Noam Shpancer, Ph.D., who currently works as a professor of psychology at Otterbein University and centers his research on child care and development, says the principle 'Actions speak louder than words' applies in the realm of self-understanding as well.

"If you want to know what you like, believe in, and find important, then look at your behavior. You may surprise yourself," Shpancer writes in Psychology Today.

According to the psychologist, what we tell ourselves we value is often not what our actions bespeak. "When you see a gap between your words (or thoughts) and your actions, trust the actions, not the words. As they say in Hollywood, 'Don't believe your own BS.'"

Another useful derivation of this principle, Shpancer says, is this: "To understand the true goal of a certain action, look at the actual outcome. Quite often, you can discern where someone truly wants to be by looking at where they keep ending up. This principle, however, only applies under three conditions."

First, it applies better for those specific, non-incidental outcomes that are unlikely to be stumbled upon by chance or mistake. "One may [discover] a nice pebble on the beach during a sunset stroll, but one does not commonly [discover] a nugget of gold lest one goes searching for it with dedication. Thus, if someone ends up finding gold, then it is safe to assume that finding gold was the goal to begin with," the psychologist explains. "Likewise, if someone ends up in a position of great social power, chances are that power was their actual deep motive to begin with, regardless of their stated aims and preferences. As a rule, you don’t stumble onto great power."

Second, this principle holds best for patterns, not anecdotes. "One failure to achieve a stated goal is probably just that—a failure. But a pattern of repeated failure to achieve a stated goal may mean that the stated goal is not the true goal," Shpancer says. 

"More often than we'd like to admit, our stated goals are in conflict with—and a cover-up for—our true, unstated ones. For example, if peace is not achieved despite repeated attempts, then perhaps the two sides are benefitting from, and thus seeking to maintain, the state of war, regardless of their claims and declarations to the contrary."

Third, the principle holds in environments where people actually have adequate choices and options — if people are powerless in their environment, then the outcome is more likely due to environmental conditions, and attributing it to personal goals, wishes, or values is unwise. "If I'm a patient in the hospital and a nurse wakes me up every four hours to check my vitals as part of hospital procedure, then we cannot conclude that it is my wish to be awoken and poked repeatedly. On the other hand, if I find myself repeatedly in stormy relationships, then odds are that being in the middle of a storm is my true aim, regardless of how much I purport to desire calm," Shpancer adds.

The psychologist suggests that in order to understand people (including ourselves) better, we are to use behavior as our guide.

So if a person's action outlives even them and hundreds of thousands of people celebrate it on the internet, we should take note. They were probably onto something.