What do you mean with “direction”? Local and global cues to biological motion perception in pigeons

AbstractBiological motion point-light displays are a rich and versatile instrument to study perceptual organization. Humans are able to retrieve information from biological motion through at least two different channels: The global articulated structure as revealed by the non-rigid, yet highly constrained deformation of the dot pattern, and the characteristics of local motion trajectories of individual dots. Here, we tested eight pigeons on a task in which they had to discriminate a left-facing from a right-facing biological motion point-light figure. Since the two stimuli were mirror-flipped versions of each other, we were not sure if the birds would be able to solve the task at all. However, all birds learned the discrimination quickly and performed at high accuracy. We then challenged them with a number of test trials introduced into the sequence of the normal training trials. Tested on backwards moving walkers, the majority of the birds indicated that they used local motion cues to solve the training task, while the remaining birds obviously used global, configural cues. Testing the pigeons on different versions of scrambled biological motion confirmed that each individual bird had made a clear decision for one of the two potentially available strategies. While we confirm a previously described local precedence in processing visual patterns, the fact that some birds used global features suggests that even the birds who relied on local cues probably dispose of the perceptual abilities to use global structure, but “chose” to not use them

Les LABEX réinventés. Les appropriations paradoxales d'un instrument d'action publique en biologie

Comme de nombreux pays occidentaux, la France a récemment lancé une vague importante de réformes destinées à concentrer plus nettement les crédits publics sur les « meilleurs » chercheurs, laboratoires et établissements. Ce Policy brief explore l’appropriation par les chercheurs en biologie de l’un de ces programmes, les laboratoires d’excellence (LABEX). Les résultats de cette enquête montrent que la mise en œuvre de cet instrument est difficilement réductible à des catégories binaires, comme l’échec ou la réussite. Dans bien des cas, les LABEX ont conforté des dynamiques déjà à l’œuvre, sans initier des réorientations profondes des agendas ou des pratiques de recherche quand elles ne correspondaient pas aux objectifs de ces appels à projets. Mais conclure à un échec de la mesure serait réducteur : les LABEX ont été appropriés par les biologistes, qui louent la souplesse de l’instrument et son utilité. Ils y ont trouvé paradoxalement un moyen de pallier le caractère compétitif et temporaire des financements de la recherche en biologie en faisant des LABEX un outil de réduction des inégalités et des incertitudes financières qui marquent aujourd’hui le travail de recherche en biologie.Like many Western countries, France has recently launched a major wave of reforms that aimed to concentrate public funding more clearly on the “best” researchers, laboratories and universities. This policy brief analyses how biologists have appropriated one of these programs – the Laboratoires d’excellence (laboratories of excellence – LABEX). The results of this survey show that the implementation of this instrument is difficult to reduce to binary categories, such as failure or success. In many cases, LABEXs have reinforced dynamics already at work, without initiating major reorientations of agendas or research practices when they did not correspond to the objectives of these calls for proposals. But to conclude that the measure failed would be simplistic: biologists appropriated LABEXs and praise the flexibility of the instrument and its usefulness. Paradoxically, they found a way to overcome the competitive and temporary nature of biological research funding by using LABEX as a tool to reduce inequalities and financial uncertainties

Preoperative prism adaptation test in normosensoric strabismus

In 19 patients with normosensoric esotropia, the squint angles measured with the alternate cover test were compared with those after prolonged prismatic correction of the squint angle and with those after prolonged occlusion of one eye. All patients showed an increase of the squint angle after prism adaptation. The angle was generally smaller after diagnostic occlusion of one eye than after prism adaptation. We assume that the increase in the squint angle after prism adaptation is caused by an anomalous sensorial relationship between the two eyes that was not detected with the usual psychophysical tests. Surgery tailored to the squint angle after prism adaptation seems advisable in patients with normosensoric esotropia

Touchscreen performance and knowledge transfer in the red-footed tortoise (Chelonoidis carbonaria)

In recent years red-footed tortoises have been shown to be proficient in a number of spatial cognition tasks that involve movement of the animal through space (e.g., the radial maze). The present study investigated the ability of the tortoise to learn a spatial task in which the response required was simply to touch a stimulus presented in a given position on a touchscreen. We also investigated the relation between this task and performance in a different spatial task (an arena, in which whole-body movement was required). Four red-footed tortoises learned to operate the touchscreen apparatus, and two learned the simple spatial discrimination. The side-preference trained with the touchscreen was maintained when behaviour was tested in a physical arena. When the contingencies in the arena were then reversed, the tortoises learned the reversal but in a subsequent test did not transfer it to the touchscreen. Rather they chose the side that had been rewarded originally on the touchscreen. The results show that red-footed tortoises are able to operate a touchscreen and can successfully solve a spatial two-choice task in this apparatus. There was some indication that the preference established with the touchscreen could transfer to an arena, but with subsequent training in the arena independent patterns of choice were established that could be evoked according to the test context

