In this report, we argue that these effects are not necessarily solid evidence for the use of mental transformations and against the use of invariants by the visual system. We report an experiment in which observers were asked to give affine-invariant coordinates of a point located in an affine frame defined by three other points. The angle subtended by the coordinate axes and the ratio of the lengths of their unit vectors systematically affected the measurement errors. This finding demonstrates that the visual system's measurement of invariants need not itself be invariant.     

The collective representation of affliction: Some reflections on disability and disease as social facts

A perspective is developed for approaching affliction as a social fact. Disability and disease are considered as two ways in which we suffer a disjunction which arises from the need to take initiative with respect to the inexorable, whether that means the mark of disability or the unconquerability of disease. The story of affliction always raises and masks in certain respects the problem of suffering as the collective representation of our experience of subjectivity where that experience passes through the separateness of being marked to the singularity of being without hope.     

Inferential processing of context: Studies of cognitively impaired subjects

Language comprehension tasks involving pronoun coreference were administered to a group of demented patients, a group of patients with cardiac disease, and groups of normal elderly persons and young adults. Pronoun coreference was constrained by either lexical, syntactic, or contextual cues. No differences were found between old and young subjects for any task. While the demented patients were impaired on all tasks, the cardiac patients were specifically impaired in the inferential processing of context.     

Poisson signal-detection theory: Link between threshold models and the Gaussian assumption

The Gaussian model of signal detection cannot fit asymmetric data as long as the variances of the distributions are kept equal. It is therefore common practice to assume unequal variances in order to fit these data. But this assumption leads to the well-known crossover problem. The present paper provides new arguments for the abandonment of the Gaussian model with unequal variances. In its stead, this paper reevaluates multiple-parallel-threshold models. In particular, the Poisson model turns out to be very useful: it can handle data with any degree of asymmetry, giving a reasonable interpretation of the two parameters of the receiver-operating characteristic. The three-state-threshold model (Krantz, 1969) is given a new interpretation in light of the Poisson model. The slope of Poisson double-probability plots turns out to be much closer to unity than is predicted by the Gaussian approximation.     

Differential effects of person in the dog and in the human

People have marked effects on dog’s heart rate, with great individual variations for different persons. Apparently people to which the dog is attached have the greatest effect upon heart rate. Replications of the animal experiments using the psychotherapist and two other people revealed no effects upon the heart rate of a schizophrenic human. In the human the effects of people are probably best demonstrated in connection with verbal communication.     

Racism: What It Is and What It Isn't

The words `racist' and `racism' have become so overused that they nowconstitute obstacles to understanding and interracial dialogue aboutracial matters. Instead of the current practice of referring tovirtually anything that goes wrong or amiss with respect to race as`racism,' we should recognize a much broader moral vocabulary forcharacterizing racial ills – racial insensitivity, racial ignorance,racial injustice, racial discomfort, racial exclusion. At the sametime, we should fix on a definition of `racism' that is continuouswith its historical usage, and avoids conceptual inflation. Isuggest two basic, and distinct, forms of racism that meet thiscondition – antipathy racism and inferiorizing racism. We should alsorecognize that not all racially objectionable actions are done froma racist motive, and that not all racial stereotypes are racist.