Mental object rotation and the planning of hand movements

Recently, we showed that the simultaneous execution of rotational hand movements interferes with mental object rotation, provided that the axes of rotation coincide in space. We hypothesized that mental object rotation and the programming of rotational hand movements share a common process presumably involved in action planning. Two experiments are reported here that show that the mere planning of a rotational hand movement is sufficient to cause interference with mental object rotation. Subjects had to plan different spatially directed hand movements that they were asked to execute only after they had solved a mental object rotation task. Experiment 1 showed that mental object rotation was slower if hand movements were planned in a direction opposite to the presumed mental rotation direction, but only if the axes of hand rotation and mental object rotation were parallel in space. Experiment 2 showed that this interference occurred independent of the preparatory hand movements observed in Experiment 1. Thus, it is the planning of hand movements and not their preparation or execution that interferes with mental object rotation. This finding underlines the idea that mental object rotation is an imagined (covert) action, rather than a pure visual-spatial imagery task, and that the interference between mental object rotation and rotational hand movements is an interference between goals of actions.     

B. Gordijn/H. ten Have (eds), ``Medizinethik und Kultur. Grenzen medizinischen Handelns in Deutschland und den Niederlanden'

Theoretical Medicine and Bioethics -     

Weshalb implizite definitionen nicht genug sind. Bedeutungstheorien und das verst?ndnis physikalischer begriffe

Ohne Zusammenfassung     

A procedure for evaluating portable heart monitors

Portable heart rate monitors are potentially useful for regulating exercise intensity. This paper describes procedures to evaluate these devices while subjects are resting, cycling, or running. Of the five monitors tested, all performed reasonably well while subjects were at rest; however, with one exception, performance deteriorated when the monitors were used during exercise. Even so, depending on the level of accuracy required, some of the monitors remained useful during cycling, but only one monitor was consistently accurate while subjects were running. This evidence indicates that, before selecting a particular monitor, potential users of such equipment should carefully consider many things, including the circumstances under which the equipment will be employed. The procedures reported in this paper should be generally useful in evaluating the performance of a variety of devices for monitoring heart rate.     

Amount and distribution of study in a personalized instruction course and in a lecture course

The rapid proliferation of courses based on Keller's Personalized System of Instruction (PSI) calls for a prompt evaluation of the relative costs involved in PSI and more traditional forms of college instruction. To determine the cost in student time required by a course taught with PSI relative to lecture, students did their studying in a special Study Center where course materials could be used but not removed. Students in the PSI section spent an average of about 50% more time in the Study Center (46 hr) than did students in the lecture section (30 hr), but that difference was made up by the lecture students spending an average of 20 hr attending lectures. Thus, total preparation time was about the same. PSI students scored slightly higher on common course exams, and while college entrance exam scores correlated highly with course exam scores, Study Center time was reliably related to course exam score only for PSI students. An analysis of the study records of individual students revealed that PSI produced fairly regular patterns of study by all students, while lecture students varied greatly in their patterns.