Psychophysics, Gestalts and Games

International audienceMany psychophysical studies are dedicated to the evaluation of the human gestalt detection on dot or Gabor patterns, and to model its dependence on the pattern and background parameters. Nevertheless, even for these constrained percepts, psychophysics have not yet reached the challenging prediction stage, where human detection would be quantitatively predicted by a (generic) model. On the other hand, Computer Vision has attempted at defining automatic detection thresholds. This chapter sketches a procedure to confront these two methodologies inspired in gestaltism. Using a computational quantitative version of the non-accidentalness principle, we raise the possibility that the psychophysical and the (older) gestaltist setups, both applicable on dot or Gabor patterns, find a useful complement in a Turing test. In our perceptual Turing test, human performance is compared by the scientist to the detection result given by a computer. This confrontation permits to revive the abandoned method of gestaltic games. We sketch the elaboration of such a game, where the subjects of the experiment are confronted to an alignment detection algorithm, and are invited to draw examples that will fool it. We show that in that way a more precise definition of the alignment gestalt and of its computational formulation seems to emerge. Detection algorithms might also be relevant to more classic psychophysical setups, where they can again play the role of a Turing test. To a visual experiment where subjects were invited to detect alignments in Gabor patterns, we associated a single function measuring the alignment detectability in the form of a number of false alarms (NFA). The first results indicate that the values of the NFA, as a function of all simulation parameters, are highly correlated to the human detection. This fact, that we intend to support by further experiments , might end up confirming that human alignment detection is the result of a single mechanism

The Acculturated Brain

Recent decades have been marked by a steadily increasing emphasis on neural determinants of behavior. Concerns with socio-cultural processes have simultaneously been diminished. Given the significance of this shift toward a cortical explanation of human behavior-in terms of both the direction of research in psychology and the implications of this research for social practices and policy-critical reflection is essential. In particular, when significant conceptual flaws are brought into focus, we find good reason to reconsider the significance of sociocultural process. And, when we take into account major vistas of neuropsychological research, the conclusion becomes evident that not only is human action unintelligible in terms of neural activity, but the brain primarily functions in the service of cultural process. To be sure, cortical functioning may both enable and limit human activity. However, given the enormous variation in human conduct, and the dependency of such conduct on the generation of cultural meaning, the most promising conclusion, both for research and for societal practice, is to view the brain chiefly as an instrument for achieving socially originated ends. This is not to argue against inquiry into brain functioning, but to be more judicious about the domains of its utility, and critical in terms of what it offers for understanding human action