Measuring individuals Bell curve I.Q. Commentary

Francis Galton biometrics

Measuring individuals

• Before biologists applied Mendel’s laws of inheritance
• to explain human differences
• and how species evolve
• Francis Galton was interested in inheritance
• of features that vary continuously
• like height, personality, and intelligence.
• He was the first to use statistics
• to study how genius and greatness
• were inherited.
• He believed that improvement of the human race
• was thwarted by attempts to protect
• the weak and underprivileged
• and might not have realized
• that this argument could be used
• to justify murdering people
• who were politically powerless.

Bell curve

• Galton found that the frequency of complex human traits
• that are influenced by multiple factors
• assume a shape defined by the Gaussian probability density function—
• the bell curve—
• in which the ends of the curve tail off rapidly toward zero.
• Economists evaluating the likelihood of financial events
• using a bell curve
• have been encouraged to discard the outliers,
• considering rare events as flukes—
• and fixing the data to suit their model.
• It is logical to discard the possibility
• of finding a human being over one-hundred feet tall
• but there is nothing logical in discarding the possibility
• of a catastrophic bank failure
• or economic collapse.

I.Q.

• Dr. Kroeber thought that Ishi could not count over ten
• and reported this in his writings and lectures.
• Ishi would count up to ten and then stop,
• saying, “No more. That’s all.”
• Ishi, paid for his work at the museum
• cashed his checks into silver half-dollar coins.
• He saved half of what he earned,
• kept his coins in the museum safe
• and asked to see them from time to time.
• An astonished Dr. Kroeber eventually observed
• Ishi by himself
• counting all his many coins.