The human brain has a remarkable ability to generate plans for sequences of actions that allow human agents to co-operate with and to manipulate the behaviour of others. It is widely claimed that the operations underlying plan developments, behaviour sequencing and inhibition of inappropriate responses to the environment are carried out in the prefrontal cortex. This implies that the prefrontal cortex is a natural system with the capacity to utilise cognitive technology. The present paper argues that social competence is a manifestation of action planning in which other agents feature as plan elements. Accordingly, plans that involve other agents are expected to be more complex than plans which do not. In the light of evidence that negative information makes particularly heavy processing demands, social judgements involving prohibition or unacceptability are expected to create most difficulty for the human action planning system. These assumptions were tested by measuring the ability of patients with prefrontal injuries to detect anomalous action sequences, using a specially constructed Action Acceptability Test. It was hypothesised that if the frontal lobes play a major role in action planning, patients with frontal lobe injuries should show impaired ability to detect faulty action plans, particularly when such plans relate to complex social action sequences, and action sequences involving unacceptable behaviours.
The hypotheses were generally supported as frontal-injury patients proved to be worse at detecting both complex social sequences and deviant action sequences than participants with non-frontal injuries and normal control participants. The results of the study are consistent with the view that human social competence results from the cognitive processes associated with action planning and the data also supports the claim that action planning processes are specifically disrupted by damage to the prefrontal cortex.
The findings provide some confirmation for the Cognitive Technology perspective, in that action planning does seem to be physically associated with a specific brain area, and including social agents and deviations from acceptability in action plans do seem to be manipulations that operate to make action plans more difficult to process, hence causing more errors in individuals with damage to the prefrontal cortex. The results also provide some encouragement for the belief that new cognitive tools can be constructed that link brain processes to other levels of description, such as social behaviour. The Action Acceptability Test, a prognostic tool developed to predict the social competence of frontal-injury patients, is offered as one such example.
