Consciousness and the Social Brain

like to clarify exactly what I mean by a decision about the presence of awareness. Suppose that you are seated in front of a computer screen participating in an experiment. Images are flashed on the screen, one after the next, and your task is to indicate the color of each image. If it is red, you press one button. If it is green, you press a different button. The information that you are conveying by button press, the information that is the subject of your decision, concerns color, not awareness. You are probably also aware of the colors, at least at first. But after a few thousand trials you may go on autopilot, pressing, responding, doing quite well, while your conscious mind is elsewhere. In my experience, it is actually easier to perform a task like this when awareness has partially or even entirely left it.
    If the images are flashed very briefly or are very dim, you may deny that anything was presented. But if forced to guess the color, you will probably be able to guess above chance. In that case, information about the image is present in your brain and can even result in a verbal report or a button press, while at the same time you are unable to detect a conscious experience attached to the color.
    Merely being able to report that a visual stimulus is present, is of a certain color, has a certain shape, or is moving in a certain way is not the same as detecting the presence of awareness. A relatively simple machine that shows no evidence of awareness can be designed to detect low-level features, yet we humans can also detect and report on the presence of an inner experience.
    Now imagine that the task is changed. The same type of image is flashed on the screen, but your job is to report whether you have a subjective experience of the image. You must introspect and decide if that special intangible stuff, awareness, is attached to the image. If yes, you press the response key. If not, naturally you skip the key press. Now the determination is not the presence of red or green, but the presence of awareness. If the images are presented slowly and clearly, and you are not overtaxed with thousands of trials, you will probably decide that awareness is present with each image. If the images are flashed too quickly or too dimly, or if you are distracted from the task, you may fail to detect any awareness, any inner experience, attached to the images.
    The purpose of these elaborate examples is to isolate one specific type of decision. The brain can certainly decide whether something is green or red, big or small, important or unimportant, dangerous or safe, complicated or simple. But we can also decide that we have, within us, conscious experience of those things. Whatever the specific property of awareness may be, it is something that a brain can detect. We can decide that we have it.
    Much has been learned recently about the neuronal basis of decision-making, especially in the relatively simple case of visual motion. 4 , 5 Suppose that you are looking at a blurry or flickering image and are asked to decide its direction of motion. It can drift either to the left or the right, but because of the noisy quality of the image, you have trouble determining the direction. By making the task difficult in this way, neuroscientists can slow down the decision process, thereby making it easier to study.
    This decision process appears to work as follows. First, the machinery in the visual system constructs signals that represent the motion ofthe image. Because the visual image is noisy, it may result in conflicting signals indicating motion in a variety of directions. Second, those signals are received elsewhere in the brain by decision integrators. The decision integrators determine which motion signal is consistent enough or strong enough to cross a threshold. Once the threshold is crossed, a response is triggered. In this way, the system decides which direction the image is likely to be moving.
    Strictly speaking, the system is not deciding whether the visual image is moving to the right or left. It is deciding between two information streams in the brain: is the left or right motion signal stronger? The decision can even be manipulated by inserting a fine electrode into the brain, into a particular part of the visual system, passing a very small electrical current and thereby boosting one or another of the motion signals. 6
    Since neuroscientists have some notion of the brain’s machinery for decision-making, what can be