One on hand, in intact families, it may be easy to observe the existence of such similarities merely by the comparisons between offspring and antecedents. Much of what forms a person is determined by imitating behaviors of those around you, the vast majority of them at early age being immediate family members. On the other hand, one example is with children who are adopted at birth and whisked far from any contact with the biological extended family, such as to another country, another continent, even another culture. Those children may exhibit similar or vastly different personality traits as the birth parents, but it's also likely that intrinsic qualities are already deeply embedded in one's psyche. It's much more difficult to track without having a lot of knowledge of those personalities in the original family line.
(Great question, by the way. Extremely thought-provoking.)
Chancellor of the King's court (trembling fearfully): "Sire, as much as it pains me to report it, word has it that a lowly peasant deigns to have corrected His Majesty."
King Randolph D the First and Only: "Have him brought before me. I shall decide which of two awards he shall receive."
I'll shorten Randy's answer as I am not so eloquent. Probably 50/50 environment/heredity. I could list a few examples, but I am too lazy. I don't know where I got that from.
The research and data collected by evolutionary biologists and even the pseudoscience of psychology answers that with a resounding YES. Even though social conditioning can have a large part amplifying or suppression of character qualities our genes still have a huge and dominate factor in developing our personalities.
Yes, but estimating the influence is very hard to measure.
It seems mental illness is mostly genetic, while personality derives primarily from family and social influences. We might imagine that if all the kids share the same genes then their personalities would be the same. But each kid is born into a different position in the family, and that position has a big effect on their subjective experience. Also, family circumstances change, and the age at which a child experiences something affects how he or she interprets it, what beliefs are formed, and which coping strategies turn out to work best.
From my experience in breeding horses, the foal's temperament is strongly affected by its parents; roughly 40% from the sire and 60% from the dam. A horse's reaction time and rate of metabolism are strongly genetic. Some individual mannerisms are inherited. In the wild, the young animal learns to socialise in the herd, understand its place in the social hierarchy, and expertly read the behaviours and body language of other animals. In the domestic setting the foal also learns how to read humans. With imprinting at birth and by creating an appropriate environment, the horse handler can make a huge difference in the horse's "personality." It's levels of timidity versus assertiveness, friendliness versus independence, pickiness versus experimentation have a genetic element but can be strongly modified with skilful, consistent training.
I think people are much the same, but we often don't realise how our behaviours affect one another. Many of us think anger, shaming and negativity are the right way to shape behaviour, while the psychologists have masses of evidence that these methods usually have the worst results.
This post was edited by Benedict Arnold at October 15, 2017 6:05 PM MDT
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Randy D 