Supplementary material for paper: "Exploring the Effects of Interior Design Elements on the Uncertainty of Passengers of Fully Automated Cars"

<strong>Abstract</strong>Humans are masters in predicting each other’s behaviour and acting relatively appropriately in ambiguous and uncertain situations. Although road accident statistics show a slight decrease in the number of road traffic deaths, these numbers are still very high. Fully automated cars are said to offer the potential to bring everyone everywhere, avoid accidents, and save parking spaces. This does not mean that the objective benefits of fully automated cars are also perceived this way by society. We may feel uncertain about the intentions, behaviour, and reliability of these fully automated cars. Our perceived psychological uncertainty influences our behaviour and the way we interact with them. Psychological uncertainty can alter our mental state and, thus, our behaviour. Psychological uncertainty further shapes perceptions of and interactions with fully automated cars. People should not feel uncertain about the capability of the fully automated car to prevent misuse, feelings of unsafety and discomfort. Interior design could play a role in mediating the perceived psychological uncertainty that passengers of fully automated cars perceive. A study was conducted to explore the effects of interior design elements on the perceived psychological uncertainty of passengers of fully automated vehicles. Results of the conducted study, with 113 participants, indicate that factors such as familiarity, trust, and perceived control are significant considerations when addressing perceived psychological uncertainty through interior design. Furthermore, the introduction of unfamiliar design elements and perceived loss of control may lead to an increase in feelings of psychological uncertainty.<br><strong>Procedure</strong>Participants were presented with photo-realistic images showcasing various interior designs of the same fully automated car in random order. They were required to evaluate their perceived psychological uncertainty towards these different interior designs. All participants were above the age of 18 years old and digitally agreed to informed consent prior to participation. This study procedure was approved by the Ethical Review Board of the Eindhoven University of Technology. Participants did not receive compensation for their contribution and participated voluntarily.<br>The survey was presented through Microsoft Forms and was accessible on multiple devices, such as phones, tablets, and desktops. Participants first provided demographic information, including their age group, gender, residential country, driving experience, opinions on automated vehicles and general perceived psychological uncertainty level. Subsequently, participants commenced the survey and were shown 25 images depicting different interior designs of the same fully automated car. The images were presented in a randomised order, but with the baseline image always being the first and repeated randomly once among the remaining images. After viewing each image, participants were prompted to rate their level of perceived psychological uncertainty on a scale from 0 to 10, where 0 indicated ‘absolutely not uncertain’ and 10 indicated ‘absolutely uncertain’. Additionally, an open-ended question asking participants to describe the elements they were uncertain about the previously shown images, was interspersed three times among the images.

**摘要**
人类擅长预测他人行为，并在模糊不确定的情境中做出相对恰当的应对。尽管道路交通事故死亡人数统计数据略有下降，但该数值仍处于高位。据称，全自动汽车（fully automated cars）具备实现全场景出行、规避交通事故并节省停车空间的潜力。但这并不意味着社会也能感知到全自动汽车的上述客观益处。我们可能会对这类全自动汽车的意图、行为与可靠性产生不确定感。这种感知到的心理不确定性会影响我们的行为模式及与全自动汽车的交互方式。心理不确定性不仅会改变我们的心理状态，进而影响行为，还会进一步塑造人们对全自动汽车的感知与交互体验。人们不应认为全自动汽车防范误用、保障安全与缓解不适的能力存在不确定性。内饰设计或可起到调节全自动汽车乘客心理不确定性感知的作用。本研究旨在探究内饰设计元素对全自动汽车乘客心理不确定性感知的影响。本研究共有113名参与者，结果显示，在通过内饰设计应对心理不确定性感知时，熟悉度、信任度与感知控制力等因素为关键考量维度。此外，引入陌生设计元素以及感知到控制力丧失，可能会加剧心理不确定性感受。

**实验流程**
参与者将按随机顺序观看展示同一款全自动汽车多种内饰设计的照片级逼真图像，并需针对这些不同内饰设计评估自身的心理不确定性感知程度。所有参与者均年满18周岁，并在参与前以电子形式签署了知情同意书。本研究流程已通过埃因霍温理工大学伦理审查委员会的批准。参与者未获得参与报酬，且均为自愿参与。

本次调研通过Microsoft Forms（微软表单）开展，可在手机、平板与桌面设备等多种终端访问。参与者首先需填写人口统计学信息，包括年龄分组、性别、居住国家、驾驶经验、对自动驾驶汽车（automated vehicles）的看法以及总体心理不确定性感知水平。随后，参与者开始调研，将看到25张展示同一款全自动汽车不同内饰设计的图片。图片以随机顺序呈现，但基准图像始终为第一张，并在其余图片中随机重复出现一次。每查看一张图片后，参与者需在0至10的量表上对其心理不确定性感知程度进行评分，其中0代表“完全无不确定性”，10代表“完全不确定”。此外，调研中穿插了三道开放式问题，要求参与者描述其对此前展示的图片中哪些元素存在不确定性。