Research with tropical frogs shedding light on human hearing and attention disorders

August 2, 2011

A study conducted by Hamilton Farris, PhD, Research Assistant Professor of Neuroscience and Otorhinolaryngology at LSU Health Sciences Center New Orleans, reveals new information about the way tungara frogs in the tropical rain forest hear, sort, and process sounds which is very similar to the way humans do.

The knowledge could be applicable to communication disorders associated with and or difficulties. Dr. Michael Ryan at the University of Texas, Austin, collaborated on the study, published online in Nature Communications on August 2, 2011.

"An important component of successful communication is being able to tell which sender among many is sending the signal," explains Dr. Farris. "In auditory it's called the 'cocktail party problem.' A good example of a mistake in source assignment is when a ventriloquist performs."

To understand how the brain solves the cocktail party problem – assigning sounds to their correct source in a noisy or multi-source environment – the researchers chose to study the tungara frog because, unlike other subject species, it easily performs this complex behavior. The way it communicates is also a research asset. Male tungara frogs produce complex calls (not just repeated notes) consisting of two components that are speech-like: the vowel-like "whine" and the consonant-like "chuck."

For female tungara frogs, assigning the distinct components of male calls to the correct source is particularly challenging because males sing in aggregations, producing overlapping calls that lead to perceptual errors just like at a cocktail party. But, it's particularly important to the mate-searching female that she can accurately distinguish the male whose call she prefers from all of the others.

Using the labs at the Smithsonian Tropical Research Institute in Panama, Drs. Farris and Ryan investigated two types of cues/parameters of the call – spatial separation and call syntax – as potential cues for proper source assignment. Interestingly, they found that the , like humans, use relative comparisons to form auditory groups that are assigned to the same source. This means that they take the available sounds and then group those that are most similar. And they are more likely to group the two components with the smallest relative differences in call parameters. This is a flexible strategy that humans use in some conditions as well.

"Thus, in noisy, complicated environments, the cognitive solution is not based on absolute stimulus rules, but one which compares all the sounds and then deduces their sources," concludes Dr. Farris. "Based on our research, we now have a better understanding of how the acoustic cues are used to solve the problem, an understanding that will guide research advances to solve communication problems associated with hearing deficits and disorders of attention."

Explore further: Rare Chinese frogs communicate by means of ultrasonic sound

Related Stories

Rare Chinese frogs communicate by means of ultrasonic sound

March 15, 2006

First came word that a rare frog (Amolops tormotus) in China sings like a bird, then that the species produces very high-pitch ultrasonic sounds. Now scientists say that these concave-eared torrent frogs also hear and respond ...

I am treefrog, feel me shake (w/ Video)

May 20, 2010

Using experiments involving a mechanical shaker and a robotic frog, researchers reporting online on May 20th in Current Biology have found new evidence that male red-eyed treefrogs communicate with one another in aggressive ...

'Virtual mates' reveal role of romance in parrot calls

August 3, 2010

Parrots are famed for their ability to mimic sounds and now researchers have used 'virtual mates' to discover if female parrots judge male contact calls when deciding on a mate. The research, published in Ethology, challenges ...

Recommended for you

A common mechanism for human and bird sound production

November 27, 2015

When birds and humans sing it sounds completely different, but now new research reported in the journal Nature Communications shows that the very same physical mechanisms are at play when a bird sings and a human speaks.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.