Males made up 72.8 per cent of the characters, and 82.1 per cent of them were white.
They were overwhelmingly heterosexual. Numbers showed 61.6 per cent of them had jobs, though older men were more likely to be depicted as working than women.
White male characters were more likely to have prestigious jobs than characters of colour, and women were generally shut out of the top ranks of fields such as law, journalism, politics, and science and technology.
Fictional seniors don't tend to be particularly religious, though 65 per cent of older Americans report that their faith is "very important".
Only a third of them pursued hobbies and activities on screen. And movies tend to depict seniors as disengaged from technology, even though 74 per cent of Americans older than 65 own cellphones and 58 per cent of them are online.
Very few of these older characters, just 10.5 per cent, were depicted as having health issues. But in a grimmer finding, older characters who died on screen overwhelmingly had violent deaths - 79.2 per cent of those characters who succumbed were shot, stabbed or crushed (the study's authors counted accidental violence, such as traffic accidents, in a separate category).
And more subtly, 52.6 per cent of the movies that featured senior characters also included comments that the researchers interpreted as ageist.
Many of those comments were spoken by other characters to older people, but in a number of movies, older characters made self-deprecating or diminishing comments about their own age.
There are clear gaps between the way Hollywood sees older people and the way they see themselves. Humana, the health and wellness company, surveyed 2000 people 60 and older about whether they felt they were depicted accurately in movies and, explained Dr Yolangel Hernandez Suarez, "the answer was a resounding no. They thought themselves to be more healthy in mind and body, more connected, and more savvy than they were portrayed in film".
As a physician, Hernandez is concerned that negative portrayals of older people may diminish the optimism that's been connected to more positive health outcomes. And she worries that younger people will take the wrong lessons from movies, too.
"As someone whose success is so rooted in the mentorship of other women and how important that was to me in my career, I am concerned that when younger people go to films, they do not see women in positions of power, whether that's in politics, or business, or medicine," she said.
"They would never think to look out to another woman because they don't exist in that world. I find that particularly troublesome."
Smith suggested that the limited portrayals of older people on screen might be linked to the fact that only a few actors - and especially, only a few women - are considered viable stars as they age.
"The sell-by date, as we know, for women on screen is 40," she pointed out. "My hunch is that the Judi Denches, the Maggie Smiths, are pushing the same stories and getting work often, which is fantastic, but it is a narrow view."
She also cited Kevin Costner and Liam Neeson, both of whom appeared in two films in 2015, as examples of "a rinse-and-repeat ... with the same actors in powerful roles".
"If you want to project a dynamic view of ageing," Hernandez argued, "it's simply missing in action on screen in cinematic content."
