Carryl L. Baldwin

DESIGNING IN-VEHICLE TECHNOLOGIES FOR OLDER DRIVERS : APPLICATION OF SENSORY-COGNITIVE INTERACTION THEORY

Drivers over the age of 65 are increasing rapidly in numbers and are driving more frequently. It is well recognized that older driver safety may be compromised due to age-related changes in cognitive functioning. Less well appreciated, however, is that sensory loss may interact with cognitive changes to compound the threat to safety. A sensory-cognitive interaction theory of ageing is described and its implications are discussed for the design of in-vehicle technologies. A particular area of focus is the difficulties of older drivers in carrying out navigational tasks while simultaneously maintaining safe control of the motor vehicle. Advanced automotive technologies including in-vehicle route guidance and navigational displays have the potential to improve safety and mobility if designed in accordance with the sensory/cognitive abilities of older drivers.

Impact of speech presentation level on cognitive task performance: implications for auditory display design

Speech displays and verbal response technologies are increasingly being used in complex, high workload environments that require the simultaneous performance of visual and manual tasks. Examples of such environments include the flight decks of modern aircraft, advanced transport telematics systems providing in-vehicle route guidance and navigational information and mobile communication equipment in emergency and public safety vehicles. Previous research has established an optimum range for speech intelligibility. However, the potential for variations in presentation levels within this range to affect attentional resources and cognitive processing of speech material has not been examined previously. Results of the current experimental investigation demonstrate that as presentation level increases within this ‘optimum’ range, participants in high workload situations make fewer sentence-processing errors and generally respond faster. Processing errors were more sensitive to changes in presentation level than were measures of reaction time. Implications of these findings are discussed in terms of their application for the design of speech communications displays in complex multi-task environments.

Mental Workload as a Function of Road Type and Visibility: Comparison of Neurophysiological, Behavioral, and Subjective Indices:

Advanced in-vehicle technologies (IVTs) are rapidly being introduced. Methods of assessing the mental workload required by the driving situation are imperative to the safe implementation of these advanced systems. The current investigation compared the sensitivity of an array of assessment techniques to changes in simulated driving task demand. P300 amplitude was sensitive to increased driving task demand due to reduced visibility (presence of fog) but was not sensitive to changes in road type (urban versus freeway). Conversely, RT and accuracy to a secondary task were sensitive to changes in road type but were not sensitive to the visibility manipulation. Subjective workload ratings were not sensitive to either manipulation. Results are discussed in terms of their implications for assessing the impact of environmental factors on the mental workload demands of the driving task and for the design and implementation of adaptive driver interfaces.

Prevention of Rear-End Crashes in Drivers with Task-Induced Fatigue through the Use of Auditory Collision Avoidance Warnings

Driver fatigue is associated with increased lane position variability, decreased response time and increased crash rate. Collision avoidance systems (CASs), which are currently installed in many vehicles, have been shown to reduce the crash rates of alert drivers. The current investigation examined the effectiveness of two auditory CAS warnings for reducing crash rates in fatigued young and older drivers faced with a potential rear-end collision. Relative to a no-warning condition, auditory CAS warnings reduced overall crash probability. The presence of a CAS warning was particularly beneficial to reducing crashes in older drivers. Results of this study indicate that auditory CAS warnings may help reduce fatigue-related rear-end crashes, particularly among older drivers.

Interference Effects on the Recall of Words Heard and Read: Considerations for ATC Communication

Two experiments were conducted to investigate the effects of interference on memory for words that were either read or heard. Interference tasks required either visual, verbal, or central executive (CE) working memory resources. Experiment 1 examined effects of simultaneous interference, whereas Experiment 2 examined the effects of posttask (subsequent) interference. When interference occurred simultaneously with word presentation, the verbal and CE interference tasks were most disruptive, regardless of whether the words were read or heard. Furthermore, hearing words facilitated recall in comparison to reading words regardless of interference source. When the interference task followed word presentation, CE interference again was the most disruptive. However, the effects of the visual and verbal interference tasks were equivalent. These results are discussed with respect to communication mode in ATC messages to pilots (i.e., textual data-link messages vs. voice transmissions).

Allowing for Individual Differences in Auditory Warning Design: Who Benefits from Spatial Auditory Alerts?

