People are stunned to have discovered numerous examples of pareidolia on the red planet. Lizards! Rats! Bigfoot! Pyramids! Frogs! Hovering alien spheres! Tharks!
Michael Shermer writes about our "tendency to find meaningful patterns in meaningless noise":
The cost of believing that the rustle in the grass is a dangerous predator when it is just the wind is relatively low compared with the opposite. Thus, there would have been a beneficial selection for believing that most patterns are real. Through a series of complex formulas that include additional stimuli (wind in the trees) and prior events (past experience with predators and wind) the authors conclude that "the inability of individuals — human or otherwise — to assign causal probabilities to all sets of events that occur around them will often force them to lump causal associations with non-causal ones. From here, the evolutionary rationale for superstition is clear: natural selection will favour strategies that make many incorrect causal associations in order to establish those that are essential for survival and reproduction."