Alfred Adler (1954) referred to the sibling rivalry between the first and secondborn when he said,
The striving for power in the case of a secondborn child also has its especial nuance. Secondborn children are constantly under steam, striving for superiority under pressure: the race-course attitude which determines their activity in life is very evident in their actions. The fact that there is someone ahead of him who has already gained power is a strong stimulus for the secondborn. If he is enabled to develop his powers and takes up the battle with the firstborn he will usually move forward with a great deal of elan, then while the first born, possessing power, feels himself relatively secure until the second threatens to surpass him (p. 126).