In my experience (given all possible observations, a rather microscopic slice of life) those that have loosened up or (possibly) lost a straight jacket sense of limited and static identity, tend to laugh a lot. Not (necessarily) in dumb and silly reactive ways, but more towards deeper, joyful, playful laughter. Play is perhaps a key theme. MMY, a flawed but perhaps relevant example) was like that, at times, in smaller settings, particularly in the pre 1975 days.
And those with a deep sense of (in their view) the absurdity of life, even if its exposition seems dry, pedantic and even morose (like the Woody Allen interview within the "Atheist" video I posted yesterday, still can have a robust sense of humor. Both are in a sense, result from finding less or little to hang onto, less ability or need to impose grand meanings and narratives on life and its events, and more a moment to moment sense of adventure to find or simply see momentary wonder, joy or irony in things as they occur. A more generalized (possibly obtuse and pompous) framework is that a static, limited sense of self are deep roots of self-deception. Those who are not as tightly tied to an identity based on common ID markers such as level of education (and schools attended) career, age, gender, income, status, possessions, steady progress in life (not the ups and downs of, you know, "losers"), what others think of them, appearance and physical flaws, a conviction regarding the correctness of their thoughts and judgments, tastes, appear to have exponentially greater degrees of freedom to "play". And in that play, express and enjoy wide ranging humor reflecting the contradictions, "absurdities", disconnects, and juxtaposition of unexpected elements. Typically, it is not, at at least less so, humor aimed at diminishing others. And having less to lose when things inevitably change, perhaps enables them more of a sense of adventure in life, rather than keeping it safe and secure. "In theory, theory and practice are the same. In practice, they are not" (Yogi Berra) In theory, I love science and its methods, despite severe limits. Particularly neuroscience, broadly defined. However, in practice, I am quite leery of psychological studies using interviews with canned questions, particularly if "Yes/No" are the alternatives. Even 10 point scales can be silly responses to complex questions. "More than once it felt good when I heard on the news that someone had been killed” “I could never enjoy being cruel.” I would hope anyone with a sense of humor as well as some sense of the diversity and richness of life to reject such questions, and scribble in: "It depends! On definitions, on context and degree (not that morality is necessarily conditional). And if you want to talk about it great, but I am not going to give you a misleading, yet easily quantifiable and scored because it makes your study easier to do and let you draw unwarranted conclusions to an unsuspecting public." And I suspect, some that would laugh at the question “I could never enjoy being cruel.” as absurd, and check and emphatic NO!, may not be the deepest, compassionate, nuanced thinkers on the block. Ethical questions regarding an off the cuff call to "nuke the towel heads" or in another arena, for example, large-scale factory farming, may never occur to them. They may have a wide-spectrum, practiced and widely acknowledged sense of humor (particularly after an extended duration of beer pong) but does this (caricature) typically reflect much self-awareness / absence of denial? What I have seen over the years (yes, limited observations) is that some who possess great outer verve and bravado and air-tight self confidence in expressing loud, black and white positions, may actually be denying quite a bit -- that may finally begin to surface later in life.
