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Steven Pinker was kind enough to publish a lovely introduction to the biological basis of morals, from discussion of evolutionary and philosophical foundations, to the analogy of the visual illusion in forming quirks in moral reasoning such as the following…

On your morning walk, you see a trolley car hurtling down the track, the conductor slumped over the controls. In the path of the trolley are five men working on the track, oblivious to the danger. You are standing at a fork in the track and can pull a lever that will divert the trolley onto a spur, saving the five men. Unfortunately, the trolley would then run over a single worker who is laboring on the spur. Is it permissible to throw the switch, killing one man to save five? Almost everyone says “yes.”

Consider now a different scene. You are on a bridge overlooking the tracks and have spotted the runaway trolley bearing down on the five workers. Now the only way to stop the trolley is to throw a heavy object in its path. And the only heavy object within reach is a fat man standing next to you. Should you throw the man off the bridge? Both dilemmas present you with the option of sacrificing one life to save five, and so, by the utilitarian standard of what would result in the greatest good for the greatest number, the two dilemmas are morally equivalent. But most people don’t see it that way: though they would pull the switch in the first dilemma, they would not heave the fat man in the second.

Link (NY Times)

Wong, Skoe, Russo, Dees & Kraus (2007) Nature Neuroscience. 10 (4): 420-422.
Abstract: Music and speech are very cognitively demanding auditory phenomena generally attributed to cortical rather than subcortical circuitry. We examined brainstem encoding of linguistic pitch and found that musicians show more robust and faithful encoding compared with nonmusicians. These results not only implicate a common subcortical manifestation for two presumed cortical functions, but also a possible reciprocity of corticofugal speech and music tuning, providing neurophysiological explanations for musicians’ higher language-learning ability.

I’ve been meaning to go over this paper for some time, after being first mentioned a few months ago. It’s a fascinating study for two reasons. Firstly, it shows that experience-related (music, in this case) plasticity in the auditory pathway is not necessarily specific to one class of stimuli. The musical experience gained by subjects in this study seems to have helped with their ability to perceive linguistic patterns. The more traditional view is that there is some sort of strict dichotomy between music and language, the most facile example being that music is right-brained and language is left-brained. The second reason why I find this study fascinating is that this effect was observed in the brainstem. That is, before the cortex — which is usually depicted as the highly flexible and dynamic organ responsible for learning.

The authors took a sample of musically-trained individuals and compared their Frequency Following Response (FFR) with that of controls when listening to pitch-differentiated Mandarin words. Mandarin is known as a tone-language, in that much of the information is conveyed in the pitch of the word. In this case, a /mi/ sound was used, which has three different meanings depending on whether a rising, dipping or level inflection is used.

The FFR, as you might imagine, reflects tracking of pitch in scalp-recorded potential, and is thought to originate from the Inferior Colliculus (a structure just before the thalamus, which serves as a relay station for most sensory information). Best demonstrated by the representative figures below:

Ah, representative figures. The grey line shows the change in frequency (pitch) of the dipping /mi/ sound, and the yellow line shows it being tracked by the FFR. Note that the musician was able to track the pitch of this (previously unfamiliar) Mandarin word, while his or her counterpart in the control group could not. The authors interpreted this as evidence that the musician brain more faithfully encodes pitch information. Representatives cases aside, Wong et al also demonstrated pitch tracking differences between groups, with the effect strongest in those who started musical training early and stuck with it for a long time. It’s worth noting that even though this response is observed prior to the cortex, it is probably still driving plasticity via top-down feedback.

The major implication of this research, hinted at in the abstract above, is that musical training can drive language development - something well worth considering when developing K-12 curriculum.