Population density and the evolution of ownership

Note to WordPress.com followers: Per Square Mile has moved to a private host. This means your old WordPress.com follows and email subscriptions won’t work as WordPress will not share that information. The URL remains the same, but be sure to head over to the new Per Square Mile for the latest.

Yours. Mine. Even a two year-old can understand the basics of ownership. Those two words are also freighted with meaning, implying volumes about resources, control, privilege, and social standing. But what they don’t say is why it is we care so much about who owns what.

There are a number of possible reasons for why we value our possessions and covet those of others. True to form, I found one paper that suggests that population density may be responsible for the evolution of ownership. It’s a game theoretic study by Japanese behavioral scientist Shiro Horiuchi in which he uses an established mathematical model—the Hawk-Dove-Bourgeois game—to sift through the possible origins of possession in both animals and humans.

The Hawk-Dove-Bourgeois game (HDB) is a modification of the classic Hawk-Dove game. In addition to the two existing player types—hawks, who fight to acquire resources or territory and viciously defend what’s theirs, and doves, who avoid conflict at all costs—HDB adds a third strategy, called bourgeois. Bourgeois are a bit of a hybrid of the two existing approaches. A bourgeois player, when challenged for ownership, will fight furiously to keep it. But unlike hawks, they won’t attack other players to acquire resources.

Horiuchi took this game and threw out the standard dove and bourgeois strategies, replacing them instead with strong and weak bourgeois. Weak bourgeois are more similar to doves, which means they are less likely to engage in conflicts. Strong bourgeois can adopt a hawk- or dove-like stance depending on their territorial boundaries: If the contested area is within their boundaries, they’ll fight like hawks. If not, they’ll sit out like doves. Players can change strategies depending on how well they are doing relative to their neighbors. The goal is to control 10 units of territory.

In layman’s terms, the strong bourgeois strategy is a proxy for ownership in its purest sense—strong bourgeois players only fight to retain what’s theirs; anything else and they abstain from conflict. And what emerged from the games was a clear picture of strong bourgeois dominance at higher population densities. That doesn’t mean strong bourgeois players controlled more territory—remember, they were limited to a maximum of 10 units. Rather it means that more players adopted that strategy, judging that it was the best way to obtain and hold the maximum territory, especially as the playing field became more crowded.

Previous studies that used the unmodified HDB game didn’t come to the same conclusion, arguing that the bourgeois strategy—ownership, in other words—isn’t advantageous when resources are high. But those findings are refuted by real world studies of primates that show groups are willing to defend resource-rich home ranges, Horiuchi points out. His modifications and results more closely match the empirical data and suggest that ownership not only arises as population densities increase, but that it’s the best way to succeed.

As an ecologist, this result did not surprise me. In ecology, resources are everything. Even organisms as sedate as plants compete ferociously for resources, employing competitive tactics that range from rapid growth to chemical warfare. But in modern, developed societies where the bare necessities are frequently met, I wondered how these findings might apply. I ran Horiuchi’s result past a friend of mine who is a social psychologist, and he indicated that ownership today is not merely about resources, but status. Controlling more territory—or even just expressing one’s wealth in ever more ostentatious ways through possessions—is just another way in which the strong bourgeois strategy could continue to exert its influence, even though we’re not struggling to survive.

Frankly, I’m not surprised. Based on anecdotal observations of the various places I’ve lived, possessions appear to play a larger role in people’s lives the denser and more populous a city becomes. In large cities, people who earn double their peers seem more inclined to flaunt that wealth compared with the same individuals in smaller towns. The social psychological explanation makes sense in this case. It’s harder to stand out in denser, more populous places, which may lead to more conspicuous consumption.

Source:

Horiuchi, S. (2007). High population density promotes the evolution of ownership Ecological Research, 23 (3), 551-556 DOI: 10.1007/s11284-007-0408-6

Related posts:

The curious relationship between place names and population density

This is your brain in the city

Read Full Post »

Which reads faster, Chinese or English?

If there’s one thing that can dazzle my Western eyes, it’s the main drag of any Taiwanese town. On my recent trip to Taiwan, I saw billboards and signs for local shops that dripped from buildings with so many hues Benjamin Moore would blush. Once my mind had adjusted to the mishmash of colors, I noticed the Chinese characters, or rather their number. On each sign, there were strikingly few.

