<story><title>Map of America&apos;s Racial Segregation</title><url>http://www.wired.com/design/2013/08/how-segregated-is-your-city-this-eye-opening-map-shows-you</url></story><parent_chain><item><author>WA</author><text>I watched once a lecture on Coursera about Schelling&amp;#x27;s model of segregation, which I found extremely insightful.&lt;p&gt;If you see maps like that with strong segregation, one of the first attempts to explain it is &amp;quot;racism&amp;quot;. However, if you divide your neighborhood in 9 blocks such that you are in the center, you have 8 neighbors.&lt;p&gt;Schelling&amp;#x27;s model now shows that even in cities where most people say:&amp;quot;I&amp;#x27;d like to live next to only 35-40% of people who are similar to me (whatever that means exactly, could be ethnical background, skin color, income, ...) and I&amp;#x27;d accept 60% of neighbors who are different from me&amp;quot;, you would still get a segregation of 80-90% in the city.&lt;p&gt;So, the reason for strong segregation is not necessarily that people are racists. People can be very tolerant, but if you try to fulfill the minimum requirement (40% like me), you end up with strong segregation patterns just because there&amp;#x27;s no other way to fulfill the minimum requirement for most people.&lt;p&gt;Note: Numbers aren&amp;#x27;t exact, but pretty close.&lt;p&gt;Edit: Link to lecture: &lt;a href=&quot;https://class.coursera.org/modelthinking-003/lecture/16&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;class.coursera.org&amp;#x2F;modelthinking-003&amp;#x2F;lecture&amp;#x2F;16&lt;/a&gt;</text></item></parent_chain><comment><author>SiVal</author><text>Yes, this is a &amp;quot;map of America&amp;#x27;s racial &lt;i&gt;distribution&lt;/i&gt;&amp;quot;. Calling it a &amp;quot;map of America&amp;#x27;s racial &lt;i&gt;segregation&lt;/i&gt;&amp;quot; means someone is pushing a political agenda. Calling it a map of racial integration would be just as accurate but probably didn&amp;#x27;t support the right narrative.&lt;p&gt;As a map of &lt;i&gt;distribution&lt;/i&gt;, you would expect significant clustering from randomness alone. We&amp;#x27;ve all seen the &amp;quot;which of these dot patterns is actually the random one?&amp;quot; tests, where few people guess the correct answer: the one with all the clusters.&lt;p&gt;If you take that clustered map as a seed, then add &lt;i&gt;any&lt;/i&gt; affinities, you get positive feedback, increasing the clustering. Those affinities don&amp;#x27;t have to be racial selection but can just be in the general form of, &amp;quot;I make decisions based on what I hear, and I hear more from people I know than from people I don&amp;#x27;t know.&amp;quot;&lt;p&gt;So, you hear from your cousin that there is a new apartment building opening across the street from him. You hear from several members of your church that X is the best school district. A factory in your town closes and the laid off employees discuss their options and decide to go check out a company in the next town that is hiring (with lots of reasonably-priced apartments nearby).&lt;p&gt;Just getting more information from people you know than people you don&amp;#x27;t know could be sufficient for Schelling&amp;#x27;s model, but add to that the tendency to get more information from people from your background (whether you actually know them or not), because it&amp;#x27;s likely to be more relevant to you, and you magnify the effect significantly. An urban liberal and his soccer-loving Mexican gardener don&amp;#x27;t have to dislike each other for the former to read more NY Times and the latter to watch more Univision, and the information about where the opportunities are as presented in those two media outlets are not the same.&lt;p&gt;This doesn&amp;#x27;t mean that there is no race-based component in deciding where to live. It just means that, as the Schelling model demonstrates, you can&amp;#x27;t tell how much there is by looking at how much clustering there is on a map.</text></comment>
<story><title>Map of America&apos;s Racial Segregation</title><url>http://www.wired.com/design/2013/08/how-segregated-is-your-city-this-eye-opening-map-shows-you</url></story><parent_chain><item><author>WA</author><text>I watched once a lecture on Coursera about Schelling&amp;#x27;s model of segregation, which I found extremely insightful.&lt;p&gt;If you see maps like that with strong segregation, one of the first attempts to explain it is &amp;quot;racism&amp;quot;. However, if you divide your neighborhood in 9 blocks such that you are in the center, you have 8 neighbors.&lt;p&gt;Schelling&amp;#x27;s model now shows that even in cities where most people say:&amp;quot;I&amp;#x27;d like to live next to only 35-40% of people who are similar to me (whatever that means exactly, could be ethnical background, skin color, income, ...) and I&amp;#x27;d accept 60% of neighbors who are different from me&amp;quot;, you would still get a segregation of 80-90% in the city.&lt;p&gt;So, the reason for strong segregation is not necessarily that people are racists. People can be very tolerant, but if you try to fulfill the minimum requirement (40% like me), you end up with strong segregation patterns just because there&amp;#x27;s no other way to fulfill the minimum requirement for most people.&lt;p&gt;Note: Numbers aren&amp;#x27;t exact, but pretty close.&lt;p&gt;Edit: Link to lecture: &lt;a href=&quot;https://class.coursera.org/modelthinking-003/lecture/16&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;class.coursera.org&amp;#x2F;modelthinking-003&amp;#x2F;lecture&amp;#x2F;16&lt;/a&gt;</text></item></parent_chain><comment><author>twic</author><text>Reminds me of a similar thing in developmental biology, where if you have two populations of cells, each having a slighly higher affinity for other cells of its own type, then they will very efficiently sort themselves into separate compartments. This is thought to be a pretty important mechanism in the formation and maintenance of structures in the body.&lt;p&gt;In case anyone&amp;#x27;s interested, here is a nice (if now rather old, although to be honest scientific writing was so much better back in the &amp;#x27;90s) review on the whole business:&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0092867400812970&quot; rel=&quot;nofollow&quot;&gt;http:&amp;#x2F;&amp;#x2F;www.sciencedirect.com&amp;#x2F;science&amp;#x2F;article&amp;#x2F;pii&amp;#x2F;S0092867400...&lt;/a&gt;&lt;p&gt;In which we find a paragraph describing this process:&lt;p&gt;&amp;quot;The selector genes do more than specify the pattern and the structures that the compartments will eventually make—they also specify, indirectly, a surface property. This property has been termed cell affinity, meaning that cells that share the same affinity, owing to the same binary code of selector genes, will intermingle during growth. There are a number of different experiments that lead to this conclusion, but perhaps the simplest is the observation that when the selector gene engrailed is removed, in vivo, from a posterior clone of cells in the wing, those cells gain anterior affinity: they now sort out from posterior cells and, if they are in contact with anterior cells, will sort into and mingle with them. Cells from neighboring compartments will have different affinities and tend to minimize their mutual contact, so that where the two compartments abut, there is a relatively straight line across which the cells do not stray.&amp;quot;</text></comment>