Free The Happiness of Pursuit: What Neuroscience Can Teach Us About the Good Life by Shimon Edelman Page A

about what usually, or at least sometimes, happens where (which would enable the itinerant animal to anticipate what will happen where the next time around).
    Put yourself in the place of a desert bighorn sheep. You live near Borrego Springs, California. It is early August, and the heat at noon can be deadly. The neighborhood is patrolled by a puma, which, unlike yourself, is not a herbivore. Your only navigation device is your brain. If you have no idea where you are or how to get back to that water hole you drank from the other day, taking in local attractions would be the last thing on your mind, even if you love the desert as much as I do. And yet, it is the same set of cognitive computational skills that makes you good at sightseeing (and remembering the sights) and at getting back from point B to point A.
    Reliable and effective way-finding, orienteering, and hoarding of personal episodic experience all depend on a representation of the layout of the environment. How does the brain do it? An effective representation supports navigation not by indicating where its owner is on some kind of mental map—if it did, bighorns would be in need of map-reading instruction and training as badly as most army cadets are. As any number of street-corner tourist maps in big cities will tell you, the answer to the question “Where am I?” is “You are here,” which is true, but not very helpful. One would hope that the brain can do better than that.
    Indeed, instead of being like tourist maps, which require interpretation, representations of space in the brain directly assist way-finding behavior by explicitly encoding various useful cues, such as up-to-date direction information to certain key locations. While I am confident that you know precisely where you are at this moment ( there ), I believe also that you know more than that. In particular, I bet that you can point in the direction of the closest source of potable water or food, and not just because I asked you earlier to imagine life as a bighorn. Speaking for myself, a decisive demonstration of my knowledge of where food is relative to where I am now would be for me to get up and head directly to the fridge, which is not visible from where I am writing these lines. (This task is not entirely out of the question: the paper-and-plaster walls of my house are no match for this grizzled specimen of H. sapiens. )
    When the ability to take shortcuts through new territory between previously visited locations was first discovered in the rat, in the 1940s, scientists interpreted it as evidence for the existence in the rat brain of cognitive maps. Recording from the hippocampus, an area of the brain that had been implicated in navigation, they eventually discovered neurons that fired at a high rate only when the rat visited particular locations. These “place cells” serve as the foundation for representing space—and, it turns out, much more.
    Location cues derived through dead reckoning from wandering about are enough to form the hippocampal representation of space: much of rats’ way-finding is done in the dark of the night, and even blind mole rats (such as Molly from Chapter 2) start taking shortcuts across the open space in the middle of an enclosure after exploring its boundaries. At the same time, any additional cues that happen to be available get tacked right onto the basic spatial scaffolding. Thus, the so-called place cells respond selectively not just to particular places but to the combination of sights, sounds, smells, and textures encountered in those locations—in other words, to episodes that the animal experienced there. 12
    The varieties of episodic memory maintained by a species depend on its habitat. For a desert bighorn, this has always meant just a patch of territory. We humans started that way too, but have by now assimilated into this category various spaces that are not entirely, or even not at all, spatial. Instead, these spaces are abstract, like the