Fooling computers that see and hear like humans

Computers can recognize traffic signs, but it's possible to fool them by adding some tape. Similarly, computers can understand speech but can be fooled by sounds that are too high for humans to hear.

An active and growing area of research is how to design systems that can't be fooled so easily like this. This will be critical expertise going forward, just like how network security is today. Great for up and coming security researchers wondering what to specialize in. 

Another interesting angle is that the very fact that these systems can be fooled by things that wouldn't fool a human means that these systems perceive the world in a different way than we do. These are the special effects and optical illusions of the computer world, and they look nothing like what we're used to.