.This sense of duality is just a mere reflection of each other like the roots and the branch of the tree, or yin and yang. One exists because of its polar opposite.

So where emotions come from? For that, I give credit to the Romantic era in which music was really emotive of the human experience. Then soon thereafter when moving pictures came about people started to hear patterns in music that music composers use during scenes of a movie. That is a short answer as to why the emotions have been labeled. Though it is not factual that MAJOR = happy, it is important to understand the cultural influences and how that might develop a perspective. Going deeper into this emotional code... If a culture is mostly listening to what they consider "happy" music, does that mean they are seeking happiness with in music to fill a void? Or listening to music in MINOR because the culture has labeled it as "sad" because they want to find someone who is feeling the same pain as they might be feeling? 

Just to recap so far, we know that Major is a tonality and it might be popular because it is labeled "happy" by the misguided masses. The last theoretical piece is something called a "leading tone." This a note (or notes) that lead you into a direction toward home (resting tone). In a MAJOR tonality we have not one but two leading tones that lead us back home. Ti > Do and we also have Fa > Mi (which leads back to Do, or you can think of it as "arriving" harmonically Do "Mi" So). This makes it easier to hear where the tonality is moving toward. Other tonalities with less or no leading tones are more difficult to audiate and sing for example the Locrian tonality having a diminished tonic chord. Which is why most music people study when they are younger is in a MAJOR tonality. MAJOR should not be the only tonality in our musical lives. There are so many other flavors that actually help teach us more about the other tonalities. As humans, we learn what something is, by learning what it is not. 

“Making comparisons, knowing what something is not helps us to know what it is…. Imagine a whole world in which everything were purple: purple sky, purple water, purple grass and trees, purple food, everything. anything purple? Would we even coin the word ‘purple’? No, we wouldn’t need it. But imagine, in all that purple, you came across a single yellow flower…. All of a sudden, yellow and purple have meaning. What is purple? Everything that isn’t yellow. And now imagine a multicolored world in which our understanding of purple is dramatically more precise because we now have so much more to compare it with.”  (Bluestine, 2000, p. 69)

Final plausible answer... Perhaps because a MAJOR tonality has two leading tones, making it easier for the ear to navigate back home to the resting tone. There also seems to be a cultural influence (empasised in the romantic era, then re-articulated with film scores) of a happy emotion labeled to the MAJOR tonality, possibly using it to feel better, or mask a negative emotion? ... which leaves me with one more question... Are you feeling okay? Take a deep breath, explore nature and hug another human. 

Another possible speculation could be that the names of these tonalities (modes) are derived from ancient civilizations 1000 BC. and the sea that surrounded these civilizations was called the Ionian sea. Could this be a sacred metaphor for the popularity for this tonality?

Solution to getting out of the box...

Listen to diverse music with different kinds of tonalities. Build a speaking vocabulary in different tonalities. Then try to improvise and your own music in those tonalities. Finally, read and write in those different tonalities. 

If a culture only listens to two different tonalities (MAJOR / MINOR), how does that affect the way they see other cultures that use different tonalities more often? Here is a non-musical example of this phycological phenomenon... A man eats, nothing but Mac & Cheese for over 17 years. You would think he would get tired of it but he actually re-wired his brain through a selective eating disorder (also known as Avoidant/Restrictive Food Intake Disorder) which has created a negative response to other foods. You do not have to be a doctor to know that you can not thrive on just Mac & Cheese. So when it comes to music, open up your ears and enjoy all the colorful flavors of tonalities. Allow your ears travel the world and explore other sounds.  

Bluestien, E. (2000). The Ways Children Learn Music: An Introduction and Practical Guide to Music Learning Theory. GIA Publications. 

According to music learning theory, students first learn (after preparatory audiation AKA informal guidance) tonal patterns on a neutral syllable, then assign those tonal patterns to solfege. After this the next logical step is to show them what that looks like on standard western notation. Teachers who choose to use iconic notation to help "prepare" the students for standard notation might be trying to make up for students lack of audiation skills. 

"Trying to teach students to read notation with aid of pre-reading techniques, such as numbers, lines, dots, and creative pitcutres (often referred to as iconic devices), is a futher impediment to progress. Students learn to read and write notational symbols naturally and quickly when they audiate what they see using verbal associations. No other transitional scheme is neccesary." (Gordon, 2012, p. 110) 

When we use iconic notation, we might be using this as a crutch for the lack of ones ability to audiate. Gordon believed that tonal solfege is to be sung and rhythm syllables are to be chants... but not read. When we use a sign that says "Do Re Mi" and point to it as we sing, this is now shifting focus of the words and the sounds. The sounds (i.e. solfege) should followed by (when appropriately scaffold) standard notation. Keep it simple and just say, "this is what that looks like."

Now what about Cerwen hand signs? This is often used with a Kodaly methology and have their reasons for using them. It depends on "why" you would use them. If you want your students to audiate, they might be preventing them to do so. Lets say you are signing a tonal pattern "Do Mi So" and you also sign it. Then ask you students to replicate it. You are expecting your students to sing the solfege and shape their hand differently for each note. This asks for more thinking than just singing the solfege. 

I personally would find it more impressive if a student could recongize that is Major tonic pattern or could make up their own tonic pattern that is different from which you created. I would even find it more impressive if a student just sung "Do" (resting tone) in tune after I sung "Do Mi So" ... paused, then breathed with them to audiate and sing the resting tone. In my opinion, hand shapes are a mental hurdle for students and can potentially prevent them from audiating the context. 

One might say, well if you are in a choral setting and you want to give non-verbal cues while students move between solfege notes (as an exercise), wouldn't that be helpful? To that I would say, understanding of basic harmonic function would be more impressive. If my students understood the piece we are singing has a chord progression of [I IV V I], I would allow them to make their own choice on how to navitgate through these harmonies while I show them what chord we are on with my fingers. Or if they can hear the progression without my hands, then they can freely make that choice on their own. THAT is impressive and helpful for understanding the piece as a whole. I guarantee the melody with be dramatically more in tune. 

Again, I am not saying that these hands signs are "BAD or WRONG", it just depends on the reason "why" we use them. I personally would not use hand signs to help develop students' audiation. 

Gordon, E. (2012). Learning Sequences in Music: A Contemporary Music Learning Theory. GIA Publications.