On using psychophysical techniques to achieve urgency mapping in auditory warnings

doi:10.1016/S0003-6870(97)00013-6

Applied Ergonomics

Volume 30, Issue 2, April 1999, Pages 167-171

https://doi.org/10.1016/S0003-6870(97)00013-6 Get rights and content

Abstract

It is well established that warning implementation should aim to achieve urgency mapping between the perceived urgency of the warning itself and the situational urgency of the condition that it indicates. This paper describes how Stevens Power Law [Psychological Review, 64, 153–181, 1957], which quantifies the relationship between objective parameters (such as the pitch of a warning) and subjective parameters (such as perceived urgency), can be applied to the design of auditory warnings to facilitate such urgency mapping. Studies that have quantified and predicted the effects of different warning parameters on perceived urgency using an application of Stevens Power Law are reported.

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Cited by (60)

Danger or avoidance indication: Dynamics interact with semantics in auditory icons to avoid collisions
2022, International Journal of Industrial Ergonomics
Citation Excerpt :
This finding is consistent with a previous study which reported that more urgent auditory warnings are perceived to be less pleasant and more annoying (Fagerlönn, 2010, 2011; Fagerlönn and Alm, 2010). However, according to the urgency mapping principle, certain parameters may increase urgency with a relatively small increase in annoyance (Hellier and Edworthy, 1999). Although increasing situational urgency can arouse negative feelings, we can minimize the reduction in subjective experience by adjusting other parameters in subsequent studies (Fagerlönn, 2010; Gonzalez et al., 2012).
This study investigates how auditory icons with inherent meanings and dynamics in collision warnings affect warning message enhancement in driving. An experiment involving 36 participants was conducted. These participants were randomly presented with three types of warning sounds, including two auditory icons with different semantics (i.e., an avoidance-indicated auditory icon horn and a danger-indicated auditory icon collision) and an “earcon” (with an abstract pure tone). Each warning sound had dynamic and static forms. Results show that the danger-indicated auditory icons and earcons led to better driving performance than the avoidance-indicated auditory icons for brake reaction time, time to collision, and time to throttle release. Meanwhile, both the danger- and avoidance-indicated auditory icons were more efficient, emergent, likable, and intelligible than earcons. Dynamic sounds also resulted in stronger braking. When designing auditory icons, the impact of both their inherent meanings and dynamics on the subjective experience of drivers should be considered.
Design principles of anti-collision auditory warning systems were proposed to indicate hazards in driving and assist drivers in an emergency, contributing to warning and ergonomics in the design industrial field.
Novel sonification designs: Compressed, iconic, and pitch-dynamic auditory icons boost driving behavior
2022, Applied Ergonomics
Citation Excerpt :
Especially for the elderly and untrained users, time-compressed speech is more difficult to learn (Wolters et al., 2012). Despite the contradiction between subjective and objective results, the urgency mapping principle shows that certain parameters may increase urgency with a relatively small increase in annoyance (Bliss et al., 1995; Hellier and Edworthy, 1999). Alerts with proper urgency mapping can help drivers understand alerts and respond effectively.
With the development of connected vehicles, in-vehicle auditory alerts enable drivers to effectively avoid hazards by quickly presenting critical information in advance. Auditory icons can be understood quickly, evoking a better user experience. However, as collision warnings, the design and application of auditory icons still need further exploration. Thus, this study aims to investigate the effects of internal semantic mapping and external acoustic characteristics (compression and dynamics design) on driver performance and subjective experience. Thirty-two participants (17 females) experienced 15 types of warnings — (3 dynamics: mapping 0 vs. 1 vs. 2) × (5 warning types: original iconic vs. original metaphorical vs. compressed iconic vs. compressed metaphorical auditory icon vs. earcon) — in a simulator. We found that compression design was effective for rapid risk avoidance, which was more effective in iconic and highly pitch-dynamic sounds. This study provides additional ideas and principles for the design of auditory icon warnings.
Effect of spectral parameters on the elderly's urgency perception of auditory warning signals
2022, Applied Acoustics
Citation Excerpt :
It is now well established from a variety of studies [4–6] that for adults, the perceived urgency could be controlled by manipulating many spectral and temporal parameters of the auditory warning signals. Later work by Hellier & Edworthy [7] tried to quantify the contributions of different acoustic parameters to perceived urgency. Some research confirmed the reproducibility over previous studies under more realistic conditions.
This study aims at revealing the effects of spectral features of warning sounds on elderly people’s urgency perception and how it differs from the young group. A serial of experiments was conducted to investigate the independent variables including the sound pressure level and frequency of pure tone, with or without harmonics, fundamental frequency, spectral shape and irregularity of harmonics on the objective reaction time and subjective urgency evaluation. The results showed that SPL and frequency had significant effects on the elderly’s reaction time to pure tones. The elderly people tended to evaluate the lower frequency domain to be the most urgent one than young group. Elderly people were also likely to perceive sounds without harmonic components to be more urgent. Considering the spectral features of harmonics, the lower fundamental frequency of harmonics, spectral shape with great proportion of energy on low frequency domain and certain level of irregular components would be beneficial for elderly people’s urgency perception. These findings indicated that the warning sounds of the elderly need to be carefully designed.
Take-over requests in highly automated driving: A crowdsourcing survey on auditory, vibrotactile, and visual displays
2018, Transportation Research Part F: Traffic Psychology and Behaviour
Citation Excerpt :