Les LABEX réinventés. Les appropriations paradoxales d'un instrument d'action publique en biologie

Like many Western countries, France has recently launched a major wave of reforms that aimed to concentrate public funding more clearly on the “best” researchers, laboratories and universities. This policy brief analyses how biologists have appropriated one of these programs – the Laboratoires d’excellence (laboratories of excellence – LABEX). The results of this survey show that the implementation of this instrument is difficult to reduce to binary categories, such as failure or success. In many cases, LABEXs have reinforced dynamics already at work, without initiating major reorientations of agendas or research practices when they did not correspond to the objectives of these calls for proposals. But to conclude that the measure failed would be simplistic: biologists appropriated LABEXs and praise the flexibility of the instrument and its usefulness. Paradoxically, they found a way to overcome the competitive and temporary nature of biological research funding by using LABEX as a tool to reduce inequalities and financial uncertainties.Comme de nombreux pays occidentaux, la France a récemment lancé une vague importante de réformes destinées à concentrer plus nettement les crédits publics sur les « meilleurs » chercheurs, laboratoires et établissements. Ce Policy brief explore l’appropriation par les chercheurs en biologie de l’un de ces programmes, les laboratoires d’excellence (LABEX). Les résultats de cette enquête montrent que la mise en œuvre de cet instrument est difficilement réductible à des catégories binaires, comme l’échec ou la réussite. Dans bien des cas, les LABEX ont conforté des dynamiques déjà à l’œuvre, sans initier des réorientations profondes des agendas ou des pratiques de recherche quand elles ne correspondaient pas aux objectifs de ces appels à projets. Mais conclure à un échec de la mesure serait réducteur : les LABEX ont été appropriés par les biologistes, qui louent la souplesse de l’instrument et son utilité. Ils y ont trouvé paradoxalement un moyen de pallier le caractère compétitif et temporaire des financements de la recherche en biologie en faisant des LABEX un outil de réduction des inégalités et des incertitudes financières qui marquent aujourd’hui le travail de recherche en biologie

Natural categorization through multiple feature learning in pigeons

between large sets of photorealistic frontal images of human faces on the basis of sex. This ability was predominantly based on information contained in the visual texture of those images rather than in their con®gural properties. The pigeons could learn the distinction even when differences of shape and average intensity were completely removed. Here, we proved more speci®cally the pigeons ’ ¯exibility and ef®ciency to utilize the class-distinguishing information contained in complex natural classes. First, we used principal component as well as discriminant function analysis in order to determine which aspects of the male and female images could support successful categorization. We then conducted various tests involving systematic transformations and reduction of the feature content to examine whether or not the pigeons ’ categorization behaviour comes under the control of categorylevel feature dimensionsÐthat is, those stimulus aspects that most accurately divide the stimulus classes into the experimenter-de®ned categories of ``Male’ ’ and ``Female’’. Enhanced classi®cation ability in the presence of impoverished test faces that varied only along one of the ®rst three principal components provided evidence that the pigeons used these class-distinguishing stimulus aspects as a basis for generalization to new instances

Deep impact? Is mercury in dab (Limanda limanda) a marker for dumped munition? Results from munition dump site Kolberger Heide (Baltic Sea)

Dumped munitions contain various harmful substances which can affect marine biota like fish. One of them is mercury (Hg), included in the common explosive primer Hg fulminate. There is still a lack of knowledge whether dumped munitions impact the Hg concentrations in the Baltic Sea environment. This study aims to answer the question if dab caught at the dump site Kolberger Heide show higher Hg concentrations released from munition sources and whether Hg in fish is a usable marker for munition exposure. Therefore, a total of 251 individual dab (Limanda limanda) were analysed including 99 fish from the dump site. In fish from the Kolberger Heide, no elevated Hg concentrations were found compared to reference sites when age-dependent bioaccumulation of mercury was considered. Therefore we conclude that Hg in fish is no suitable indicator for exposure to munition dumping, e.g. in the frame of possible future monitoring studies as Hg exposure originating from dumped munition is only a small contributor to overall Hg exposure of fish