An examination of indexes for determining the number of clusters in binary data sets

The problem of choosing the correct number of clusters is as old as cluster analysis itself. A number of authors have suggested various indexes to facilitate this crucial decision. One of the most extensive comparative studies of indexes was conducted by Milligan and Cooper (1985). The present piece of work pursues the same goal under different conditions. In contrast to Milligan and Cooper's work, the emphasis here is on high-dimensional empirical binary data. Binary artificial data sets are constructed to reflect features typically encountered in real-world data situations in the field of marketing research. The simulation includes 162 binary data sets that are clustered by two different algorithms and lead to recommendations on the number of clusters for each index under consideration. Index results are evaluated and their performance is compared and analyzed.Author names are listed in alphabetical order.This piece of research was supported by the Austrian Science Foundation (FWF) under grant SFB#010 (Adaptive Information Systems and Modeling in Economics and Management Science).The authors would like to thank the anonymous reviewers and especially the associate editor for their helpful comments and suggestions.     

Differentiating the differential rotation effect

As an observer views a picture from different viewing angles, objects in the picture appear to maintain their orientation relative to the observer. For instance, the eyes of a portrait appear to follow the observer as he or she views the image from different angles. We have explored this rotation effect, often called the Mona Lisa effect. We report three experiments that used portrait photographs to test variations of the Mona Lisa effect. The first experiment introduced picture displacements relative to the observer in directions beyond the horizontal plane. The Mona Lisa effect remained robust for vertical and/or diagonal observer displacements. The experiment also included conditions in which the portrait had averted gaze directions. An interaction between picture position relative to the observer and gaze direction was found. The second experiment followed up on very pronounced individual differences, suggesting that the Mona Lisa effect is even stronger than it should be for half of all observers (over-rotators). These individual differences do not correlate with any of the standard personality dimensions (Big Five) or with spatial intelligence. In the third experiment, we extended the experiment to virtual 3D heads using the same gaze directions and picture displacements as for the 2D portrait faces. Besides the picture displacements relative to the observer, we also added observer displacements relative to the picture. 3D pictures showed the Mona Lisa effect, but to a smaller extent than did 2D pictures.     

‘He is among us,get it into your head,he is alive and always here’: saintly presence at the pilgrimage centre of Padre Pio and the importance of ‘being there’

The paper will focus upon the issue of saintly presence and the ways in which this is felt, experienced and enacted at the pilgrimage centre of Padre Pio. This issue will be examined in relation to the material and spatial structures of the pilgrimage centre and in particular the Sanctuary of Santa Maria delle Grazie, at the crypt of which the tomb of Padre Pio was until recently emplaced. In examining the issue of saintly presence in relation to the sanctuary's materiality, the paper will also explore the relationship of two of the dimensions Eade and Sallnow ([1991] 2000, ‘Introduction’, in Contesting the Sacred: The Anthropology of Christian Pilgrimage., 2nd ed., edited by John Eade and Michael J. Sallnow, 1–29, Urbana: University of Illinois) propose for the examination of pilgrimage, namely person and place. Drawing on ethnographic data gathered during fieldwork (2004–2005), it will argue that the feeling of saintly presence is mainly generated by the knowledge people have of Padre Pio having lived and being buried there. This knowledge shapes their pilgrimage experience.     

Action as the Conclusion of Practical Reasoning; The Critique of a Rödlian Account

In this paper I take up the question of whether and in what sense action might be the conclusion of practical reasoning and argue against the answer provided by Sebastian Rödl's account of practical reasoning. Rödl's account aspires to steer a middle ground between the attitudinal and the neo‐Aristotelian accounts of practical reasoning, by proposing that its conclusion is at once a thought and a movement. This account is worth considering for it promises to explain both practical reasoning's practicality (that it brings about action) and its rationality (that it is subject to thought governing norms) in one move. But, I argue in this paper, a Rödlian account—an account which grants Rödl's central theses—fails to deliver on its promise. The reason is that, like others, a Rödlian also assumes that the only sense in which practical reasoning is practical is the sense in which it has a conclusion. Challenging this assumption in the right way, I finally suggest, helps us reassess the task of explaining practical reasoning in a way that goes beyond Rödlian, attitudinal and neo‐Aristotelian accounts alike.     

A critical review of the physicalistic approaches of the mind and consciousness

The aim of this paper is to construct a critical evaluation of the advantages and disadvantages of the physicalistic theory concerning mental phenomena and consciousness. Physicalism can, better than other theories, explain mental phenomena, such as intentionality and reasonability of human beings and other biological organisms. Modern neuroscience corroborates the conviction that the brain is a physical mind capable of giving meaning to, evaluating and further cognitively and behaviorally transforming complex aspects of the world. On the other hand, the emergence of consciousness from brain states seems to be a paradoxical, intransparent, physical coincidence hardly explained by the mental function of the brain at the physical level. Moreover, the intentionality and reasonability of psychic phenomena per se cannot be explained as a repercussion of the same attributes characterizing the brain function. In conclusion, the old debate between physicalism and other philosophical theories remains open. It can be expected that the progress of sciences will inspire novel approaches to the problem of the relations between matter, mind and consciousness.