How do humans localize sound? In other words, how does someone with their eyes closed know where sound is coming from? Solution Localization of sound refers to the ability of a person to identify the location or the origin of sound, its direction and the approximate distance from which it is comming. In order to investigate this complex ability, mammalian auditory system has been studied in detail. Sound localization ability involves psychological and physiological acoustics as well as person\'s artificial intelligence. It includes the interpretation of cues from the environment regarding the information recognition, feeling of living in 3D environment, spectral information, sense of timing and correlation analysis. These cues also include changes which occur with direction of sound and the time its arrival at the ears. Cues of differences between the sound reception of two ears (binaural) and sensing pressure difference reception of the two ears, is also used as information. The sound travels between ears and eardrums are activated at its outer and inner surface. This helps the animal locate the source of the sound. The ear which faces closer to the sound source vibrates with a larger amplitude, compared to the eardrum facing away. Humans have very good ability to determine the source of sounds and they use the \'pressure reception\' as a major cue. The resonance effect in external auditory canal causes the sound signal amplification. In humans, only the outer surface of the ear is exposed to sound. Eustachian tube equalizes the pressure, and does not allow the sound to enter the middle ear. Hence the outer ear serves dual function of localizing the source of sound and amplifying the acoustic signals. Inner ear is protected by middle ear. Cochlea, which is the main part of the inner ear convert the acoustic signals to nerve stimulation..