In both my psychology, biology and neuroscience classes, professors are constantly talking about 'noise'. For instance, our perception is limited due to 'sensory noise' in our neurons. I am utterly confused about this concept. What is 'noise'? Can someone please conceptually describe what is is in laymen's terms?
noise can mean a number of different (more or les related) things is used in a number of different fields such as signal processing, psychology and statistics.
Outside of its context, it is impossible to say for certitude what you professors were referring to.
Psychological noise results from preconceived notions we bring to conversations, such as racial stereotypes, reputations, biases, and assumptions. When we come into a conversation with ideas about what the other person is going to say and why, we can easily become blinded to their original message. Most of the time psychological noise is impossible to free ourselves from, and we must simply strive to recognize that it exists and take those distractions into account when we converse with others.
Physiological noise has to do with distractions from the natural effects of the body, such as being tired or hungry.
Physical noise is any external or environmental stimulus that distracts us from receiving the intended message sent by a communicator (Rothwell 11). Examples of physical noise include: others talking in the background, background music, a startling noise and acknowledging someone outside of the conversation.
This is noise caused by the sender. i.e., the encoder. This type of noise occurs when grammar or technical language is used that the receiver (the decoder) cannot understand, or cannot understand it clearly. It occurs when the sender of the message uses a word or a phrase that we don't know the meaning of, or which we use in a different way from the speakers. This is usually due to the result that the encoder had failed to practice audience analysis at first. The type of audience is the one that determine the jargon one will use.
Statistical noise is the colloquialism for recognized amounts of unexplained variation in a sample.
In signal processing, white noise is a random signal with a constant power spectral density.1 The term is used, with this or similar meanings, in many scientific and technical disciplines, including physics, acoustic engineering, telecommunications, statistical forecasting, and many more. White noise refers to a statistical model for signals and signal sources, rather than to any specific signal.
Noise in its everyday use
Noise is a variety of sound. It means any unwanted sound. Sounds, particularly loud ones, that disturb people or make it difficult to hear wanted sounds, are noise. For example, conversations of other people may be called noise by people not involved in any of them; any unwanted sound such as domesticated dogs barking, neighbours playing loud music, portable mechanical saws, road traffic sounds, or a distant aircraft in quiet countryside, is called noise.
In electronics, there are concepts of signal and noise; what is not signal is noise. Signal is an "intended" or expected impulse or waveform; noise is any other impulse or waveform - unwanted or unintended.
Taking this into a biological context, sensory noise would then be sensory impulses, whatever the cause, which don't convey useful or meaningful information.