Laure Zago studies the functional difference and the complementarity of the functions of the two hemispheres of the brain. This asymmetry has an impact on the phenomenology of consciousness, as shown for example by the non-awareness of certain stimuli in patients affected by certain unilateral brain lesions. It is moreover by questions concerning a concept linked to consciousness, namely attention, that Laure Zago approaches her point. She thus deals with the attentional biases assumed to be linked to lateralization; behavioral biases, of which she lists different types and describes their characteristics in patients with brain damage affecting the right hemisphere, in comparison with healthy subjects. She shows some results around the correlation between the importance of these biases and the intensity of the lateralization of the concerned processes. A final section takes up the question of the origin of the specialization entrusting visuospatial processes to the right hemisphere and those of language to the left hemisphere. The results seem to show that the population of left-handers (less than 10% of the general population) is a population to be favored for "understanding the rules for implementing hemispheric specialization of lateralized cognitive functions".