Mesurer le « développement durable » pour aider à le réaliser ?

Avec les enjeux du « développement durable », la production d’informations formalisées, organisées, chiffrées, a trouvé un nouveau domaine où elle est devenue stratégique. Les « indicateurs de développement durable » sont censés compléter les capacités de régulation publique pour sortir d’évolutions dommageables pour l’humanité et la planète. Cet article, à partir notamment des démarches des instances françaises et européennes, remet au jour les dimensions et dynamiques qui jouent dans le déploiement de ces indicateurs. Ils bénéficient en effet d’un réseau institutionnel et épistémique qui marque un degré d’organisation croissant dans une forme de surveillance à distance. Ils participent aussi à la structuration des cadres d’appréhension des problématiques et des enjeux en discussion. Forme de mesure mais aussi de perception, ces indicateurs se rapprochent d’une tentative de saisie du monde et constituent en quelque sorte des prises pour cette opération. Au-delà donc d’un simple aspect d’aide décisionnelle, ils peuvent alors être appropriés d’une manière qui en fait des technologies de gouvernement du changement.The issues of sustainable development have opened up a new area where the production of formalised, organised and quantified information is particularly strategic. The « Indicators of sustainable development » are intended to supplement the capabilities of public regulation, in order to withdraw from trajectories harmful to both humanity and the planet. Notably based on the initiatives of French and European authorities, this article sheds light on the dimensions and dynamics that come into play in the deployment of these indicators. Indeed, these make use of an institutional and epistemic network that reveals the increasing degree of organisation of a form of remote monitoring. They also play a part in the structuring of the frameworks used in apprehending concerns and issues for discussion. In that they are a form of measurement as well as perception, these indicators can be seen as tools to better grasp the world. Therefore, besides providing guidance for decision-making, they can become suitable as technologies of change management

Effects of stimulus duration on audio-visual synchrony perception

The integration of visual and auditory inputs in the human brain occurs only if the components are perceived in temporal proximity, that is, when the intermodal time difference falls within the so-called subjective synchrony range. We used the midpoint of this range to estimate the point of subjective simultaneity (PSS). We measured the PSS for audio-visual (AV) stimuli in a synchrony judgment task, in which subjects had to judge a given AV stimulus using three response categories (audio first, synchronous, video first). The relevant stimulus manipulation was the duration of the auditory and visual components. Results for unimodal auditory and visual stimuli have shown that the perceived onset shifts to relatively later positions with increasing stimulus duration. These unimodal shifts should be reflected in changing PSS values, when AV stimuli with different durations of the auditory and visual components are used. The results for 17 subjects showed indeed a significant shift of the PSS for different duration combinations of the stimulus components. Because the shifts were approximately equal for duration changes in either of the components, no net shift of the PSS was observed as long as the durations of the two components were equal. This result indicates the need to appropriately account for unimodal timing effects when quantifying intermodal synchrony perceptio

The standard observer : a controversial subject

The efficiency of monochromatic light for the eye is expressed in the relative spectral sensitivity of the eye. In 1924, the ‘Commission Internationale de l’Eclairage’ (CIE) recommended a curve for this purpose that had to be representative for the average photopic observer. In 1931 this was incorporated in the CIE Standard Observer. The particularly important conception of luminance is defined with the aid of the relative spectral sensitivity. It is a measure for brightness and enables us to compare the light flow of sources of different color. It affords the possibility of specifying the adaptive condition under which visual tests have to be carried out. When more data became available, however, it appeared that the standard observer is less representative than initially thought. For example, its sensitivity in the blue is too low, and the spectral sensitivity of the eye proved to depend on many parameters, like field size and location on the retina. Moreover, the visual spectral sensitivities determined according to various methods prove to be mutually different. This results in the increasingly urgent question, i.e. under which circumstances a light measurement, normally based on the sensitivity of the standard observer, is adequate or not. In view of this, in the latest session of the CIE (1971) a new study of the methodologic foundations was recommended. At the same time, high priority was recommended for research into the spectral sensitivity of small fields and the specification of mesopic light. Both are of importance for perimetry and mesoptometry

Dynamic properties of vision-II:theoretical relationships between flicker and flash thresholds

\u3cp\u3eOn the basis of some general system properties theoretical relationships have been established between parameters which characterise the sensitivity and inertia of the visual system in flicker and flash experiments. The results are in good agreement with the experimental relationships found in Part I over a background intensity range of five decades. \u3c/p\u3