If your first thought after being woken up one early morning by your neighbor operating a loud lawnmower is that the machine sounds like an A-sharp, you might have perfect pitch. And the patience of a saint.

Some people have a natural ability to recognize the pitches of musical notes and everyday noises, but to what degree genetics contribute to this, in addition to musical training from an early age, is unclear. Perfect pitch seems more likely to develop in speakers of tonal languages like Mandarin -- where pitch and inflection can change the meaning of a word -- but is less common in speakers of non-tonal languages like English.

"What is clear is that musically trained individuals who speak a non-tone language can acquire absolute pitch, but it is still a remarkably rare talent. What has been less clear is why most others with equivalent musical training do not,” University of California San Diego psychologist Diana Deutsch said in a statement Tuesday.

Deutsch and colleague Kevin Dooley may have found evidence that there may be a distinct genetic origin of perfect pitch. They presented their research on Tuesday at a meeting of the Acoustical Society of America in Kansas City, Missouri.

The researchers examined 27 English-speaking adults, 7 of whom had perfect pitch. All of the subjects had begun training in music at or before six years old.

In the experiments, the study participants were tested on their memory skills by seeing how many numerical digits they could recall in order after hearing the numbers spoken or seeing them on a computer screen. Those with perfect pitch turned out to be substantially better at recalling digits presented as spoken words, but did not have an advantage when recalling numbers presented digitally.

That suggests that some predisposition towards an unusually strong memory for spoken words could be at the heart of perfect pitch. An inherited trait as a prerequisite for perfect pitch could then explain why some people with music training starting in very early childhood never develop it.

Other researchers have shown that an unusually good memory for to recall spoken digits has a genetic basis, according to Deutsch.

Some scientists have investigated possible connections between perfect pitch and autistic traits. One 1995 paper examined the musical abilities of a male autistic savant. Based on psychological testing, they found that the subject had “difficulties in verbal reasoning but high levels of concentration and memory,” and other members of his family were also skilled musically.

A more extensive look at the autism-perfect pitch link was published in the journal PLoS ONE this past May. Researchers measured the levels of autistic traits in 16 musicians with perfect pitch, 18 musicians without perfect pitch, and 16 non-musicians.

While the researchers did find a higher degree of autism traits in musicians with perfect pitch compared to the other two groups, perfect pitch was not associated with exhibiting the social and communication traits along the autism spectrum. People with perfect pitch all scored well below the clinical threshold for autism.

“Whilst these findings do link [perfect pitch] with autism, they also show that [perfect pitch] ability is most strongly associated with personality traits that vary widely within the normal population,” the authors wrote.