As people get older and their hearing worsens, they have more difficulty understanding speech in noisy environments, but recent studies suggest that familiarity with certain voices can partly compensate for poor hearing."When you get older, your hearing declines, your vision and memory decline. But what older people have a lot of is knowledge and experience," and this can help them, said Ingrid Johnsrude, a professor of psychology at Queen's University in Ontario, who studies speech perception and aging.
Listening to a single conversation amid a noisy environment challenges the brain's auditory system – yet somehow, people are able to tune into the sound of a single voice, understand it and follow a conversation. This phenomenon is called the "cocktail party effect." [Top 10 Mysteries of the Mind]
In studying the effect, scientists have focused on the factors that help the brain tease out voices from a mixture of sounds arriving to the ear. Researchers have looked at the pitch of the voices and where the speakers are located relative to the listener, among other factors.

However, recent research shows that the brain does not rely only on the incoming sounds themselves to understand speech, but also uses information from other senses, as well as past experience. Those findings come from research Johnsrude presented last month at a meeting of the Canadian Association for Neuroscience in Montreal.
Who you choose to talk to matters
In their experiments, Johnsrude and colleagues had participants listen to speech amid interfering voices and noise, and examined how the participants' attention, familiarity with the voices and knowledge of what was being said helped them understand the speech.
In one of these studies, the researchers looked at middle age and elderly couples who had been married for at least 18 years. Published in the journal Psychological Science in 2013, the study found that people are more successful in focusing on a voice and blocking out noise if the voice belongs to their spouse.
"We found that older people really benefit a lot from having a familiar voice in the mix," Johnsrude told Live Science. "Not only do they hear that voice better than a matched stranger's voice, but they can also use the voice they know to ignore it so as to attend to another voice more easily."
Knowledge helps
Knowledge about the context of the conversation can also help people understand hard-to-hear speech. In a series of experiments, Johnsrude and colleagues had participants listen to a sentence that was read in the context of bad-quality sound, while also seeing the text of the sentence. Each word of the sentence appeared, one by one and on a screen, 200 milliseconds before the word was heard.
Looking at brain scans, the researchers found that reading the sentence was linked to a greater change in the activation of the brain's primary auditory cortex, which handles incoming auditory signals, compared to seeing a meaningless string of consonant letters shortly before hearing each word.
"The auditory cortex was sensitive to the difference between getting that meaningful information visually and not getting it. And we know the auditory cortex doesn't read," Johnsrude said. "So that modulation based on what you read must be coming from somewhere else in the brain." The findings were detailed in the journal Neuroimage in 2012.
Learning from the brain
Researchers have explored the role of knowledge and experience in influencing perception in other senses such as the visual and olfactory systems. For example, people can more easily figure out a scrambled picture if they know what to look for, and they take less time to identify odors they have smelled previously.
The auditory system seems to be no exception, and for older people, this can come handy, Johnsrude said.
"If we are looking at ways to help older people, or if we want to understand how they are able to perceptually organize their world despite diminished hearing, we need to understand how knowledge and experience can influence their performance," Johnsrude said.

When it comes to creatures with keen hearing ability, sea anemones are not at the top of the list. Nonetheless, new research suggests that certain proteins that help these animals repair their feathery tentacles could also eventually be used to help repair damage to cells within a mammal's inner ear.
The finding comes from a study done in mice and could be an early step toward finding a treatment for people with hearing loss, the researchers said.
In mammals, including humans, sound is translated from vibrations in the air into nerve signals that can be sent to the brain by highly specialized cells called hair cells. These are found within the cochlea, a fluid-filled structure of the inner ear. Damage to these hair cells, which can be caused by exposure to loud noise, can result in hearing loss, and mammals are not able to repair hair cells once they are harmed. [Marine Marvels: Spectacular Photos of Sea Creatures]
It turns out that sea anemones have similar hair cells on their tentacles, which the animals use to sense ocean vibrations and approaching predators, according to a statement from the Journal of Experimental Biology, which published the new study on Aug. 3.Previous research showed that after anemones reproduce — which they do by tearing themselves in half — they repair their tentacles, and their hair cells, using repair proteins in the mucus that coats the creatures' bodies, according the statement.
"It occurred to me that if any animal could recover from damage to its hair bundles, anemones would be the ones," study author Glen Watson, a biology professor at the University of Louisiana at Lafayette, said in the statement.
Watson and his colleagues identified a group of secreted proteins that allowed the anemone hair cells to recover, and wondered if those same proteins could also repair damaged hair cells from a mouse's ear, Watson said. [7 Medical Myths Even Doctors Believe]
To investigate this, the researchers first removed the cochleas from mice, and treated the organs with a solution that damaged the hair cells. Specifically, the solution damaged the tiny, hair-like structures called stereocilia on the surfaces of those cells in the way that loud noise would.
Next, the researchers treated the cochleas with a solution of repair proteins isolated from starlet sea anemones that had damaged tentacle hair cells. Results showed that the mouse stereocilia "recovered significantly," the statement said. 
Mice have proteins that are related to the sea-anemone repair proteins, the researchers found. They hypothesized that in the future, it might be possible to harness those proteins to repair mammalian hair cells.
However, much more research is needed first, to see whether the proteins work the same way in people, "putting this sort of therapy years into the future," Watson told Live Science.
Original article on Live Science, credit photos by shutterstock.

A descendent of Vincent van Gogh redefined "lending an ear" when he donated his DNA to help an artist create a living replica of the Dutch painter's famously severed feature.The 3D-printed ear, identical in shape to Vincent van Gogh's, is on display at ZKM Karlsruhe Museum in Germany, where visitors are encouraged to talk into the ear through a microphone.
Diemut Strebe, an artist who often incorporates biological material into her work, wanted to reconstruct the ear that van Gogh sliced off in 1888 during a psychotic episode. To make it as genetically close to the real thing as possible, Strebe reached out to Lieuwe van Gogh, the great-great-grandson of van Gogh's brother Theo, and asked him to provide DNA from his ear cartilage cells, AFP reported. [The 10 Weirdest Things Created By 3D Printing]

Strebe and a team of scientists combined preserved DNA from an envelope historians believe Vincent van Gogh used in 1883 with the cartilage cells donated by Lieuwe van Gogh. They attached the living cells to synthetic DNA and squirted it into a synthetic, ear-shaped mold. The scientists then used computer modeling to ensure the mold was as close to the size and shape of Vincent van Gogh's ear as possible.When visitors talk to the ear using the microphone, sound travels through the nutrient solution the ear is preserved in, where a computer simulates nerve impulses. The sound is then broadcast through a speaker.
Scientists have been 3D printing human body parts, tissues and organs for several years. The new technology is revolutionizing organ transplants and is making it possible to replace failing organs or missing body parts. But Strebe's goals were a little more esoteric.
The title of the living art piece, "Sugababe," is a reference to a philosophical problem, which the Greek historian Plutarch wrote about nearly 2,000 years ago in "The Life of Theseus": If a ship is restored by replacing all its parts, does it remain the same ship? (This type of question is sometimes referred to as the Sugababe paradox, after a British pop band with an ever-changing line-up.) Similarly, the van Gogh ear replica explores the idea of how much an individual's genetic code is a part of who he or she is.
Strebe's past work has included genetically engineered plants, photographs of scientists with litmus paper in their mouths and an art piece that was launched into space. The van Gogh ear replica is on display until July. Strebe will move her art collection, including the ear, to New York early next year.