It's easy to get lost in these pictures, thinking about how their subjects have changed over time, but we should also do that with ourselves.

As executive coach Jennifer Porter explained in Harvard Business Review, at its simplest, reflection is about careful thought, but the kind of reflection that is really valuable is more nuanced than that and requires conscious consideration and analysis of our beliefs and actions if we want to learn anything.

"Reflection gives the brain an opportunity to pause amidst the chaos, untangle and sort through observations and experiences, consider multiple possible interpretations, and create meaning," Porter wrote. "This meaning becomes learning, which can then inform future mindsets and actions."

Research by Giada Di Stefano, Francesca Gino, Gary Pisano, and Bradley Staats in call centers demonstrated that employees who spent 15 minutes at the end of the day reflecting about the lessons they had learned performed 23% better after just 10 days than those who did not.

A study in the UK found a similar result when those who were prompted to use their commute to think about and plan for their day were happier, more productive, and less burned out than people who didn't.

If you want to become more reflective, Porter suggested a few tips:

Identify some important questions. They can be something along the lines of, 'What are you avoiding?' 'How are you helping your colleagues achieve their goals?' 'How are you not helping or even hindering their progress?' 'How might you be contributing to your least enjoyable relationship at work?' 'How could you have been more effective in a recent meeting?' But don't hurry to answer them. These things take time.

Select a reflection process that matches your preferences. Many people reflect through writing in a journal. But if that sounds terrible, consider talking with a colleague or a friend. As long as you're reflecting and not just chatting about the last concert you've been to, your approach is up to you.

Schedule your reflection time and then commit to keeping it. If you find yourself trying to skip it or avoid it, reflect on that!

Start small. If an hour of reflection seems like too much, try 10 minutes. Teresa Amabile and her colleagues found that the most significant driver of positive emotions and motivation at work was making progress on the tasks at hand. Set yourself up to make progress, even if it feels small.

Do it. Go back to your list of questions and explore them. Be still. Think. Consider multiple perspectives. Look at the opposite of what you initially believe. Brainstorm. You don't have to like or agree with all of your thoughts — just think and examine your thinking.

Ask for help. A lack of desire, time, experience, or skill can get in the way of reflection. Consider working with a colleague, therapist, or coach to help you make the time, listen carefully, be a thought partner, and hold yourself accountable.

But before you sit down on a park bench to think about yourself, Allen R. McConnell, Ph.D., who is a Distinguished Professor and Chair of the Department of Psychology at Miami University, wants you to know that you shouldn't be too critical.

"There is a happy medium in how much negativity we experience in order for change to take place," McConnell pointed out in Psychology Today. "That is, if we are overwhelmed or become paralyzed by the magnitude of our shortcomings, we can shut down and tune out rather than double down and persevere. Thus, the morbidly obese person should not adopt the goal of becoming 'a size 4' if she is 'a size 22' because such a huge discrepancy might overwhelm her rather than motivate her. However, by picking smaller, more manageable goals, progress rather than paralysis can result."

But at the end of the day, the effort is worth it. No wonder so many traditions spanning thousands of years emphasize the same things we see in contemporary psychological literature.

"Whether it's Buddhists engaging in meditation, alcoholics at AA meetings, or philosophers of the Enlightenment studying the texts of Immanuel Kant, being aware of ourselves is an essential step in self-improvement," McConnell added.