Comparing several robust tests of stochastic equality with ordinally scaled variables and small to moderate sized samples

In a comparison of 2 treatments, if outcome scores are denoted by X in 1 condition and by Y in the other, stochastic equality is defined as P(X < Y) = P(X > Y). Tests of stochastic equality can be affected by characteristics of the distributions being compared, such as heterogeneity of variance. Thus, various robust tests of stochastic equality have been proposed and are evaluated here using a Monte Carlo study with sample sizes ranging from 10 to 30. Three robust tests are identified that perform well in Type I error rates and power except when extremely skewed data co-occur with very small n. When tests of stochastic equality might be preferred to tests of means is also considered.     

Visual search is modulated by action intentions

The influence of action intentions on visual selection processes was investigated in a visual search paradigm. A predefined target object with a certain orientation and color was presented among distractors, and subjects had to either look and point at the target or look at and grasp the target. Target selection processes prior to the first saccadic eye movement were modulated by the different action intentions. Specifically, fewer saccades to objects with the wrong orientation were made in the grasping condition than in the pointing condition, whereas the number of saccades to an object with the wrong color was the same in the two conditions. Saccadic latencies were similar under the different task conditions, so the results cannot be explained by a speed-accuracy trade-off. The results suggest that a specific action intention, such as grasping, can enhance visual processing of action-relevant features, such as orientation. Together, the findings support the view that visual attention can be best understood as a selection-for-action mechanism.     

Transforming animal species: the case of ‘oncomouse’

In this paper I deal with ethical implications arising from animal biotechnology. I analyse some general questions surrounding the production of transgenic animals through a specific case study: the oncomouse. In particular, I explore ethical factors involved in the production of oncomice. This is because biologists genetically modify animals’ germ cells and refuse to modify human germ cells. I will underline how the international community has thus far justified this ‘ethical difference’. The opinions here expressed are personal and do not commit the European Commission. Maurizio Salvi is member of the Scientific Staff of the Higher Institute of Philosophy, University of Leuven. Currently he is a Scientific Officer (National Expert Detached) of the European Commission, (Directorate-General XII, Science Research and Development, Directorate B.II.3) dealing with Bioethics research.