Timing in the performance of Erik Satie's ‘Vexations’

In traditional studies of single cue probability learning the subject's errors and the covariation he/she establishes between the judgments and the cue (cue dependency) are confounded. Learning results in increased cue dependency which is necessarily accompanied by decreasing errors. This paper presents a method for disentangling errors from cue dependency. This is done by (1) making the criterion contingent upon the judgments instead of the cue, and (2) giving standard instructions, implying that the cue is informative about the criterion. In this way errors are controlled independently of any covariation that the subject may create between the cue and the judgments, and indirectly between the cue and the criterion (task regularity). The paper examines whether subjects aim at small errors or task-regularity when the task does not allow them to do both. It was found that error reduction does occur only when task-regularity can be maintained. Conclusion: task regularity, and thus cue-dependency, has priority to error reduction under the standard conditions used in single cue probability learning experiments. The study may be viewed as an example of conditions under which a cue illusion (false beliefs in the validity of a cue) arises.     

On testing the equality of proportions in the paired case with incomplete data

The problem of testing two correlated proportions with incomplete data is considered by means of Monte Carlo simulations studies. A test proposed in this paper, which can be regarded as a generalization of McNemar's test, is recommended in all cases with incomplete data and not too small samples.     

PERCEPTION OF MOTION AND CHANGING FORM: A study of visual perception from continuous transformations of a solid angle of light at the eye

It is shown how geometrically changing projections of objects which move and/or change their shape carry no specific information about form and three-dimensional motion. How, then, does the visual apparatus produce specific percepts from such non-specific changing stimuli? By applying an analogue computer technique, changing projections of artificial objects are generated on a CRT screen. These projections are fed into the eye by means of an optical device where they form a continuously changing solid angle of homogeneous light. The main conclusion is that it is a principle of perceptual three-dimensionality which gives specificity to the percepts. Preliminary statements of principles for prediction of perceived motion in depth from a given change in proximal stimulus are presented.     

DIFFERENTIATION OF CHARACTER NEUROSIS AND SYMPTOM NEUROSIS ON THE BASIS OF DIFFERENCES BETWEEN TWO SERIAL EXPERIMENTS

The difference between two serial tests as regards signs of hysteria and obsession-compulsion is compared with differences in number of symptoms reported by the patient. Signs in the more formal colour-word test, measuring habitual behaviour patterns, correspond to fewer symptoms than signs in a tachistoscopic test revealing more of the perceptual representation (content) of behaviour disorders. This difference is supposed to reflect important aspects of the difference between character neurosis and symptom neurosis.     

THE STABILITY OF PATHOLOGIC SIGNS IN THE PERCEPTUAL PROCESS AS REVEALED BY A SERIAL TACHISTOSCOPIC EXPERIMENT

S mith , G. J. W., and J ohnson , G. The stability of pathologic signs in the perceptual process as revealed by a serial tachistoscopic experiment. Scand. J. Psychol ., 1961, 2, 142–148.—The study demonstrates high inter-rater and inter-set consistency in a serial tachistoscopic experiment utilizing pairwise presentations of stimuli A and B, B being presented at constant time levels, A at gradually increasing ones. Two parallel sets contain two series each. In one series A is incongruent with B, in another a threat directed against B. Fifty psychiatric patients are given the two sets with a one-day interval. Reports of change in A and B during the micro-genesis of A are scored in the dimensions of repression, isolation, projection, and depression.     

Sensitivity for Treatment Effects of the Screen for Child Anxiety Related Emotional Disorders

The Screen for Child Anxiety Related Emotional Disorders (SCARED) is a relatively new self-report questionnaire that measures DSM-defined anxiety disorders symptoms in children. The present study examined the treatment sensitivity of the SCARED. Eleven anxiety-disordered children aged 10 to 13 years received cognitive-behavioral treatment, an intervention that is generally known to be effective. Children completed the SCARED on three occasions: (1) 3 months before treatment (i.e., baseline), (2) at pretreatment, and (3) at posttreatment. Before and after treatment, scores on traditional childhood anxiety measures (i.e., State-Trait Anxiety Inventory for Children, Revised Children's Manifest Anxiety Scale, and Fear Survey Schedule for Children) were also obtained. Results showed that children's SCARED scores remained relatively stable from baseline to pretreatment. However, from pre- to post-treatment, significant decreases were evident for the SCARED and for all traditional measures. These results suggest that the SCARED reliably taps treatment effects and, thus, provide further support for its utility as a self-report index of childhood anxiety in clinical and research settings.     

Minimization of modal contours: an essential cross-species strategy in disambiguating relative depth

Two chromatically identical patterns, a diamond and a ladder, were shown on a computer touchscreen. Domestic hens were reinforced for pecking at the pattern that was the highest up on a grid that provided pictorial depth information, i.e. on the pattern that to a human appears as being the furthest away. Every tenth trial was a non-rewarded probe trial with the two patterns partially overlapping. In the absence of other cues depth stratification can occur on the basis of a minimization of interpolated occluding contours. In humans the diamond is usually perceived to be in front of the ladder because shorter interpolated contours are needed to account for the occlusive effect of the diamond on the ladder. The hens pecked more often at the ladder during the probe trials. The results suggest that the avian and mammalian visual systems operate along similar principles when dealing with the problem of solving occlusion indeterminacy in chromatically homogeneous patterns. Received: 26 March 1999 / Accepted after revision: 17 September 1999     

Effects of public posting on driving speed in Icelandic traffic

We replicated a study by Van Houten, Nau, and Marini (1980) that had revealed reductions in vehicle speeding following the posting of percentages of drivers not speeding on a sign at roadside. Our subjects were drivers entering a residential area where the speed limit changed from 90 km/hr (55.9 mph) to 60 km/hr (37.3 mph). A total of 4,409 vehicle speeds were taken from two observation sessions per day for 20 consecutive weekdays. The intervention consisted of a single posting condition, in which a hypothetical daily percentage of drivers not speeding was posted on a feedback sign, followed by a double posting condition, in which a sign posting a best result was erected beyond the feedback sign. Results revealed a significant speed reduction from an average of 69.0 km/hr (42.9 mph) during baseline to 63.4 km/hr (39.4 mph) during single posting. Average speed during double posting was 62.9 km/hr (39.1 mph). The percentage of drivers exceeding 70 km/hr (43.5 mph) dropped from 41.0 during baseline to 20.5 during single posting. The significant speed reductions add to the generality of findings of similar studies in Canada and Israel and offer possible explanations for the failure of feedback posting to reduce speed in the U.S.     

The tower experiment and the Copernican revolution

During the Copernican revolution the supporters of the Ptolemaic theory argued that the tower experiment refuted the Copernican hypothesis of the (diurnal) motion of the earth, but was in agreement with the Ptolemaic theory. In his defence of the Copernican theory Galileo argued that the experiment was in agreement both with Copernican and Ptolemaic theory. The reason for these different views of the same experiment was not that the two theories were incommensurable, as Paul Feyerabend argues, but that Galileo introduced a new theory of motion which he used as an auxiliary hypothesis in his discussion of the tower experiment, while those defending the Ptolemaic theory used the old Aristotelian theory of motion. Already before the Copernican revolution the Aristotelian theory of motion was criticized by philosophers in Paris, who suggested the impetus theory of motion. The later versions of this theory had the consequence that the tower experiment no longer refuted the hypothesis of the (diurnal) motion of the earth. Thus the impetus theory removed an old and important objection to the heliocentric theory. Galileo's inertial dynamics had the same function in the discussion of the tower experiment.