Stimulus frequency influences spontaneous perceptual reversals in ambiguous apparent motion

The temporal integration of continuous sensory information into a temporally extended percept becomes evident in spontaneous reversals of ambiguous apparent motion. To study the temporal relation of spontaneous percept reversals and temporal stimulus properties, we systematically varied presentation frequency in an ambiguous-apparent-motion paradigm. Moreover, we triggered percept reversals in a manner that was not consciously perceived by manipulating the duration of single frames. We found that the reversal rate depended on the stimulus frequency (with higher frequencies resulting in faster percept reversals) and that we could externally trigger perceptual reversals. Our findings support the idea that spontaneous reversals of ambiguous apparent motion are influenced by bottom-up effects at early processing levels. The paradigm allows for specific contrasts of spontaneous and externally triggered (but otherwise identical) perceptual reversals and, by this means, for further study of the underlying mechanisms.     

Microswitch-based programs for persons with multiple disabilities: an overview of some recent developments

Persons with multiple disabilities are often unable to interact with their environment due to their limited response repertoire. Microswitch programs are designed to help them control environmental events, generally preferred stimulation, through simple (feasible) responses. To make microswitch programs a more widely usable and relevant resource for intervention with these persons, a number of new developments were pursued in recent years. This paper examines three of those developments as specifically addressed in our research activity, namely, (a) assessment of new, nontypical responses and matching microswitches, (b) fostering of multiple responses and exercise of choice, and (c) targeting of habilitative and clinical (therapeutic) objectives. The encouraging outcomes of these developments are reviewed in relation to their potentially wide implications for daily practice and the need of additional developments in the area.     

The ontology of meanings

In part 4 of Meaning, Expression, and Thought, Davis rejects what he calls Fregean ideational theories, according to which the meaning of an expression is an idea; and then presents his own account, which states that, e.g., the meaning of ‘Primzahl’ in German is the property of meaning prime number. Before casting doubt on the latter ontology of meanings, I come to Frege’s defence by pointing out that he was not an advocate of the position Davis named after him because Fregean senses are not lexical meanings and Fregean thoughts are not types of mental events.

The folk strike back; or,why you didn’t do it intentionally,though it was bad and you knew it

Recent and puzzling experimental results suggest that people’s judgments as to whether or not an action was performed intentionally are sensitive to moral considerations. In this paper, we outline these results and evaluate two accounts which purport to explain them. We then describe a recent experiment that allegedly vindicates one of these accounts and present our own findings to show that it fails to do so. Finally, we present additional data suggesting no such vindication could be in the offing and that, in fact, both accounts fail to explain the initial, puzzling results they were purported to explain.

The Donkey Problem

The Donkey Problem (as I am calling it) concerns the relationship between more and less fundamental ontologies. I will claim that the moral to draw from the Donkey Problem is that the less fundamental objects are merely conventional. This conventionalism has consequences for the 3D/4D debate. Four-dimensionalism is motivated by a desire to avoid coinciding objects, but once we accept that the non-fundamental ontology is conventional there is no longer any reason to reject coincidence. I therefore encourage 4Dists to become even more radical—embrace the Donkey Problem’s conventionalism and deflate the debate between 3Dists and 4Dists.

Weak and global supervenience are strong

Kim argues that weak and global supervenience are too weak to guarantee any sort of dependency. Of the three original forms of supervenience, strong, weak, and global, each commonly wielded across all branches of philosophy, two are thus cast aside as uninteresting or useless. His arguments, however, fail to appreciate the strength of weak and global supervenience. I investigate what weak and global supervenience relations are functionally and how they relate to strong supervenience. For a large class of properties, weak and global supervenience are equivalent to strong supervenience. I then offer a series of arguments showing that it is precisely because of their strength, not their weakness, that both weak and global supervenience are useless in characterizing any dependencies of interest to philosophers.

The ontological commitments of inconsistent theories

In this paper I present an argument for belief in inconsistent objects. The argument relies on a particular, plausible version of scientific realism, and the fact that often our best scientific theories are inconsistent. It is not clear what to make of this argument. Is it a reductio of the version of scientific realism under consideration? If it is, what are the alternatives? Should we just accept the conclusion? I will argue (rather tentatively and suitably qualified) for a positive answer to the last question: there are times when it is legitimate to believe in inconsistent objects.     

What is false memory development the development of? Comment on Brainerd, Reyna, and Ceci (2008)

In this commentary, assumptions about the nature and development of children's false memories as described in a recent article by C. J. Brainerd, V. F. Reyna, and S. J. Ceci (2008) are reviewed. Specifically, questions are raised about what drives the development of false memories in fuzzy-trace theory (FTT). Recent studies that challenge a core assumption of FTT, that false memory illusions increase across development as children learn to establish meaningful connections across items (i.e., establish gist), are discussed. An alternative conceptualization of the development of false memory illusions, associative-activation theory (AAT), is presented. AAT provides as viable an account of the development of false memory illusions as does FTT and anticipates a unique set of outcomes that have recently appeared in the developmental literature on false memory illusions.     

Receiver operating characteristics for the brief symptom inventory depression, paranoid ideation, and psychoticism scales in a large sample of clinical inpatients

A commonly used screening tool for psychopathology, the Brief Symptom Inventory, provides normative data for assessing current mental functioning across multiple domains. Using data from 654 psychiatric inpatients, receiver operating characteristic (ROC) analyses were conducted for three scales, Depression, Paranoid Ideation, and Psychoticism. t ratios identified significant group differences on the Depression scale between patients diagnosed with or without depression but no differences on the Paranoid Ideation and Psychoticism scales between patients diagnosed with or without schizophrenia. Area under the curve for Depression was .65, indicating that the scale improved diagnostic prediction somewhat beyond chance; for Paranoid Ideation, the area was .52 and for Psychoticism, the area was .53, indicating that these two scales did not significantly improve diagnostic prediction beyond chance.     

Do captive mandrills invent new gestures?

Studies of intraspecific behavioral variability have documented cases where behaviors are present in some populations or groups but are absent in others. In some cases these differences cannot be explained by recourse to environmental or genetic variation, and may instead represent “traditions”. Despite many examples of animal traditions in acoustic communication, relatively few examples exist of gestural traditions. Here I report on a study of communication across eight captive groups of mandrills (Mandrillus sphinx) in which a prominent gesture (Hand extension) was unique to two groups. Habitat variability, genetic differences, and sampling bias were not sufficient to account for the gesture’s limited distribution across the study groups. Within the two groups where the gesture did occur only the juveniles in the group performed it, consistently directing it toward adults. Quantitative analysis of the contexts and responses associated with the gesture suggested that juveniles utilized it to provoke adults. Moreover, the gesture appeared to minimize the risk juveniles incurred while inciting adults, suggesting that repeated social interactions shaped the gesture’s form. Interestingly, both the groups where the gesture emerged contained few juveniles. With limited play partners, these juveniles may have resorted to harassing adults as an alternative social play outlet. The creation of this novel gesture may thus be due to the combined influence of a shortage of play partners and of the increased free time for playful social exploration afforded by captivity. Although juveniles frequently “eavesdropped” on dyadic interactions involving the gesture and would subsequently initiate an interaction with the recipient of the gesture, there was no definitive evidence for social transmission; the gesture could instead have been independently invented by each juvenile. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.