Now that the internet has had two years to take a side in the great "Laurel or Yanny" debate, another viral audio clip has resurfaced that has everyone second-guessing what they're hearing.
The brainteaser brings back memories of the audio clip from 2018 that had the internet battling over whether a man's recorded voice was saying "Laurel" or "Yanny."
Once the science crowd chimed in, it was determined that the differences in sound were all about the audio frequency. Lower frequencies sounded like Laurel and higher frequencies sounded like Yanny.
The resurfaced "brainstorm" or "green needle" debate involves a 2012 video of a review of toys from the children's television show Ben 10 Alien Force. The creator of the video told The Telegraph in London that the toy is programmed to say the word "brainstorm," but not everyone is hearing it that way.
The wrinkle this time might not be the audio frequency as much as the power of suggestion.
"You can hear 'Brainstorm' or 'Green Needle' based on whichever one you think about," the British company Tomango wrote in a 2018 tweet.
Focusing on one word or the other conditions your brain to want to hear that word.
"The effect seems to work as follows: When you ‘think’ green needle you hear that word, but when you ‘think’ brainstorm, you hear the other," Valerie Hazan, a professor of speech sciences at University College London, told The Telegraph in 2018.
“Basically, you are priming your brain to expect acoustic patterns that match expected patterns for a particular word. When faced with an acoustic signal which is somewhat ambiguous because it is low-quality or noisy, your brain attempts a ‘best fit’ between what is heard and the expected word."