According to a study published in the journal Science female túngara frogs may be fooled by the decoy effect. This effect is commonly used as a marketing trick: when a customer cannot decide between two products the salesman presents a third unappealing opinion which makes the customer decide upon one of the two original products, preferably the expensive one.
For example if one customer cannot decide between a cheap but not that satisfying product and a satisfying but also expensive product, the salesman could present the customer a product just as satisfying as the original expensive product, but only far more expensive. This way the buyer is tricked into choosing the least expensive product which is anyway better for the business if he had chosen the cheaper product.
For the study researchers used 80 female túngara frogs, a species which lives in Central America. Three recorder mating calls were recorded in the research, each of it varying in speed of repetition and attractiveness.
Usually the male túngara frog woos the female by making calls. Females have the tendency to like low-frequency, faster, longer calls because they indicate that the male is more energetic.
The research team led by Mike Ryan from the Smithsonian Tropical Research Institute in Panama and Amanda Lea from the University of Texas at Austin presented the female túngara frogs with two types of calls from which the amphibians preferred the one that was most quickly repeated. However, when the females had a third option which as attractive as the call they had just rejected, only much slower, they changed their mind.
So the female frogs were likely to change their preference over two mating calls when they heard an unattractive third call. The authors of the study wrote:
We tested female frogs with three simulated males who differed in relative call attractiveness and call rate. In binary choice tests, females’ preferences favored stimulus caller B over caller A; however, with the addition of an inferior “decoy” C, females reversed their preferences and chose A over B.”
It seems that once exposed to a third option the female has a hard time making a choice, which can pretty much be applied to humans as well.
Image Source: Live Science