Articulation correction of the deaf by means of visually displayed acoustic information
Dirk-Jan Povel · Radboud Repository (Radboud University) · 1974
SPEECH PRODUCT IONFrom the flow diagram given one could conclude that the process under consideration is an open loop process, i.e. does not make use of feedback.Since the problem of the deal , as regards his attempts to speak, is caused by feedback deprivation, we shall also in the-flute comparison look in considerable detail at the role of feedback.Ihe role of leedback in fiuti pld>ing Pie sensory leedback that thi.subject receives during (and after) the perlormance of skilled behaviour can, v\ith respect to its function in the piocess, be divided into two types, fhe first type of feedback is information that is used for the computation of the on-going behaviour, the second type of feedback has no role in the control of the behaviour hut fulfills a 'monitoring' function.It does not seem likely that all the feedback that is available during flute playing will be of the fust type, since this process consists of achieving continually changing targets (the finger positions).Whether feedback can be used for the computation of the on-going behaviour is not only dependent ön the frequency of changes of taiget but also on the duration of the feedback loops.Feedback of the second type is information that arrives centrally too late to be used for the control of the on-gomg behaviour.This information can, however, be used as a check on already generated behaviour and when a discrepancy is detected between that behaviour and a certain criterion it will be stopped and may be corrected This type of information presumably plays a major role m the acquisition stage.We will now give a more detailed description of that part of the process of flute playing in which feedback may be expected to play a role.This is the stage of the process in which the sequence of finger positions is transformed into a sequence of actions.Theoretically there are two possible alternatives which will be treated successively.1. Open loop.In the open loop model, every action will be determined centrally, it will not make use of feedback on the actual state of the peripheral organs.The knowledge about this state, necessary in determining the actions to follow, may be assumed to be centrally available, since this state was the target of the proceeding action.This type of behaviour regulation is described by Keele (1968) as controlling by means of a motor program.According to Keele, 'the concept of a motor