Whales have spindle cells in greater numbers and are maintained for twice as long as humans. The exact function of spindle cells in whale brains is still not understood, but Hof and Van Der Gucht believe that they act as some sort of "high-speed connections that fast-track information to and from other parts of the cortex". They compared them to express trains that bypass unnecessary connections, enabling organisms to instantly process and act on emotional cues during complex social interactions. However, Hof and Van Der Gucht clarify that they do not know the nature of such feelings in these animals and that we cannot just apply what we see in great apes or ourselves to whales. They believe that more work is needed to know whether emotions are the same for humans and whales.