Recently we proposed a theory of consciousness, the attention schema theory, based on findings in cognitive psychology and systems neuroscience. In that theory, consciousness is an internal model of attention or an ‘attention schema.’ Consciousness relates to attention the same way that the internal model of the body, the ‘body schema,’ relates to the physical body. The body schema is used to model and help control the body. The attention schema is used to model and help regulate attention, a data-handling process in the brain in which some signals are enhanced at the expense of other signals. We proposed that attention and the attention schema co-evolved over the past half billion years. Over that time span, the attention schema may have taken on additional functions such as promoting the integration of information across diverse domains and promoting social cognition. This article summarizes some of the main points of the attention schema theory, suggests how a brain with an attention schema might conclude that it has a subjective awareness, and speculates that the same basic properties can be engineered into machines.