An auditory spatial Stroop paradigm was used to examine the effects of semantic and spatial audio cue conflict on accuracy and response time. Participants responded to either the semantic meaning or the spatial location of a directional word, which was either congruent (i.e. the word “right” being presented from the right) or incongruent (i.e. the word “right” being presented from the left). Navigational strategy was also assessed to determine if individual differences on this measure could affect responses to semantic or location information. An interaction between task type and navigational strategy indicated that people who preferred a verbal strategy responded faster to semantic content and people who preferred a spatial strategy responded faster to location information. Implications of these results are discussed in terms of the design of collision avoidance systems.

Method for Characterizing and Identifying Task Evoked Pupillary Responses During Varying Workload Levels

Understanding when operators are experiencing high workload is important in the design and implementation of Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR) systems. Fortunately physiological metrics, such as pupillary reflexes, have been shown to correlate with increases in mental workload. This paper proposes an automated method for characterizing and identifying task evoked pupillary responses (TEPR) during various workload levels. This method captures findings and observations from previous TEPR studies in an automated algorithm. This algorithm characterizes the rate of pupil dilation and constriction into a TEPR area metric, which is then used to identify times of increased operator workload. Independent trial analysis shows the benefits of using the TEPR area for distinguishing different workload responses but additional investigation is needed to make the algorithm more robust to individual variability.

The Role of Age-Related Neural Timing Variability in Speech Processing

Age-related difficulties in speech processing remain a concern, especially as technology continues to depend heavily on successful speech comprehension on the part of users. Event-related potentials (ERPs) have frequently been used to assess age-related changes in the processing of language. Specifically, the amplitude of the ERP is often compared between conditions or groups of interest. In constructing ERPs, many neurophysiologic responses are averaged together to reduce the contribution of uncorrelated background activity in the electroencephalogram (EEG). However, if variability in the timing of each potential on a trial-by-trial basis (i.e., “latency jitter”) is confounded with a variable of interest, then the presence of amplitude differences observed in the average ERP might not be solely the result of genuine amplitude differences, but also timing variability. We examined the role latency jitter may play in the well-established observation of age-related changes in the processing of natural speech as indexed by the N400. Older and younger adults were presented with sentences that ended in either expected or unexpected final words. In agreement with previous findings, a reduction in N400 amplitude was observed in the older adults compared with the younger adults in response to the unexpected final words. However, analyzing ERPs on a single trial basis reveals the older adults to have significantly greater intra-subject variability in N400 latency for incongruent speech stimuli, in comparison to younger adults. This increased intra-individual latency variability may contribute to the smaller N400 amplitudes observed in each subject’s average ERP. Age-related reductions in N400 amplitudes may indicate less precise timing of neurological processes. Conversely, they may indicate that the older brain exhibits greater specificity in the processing of individual sentence stimuli.

EEG Spectral Analysis of Workload for a Part-task UAV Simulation

Electroencephalography (EEG) has the prospect of providing a means to gauge operator workload in a manner that does not intrude on the task being performed. Specifically, it has been proposed that the technique could be used as a method to speed the learning of a task, by adjusting the task to suit the state of the learner. The present study recorded EEG while participants performed a simulated Unmanned Aerial Vehicle (UAV) reconnaissance task. Analysis of power in three EEG frequency bands of interest found differences between the types of task being performed; however more complex analysis may be necessary to discern levels of difficulty within the task.

Interference Timing and Acknowledgement Response with Voice and Datalink Atc Commands

Datalink is a text system used to send messages between ATC and pilots. There are concerns related to changes in information processing demands and responses associated with executing speech and text ATC commands. The timing of interference and the acknowledgement response on command execution performance were examined during the processing of simulated ATC commands. Verbal and central executive (CE) interference tasks were presented before or after the acknowledgement. Participants received both speech and text commands, responded by a verbal or manual acknowledgement, and set the controls in a flight simulator. Results demonstrated an advantage for a manual acknowledgement with longer messages. CE as opposed to verbal interference prior to an acknowledgement had a greater negative effect that was exacerbated in the text condition. The findings are interpreted within the context of a working memory and multiple-resource perspective and implications are discussed with regard to communication processes in aviation.