In the context of the passage. the primary function of lines 63J7 is to list the occupations that Alvaro: farming. his youth. envisioned as being withRn his reach were he to succeed in farming cotton. ACT-B02 31 GO ON TO THE NEXT PAGE. Passage11 55 brains cyolvcd because our primate ancestors be(yan to engage in more sophisticated food gathering: instead of just eating grasses and leaves they began eatin(F fruit, which takes more thinking power. You travel tnuch far- ther to find fruit than leaves, so you need to be able to 60 create mental Maps. You have to worry about ripeness. You have to peel parts away in order to eat the flesh of a fruit. and so on. The problem with that theory is that if you try to match up brain size with eatiiig patterns among primates, it doesn't work. So what does corre- 65 late with brain size9 The answer, Dunbar aruues. is group size. If you look at any species of primate-at every variety of monkey and ape-the larger their neo- ortex is. the larger the average size of the groups they livc with. SOCIAL SCIENCE: This passage is adapted from The ripping Point.. How Little Thlngs Can Make a Big Diflerence by Malcolm Gladwell I 2002 by Malcolm Gladwell). There is a concept in cognitive psychology called the channel capacity, which refers to the amount of space in our brain for certain kinds of information. Sup- pose, for example. that I played you a number of differ- 5 ent musical tones, at random, and asked you to identify each one with a number. If I played you a Teally low tone, you would call it one, and if I played you a medium tone you would call it two. alld a high tone you would call three. The purpose of the test is to find out 10 how long you can continue to distinguish among differ- ent tones. Most people can divide tones into only about six diffcrent categories before they begin to make mis- takes and start lumping different tones in the same cate- gory. This is a remarkably consistent finding. If. for 15 exan]ple, I played you five very high pitched tones. you'd be able to tell them apart. And if I played you fiye very low pitched tones. you'd be able to tell them apart. You'd think, then, that if I combined those high and low tones and played thetn for you all at once, 20 you'd be able to divide them into ten categorics. But you won't be able to. Chances are you'll still be stuck at about six categoTies. 70 Dunbar's argument is ihat brains evolve, the), tret biuger, in order to handle the complexities of laroer social groups. If you belong to a tsroup of five people, Dunbar points out, you have to keep track of ien sepa- rate relationships: your relationshipg with the four 75 Others in your Circle and the six other two-wa)I relation- ships between the others. That's what it means to know evcryonc in the circle. You have to understand the per- sonal dynamics of the group. If you belollg to a group of twenty people, however. there are now 190 two-way 80 relationships to keep track of- L9 involving yourself and 171 involving the rest of the group. Even a relatively Sm1 increase in the size of a trroup creates a signifi- cant additional sockal and iFJtellectual burden. Humans socialize in the largest groups of all primates because 85 we are the only animals with brains large enough to handle the complexities of that social arrangement. As human beings, we can only handle so much inforniation at once. Once we pass a certain boundary. 25 we become overwhelmed. What I'm describiniF here is an intellectual capaciiy-our ability to piocess raw iuformation. But if you think about it, we clearly have a Ghannel capacity for fcelings as well. Take a minute, for example, to make a list of all 30 the people whom you would consider yourself truly close to. The average answer is 12 names. Those names make up what psychologists call our sympathy group. Why aren't groups any larger? Partly it's a question of time. If you look at the names oll your sympathy list, 35 they arc probably the people whom you devote the most attention to. If your list was twice as long, would you still be as close to everyone? Probably not. To be some- one's friend requires a minimum investment of time. More than that. thollgh. it takes emotional energy. At a 40 certain point, at somewhere between JO and 15 people, we begin to overload, just as we begin to overload wheu we have to distinguish between too many tones.