Compared with English, Chinese is a dense language. Its complex characters can convey considerable information in a very small amount of space, or where space isn’t a concern, convey that information more boldly. Given Chinese’s compact written form, I wondered how language density affected the speed at which people read.

My intuition told me that of two native speakers—one Chinese, one English—the Chinese speaker could zip through an equivalent passage in less time because each character says more. But information density can also work against a reader. Chinese’s trade-off is its complexity, both in terms of the immense number of characters—tens of thousands according to some dictionaries, though only about 4,600 are commonly used today—and the fact that nearly all of them are more baroque than any letter in the alphabet. This means someone reading Chinese must dig into the structure of each character to decipher its meaning.

Chinese characters aren’t all unique, though. Similar to English words, there are some repeating themes among them. Each character, or hanzi, consists of strokes and radicals. Strokes are single lines or curves, of which there are about 20. Radicals are constructed from several strokes, and there are about 200 of them. Characters are built by varying the presence and number of strokes and radicals. This has its advantages: proficient readers can decipher both the meaning and pronunciation of an unfamiliar character by deconstructing it. While some characters constitute an entire word, others are multiple characters strung together, much like words in English. Still, Chinese words tend to be short on average—only 1.5 characters per word, compared with 5.1 letters per word for English.

So which is more quickly read, English or Chinese? Chinese’s high information density could work for it—more complexity could impart more meaning per glance— or against it—each character could require a longer stare to decipher. The answer is neither.

English and Chinese are, by and large, read at the same speeds. In one study, both languages were read at approximately the same rate—English at 382 words per minute and Chinese at the equivalent of 386 words per minute. A statistical tie. Another study found the percentage of times a person moves backward in a text—a sign the person is having trouble processing the words—to be about the same for English and Chinese.

What simple statistics on reading speed don’t convey is how dramatically different the experience of reading is for each language. When reading English, our eyes perceive 7–8 letters a time, whereas with Chinese we perceive only 2.6 characters at once. This span—known as a saccade—multiplied by how long we fixate on it equals reading speed. Since readers of English and Chinese tend to fixate on a saccade for the same amount of time, naïve multiplication would lead you to believe that Chinese is read more slowly. After all, a reader of Chinese processes fewer characters per saccade than an English reader, and each saccade lasts about the same amount of time in both languages. But that’s only if you ignore information density. Written Chinese is dense, so though comprehension of characters is slower than letters, meaning is conveyed at the same rate as in English.

This jibes with the gist of a recent study on spoken language speed, which found that while some languages like Spanish sound faster than others, the amount of information imparted is the same. That’s because each syllable in a fast-sounding language like Spanish has less meaning than a slower one like English or Chinese. Spanish speakers have to run through more syllables to get the same point across, thus sounding faster.

Earlier linguists had suggested that Chinese might be faster to read because of a physiological quirk of our eyes—they thought the square shape of Chinese characters fit the most acute region of our retina (the fovea) better than long, string-like English words. But the authors of the first written language study I mentioned—the one that measured words read per minute—speculated that reading speed is instead limited by a cognitive bottleneck. The fact that both reading and speaking seem to follow to the same rules suggests they were right. Cognition—not language—appears to control the rate at which we communicate.

Sources:

Sun F, Morita M, & Stark LW (1985). Comparative patterns of reading eye movement in Chinese and English. Perception & Psychophysics, 37 (6), 502-6 PMID: 4059005

Sun, F, & Feng, D (2010). Eye movements in reading Chinese and English text Reading Chinese Script: A cognitive analysis, Eds. Jian Wang, Albrecht W. Inhoff, Hsuan-Chih Chen., 189-205 ISBN: 9780805824780

Yan, G., Tian, H., Bai, X., & Rayner, K. (2006). The effect of word and character frequency on the eye movements of Chinese readers British Journal of Psychology, 97 (2), 259-268 DOI: 10.1348/000712605X70066

Photo by Tim De Chant.

Related posts:

This is your brain in the city

Thinking about how we think about landscapes

Southern regions nurtured languages

Read Full Post »