What do a dark, shadowy forest and a banking app on your phone have in common? Both instances provoke questions like “is this safe?” and “is this a situation that might cause me harm?” Our recent research suggests that shadowy forests and banking apps might not be so different: the cognitive processes that guide security judgements in modern humans are related to those that governed the behavior of homo habilis and homo erectus. The difference: one of these situations was common for our ancestors and one is common for the modern human.
Modern humans preferentially process information that is evolutionarily relevant, specifically information that was once associated with evolutionary danger (Öhman, 2007). For example, bright warm colors, motion, and loud sounds can capture attention even without conscious awareness (James, 1890).
Can you think of a time when a loud noise or an object’s rapid onset startled you? You have your ancestors to thank for that. Researchers believe the qualities of potential threats were selected by evolution to become automatic triggers that facilitate the allocation of attention to safety-critical areas (Posner, 1980; Yantis & Johnson, 1990). These qualities helped our ancestors effectively navigate the danger of the shadowy forests thousands of years ago.
These evolutionary-relevant qualities helped our predecessors evade risky situations; is it possible that they still influence how modern humans make decisions? Do they affect the way modern humans navigate the dangers of technology?
Recently, we conducted research to investigate how specific design elements impact users’ security perceptions of mobile apps. We manipulated background color, accent color, and shadowing across iterations of a hypothetical money-sharing app: the modern human’s idea of a “risky” situation. We measured how much users trusted each app iteration, how secure users thought each iteration was, and how likely they would be to use each.
What did we find?
Dark backgrounds, bright warm colors, and shadowing (even when subtle) can make users feel like an app is untrustworthy, which ultimately guides security judgements and usage intentions. As you can see in the visualization below, an interface with pink accents received substantially lower trust and security ratings relative to the other iterations of the app. Additionally, flat interfaces (without shadowing) with less bright, less warm accents (like blue and green) received the highest trust ratings and promoted the highest feelings of security.
In some situations, users even reported not noticing a difference between iterations of the app - like when there were and were not drop shadows included - but their security perceptions were still affected by the manipulation (see these two iterations in the images below).
It’s important to note that we designed our experiments to simulate a modern situation of risk; participants were informed that the app in consideration was built for the purpose of money sharing. Accordingly, our results primarily apply to products that are used to complete “risky” tasks, like mobile banking, money sharing, and perhaps even shopping: any task where users perceive there is something at stake. That said, the inclusion of darker backgrounds, bold accent colors, and/or shadowing may be inconsequential - maybe even beneficial - within experiences designed for less risky tasks, such as entertainment apps or mobile games. Accordingly, these results should be applied thoughtfully
What does it mean?
Overall, our results suggest that the decisions of modern humans are still guided by the experiences of our ancestors. Thousands of years ago, bright colors were typically associated with danger. There is empirical evidence that suggests poisonous snakes played a pivotal role in shaping the way humans perceive, attend to, and process visual information (Isbell, 2006).
Furthermore, to our predecessors, dark colors and shadows were associated with the unknown: a situation that held the potential for hidden predators to attack. It stands to reason that humans developed cognitive mechanisms to classify these qualities as negative and/or potentially dangerous, which produce negative emotional responses. Our research suggests that we still possess and utilize these mechanisms in our decision making processes today.
Designing trustworthy experiences
These results are provocative and compelling, but what do they mean to designers, researchers, product owners, and other stakeholders? They provide insight into how to create experiences that promote trust, perceptions of a secure experience, and increased intent to use the products we create.
We’ve crafted a secure design style guide on the basis of this body of research; this style guide can act as a checklist to ensure security and trust-critical design decisions are considered for products that contain some level of risk. At WillowTree, we use this style guide as a rubric for all projects that require the consideration of users’ trust to evaluate design decisions.
We, as modern humans, inherited physical qualities from our ancestors: opposable thumbs, skeletal changes that supported bipedalism, and refined facial structures. In addition to physical attributes, it’s increasingly evident that we also inherited cerebral qualities that continue to influence modern human interactions. It turns out we aren’t so different from our ancestors. Modernity has modified our daily threats, shifting from loss of life to loss of livelihood, but the signals that sound our alarms are still guided by the primitive mind.
Isbell, L. A. (2006). Snakes as agents of evolutionary change in primate brains. Journal of human evolution, 51(1), 1-35.
James, W. (1890). (1983). The principles of psychology. Cambridge, MA: Harvard University Press.
Öhman, A. (2007). Has evolution primed humans to “beware the beast”?. Proceedings of the National Academy of Sciences, 104(42), 16396-16397.
Posner, M. I. (1980). Orienting of attention. Quarterly journal of experimental psychology, 32(1), 3-25.
Yantis, S., & Johnson, D. N. (1990). Mechanisms of attentional priority. Journal of Experimental Psychology: Human Perception and Performance, 16(4), 812.