Observers’ sensitivity to dynamic anomalies in collisions

The present study examined observers’ ability to discriminate canonical and dynamically anomalous collisions that were presented in either frictionless or frictional systems. Whereas previous research has provided qualitative demonstrations that dynamic information can be extracted from visual events, the current study provides a parametric assessment of observers’ sensitivity to dynamic invariants. Our findings indicate that observers are competent when viewing both familiar, terrestrial (frictional) systems and unfamiliar but computationally simpler, 0-G (frictionless) systems. Thus, our sensitivity to these dynamic invariants in visual events is robust in natural systems whose dynamic properties differ from those of the environment in which we evolved and developed.     

Multidimensional assessment of depression

A brief version of the Multiscore Depression Inventory was evaluated. Good coefficient alpha and test-retest reliabilities were obtained for the total score and the subscales. Two factor analyses were reported which appear to justify the use of a multiscore approach for at least 8 of the 9 subscales: helplessness, energy level, guilt, social introversion, cognitive difficulty, irritability, pessimism, and low self-esteem. Sad mood apparently overlapped with energy level on one analysis (replicating findings with the 118-item Multiscore Depression Inventory), and with self-esteem on the second analysis. Normative data are provided on diverse samples totaling 849 subjects.     

Grading the ‘cultural literacy’ project

The essay examines the argument advanced by E.D. Hirsch, Jr., for instituting ‘cultural literacy’ as a fundamental priority of schools. A number of confusions and equivocations in Hirsch's reasoning are identified, and the propensity of his project to indoctrinate is exposed. Among the features of Hirsch's argument shown to be troubling are his shifting construal of ‘language’, his inconsistency about the requirements of cultural literacy, and his uncritical relation to traditional images of the American past and present. The upshot is to raise the question why Hirsch's project has elicited wide support and praise.     

Frege''s objects of a quite special kind

A previous version of this paper was read at the universities of Glasgow, Munich, Oxford and St. Andrews; the penultimate version was presented at the universities of Bologna, Erlangen-Nürnberg, Minnesota, Puerto Rico and at University College, London. I am grateful to Verena Mayer, Eva Picardi, Peter Clark, Michael Dummett, Bill Hart, Andreas Kemmerling, Brian McGuinness, Guillermo E. Rosado Haddock, Joachim Schulte, Leslie Stevenson and especially to Christian Thiel and Crispin Wright for helpful comments.     

Directed forgetting in pigeons resulting from the reallocation of memory-maintaining processes on forget-cue trials

When procedural artifacts are controlled, it has been difficult to demonstrate directed forgetting in pigeons. However, previous research with pigeons has not allowed for the reallocation of working memory (from forget items to remember items) on forget-cued trials as is possible in human directed forgetting experiments. In the present experiment, directed forgetting was found while controlling for procedural artifacts and allowing the pigeons to reallocate memory resources on forget trials. The results indicate that under these conditions, pigeons have active control over memory processing.     

Referenzsemantik in der Partnermodellierung

How can we explain that an assertion on something perceived can be understood in the same manner by somebody who cannot perceive that scene? This problem bases the interest in computational linguistics in how listener modeling could possibly be harmonized with reference semantics. Mental images substituting real perception appear as a way out. The architecture of the listener model has to be adapted to the creation and use of such pictorial data structures. Furthermore, the relation between the latter and a verbal (i. e., propositional) representation must be understood. The resulting architecture of a listener model with reference semantics can be employed to solve communicational problems from three general classes in a better way, as is demonstrated by an example implementation.     

Rotational and translational components of motion parallax: observers' sensitivity and implications for three-dimensional computer graphics

The motion of objects during motion parallax can be decomposed into 2 observer-relative components: translation and rotation. The depth ratio of objects in the visual field is specified by the inverse ratio of their angular displacement (from translation) or equivalently by the inverse ratio of their rotations. Despite the equal mathematical status of these 2 information sources, it was predicted that observers would be far more sensitive to the translational than rotational component. Such a differential sensitivity is implicitly assumed by the computer graphics technique billboarding, in which 3-dimensional (3-D) objects are drawn as planar forms (i.e., billboards) maintained normal to the line of sight. In 3 experiments, observers were found to be consistently less sensitive to rotational anomalies. The implications of these findings for kinetic depth effect displays and billboarding techniques are discussed.