字幕表 動画を再生する 英語字幕をプリント Good music gets us grooving in no time. Our feet move with the beat, our hands clap with the drums and our hips sway the rhythm. We can't help it...but why? Why do we find ourselves busting a move when we hear music? Let's start at the beginning: the brain and how it perceives sound. When our ears perceive sound waves, they send this information to the auditory cortex in the brain. The auditory cortex decodes the information in the sound: its volume, pitch, frequency, and so on. For random and incoherent sound, what we call noise, the auditory cortex perceives it as such and pays no heed to it unless it causes us pain. But ordered periodic sound, or music, yields tickles the brain in interesting ways. You see, the auditory cortex is linked to many different parts of the brain: cognition, emotion, language, and movement. When we listen to music, all these regions light up; the motor regions allow us to bust a move and reward circuits secrete neurotransmitters and hormones that make us feel good. There is also evidence that dancing to music releases the body's natural pain killers making us more tolerant to pain. The additional fact music makes us reflexively dance is curiouser still. So, what's so special about dance and music? This points to a long evolutionary link of life with music, though why such a link developed in the first place is unclear. Some hypothesize that music began as small rhythmic beats, like tapping one's foot, maybe to scare away predators. We soon learnt to coordinate with others to create more complex rhythms. Synchronising with other people allowed us to create social bonds. Several archaeological sites have found musical instruments that date back as far as 42,000 years ago. For all this, it would be beneficial to have neural connections that help us sync with our group mates. This might help explain why we break out into our very own air guitar solos while listening to rock. Our brains probably think we're all part of the same orchestra. This coordination, at some point, resulted in dance. When we look deeper into the brain, on a cellular level, a special type of neuron might be the reason we can move to the rhythm so well. These neurons are called mirror neurons, and as the name suggests they mirror observation into actions. What this means is that these neurons are activated when we see someone else perform actions as well as when we perform that same action. In short, they help us copy. They've been implicated in our ability to dance. Many species of birds also dance to music. Research on Snowball, the cockatoo showed that the bird has choreography, 14 distinct moves to be precise. This indicates that other animals might also have neural connections that allow them to appreciate music. Besides social grouping, dancing might also have started a mating strategy. From birds to insects, animals dance to impress their mates. Scientists think it is a representation of the animal's fitness, or how good their DNA is. This propensity to dance and make music in groups has led scientists to propose that this might be one reason humans manage to form and remain in large groups or societies. Almost every society has a dance unique to its culture and we've found evidence that we've been dancing since we could first paint on walls. All things considered, dance is a pretty wonderful thing, and though we might not fully understand what's going on in the brain and body, it doesn't really matter as long as we can get groovy.