An example cognitive hierarchy

Our research group was an early proponent of blackboard architectures for sharing data between a robot’s cognitive processes. A blackboard provides a global shared memory facility that acts as both a communications infrastructure as well as a storage mechanism for a robot. The blackboard typically offers both publisher-subscriber based asynchronous communications as well as synchronous query-answering communications. The storage of the blackboard provide both short-term and long-term memory.

More recently our group has developed a novel meta-model for formalising cognitive hierarchies. At its most basic level a cognitive hierarchy consists of a set of nodes connected together in a hierarchical graph. Every node in the hierarchy is involved in world-modelling and behaviour generation and represents a particular abstraction of the world; with the lowest-level node as a proxy for the (actual) external world.

Our formalisation is described as a meta-model as it provides the formal structure for a node and hierarchy but does not commit to any particular representation for node internals. For example, it requires that a node consists of a set of possible beliefs but does not restrict the form of those beliefs. In this way the formalisation provides the flexibility to instantiate and integrate nodes of arbitrary structures, such as symbolic as well as sub-symbolic reasoning mechanisms. Furthermore, the formal nature of the model provides the basis from which to formally prove properties of the system as a whole.

Publications include:

• B. Hengst, C. Keith, M. Pagnucco, D. Rajaratnam, P. Robinson, C. Sammut, and M. Thielscher, A framework for integrating symbolic and sub-symbolic representations. 25th International Joint Conference on Artificial Intelligence IJCAI-16. New York, New York, USA, 2016.
• D. Rajaratnam, B. Hengst, M. Pagnucco, C. Sammut and M. Thielscher. Composability in Cognitive Hierarchies. Proceedings of the Australasian Joint Conference on Artificial Intelligence, 2016.
• C. Sammut, The child machine vs the world brain. Informatica, vol. 37 pp. 3–8, 2013.
• A. Haber and C. Sammut, A Cognitive Architecture for Autonomous Robots, Advances in Cognitive Systems, vol. 2, pp. 257–275, 2012.
• A. Haber, and C. Sammut, Towards a cognitive architecture for extended robot autonomy. Advances in Cognitive Systems, Palo Alto, CA, 2012.
• C. Sammut, When do robots have to think? Advances in Cognitive Systems vol. 1 pp. 73–81, 2012.