Do mental speed and musical abilities interact? 
The relation between mental speed and musical ability was investigated.  Seventeen subjects aged 3-7 years were divided into two subgroups: one (G1; n = 9) consisted of children who participated in an early childhood music program and who received informal musical guidance, but no special training; the other (G2; n = 8) consisted of highly talented young violin players who received intensive parental support and special training by daily deliberate practice.  Mental and musical abilities of both groups were controlled by standardized tests (Kaufman's ABC and Gordon's PMMA) and compared with data taken from recordings of saccadic eye movement using online identification from an electrooculogram (EOG).  Results of EOG measurement are referred to as "mental speed," which correlates highly with general mental abilities (intelligence).  These results were compared with EOG scores taken from a larger sample of children of the same age range (n = 82) who received no music instruction.  The grand average of their scores served as a reference line for mental speed, which is normally expected to be performed by an equivalent age group.  Data in the two experimental groups did not differ statistically; however, all musically experienced children had a highly significant advantage in mental age (P <0.01) compared to the reference line of the normal population who did not exhibit any effect of training and practice.  This indicates strong interaction between mental speed and music ability, which can be interpreted in terms of the expertise model and cognitive transfer effects.