Conscious visual perception can fail in many circumstances. However, little is known about the causes and processes leading to failures of visual awareness. In this study, we introduce a new signal detection measure termed subjective discriminability of invisibility that allows one to distinguish between subjective blindness due to reduction of sensory signals or to lack of attentional access to sensory signals. The SDI is computed based upon subjective confidence in reporting the absence of a target . Using this new measure, (...) we found that target misses were subjectively indistinguishable from physical absence when contrast reduction, backward masking and flash suppression were used, whereas confidence was appropriately modulated when dual task, attentional blink and spatial uncertainty methods were employed. These results show that failure of visual perception can be identified as either a result of perceptual or attentional blindness depending on the circumstances under which visual awareness was impaired. (shrink)

Every perceptual experience has an objective and a subjective side. We see object size, independent of distance, but we also see that distant objects project smaller images. Early modern conceptions focused on local stimulation and thus on the subjective aspect. Helmholtz and Hering emphasized the objective aspect. Helmholtz split visual experience into two stages, with sensation representing the subjective side and perception, through cognitive processes, the objective side. Gestalt theory denied this dualism, rejecting both sensory and cognitive stages. Despite contrary (...) evidence, the sensation/perception dualism persists, in brightness models and past experience theories. That we can detect visual angle and luminance does not mean that these are raw sensations out of which perception of size and lightness is built. Size and color constancy are truly visual, not cognitive. Instructions to subjects in vision experiments must avoid the proximal mode on the one hand and cognitive judgments on the other. (shrink)

We explored the possibility of a general brightness bias: brighter pictures are evaluated more positively, while darker pictures are evaluated more negatively. In Study 1 we found that positive pictures are brighter than negative pictures in two affective picture databases (the IAPS and the GAPED). Study 2 revealed that because researchers select affective pictures on the extremity of their affective rating without controlling for brightness differences, pictures used in positive conditions of experiments were on average brighter than those used in (...) negative conditions. Going beyond correlational support for our hypothesis, Studies 3 and 4 showed that brighter versions of neutral pictures were evaluated more positively than darker versions of the same picture. Study 5 revealed that people categorised positive words more quickly than negative words after a bright picture prime, and vice versa for negative pictures. Together, these studies provide strong support for the hypotheses that picture brightness influences evaluations. (shrink)