Overlay presentation speeds up human string comparison with mixed accuracy
Usable String Matching by Humans through Overlaid Presentation
Cryptography and SecurityHuman-Computer Interaction
Summary
Comparing two strings of text to see if they match is something people often need to do in important situations, but it can be easy to make mistakes. The authors studied how different ways of showing pairs of strings affect how fast and accurately people can tell if they are the same. They found that showing strings overlaid on top of each other helps people check longer strings faster and sometimes more accurately. However, even with this method, people still made errors often enough that it might not be good enough for critical checks where mistakes could be costly.
What this means in practice
- •For banking operations teams: Use overlay presentation to help staff quickly verify transaction reference strings to reduce delays despite some error risk.
- •For identity verification services: Implement overlay display methods in user workflows to speed up manual confirmation of identity strings where automatic checks fail.
Authors
Enka Blanchard, Ted Selker, Alan T. Sherman, Levi Gabasova, Mehdi Bouhamidi, Ryan Robucci
Abstract
We explore the ability of humans to compare strings, an error-prone activity which occurs in critical contexts (e.g., bank wire transfers), where it is not always possible to trust a machine to help. We hypothesize that understanding human cognitive and perceptual limitations can improve how people verify whether two character strings are identical. We vary the strings' relative positions and presentation formats to measure comparison speed and accuracy. We present results from two online experiments with 178 human subjects who compared pairs of strings to determine whether the two strings were identical. The strings varied by length (5 characters to small paragraphs), difference (matching versus making a random change or a hard-to-detect one), alignment (vertical versus horizontal), and presentation (Overlay versus Adjacent). Our experiments test whether, by encoding and memory tasks into perceptual tasks, overlay formats can offer advantages in speed and accuracy. Results show that overlay offers a substantially faster method, with improved accuracy for long strings. Nevertheless, mean error rates were at least 4 percent, indicating that even the improved approach may be insufficiently accurate for many verification tasks.