Unlocking the Expressivity of Point Lights

Since the advent of the electronic age, devices have incorporated small point lights for communication purposes. This has afforded devices a simple, but reliable communication channel without the complication or expense of e.g., a screen. For example, a simple light can let a user know their stove is on, a car door is ajar, the alarm system is active, or that a battery has finished charging. The development of commercially viable light emitting diodes (LEDs) in the 1970s greatly expanded their penetration and use. Low cost, small size, durability, and remarkable power efficiency has enabled their integration into almost every class of electronic device.

For simplicity, we consider a point light source to be a small, single color light emitting element with an intensity that can be varied over time (e.g., an LED or small incandescent bulb). Although comparatively simple (and inherently one-dimensional), with good design, point lights can be quite expressive. With multiple lights and colors, the design space could be even richer. However, cultural color connotations must be weighed, potentially reducing generality. Context is also important to consider when users are interpreting iconic elements. In this paper, we start with the most severe constraints to demonstrate the potential lower bound richness.

Unfortunately, very few products seem to take full advantage of the expressive capability simple lights can provide. The most commonly encountered light behaviors are quite simple: light on, light off, and light blinking. Not only is this vocabulary incredibly small, but the behaviors are not particularly iconic (e.g., what does a blinking light on a toaster mean? Is the toast done? Is it cooking? Is it jammed?). This often means people have to learn by rote what each light behavior means on each device. This is unwieldy given the multitude of devices we use today.

We hope to reignite people’s imagination by demonstrating the impressive and largely unrealized richness of point lights, and their utility in ever-more capable modern electronic devices. Armed with this knowledge, we hope that improved devices - that remain simple, but communicate better - can be built.



Harrison, C., Horstman, J., Hsieh, G. and Hudson, S. E. 2012. Unlocking the Expressivity of Point Lights. In Proceedings of the 30th Annual SIGCHI Conference on Human Factors in Computing Systems (Austin, Texas, May 5 - 10, 2012). CHI '12. ACM, New York, NY. 1683-1692.

© Chris Harrison