popularopinion
It turns out the answer is yes. In 2002, a (very influential) study was performed on vervet monkeys and found that male vervet monkeys showed significantly greater interest in the masculine toys (i.e. a ball and a police car), and the female vervet monkeys showed significantly greater interest in the feminine toys (a doll and a red pan). There wasn't much difference in preference for the neutral toys.
One study is not enough to show such a trend. So in 2008, the study was repeated a different species of monkey (rehesus) and a different set of toys. The authors found the same results: males preferred stereotypically male toys, and females preferred stereotypically female toys.
So we have two studies in two species of primates that found that males prefer "masculine" toys, and females prefer "feminine" toys. From this, it is fairly plausible that innate differences in toy preference will show up in humans as well.
Sources:
Vervet Study: http://www.ehbonline.org/article/S1090-5138(02)00107-1/fullt...
Rhesus Study: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2583786/
Summary of both studies: http://www.psychologytoday.com/blog/the-scientific-fundament...
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Hacker News Guidelines - What to Submit
On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.
http://www.fromquarkstoquasars.com/wp-content/uploads/2013/1...
If you need help on any of the puzzles, hints and answers are on the talk page. For this specific puzzle, the talk page links to a paper by William Wu that answers this exact question with asymptotic analysis.
http://www.ocf.berkeley.edu/~wwu/papers/100prisonersLightBul...
http://books.google.com/books?id=ePNi4ZqYdVQC&pg=PT95&dq=tha...
From looking at the graph, it is quite clear that modern society is much less violent than many other indigenous societies. It seems quite reasonable to conclude that societies are becoming increasingly nonviolent. I wish that the author of the review addressed this in his article.
[1] In the first paragraph of the section, Pinker references a Thanksgiving editorialist quote from Chapter 1. Here's the quote:
"I would submit that the world native Americans knew was more stable, happier, and less barbaric than our society today.... there were no employment problems, community harmony was strong, substance abuse unknown, crime nearly nonexistent. What warfare there was between tribes was largely ritualistic and seldom resulted in indiscriminate or wholesale slaughter. While there were hard times, life was, for the most part, stable and predictable.... Because the native people respected what was around them, there was no loss of water or food resources because of pollution or extinction, no lack of materials for the daily essentials, such as baskets, canoes, shelter, or firewood."
https://lesacreduprintemps19.files.wordpress.com/2011/04/nyb...
From my quick reading of the paper, Nyborg is arguing that based on Denmark's current immigration and minority birth rates, “by 2072 the total population [in Denmark] may consist of 60% ethnic Danes and 40% people of foreign origin.” Since these minority groups have lower average IQs than native Danes [1], the average Danish IQ will decrease from about 97 in 2013 to 93 in 2072. This "reverse Flynn-effect" will only increase with time since these foreign borns have a higher birth rate than native Danes. Nyborg then cites the correlation between a country's Average IQ and National GDP [2], and suggests that a drop of 5 IQ points is correlated with a 35% drop in Danish GDP. He ponders why many Danish politicians and intellectuals have ignored this data and encourages them to reconsider their policies before there is "an anti-Darwinian death spiral that dooms democracy, civilization, [and] welfare" (an argument very similar to that of Norway's Anders Breivik [3]).
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[1] Racial differences in IQ have been well established for decades but there is no conclusive evidence for its cause. To give some concrete numbers, for the United States, the authors of a 1994 book found the average IQ of African Americans to be 85, Latinos 89, Whites 103, East Asians 106, and Ashkenazi Jews 113. Amerindians tend to score worse on average than white populations but better on average than black populations. These differences appear to be consistent over the past four decades, and still exist (although to a weaker degree) even after controlling for SES.
If you don't believe me (which you should, since this is a highly controversial topic), there's more information on the Wikipedia article about Race and Intelligence. https://en.wikipedia.org/wiki/Race_and_IQ
[2] It's not the article he cited, but here is an excellent article that attempts to extend this theory. http://www.lagriffedulion.f2s.com/sft.htm
[3] In his manifesto, Breivik, who killed 77 people in the 2011 Oslo bombings, argued that Norway's (and the rest of Europe's) immigration policies are letting in too many immigrants, and these immigrants will eventually destroy Norway's national culture/heritage and bankrupt the nation's generous social policies. Breivik committed the attacks because he wanted Norwegians to discuss these policies before it was too late to change them.
http://www.bizjournals.com/sanfrancisco/blog/2013/11/google-...
[1] https://en.wikipedia.org/wiki/Race_and_ethnicity_in_the_NBA
This is not correct. During birth, babies are exposed to their mother's vaginal fluid which then transfers bacteria into the baby's mouth. This transfer introduces a nice bacterial balance and makes it more difficult for a single species of bacteria to monopolize the mouth and digestive system. This exchange doesn't occur when babies are born via C-section, so doctors usually swab some of the mothers vaginal fluid in the baby's mouth so he will also have a healthy balance of bacteria.
See here for more info
http://www.usnews.com/science/articles/2010/06/22/babys-firs...