Is it established that personal success or happiness is primarily determined by personality and is largely independent of social identities?

Question

In a discussion about choices about occupation, I shared the image of this tweet. The following was one of the replies:

Of course you can sit and complain about it, but it tells you about your own shortcomings be it laziness, cowardice, fears of all kinds lack of initiative etc.

Further the commenter pointed out that

Personal success or happiness after (everything else being equal) is determined by your personality.

He claims this using the theory of delayed gratification. His point being [from the wiki link]:

In follow-up studies, the researchers found that children who were able to wait longer for the preferred rewards tended to have better life outcomes, as measured by SAT scores, educational attainment, body mass index (BMI), and other life measures.

Actually he might be right. I have no idea of modern cognitive science results. So I want to know the following:

Are there results in cognitive sciences that show personal success or happiness is determined by one's personality? And that any occupation failure is determined mostly by personal shortcomings and is largely independent of social identities?

Answer 1

There is a growing body of work around social emotional learning that states that factors such as, self-control, grit, and mindset can have a huge impact on long-term success.

But, these are often coined character strengths, not personality. And as such, these strengths can be trained. The Marshmallow Tests may have given evidence that self-control positively correlates with success, but much more importantly that self-control can be trained and is not wholly innate. In his latest book, Walter Mischel (author of The Marshmallow Test, study and book) goes to say that what we grow to become is neither wholly nature or nurture, but a conglomerate.

Angela Duckworth (grit) and Carol Dweck (mindset) have similar views about how we can train our character strengths to better help us succeed.

So, "is determined by?" Probably not. Too much goes into what makes a human human and even personality changes over time.

Independent of social identities? Definitely not. All of the above authors have had their work criticized for letting their work be distributed as, "just the harder and you'll be fine" regardless of social standing (race, sex, income)

Answer 2

This seems to me the old nature versus nurture debate and there is no real answer to this. However, I highly doubt that it is personality (as an inherent trait of you - nature) that's the most important factor for personal success. The question is what shapes your personality.

Family matters a lot, so building your personality over the right type of Childhood experiences seems to have strong effects on personal performance.

Yet, even such mundane things like names can have a huge impact on personal success regarding job oppurtunities.

Answer 3

I don't think you can separate personality from social identity (?) With the marshmallow test, for example, the children who have learned not to trust adults or who live in chaotic environments have more motivation to grab the first marshmallow rather than wait. Their outcomes in life are therefore as likely to be a result of their relationships and environment as they are to be related to unchanging aspects of their personality. I'm sure they've done the experiments controlling for socioeconomic circumstances, etc., but there's no way of controlling for the quality of relationships.

So the answer for me is no, I don't think it's possible to prove such a thing.