In a previous communication to the Society (published in Kybernetes 18, 4, 19-28, 1989), the concept of a 'tern' was defined and a Principle of Ternality stated. It was shown that propagation and work are both terns.
All human-computer interaction consists of propagation between the two systems, and is engaged in so that they can collaborate in some kind of work. Allocation of function - the division of labour between human and machine - has always been a major consideration in ergonomics.
A technique of Ternary Analysis is described, with an outline of its use to analyse situations where humans are conversing with each other, or where humans are interacting with machines, with special reference to allocation of components of the interaction between the secondary and tertiary domains. This has implications for the allocation of components of the collaborative work between the two participants.
Ternary Analysis offers, among other things, a way of analysing human institutions to facilitate the introduction of computers to enhance or to replace the human work involved. Inevitably, the way in which it offers a way of dealing with judgement and evaluation is of special interest. Some examples are given of existing and proposed systems which can benefit from this approach.
There are practical reasons why a general theory of allocation of function between human and computer, particularly with respect to the handling of judgement and evaluation, may be of particular importance at this time.