Transcending the self in immersive virtual reality

Cognitive neuroscientists have discovered various experimental setups that suggest that our body representation is surprisingly flexible, where the brain can easily be tricked into the illusion that a rubber hand is your hand or that a manikin body is your body. These multisensory illusions work well in immersive virtual reality (IVR). What is even more surprising is that such embodiment induces perceptual, attitudinal and behavioural changes that are concomitant with the displayed body type. Here we outline some recent findings in this field, and suggest that this offers a powerful tool for neuroscience, psychology and a new path for IVR.

Lack of support for the association between facial shape and aggression: a reappraisal based on a worldwide population genetics perspective

Antisocial and criminal behaviors are multifactorial traits whose interpretation relies on multiple disciplines. Since these interpretations may have social, moral and legal implications, a constant review of the evidence is necessary before any scientific claim is considered as truth. A recent study proposed that men with wider faces relative to facial height (fWHR) are more likely to develop unethical behaviour mediated by a psychological sense of power. This research was based on reports suggesting that sexual dimorphism and selection would be responsible for a correlation between fWHR and aggression. Here we show that 4,960 individuals from 94 modern human populations belonging to a vast array of genetic and cultural contexts do not display significant amounts of fWHR sexual dimorphism. Further analyses using populations with associated ethnographical records as well as samples of male prisoners of the Mexico City Federal Penitentiary condemned by crimes of variable level of inter-personal aggression (homicide, robbery, and minor faults) did not show significant evidence, suggesting that populations/individuals with higher levels of bellicosity, aggressive behaviour, or power-mediated behaviour display greater fWHR. Finally, a regression analysis of fWHR on individual"s fitness showed no significant correlation between this facial trait and reproductive success. Overall, our results suggest that facial attributes are poor predictors of aggressive behaviour, or at least, that sexual selection was weak enough to leave a signal on patterns of between- and within-sex and population facial variation.

The challenge of representative design in psychology and economics

The demands of representative design, as formulated by Egon Brunswik (1956), set a high methodological standard. Both experimental participants and the situations with which they are faced should be representative of the populations to which researchers claim to generalize results. Failure to observe the latter has led to notable experimental failures in psychology from which economics could learn. It also raises questions about the meaning of testing economic theories in abstract environments. Logically, abstract tests can only be generalized to abstract realities and these may or may not have anything to do with the empirical realities experienced by economic actors.

Psychology in Catalonia: 1996-2002

En aquest article es presenta el resum del Report de la Recerca en Psicologia a Catalunya durant el període 1996-2002, publicat l'any 2004 per l'Institut d'Estudis Catalans. A partir de informacions diverses, procedents especialmentd'institucions educatives de nivell universitari, Administració de Catalunya (Departament d'Universitats, Recercai Societat de la Informació, DURSI), i els propis coordinadors de Grups de Recerca -prèviament detectats mitjançant laelaboració d'un qüestionari ad hoc-, s'ha perfilat un mapa de la recerca en Psicologia a Catalunya durant el períodeestudiat, el qual inclou investigadors procedents de les sis Universitats catalanes en les quals s'imparteixen estudis dePsicologia (o, en el cas de la Universitat de Lleida, de Psicopedagogia). Els eixos organitzadors de la informació hanestat les Àrees de Coneixement i les Universitats. La informació recollida s'ha articulat al voltant de diversesqüestions cabdals relatives als Grups de Recerca: Projectes de recerca obtinguts per part de diversos organismes subvencionants, la productivitat contemplada des de la vessant de la publicació d'articles científics, el finançament obtingut per part de diverses Administracions i entitats privades, la infrastructura amb la que compten, les característiques d'arranjament d'aquests Grups, i, finalment, les condicions, valoracions, expectatives i gestió dels recursos dels Grups de Recerca.

El control experimental

Se ha situado el control experimental en una de las fases más importantes de la planeación de experimentos, abundando en señalar que entraña la regulación de la variable dependiente en función de las que manipulamos directamente y de todas las demas que ejercen una influencia en el experimento. Mediante el control, el experimentador puede manejar y dominar la situación, para lo cua1 se propone conseguir que la variable independiente sea la única cuyos efectos sean los responsables de la variación de la variable dependiente, controlar las variables extrañas que intervienen en la experimentación y uniformar las variables individuales y los métodos de medida de los datos.

Problemática metodológica de la validez experimental

El propósito de este trabajo consiste en analizar, en profundidad, la temática de la validez experimental desde una perspectiva metodológica. En 61 se plantea un enfoque alternativo a la concepción clasica propuesta por Campbell y Stanley (1962). Se estudian, también, las principales fuentes de confundido que pueden llegar a comprometer la validez de 10s experimentos al tiempo que se describen las principales técnicas de control aplicables a cada una de éstas. El trabajo termina con una discusión sobre el diseño experimental y cómo, mediante el diseño, se puede conseguir un adecuado equilibri0 entre las dos principales clases de validez en la investigación conductual.

