Hollingworth’s research in intelligence showed that the communications range from one person to another extends about two standard deviations(*) of IQ(**) points. [Suddenly certain communications barriers you may have make perfect sense, no? 😀 ]
(*) Note that discussions on IQ rarely mentions which standard deviation is used which of course makes the number almost meaningless. The typical sd used are sd=15 (Wechsler), sd=16 (Binet), and sd=24 (Cattell). Most tests, texts these days use Binet numbers. Most older texts use Cattell numbers. Hence, an IQ of 145, 148, and 172 can be the same one (all 3 sd). However, unless you have a percentile, you can never be quite sure. If you do have a percentile, the IQ distribution is considered to be Gaussian (not quite true, it has exhibits kurtosis), so one sd above mean corresponds to the 84.1 percentile, two sd above mean corresponds to the 97.8 percentile, and so on.
(**) For lack of something better, IQ is a so-so useful measure of intellectual capacity in much the same way as height is a so-so measure for slam dunk capacity. It is quite likely that qualitative terms are more useful than pure quantitative numbers to capture the richness of the human brain; some brains anyway.
Further research shows that optimal explanatory power occurs if the difference is around one standard deviation. Hence, the best person to explain something to a person of average intelligence is a person with an IQ around 115-120ish(*). A person with a higher level of intelligence will be less successful despite creating better solutions and explaining them with greater eloquence because the ideas and solutions are simply too complex for the average person to grasp.
(*) It is interesting to note that national leaders generally tend to have IQs around the 120 range. This is also true for hierarchies when promotion occur through career ladders. To wit, a leaders selected from average intelligent people should have an IQ around 120 to be successful, not 140 which is too smart. The problem occurs when leaders of these leaders are to be found in the pool of “120” candidates because nobody will have the required IQ of 140 as those were not successful at the first step. “140” leaders thus have to be brought in from the sidelines using another process. One solution would be to start with a pool already filtered to exclude <120 but still containing the 140 and go from there promoting the 140. In fact much of our selectivity, excuse me, educational system works this way by simply not permitting people without a, say, college degree to join the pool of candidates. However, in a democracy leaders are democratically elected by Joe Average. This limits the people's choice of their leader to an IQ of 120 and this is a problem because our world is growing steadily more complex. It is not unlikely that problems will outpace our ability to solve them and create an ingenuity gap particularly when an IQ ceiling is established.
It is, therefore, a good thing that the people in a representative democracy don’t really get to choose the choices and this provides a possible way out to field smarter candidates. Here parties must be careful not to field a candidate who is substantially smarter than his competitors as this defeats the purpose of “guiding” the democratic process towards a more desirable outcome.
Ironic isn’t it? 😎
Additional comments: IQ is a fairly one dimensional measure of intellectual capacity and complexity; it is just one number. This number can certainly be expanded to a multidimensional “vector” which would be a better description (Gartner describes 7 intelligences). Yet even projecting into dimensions would not reveal connections. A prevalent description of genius would be multi-talented and original which would require a certain interconnectivity between the intelligences. To describe this inerconnectivity would require a matrix, e.g. if there were 7 intelligences, this would be a 7×7 matrix with 7+6+5+..+2+1 numbers to describe “two-body” correlations. For anything requiring three intelligences working together, we’re talking a rank 3 tensor, and so on to a rank 7 monster of a tensor which would provide a complete picture. I am unaware of whether this kind of research has ever been pursued. It would be a neat experiment.
Originally posted 2009-12-27 02:11:11.