Yes, it is not uncommon for people to experience auditory illusions or "musical ear syndrome" when listening to white noise or repetitive sounds for an extended period. This phenomenon is often referred to as "musical ear syndrome" or "musical tinnitus."
There are a few reasons why this might happen:
Auditory System Adaptation: When you expose your auditory system to a continuous sound like white noise for a prolonged period, your brain's auditory processing centers may adapt to the pattern and start looking for other patterns within the noise. This process can lead to the perception of repeating sounds or little melodies that aren't actually present.
Pattern Recognition: The human brain is excellent at recognizing patterns, even in seemingly random or chaotic stimuli. This pattern recognition ability can cause the brain to organize the white noise into familiar patterns, such as melodies or repeating sequences.
Neural Excitability: The auditory cortex, the part of the brain responsible for processing sound, can become more excitable when subjected to prolonged and repetitive auditory stimulation. This increased excitability can lead to the perception of auditory hallucinations, such as melodies or repetitive sounds.
Cognitive Factors: Your cognitive state and expectations can also influence how you perceive the sounds. If you are consciously or subconsciously trying to find patterns or melodies in the white noise, you are more likely to perceive them.
When you turn off the white noise machine, the auditory illusions typically go away because the auditory system is no longer exposed to the continuous stimulation that led to the perceptual changes. As the brain returns to its baseline state, the auditory hallucinations fade.
It's essential to note that experiencing auditory illusions or musical ear syndrome is relatively common and usually harmless. However, if you find the experience distressing or if it persists outside of the white noise exposure, it's a good idea to consult with a healthcare professional to rule out any underlying auditory or neurological conditions.