CORVALLIS (Ore.) - A graduate student at Oregon State University's College of Science challenged the traditional wisdom that had governed the study of a toad considered endangered in a part of its range for over a century.Anne Devan-Song used the spotlighting technique - shining a flashlight in a dark area and looking for eye reflections to locate large numbers of eastern spadefoot toads. This study shows how confirmation bias, a tendency to interpret new data as ratifications of existing theories, can hinder discovery and the development better theories.Her findings which showed that the toad spends more time above the ground than is commonly believed were published in Journal of Herpetology.The eastern spadefoot toad is known for its bright yellow eyes and elliptical pupils. It also has a spade on each foot. This toad can be found from the southeast corner to the Atlantic Coast of New England. It is scientifically known as Scaphiopus holbrooki and is a species of conservation concern in its northern reaches.Devan-Song is a Ph.D. student studying integrative biology. She was born in Singapore and learned that she can use spotlighting to search for reptiles. The endangered eastern spadefoottoad has been found in Rhode Island, where she received a master's degree.Devan-Song noticed one eastern spadefoot after the other while she was surveying amphibians in Virginia on a rainy night. She was surprised because they were only detectable on very rare rainy nights each year when the toads emerge from underground burrows and mate in wetlands.She kept looking for eastern spadefoots, and she continued to find them in dry areas. Devan-Song was able to identify the toads by simply looking at them in the spotlight.She said that they need to be able to reach the top of the earth to hunt insects and to build up energy for mating. "That's why they were found when and where the conventional wisdom suggested we shouldn't be."She tried spotlighting for spadefoots in Rhode Island. It took her only 15 minutes to find one. This success resulted in a 10-night survey at two locations last summer, which produced 42 sightings. This is nearly twice the amount of eastern spadefoots seen in Rhode Island in the past seven decades.Devan-Song learned that the eastern spadefoot is so secretive that it almost always escapes detection. Devan-Song stated that it was first suggested in scientific literature, back in 1944, that the toad could not be found outside of rainfall-induced migration or breeding aggregations. In 1955, spotlighting was used by researchers to detect large numbers of eastern spadefoots living in Florida. However, the technique soon fell into disuse.Devan-Song stated that confirmation bias perpetuated the fallacy that the eastern spadefoot was not found. "We did not observe any migration or breeding during our surveys. We found thousands of toads both in Virginia and Rhode Island. Subadults were the majority, which is a demographic group that is often overlooked in the literature. A misconception that persists despite evidence to the contrary has impeded progress in our understanding of the toad's ecology and conservation.She said that confirmation bias was a result of the ease with which many toads were found during breeding and a lack data on toads living in upland habitats.Devan-Song stated that everyone assumed they were underground, so nobody was actually looking for them. Our research shows that they can be detected all year, but are still very rare in Rhode Island. They are not as common as scientists thought.###This research was supported by the National Park Service through a cooperative agreement between the University of Rhode Island.
