With training, pigeons are uncommonly good at distinguishing normal versus cancerous breast tissue.
“With some training and selective food reinforcement, pigeons do just as well as humans in categorizing digitized slides and mammograms of benign and malignant human breast tissue,” says Richard Levenson, professor of pathology and laboratory medicine at the University of California, Davis, Health System and lead author of the study.
“The pigeons were able to generalize what they had learned, so that when we showed them a completely new set of normal and cancerous digitized slides, they correctly identified them,” Levenson says.
“Their accuracy, like that of humans, was modestly affected by the presence or absence of color in the images, as well as by degrees of image compression. The pigeons also learned to correctly identify cancer-relevant microcalcifications on mammograms, but they had a tougher time classifying suspicious masses on mammograms—a task that is extremely difficult, even for skilled human observers.”
The pigeons’ successes and difficulties provide a window into how physicians process visual cues present on slides and x-rays to diagnose and classify disease risk.
This work also suggests that pigeons’ remarkable ability to discriminate between complex visual images could be put to good use as trained medical image observers, to help researchers explore image quality and the impact of color, contrast, brightness, and image compression artifacts on diagnostic performance.
Although a pigeon’s brain is no bigger than the tip of an index finger, it turns out that the neural pathways involved, including the basal ganglia and cortical-striatal synapses, operate in ways very similar to those at work in the human brain.
According to coauthor Edward Wasserman, professor of psychological and brain sciences at the University of Iowa, the common pigeon (Columba livia) has a tremendous capacity to discriminate and categorize a wide range of objects and images.
Check out the research video on the next page that shows these smarty birds in action…