Human Decisions in Moral Dilemmas are Largely Described by Utilitarianism: Virtual Car Driving Study Provides Guidelines for Autonomous Driving Vehicles

Abstract

Ethical thought experiments such as the trolley dilemma have been investigated extensively in the past, showing that humans act in utilitarian ways, trying to cause as little overall damage as possible. These trolley dilemmas have gained renewed attention over the past few years, especially due to the necessity of implementing moral decisions in autonomous driving vehicles (ADVs). We conducted a set of experiments in which participants experienced modified trolley dilemmas as drivers in virtual reality environments. Participants had to make decisions between driving in one of two lanes where different obstacles came into view. Eventually, the participants had to decide which of the objects they would crash into. Obstacles included a variety of human-like avatars of different ages and group sizes. Furthermore, the influence of sidewalks as potential safe harbors and a condition implicating self-sacrifice were tested. Results showed that participants, in general, decided in a utilitarian manner, sparing the highest number of avatars possible with a limited influence by the other variables. Derived from these findings, which are in line with the utilitarian approach in moral decision making, it will be argued for an obligatory ethics setting implemented in ADVs.

Moral Judgements on the Actions of Self-driving Cars and Human Drivers in Dilemma Situations from Different Perspectives

“…Both variations of these scenarios are equivalent in the implied outcome: either car occupants or pedestrians will be harmed. While Faulhaber et al (2018) only investigated endangering car occupants in the context of a cliff setting, we wanted to contrast this scenario with a less extreme setting. By having the car veer toward a parked van, harm toward car occupants is still implied, but the scenario is overall more integrated into a typical traffic setting.…”

“…We chose these specific types of scenarios as they allow us to contribute to related findings and discussions in recent literature. The influence of potential victims' ages has been investigated by Sütfeld et al (2017), Awad et al (2018), and Faulhaber et al (2018) (further elaborated by Bergmann et al, 2018). The potential protection afforded to pedestrians on a sidewalk has been studied in Faulhaber et al (2018) (further elaborated by Bergmann et al, 2018).…”

“…The influence of potential victims' ages has been investigated by Sütfeld et al (2017), Awad et al (2018), and Faulhaber et al (2018) (further elaborated by Bergmann et al, 2018). The potential protection afforded to pedestrians on a sidewalk has been studied in Faulhaber et al (2018) (further elaborated by Bergmann et al, 2018). The issue of prioritizing car occupants or pedestrians has been theoretically discussed by Lin (2015) and Gogoll and Müller (2016) Table 1.…”

“…There were twice as many pedestrians on the road compared to the sidewalk, and twice as many adults as children. These particular ratios were chosen based on the results from the study reported by Faulhaber et al (2018), which were further elaborated by Bergmann et al (2018). The number of car occupants and pedestrians at risk were equal in the car occupants vs. pedestrians scenario.…”

“…Sütfeld et al (2017) found that the behavior of participants in the role of car drivers could be well described by a valueof-life model, such that people are valued more than animals and younger people are valued more than older. Faulhaber et al (2018) (further elaborated by Bergmann et al, 2018), Li et al (2019) showed that car drivers also tend to act in ways that endanger fewer lives, even at the expense of their own. Ju et al (2019) found that personality characteristics predict the likelihood of drivers endangering themselves.…”