Consciousness

Look at a ripe strawberry. You can recognize its color and say “red,” but the color also looks a particular way to you. Consciousness is that experienced side of seeing, hearing or feeling. How does activity in a brain relate to an experience?[1]

Red looks a particular way to you, and pain hurts. How do brain processes relate to those experiences, and what would count as explaining why they feel the way they do?

Researchers distinguish the felt character of an experience from the ways its information can be used. Phenomenal consciousness is what an experience feels like: how red looks or how pain feels. Access consciousness means that information is available for you to use in reasoning, choosing an action, or describing what you perceive. Distinguishing these targets does not establish that they require separate brain processes. Neural-correlate experiments often compare conditions with and without a reported experience. The resulting differences can mix the mechanism of experience with prerequisites such as attention, or consequences such as a decision and button press. A candidate mechanism must be distinguished from both.

The philosophical question is what more, if anything, explanation requires once those mechanisms are known. Some accounts identify experience with physical or functional organization; others argue that such descriptions leave its felt character unexplained.[1] [5]

We can measure brain activity and ask people what they see. The hard part is telling which activity supports the experience and which helps them describe it. Researchers also disagree about what would fully explain the feeling itself.[1] [5]

The 2025 Cogitate study agreed predictions with theory proponents before collecting data from 256 people using fMRI, magnetoencephalography and intracranial EEG. Global neuronal workspace theory predicted representations in prefrontal cortex, toward the front of the brain, and brief “ignition” events when images appeared and disappeared; integrated information theory predicted sustained activity and synchronization in posterior cortex, toward the back. Sustained responses in posterior visual regions fit some IIT predictions, but the predicted sustained posterior synchronization was not found. GNWT faced a lack of ignition at image offset and limited prefrontal coding of some conscious contents. These tests constrain proposed biological implementations, rather than directly testing the two theories’ mathematical or computational cores.

Measurement adds another difficulty. In a 2026 experiment with faint patterned images, rewards and how often the image was present biased detection judgments and, when detection trials were included, reproduction of an image’s contrast. A control experiment with the image-frequency manipulation lost this bias when detection judgments were removed. The work advances measurement without making reproduction a bias-free readout of experience.[2] [3]

Understanding consciousness could help us assess whether an AI or an animal such as a shrimp has experiences. That matters when deciding how to treat them. It could also help us recognize awareness in someone who cannot speak after a brain injury.[4] [6] [7]

These questions matter whenever experience may be hidden. In a 2024 six-center study, 60 of 241 adults without visible command-following showed a task response on fMRI or EEG. That is evidence of preserved command-following capacity, not a reading of their experience. Convenience sampling limits generalization, and negative task results can miss awareness. Better detection could inform care and attempts at communication.

The ethical stakes extend to animals and AI. For shrimp, researchers weigh nervous-system and behavioral evidence, which differs among groups. For AI, fluent statements about feelings can be imitation; proposed assessments also examine internal processing. Extending a human theory to another animal or a machine requires evidence that the relevant mechanisms carry over. Better understanding could help us decide whose experiences or suffering should influence how we treat them.[4] [6] [7]