8. Family and identical twin study  

Finally, some substantial curiosities of family and IQ identical twin study are mentioned to gain a better understanding about this type of graphs and the Global model and, of course indirectly, the evolution of intelligence's Globus model.

• Similarity of variable C's behaviour in the q081 graph can be interpreted in the sense that the coefficients could correspond to identical twins whereas the W would only be a normal sibling since it has been computer generated with the data of the same parents.
  
  This performance can be found on numerous occasions when the rearrangement criterion is one of the C variables of the children (Standord Binet test, Wechsler intelligence test and others)
  
  In the case shown in the q082 graph, W is used as the criterion of arrangement, and the behaviour is slightly different; it seems that the four variables correspond to identical twins. This is, of course, a particular case.

• Graphs q083° and q084° show how W can resemble one or another C variable of children based on the implied randomness. This commentary will be perfectly understood if these images are compared with q053 and q056 respectively.
  
  Actually, we know that all C variables correspond to mono-environmental monozygotic twins, whereas W will only be a sibling; for that reason, sometimes they will look alike and others not so much.

  (Public image domain)
  

  It does not seem hard to imagine some interesting studies on these peculiar matters.

• Another substantial curiosity is the different behaviour of W and its variations shown on the images relative to the ancestors M and F as rearrangement criteria.