Extensive work has been conducted on the relationship between display characteristics and evoked perceived urgency. As Baldwin et al. (2012), Hellier, Edworthy, and Dennis (1993), Hellier and Edworthy (1999), and Park and Jang (1999) showed, Stevens (1957) power law, which associates the objective magnitude of a physical stimulus with its perceived intensity, can be used to predict the perceived urgency of a warning. It has been found that perceived urgency increases with smaller interpulse intervals and that this effect holds for each of the modalities (visual, auditory, & vibrotactile) and combinations thereof (Haas & Casali, 1995; Haas & Edworthy, 1999; Van Erp, Toet, & Janssen, 2015).
An important research question in the domain of highly automated driving is how to aid drivers in transitions between manual and automated control. Until highly automated cars are available, knowledge on this topic has to be obtained via simulators and self-report questionnaires. Using crowdsourcing, we surveyed 1692 people on auditory, visual, and vibrotactile take-over requests (TORs) in highly automated driving. The survey presented recordings of auditory messages and illustrations of visual and vibrational messages in traffic scenarios of various urgency levels. Multimodal TORs were the most preferred option in high-urgency scenarios. Auditory TORs were the most preferred option in low-urgency scenarios and as a confirmation message that the system is ready to switch from manual to automated mode. For low-urgency scenarios, visual-only TORs were more preferred than vibration-only TORs. Beeps with shorter interpulse intervals were perceived as more urgent, with Stevens’ power law yielding an accurate fit to the data. Spoken messages were more accepted than abstract sounds, and the female voice was more preferred than the male voice. Preferences and perceived urgency ratings were similar in middle- and high-income countries. In summary, this international survey showed that people’s preferences for TOR types in highly automated driving depend on the urgency of the situation.
Supporting the changing driver's task: Exploration of interface designs for supervision and intervention in automated driving
2016, Transportation Research Part F: Traffic Psychology and Behaviour
Citation Excerpt :
With respect to perceived signal’s urgency, there is a fundamental relationship between the signal’s intensity (frequency, wavelength, pace and duration, etc.) and perceived urgency. For example: If the frequency of a sound increases, and/or as the time interval between pulses of sound decreases, it is perceived as increasingly urgent (Edworthy, Loxley, & Dennis, 1991; Hellier & Edworthy, 1999). Likewise, as the wavelength of visible light increases (hue or perceived colour changing from green to yellow to red) it is perceived as more urgent (Chapanis, 1994; Wogalter, Conzola, & Smith-Jackson, 2002).
Driving automation leads to a changing role for drivers, that is from manual vehicle control to supervising automation. Supervision of partial automation requires now and then intervention. Since the automation causes low vigilance and out-of-the-loop performance problems, this changing role is not well suited for human operators. To explore how driver-vehicle interfaces can support drivers in their changed role, we tested three concepts. Concept A was a baseline reference, providing only acoustic warnings. Concept B presented status-information and warnings behind the steering wheel. Concept C used illumination and haptic feedback in the seat-pan to direct attention outside the vehicle and to stimulate response. Concept C only provided vibrotactile feedback when intervention was needed. Results of our study show improved support for supervision with the illumination-concept, i.e. better hazard-detection and raised levels of Situation Awareness in some scenarios relevant for supervisory control. Knowing that supervision will be the dominating driver’s responsibility during partially automated driving, the illumination-concept is a recommended solution for support of the driver’s changing role. Nonetheless, neither concept B, nor C, showed additional support for intervention compared to the baseline. It was hypothesised that the combination of concept C’s stimuli for intervention-support caused counter-productive levels of annoyance. Furthermore, we concluded that intervention and supervision benefit from different interface-features and discussed possible causes underlying ambiguity between support for supervision and support for intervention shown with concept C. Therewith, the considerations in this paper contribute to further development of – and knowledge about – appropriate driver-vehicle interaction while vehicle-operation advances into operating partially automated driving systems.
Sonifying the location of an object: A comparison of three methods
2016, IFAC-PapersOnLine
Auditory displays are promising for informing operators about hazards or objects in the environment. However, it remains to be investigated how to map distance information to a sound dimension. In this research, three sonification approaches were tested: Beep Repetition Rate (BRR) in which beep time and inter-beep time were a linear function of distance, Sound Intensity (SI) in which the digital sound volume was a linear function of distance, and Sound Fundamental Frequency (SFF) in which the sound frequency was a linear function of distance. Participants (N = 29) were presented with a sound by means of headphones and subsequently clicked on the screen to estimate the distance to the object with respect to the bottom of the screen (Experiment 1), or the distance and azimuth angle to the object (Experiment 2). The azimuth angle in Experiment 2 was sonified by the volume difference between the left and right ears. In an additional Experiment 3, reaction times to directional audio-visual feedback were compared with directional visual feedback. Participants performed three sessions (BRR, SI, SFF) in Experiments 1 and 2 and two sessions (visual, audio-visual) in Experiment 3, 10 trials per session. After each trial, participants received knowledge-of-results feedback. The results showed that the three proposed methods yielded an overall similar mean absolute distance error, but in Experiment 2 the error for BRR was significantly smaller than for SI. The mean absolute distance errors were significantly greater in Experiment 2 than in Experiment 1. In Experiment 3, there was no statistically significant difference in reaction time between the visual and audio-visual conditions. The results are interpreted in light of the Weber-Fechner law, and suggest that humans have the ability to accurately interpret artificial sounds on an artificial distance scale.

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^☆: This paper was originally presented at CybErg 1996—the first international cyberspace conference on ergonomics

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Technical NoteOn using psychophysical techniques to achieve urgency mapping in auditory warnings☆

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Technical Note
On using psychophysical techniques to achieve urgency mapping in auditory warnings☆