Utilisation of prosodic and semantic cues of nonunderstanding during readback/hearback verbal transactions in technical environments

The readback/hearback protocol is a communicative procedure used within many technical environments to minimise the risk of communication errors over the radio or telephone. This protocol requires the receiver of a verbal instruction to repeat or 'read back' the instruction to the sender to ensure that it has been heard correctly. It does not, however, ensure that it has been understood correctly. An instance where a receiver has failed to understand an instruction is referred to as a nonunderstanding. In high-risk, high-consequence environments, nonunderstandings pose the greatest risk when they are concealed by a receiver, as the sender is consequently unaware that an error has taken place. The primary aim of this program of research was to identify the prosodic and semantic cues that are used by senders to recognise nonunderstandings during readback/hearback exchanges. An allied aim of the thesis was based on the reasonably consistent observation that experienced operators within technical environments have a greater capacity to extract and utilise visual cues in their environment to understand a situation, compared to their less experienced counterparts. This observation, however, has been limited to the investigation of the use of visual cues to the exclusion of those from other modalities. The current thesis, therefore, examined whether operators who demonstrated a relatively greater capacity for the utilisation of visual cues also demonstrated the same capability in the utilisation of auditory (prosodic and semantic) cues during assessments of nonunderstanding. Within the context of electricity transmission control, Paper 1 examined whether the prosodic cues that listeners use to interpret uncertainty (namely intonation, inter-turn delay and filler), are also used to judge instances of nonunderstanding. Intonation and filler were identified as prosodic cues that are used to discern levels of nonunderstanding on the part of the receiver ('speaker'). Within the same domain, Paper 2 found no evidence for a relationship between auditory and visual cue utilisation. Paper 3 sought to establish whether the use of prosodic cues to detect instances of nonunderstanding reflected a universal capability or whether it reflected expertise in the use of industry-specific phraseology. Using electrical rail control operators and naïve psychology students as participants, the results revealed that the use of prosodic cues during assessments of nonunderstanding reflected a universal capability, independent of industry-related expertise. The final study described in Paper 4, sought to establish whether there were differences in the use of prosodic cues depending upon the use of standard and non-standard phraseology amongst receivers. The results indicated that a filler acted as a prosodic cue during perceptions of nonunderstanding in the case of standard phraseology (i.e., a full readback response), and that filler and intonation acted as prosodic cues during non-standard responses (i.e., partial readback responses). It was also evident that the use of standardised phraseology provided operators with an important indicator as to the level of understanding of the receiver. Finally, greater levels of visual cue utilisation were associated with a relatively greater attention to filler and the use of standardised phraseology as indicators of nonunderstanding. The outcomes of the thesis have implications for the training and assessment of operators in environments that depend upon the accuracy of readback/hearback exchanges in reducing the potential for communication error.