Cognitive error: What do you see?

The well-known phrase, “What you see is what you get,” suggests that what we see is conclusive and without doubt … but is that true? Seeing clearly when making a dermatologic diagnosis is critical to patient care, according to Christine J. Ko, MD, professor of dermatology and pathology at Yale University Medical School. Dr. Ko shared her keen observations of the role of visual intelligence in the practice of dermatology during the session “Cognitive Error and Visual Intelligence in Dermatology Diagnoses” (U025).

Christine J. Ko, MD.

Visual intelligence underlies an expert dermatologic diagnosis, Dr. Ko said. Visual intelligence encompasses identifying and understanding concepts in visual perception, recognizing how we come to a diagnosis, using methods to reduce diagnostic error, and preventing perceptive errors.

“Diagnostic error is often the result of a processing error. What this means is that error is not a result of incomplete knowledge but rather due to misinterpreting data, not collecting enough data, and cognitive biases,” Dr. Ko said. “Diagnostic error often boils down to perceptive errors, which are relatable as optical illusions.”

Dr. Ko shared an example of an optical illusion, the Ebbinghaus illusion (or Titchener circles), in which two identical colored circles appear to be of different sizes due to the circles surrounding them. The optical illusion is a concrete example of cognitive bias, as the brain has learned to perceive size using relative ratios and context. The bias is so strong in most adults, she said, the circles continue to appear different, even when you measure them with a ruler.

Ebbinghaus illusion (or Titchener circles).

Learning to see takes time

Becoming an expert in dermatology takes time. Leveraging the claims in Malcolm Gladwell’s book, Outliers: The Story of Success, Dr. Ko suggested that becoming an expert dermatologist could take approximately 10,000 hours. This equates to five hours per day over six years of deliberate practice in dermatology. And that is augmented by knowledge of specific cognitive principles that affect visual perception, she said.

“Gladwell’s rule is based on studies of chess masters and musicians. This is in line with what I was always told as a resident — that it generally takes three to five years of being out in practice, post-residency, to become more expert,” Dr. Ko said. “For most dermatologists, residency is three years, and three years post-residency would make six years — fulfilling Gladwell’s 10,000-hour rule.”

Steps to a clear vision

According to Dr. Ko, a dermatologic diagnosis relies on vision first. An accurate diagnosis is predicated on seeing and perceiving a skin condition, categorizing and naming the condition correctly, and comparing visual and other data with the dermatologist’s own working mental database of dermatologic knowledge.

“We might assume, incorrectly, that an expert dermatologist always sees correctly and transitions easily into categorizing and naming and integrating other data. However, each of these steps has inherent challenges, and the transitions between steps can also be problematic,” she said.

Overcoming bias

As seen with the Ebbinghaus illusion, perception can be influenced by context, she said, including our own experiences and where we are from, our likes and dislikes, and information from others. This can lead to diagnostic error.

To reduce diagnostic error, Dr. Ko urged dermatologists to be aware of cognitive biases and traps, use deliberate checklists to confirm a diagnosis, double-check all data, question whether any other diagnosis is possible, and ask for feedback, including a second (or third) opinion.

“Visual perception is an interpretation of what we see, with ‘seeing’ defined as what crosses the visual field. We don’t perceive everything that is actually there,” Dr. Ko said. “It’s important to recognize that dermatologic diagnosis, as is true with any visually based field, relies on pattern recognition — you see it and you know it. But as in the animal kingdom, where some animals look very different (e.g. elephant, giraffe) and some animals can look very much the same (e.g. alligator and crocodile), conscious awareness of the distinguishing features is key to rapid recognition.”