The body may not seem cultural, but it is. Long ago, larger women were considered desirable due to a belief that they were more likely to survive pregnancy and childbirth. Today, many women face great cultural pressure to be thin. The rising obesity in the United States is seen by some countries as a decadent sign of wealth while other countries suffer malnutrition. Judgement is heaped upon the overweight and such nitpicking exists that healthy young women are shown doctored photos that make similar women appear even thinner, as a false standard of beauty that many consider harmful; this is cultural pressure and a value judgement.
Ageism is real and felt at all ages, while often targeting the old. A society which values youthful productivity might consider the elderly a problem that should be locked away in retirement communities and denied rights, like a driver’s license and simple human dignity, because that society values youth and productivity. Another society might teach great respect and reverence for their elders because they value wisdom and experience. There’s more to ageism than the body, of course, as mental capacity and maturity are related.
Someone’s general appearance is also cultural. Social norms change with our location and even time of day. In business, we make ourselves more presentable while being more casual at home and on the weekends. But perhaps we have a culture where formality reigns so that even a trip to the drug store means not having a proverbial hair out of place. Or perhaps a culture acknowledges that people can be very productive at work despite casual attire. There’s also the question of a bare minimum of make-up for women (or men), groomed hair/beards, and clothes that aren’t wrinkled, for example.
Facial expressions are considered universal across cultures, so that’s one element world builders don’t have to worry about, at least among humans. To make our lives easier, we can take the same approach to other humanoid species. We might decide that an ogre is smiling for a different reason, like the pleasure of imagining bashing your head in, but it’s still pleasure. Changing a smile to mean what a frown does, for example, will not only confuse characters but our audience. There are other ways to have characters misunderstand something, such as seeing the smile as benevolent when it’s not.
Posture, walking, standing, sitting, and even how we hold our head or carry ourselves can be specific to an individual but also part of culture. A dignified culture might espouse standing tall, with chin up. An oppressive culture might see that as arrogant and have dominated people so much that being hunched, with head hanging low, has become a cultural expectation. Sitting with back straight is a sign of a strict culture, whereas slouching might be accepted in a lackadaisical one. Walking might be brisk in a fast paced one, but slow shuffling or casual meandering might reflect oppression or peaceful relaxations. As with most cultural issues, we want to determine what’s common so that we know when someone is deviating from it and how that deviation is perceived.
The concept of personal space is one that can vary among cultures and across fictional species. Being close can express dominance, aggression, or signal intimacy. It can make people uncomfortable for all three reasons. Too much distance can seem impersonal, standoffish, and dismissive. To decide how close is considered normal or unoffensive, think of the cultural vision. A more reserved society will want greater distance while a boisterous one might find that distancing an affront, as if we’re better than them.
Eye contact can range from too constant to too fleeting. Some cultures see looking down or away as appropriate deference, particularly when facing someone of higher station, whereas others see this as contemptible weakness. It can also suggest aggressiveness, whether that’s simple meeting of gazes, a glare, or even refusing to look at someone at all. I’ve had some people stare at me so relentlessly that, aside from reminding me of a cat, they gave me the creeps. In a culture where status is highly valued and strictly enforced, deference is likely, but in a society where status is gained through conduct (whether social skill or achievement), a show of visual strength through maintained eye contact might dominate. We can tweak the length of expected gazing, but audiences don’t want to be told that four seconds is fine, and anything less is not; instead, just state that a character looked away sooner than expected.