1. if all else was equal;
2. if favoring your ethnic group imposed a minor cost on you;
3. if favoring your ethnic group would impose a substantial cost on you.
Irwin found a surprising degree of ethnic nepotism in the cost-free situations. Roughly 90% of the responses favored helping their own ethnic group. This is strikingly high for Canada, where the Protestant majority is relentlessly lectured against discriminating in favor of themselves.
Ethnic nepotism, however, fell off rapidly as the costs mounted. On a 0 to 3 scale (where 0 is favoring the Other ethnic group in the cost free-situation, 1 is favoring your ethnic relatives when the cost is zero, two is favoring your co-ethnics when the cost is small but real, and 3 is when the cost is substantial), scores ranged from around 1.1 to 1.6 depending on the ethnicity of the subject.
The least ethnocentric group was the WASPs, while the most was the Jewish-Canadians. (French Canadians didn't show up as their own group. And there were only 15 East Asians in the study, so the finding that East Asians are the 2nd least ethnocentric group must be taken with a grain of salt.)
Since ethnic nepotism, at least by Anglo whites, is deeply unfashionable on Canadian campuses, these scores should be taken as reflecting public attitudes more than private feelings, but they're still interesting.
I tried to give Silverman's test to my neighbor Shelly, who has more real-world experience than do college students. Shelly is, more or less, Italian-American. For the "Other" ethnic group, she picked the Swiss.
"All right," I began, "Say you're buying an expensive item like a washing machine or a camera. Would you pay 15% more to buy it from an Italian-owned firm rather than a Swiss-owned firm?"
"Definitely," Shelly replied, "It would be well worth paying 15% extra for Swiss manufacturing quality."
Steve: "Well, yes, but the question here is whether you'd pay 15% extra for an Italian-made product."
Shelly: "Don't be ridiculous. Who in the world would pay 15% extra for a Fiat over a Volvo?"
Steve: "Well, Volvos are made in Sweden, not Switz --"
Shelly: "Exactly. Now if it was furniture, say, or clothes, or some other fashion item, I'd certainly pay more for Italian. And I'd pay lots more to go to an Italian restaurant. Who goes to a Swiss restaurant?"
Steve: "Yes, but it says here in the question that the Swiss-made and the Italian-made appliances are exactly equal in quality."
Shelly: "My mind refuses to deal with such an implausible assertion."
Thus, the more you know about how much ethnic groups tend to differ in economic skills, the less likely you are to believe that favoring your own ethnic group would be cost free. Therefore, to reduce the number of ethnocentric actions, instead of being told that everybody's the same, college students should be required to read books like Thomas Sowell's "Ethnic America" so they can more quickly get up to speed on ethnic stereotypes.