The Three Laws are also a in brain sophistication. Very complex brains designed to handle world economy interpret the First Law in an expanded sense to include humanity as opposed to a single human; in Asimov's later works like "Robots and Empire" this is referred to as the "Zeroth Law". At least one brain constructed as a calculating machine, as opposed to being a robot control circuit, was designed to have a flexible, childlike personality so that it was able to pursue difficult problems without the Three Laws inhibiting it completely. Specialized brains created for overseeing world economics were stated to have no personality at all.