Abstract : In order to explain Humans' success in interceptive actions of gravitationally accelerated objects, despites the low capacity of the visual system to detect it, several studies have recently suggested that gravity has been embodied in a quantitative internal model of gravity thereby permitting access to exact time-to-contact (TTC) when intercepting a free falling object. However, we may wonder if theoretical and methodological concerns in these experiments cannot call into question the effective demonstration of the existence and use of such a model. The goal of this doctoral work was to determine how our knowledge of gravity influences our perception and actions. We conducted six experimentations issued from three different paradigms, perceptive judgement, indirect interception and direct interception. Our results refute the use of a quantitative internal model of gravity, and plead in favour of the use of our knowledge of gravity as a qualitative implicit physics knowledge, which would modulate our perceptive judgements and interceptive movements but without giving access to the quantitative effects of gravity.