A software bot inspired by a popular theory of human consciousness takes the same time as humans to complete simple awareness tasks. Its creators say this feat means we are closer to understanding where consciousness comes from. It also raises the question of whether machines could ever have subjective experiences.

The bot, called LIDA for Learning Intelligent Distribution Agent, is based on “global workspace theory”. According to GWT, unconscious processing – the gathering and processing of sights and sounds, for example, is carried out by different, autonomous brain regions working in parallel. We only become conscious of information when it is deemed important enough to be “broadcast” to the global workspace, an assembly of connected neurons that span the brain. We experience this broadcast as consciousness, and it allows information to be shared across different brain regions and acted upon.

Recently, several experiments using electrodes have pinpointed brain activity that might correspond to the conscious broadcast, although how exactly the theory translates into cognition and conscious experience still isn’t clear.

To investigate, Stan Franklin, of the University of Memphis in Tennessee, built LIDA – software that incorporates key features of GWT, fleshed out with ideas about how these processes are carried out to produce what he believes to be a reconstruction of cognition.

Franklin based LIDA’s processing on a hypothesis that consciousness is composed of a series of millisecond-long cycles, each one split into unconscious and conscious stages. In the first of these stages – unconscious perception – LIDA scans the environment and copies what she detects to her sensory memory. Then specialised “feature detectors” scan sensory memory, pick out certain colours, sounds and movements, and pass these to a software module that recognises them as objects or events. For example, it might discover red pixels and “know” that a red light has been switched on. In the next phase, understanding, which is mainly unconscious, these pieces of data can be strung together and compared with the contents of LIDA’s long-term memory. Another set of processes use these comparisons to determine which objects or events are relevant or urgent. For example, if LIDA has been told to look out for a red light, this would be deemed highly salient. If this salience is above a certain threshold, says Franklin, “it suddenly steps over the edge of a cliff; it ignites”. That event along with some of its associated content will rise up into consciousness, winning a place in LIDA’s global workspace – a part of her “brain” that all other areas can access and learn from. This salient information drives which action is chosen. Then the cycle starts again.

Franklin reckons that similar cycles are the “building blocks for human cognition” and conscious experience. Although only one cycle can undergo conscious broadcast at a time, rather like the individual frames of a movie, successive broadcasts could be strung together quickly enough to give the sense of a seamless experience.

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