Wandering Down to Walmart
    To gain a clearer perspective regarding what this means in terms of our daily contacts with people, let's take a trip down to a local Walmart. Let's suppose we're visiting the only Walmart in a small, rural town, so that neighborhood inhomogeneities don't affect the cohort of shoppers we'll find at the store. That way, we'll be seeing a nearly random cross-section of the public on our trip.
    OK. Here we are at Walmart. I can already see quite a few people out here in the parking lot.
    Let's suppose that we're going to see 100 other customers while we're here shopping (with, perhaps,  about 60 to 70 cars in the parking lot), and then consider their breakdown by IQ. On the basis of the law of averages, we'd expect to see one person here with an IQ below 64. There'd be someone else with an IQ between 64 and 68. There should be 3 more with IQs between 69 and 75. In other words, if this is a random crowd, 1 out of 20 people we're going to meet will have IQs below 75, and will be retarded. Keep your eyes peeled. See if you can spot 'em. About 1 out of 10 people we'll walk past here at Walmart has an IQ below 80, or about 10 of the 100 people who cross our paths here in the store. Hey, look! Does she look kind of sagaciously-challenged to you? One out of 5, or 20 of the 100 people we're seeing have IQs below 87, with about 1 in 10 in the 80 to 87 IQ range. Half the crowd, or 50 out of the 100, has below-average intelligence. And of course, the other half has above-average intelligence. Twenty of them (1 out of 5) have IQs above 113. Ten of them, or 1 in 10, have IQs above 120. Five of them have IQs above 125, and have the potential to become university professors with Ph. D's. Two of them have IQs of 132 or above, and are potential members of Mensa. One of them has an IQ above 136.
    Did you spot them? I saw one or two possible candidates, but I suppose we'd better not walk up and say,
"Pardon me, ma'am. You look mentally challenged. Are you?"
    She might hit us with her purse.
    If we spent time at a large urban mall, we might rub elbows with 1,000 shoppers. In an average, unenriched setting, where we saw 1,000 other shoppers at Christmas-time, IQs might typically be expected to range between 50 and 150. In a blue-stocking suburb like Norcross, Georgia, or Corte Madera, California, we might expect to find one or more folk with IQs above 150, and perhaps, an individual or two with an IQ above 160. This is a huge range of IQs.
    I think that the range of intellects that we walk past in the world is awesome. The span between top and bottom among 100 people chosen at random would be about 75 points of IQ. And we've been walking past them every day.
    Until I wrote this up this afternoon, I had never stopped to think just what intellectual diversity awaits us at our local shopping centers. Half the people we meet in cars on the road have below-average intelligence, and 1 in 20 must be seriously retarded, with a mental age of 12 or below. It's a tribute to every driver that we do so well on the road.