Studies have shown that four-day old infants demonstrate a left-ear preference for music Ð that is, in tests that measure Òsucking recovery,Ó babies prefer to listen to speech in their right ear and music in their left. Another illustration of the domain specificity of music processing arises from the study of people with BrocaÕs aphasia. Unable to produce fluid speech, these individuals are nonetheless capable of singing in unbroken words. These observations indicate that music exists in a domain of processing distinct from that of language. There are also indications that music localized in a small area on the right hemisphere of the brain; individual with amusia, a temporal lesion on the right hemisphere of the brain lack the ability to distinguish tone, volume, prominence, duration, and timbre Ð the basic elements of music. [More accurately, certain areas of the right hemishpere are implicated in musical knowledge, although areas on the left side are also involved.]
The most fundamental unit of music is tonality; tones possess both a fundamental frequency and overtones (or harmonics). Humans seem to have a Òmusical grammar,Ó which allows them to distinguish between pleasing and unpleasing sequences of tones. There must be a set of standard intervals built into the human music processor. Evidence of this set includes the existence of musical chords that are universally accepted. The major triad Ð the combination of a base note, a major third, and a perfect fifth Ð is one example. Although music written with atonal scales exists, it sounds less natural to most audiences. Humans also seem to have preferred ways of grouping music into phrases. Not apparent in the way the music is written, humans appear to organize the music according to their internal representations of what they hear.
Humans organize sequences of tones into strong and weak beats. Repeated tones, relatively higher dynamics, increased duration, and sudden shift of pitch characterize strong beats. Humans posses an instinctive ability to predict rests and prominences in music; in a similar manner, people expect prominences in stress according to syntactic analysis of language.
Illustrating another parallel between language and music processing, humans exhibit the ability to ÒreduceÓ in both domains. Individuals represent both linguistic and musical phrases in a tree structure; each representation possesses a base or parent node, upon which the entire phrase structure is based. In the process of reduction, humans remove all but the base node of the structure. The basic character of a melody is retained Ð only detail is lost. One indication that this process actually occurs in the mind is the singing of young children; they often reduce a full melody into a simple sequence of notes. [Question: is musical reduction a performance issue or a property of the representational domain of music?]
There are individuals who possess math aphasia; they are unable to compare numbers, increment/decrement, and lack Òset theory.Ó From this evidence, we can assume that math occupies its own domain of processing.
The ways in which languages verbally communicate numbers depend on the base of the number system itself. The ÒbaseÓ is the number at which a language begins to use a rule to express the quantity Ð there is no longer a one-to-one correspondence between individual number words and quantities. In this way, a language can communicate an infinite number of quantities without an infinite number of words. Languages use a variety of multiplicative, additive, and subtractive methods to create these larger number words. Despite the existence of four to six thousand languages, there are only four or five different bases used throughout, such as 4, 10, 12, and 20. This universality in this choice indicates an innate tendency for humans to think in terms of certain bases.
Theory of mind is the possession of a representation of the internal mental states of animate objects; we have an idea of the beliefs, desires, and intentions of other humans. The fact that children are not explicitly taught this skill by their parents suggests that it is innate. One experiment which supports this claim involves showing young children an image of a smiley face with large eyes looking down and to the right; at the four corners of the image are pictures of popular candy bars. The children were asked which candy bar the smiley face wanted; most children beyond a certain age said that it was the one in the lower right corner.
[The issue here is: what is the conceptual organization of theory of mind TOM? The received view gors that TOM propceeds from goals, to desires to beliefs; this can be tracked in the way children use eye gaze to infer intentions of others.]
[Some studies of chimps (Povinelli) suggest that chimps lack TOM.]