According to communication principles, what do humans remember less than?

The statement that humans remember less than 15% aligns with common research findings in communication theory, specifically related to retention of information after a presentation or a conversation. Studies suggest that individuals typically retain only a small fraction of what they hear or receive through verbal means, especially after a short period. The figure of 15% serves as a reminder of the efficacy of employing techniques to enhance communication, such as the use of visuals, summarization, and engagement strategies that can significantly improve retention.

When considering the other options, 10% represents a lower retention estimate, while 20% and 25% imply a higher level of recall that does not commonly reflect typical retention rates seen in communications studies. Thus, the 15% figure is notable for illustrating the importance of effective communication methods to help increase listener understanding and memory retention.