The building blocks of the full body ownership illusion

Previous work has reported that it is not difficult to give people the illusion of ownership over an artificial body, providing a powerful tool for the investigation of the neural and cognitive mechanisms underlying body perception and self consciousness. We present an experimental study that uses immersive virtual reality (IVR) focused on identifying the perceptual building blocks of this illusion. We systematically manipulated visuotactile and visual sensorimotor contingencies, visual perspective, and the appearance of the virtual body in order to assess their relative role and mutual interaction. Consistent results from subjective reports and physiological measures showed that a first person perspective over a fake humanoid body is essential for eliciting a body ownership illusion. We found that the illusion of ownership can be generated when the virtual body has a realistic skin tone and spatially substitutes the real body seen from a first person perspective. In this case there is no need for an additional contribution of congruent visuotactile or sensorimotor cues. Additionally, we found that the processing of incongruent perceptual cues can be modulated by the level of the illusion: when the illusion is strong, incongruent cues are not experienced as incorrect. Participants exposed to asynchronous visuotactile stimulation can experience the ownership illusion and perceive touch as originating from an object seen to contact the virtual body. Analogously, when the level of realism of the virtual body is not high enough and/or when there is no spatial overlap between the two bodies, then the contribution of congruent multisensory and/or sensorimotor cues is required for evoking the illusion. On the basis of these results and inspired by findings from neurophysiological recordings in the monkey, we propose a model that accounts for many of the results reported in the literature.

Unifying Time to Contact Estimation and Collision Avoidance across Species

The -function and the -function are phenomenological models that are widely used in the context of timing interceptive actions and collision avoidance, respectively. Both models were previously considered to be unrelated to each other: is a decreasing function that provides an estimation of time-to-contact (ttc) in the early phase of an object approach; in contrast, has a maximum before ttc. Furthermore, it is not clear how both functions could be implemented at the neuronal level in a biophysically plausible fashion. Here we propose a new framework the corrected modified Tau function capable of predicting both -type ("") and -type ("") responses. The outstanding property of our new framework is its resilience to noise. We show that can be derived from a firing rate equation, and, as , serves to describe the response curves of collision sensitive neurons. Furthermore, we show that predicts the psychophysical performance of subjects determining ttc. Our new framework is thus validated successfully against published and novel experimental data. Within the framework, links between -type and -type neurons are established. Therefore, it could possibly serve as a model for explaining the co-occurrence of such neurons in the brain.

The Dialogic Turn in Educational Psychology

The increasing presence of and claim for dialogue in today"s society has already had an impact on the theory and practice of learning. Whereas in the past individual and cognitive elements were seen as crucial to learning, since about two decades ago, scientific literature indicates that culture, interaction and dialogue are the key factors. In addition, the research project of highest scientific rank and with most resources dedicated to the study of school education in the Framework Program of the European Union: INCLUD-ED shows that the practices of successful schools around Europe are in line with the dialogic approach to learning. This article presents the dialogic turn in educational psychology, consisting of moving from symbolic conceptions of mind and internalist perspectives that focus on mental schemata of previous knowledge, to theories that see intersubjectivity and communication as the primary factors in learning. The paper deepens on the second approach.

Unifying Time to Contact Estimation and Collision Avoidance across Species

The -function and the -function are phenomenological models that are widely used in the context of timing interceptive actions and collision avoidance, respectively. Both models were previously considered to be unrelated to each other: is a decreasing function that provides an estimation of time-to-contact (ttc) in the early phase of an object approach; in contrast, has a maximum before ttc. Furthermore, it is not clear how both functions could be implemented at the neuronal level in a biophysically plausible fashion. Here we propose a new framework- the corrected modified Tau function- capable of predicting both -type ("") and -type ("") responses. The outstanding property of our new framework is its resilience to noise. We show that can be derived from a firing rate equation, and, as , serves to describe the response curves of collision sensitive neurons. Furthermore, we show that predicts the psychophysical performance of subjects determining ttc. Our new framework is thus validated successfully against published and novel experimental data. Within the framework, links between -type and -type neurons are established. Therefore, it could possibly serve as a model for explaining the co-occurrence of such neurons in the brain.

A carboxylesterase, Esterase-6, modulates sensory physiological and behavioural response dynamics to pheromone in Drosophila

Background: Insects respond to the spatial and temporal dynamics of a pheromone plume, which implies not only a strong response to"odor on", but also to"odor off". This requires mechanisms geared toward a fast signal termination. Several mechanisms may contribute to signal termination, among which odorant-degrading enzymes. These enzymes putatively play a role in signal dynamics by a rapid inactivation of odorants in the vicinity of the sensory receptors, although direct in vivo experimental evidences are lacking. Here we verified the role of an extracellular carboxylesterase, esterase-6 (Est-6), in the sensory physiological and behavioral dynamics of Drosophila melanogaster response to its pheromone, cis-vaccenyl acetate (cVA). Est-6 was previously linked to post-mating effects in the reproductive system of females. As Est-6 is also known to hydrolyze cVA in vitro and is expressed in the main olfactory organ, the antenna, we tested here its role in olfaction as a putative odorant-degrading enzyme. Results: We first confirm that Est-6 is highly expressed in olfactory sensilla, including cVA-sensitive sensilla, and we show that expression is likely associated with non-neuronal cells. Our electrophysiological approaches show that the dynamics of olfactory receptor neuron (ORN) responses is strongly influenced by Est-6, as in Est-6° null mutants (lacking the Est-6 gene) cVA-sensitive ORN showed increased firing rate and prolonged activity in response to cVA. Est-6° mutant males had a lower threshold of behavioral response to cVA, as revealed by the analysis of two cVAinduced behaviors. In particular, mutant males exhibited a strong decrease of male-male courtship, in association with a delay in courtship initiation. Conclusions: Our study presents evidence that Est-6 plays a role in the physiological and behavioral dynamics of sex pheromone response in Drosophila males and supports a role of Est-6 as an odorant-degrading enzyme (ODE) in male antennae. Our results also expand the role of Est-6 in Drosophila biology, from reproduction to olfaction, and highlight the role of ODEs in insect olfaction. Keywords: carboxylesterase, esterase 6, olfaction, pheromone, signal termination