Understanding other people’s emotions peaks in your 40s and 50s.

Scientists gathered about 10,000 people, showed them pictures cropped very tightly around the subject's eyes, and asked them to describe what emotion the person pictured was feeling. They found a long plateau in people's 40s and 50s where the ability to correctly identify emotions based only on the eyes was strongest.

I'd like to see the science on vocabulary. 

It peaks in the 60s and 70s:

http://pss.sagepub.com/content/early/2015/03/06/0956797614567339.abstract

It turns out people's scores on multiple choice vocabulary tests keep climbing into their late 60s and early 70s. And you don't even need to sit around reading the dictionary all day to make it happen. Although it can't hurt.

Life satisfaction peaks again at 69.

Remember that study in Germany that found 23-year-olds were particularly satisfied with their lives? After a dip in middle age, life satisfaction peaked again around 69 years old. Even more intriguingly, actual life satisfaction was higher for people over 60 than people 55 and up had predicted they would feel five years down the line.

Men and women feel best about their bodies after 70.

In a Gallup survey, an incredible two thirds of Americans over 65 said they always like the way they look. Men's self-perception appears to peak in their early 80s, when three quarters agree with the statement "You always feel good about your physical appearance." Women's rates of agreeing with that statement is a little below 70% as soon as they hit 75 years old.

People really do get wiser as they get older.

It turns out life really is the best classroom. A team of psychologists asked people to read about a conflict, then asked them questions about it. The scientists then analyzed the responses for characteristics like being able to take someone else's point of view, anticipating change, considering multiple possible turnouts, acknowledging uncertainty, and searching for compromise. They found that the oldest group they studied, people who were between 60 and 90 years old, did better than other ages on almost every count.

Psychological wellbeing peaks around 82.

In a study published in the Proceedings of the National Academy of Science, scientists asked people picture a ten-step ladder, with the best possible life on the top rung and the worst possible life on the bottom rung. The oldest group they studied, of 82- to 85-year-olds, gave the highest average rung number, about 7.

People are most likely to make big decisions when their age ends in 9.

There really is something daunting about approaching a round birthday. Researchers looking at people who were 29, 39, 49, or 59 found that they were more likely to make a big life change — good or bad. They found that these "9-enders" were overrepresented in groups of people seeking to have an affair, people committing suicide, and people running a marathon for the first time.