Consciousness and information integration

Integration information theories posit that the integration of information is necessary and/or sufficient for consciousness. In this paper, we focus on three of the most prominent information integration theories: Information Integration Theory (IIT), Global Workspace Theory (GWT), and Attended Intermediate-Level Theory (AIR). We begin by explicating each theory and key concepts they utilize (e.g., information, integration, etc.). We then argue that the current evidence indicates that the integration of information (as specified by each of the theories) is neither necessary nor sufficient for consciousness. Unlike GWT and AIR, IIT maintains that conscious experience is both necessary and sufficient for consciousness. We present empirical evidence indicating that simple features are experienced in the absence of feature integration and argue that it challenges IIT's necessity claim. In addition, we challenge IIT's sufficiency claim by presenting evidence from hemineglect cases and amodal completion indicating that contents may be integrated and yet fail to give rise to subjective experience. Moreover, we present empirical evidence from subjects with frontal lesions who are unable to carry out simple instructions (despite appearing to understand their meaning) and argue that they are irreconcilable with GWT. Lastly, we argue that empirical evidence indicating that patients with visual agnosia fail to identify objects they report being conscious of present a challenge to AIR's necessity claim.