using facial expresions are a good way to tell someone u are mad or happy. but sometimes u cant tell the diffrence unless people smile all the time. for instince when i walk i have a mean face that dosent mean im mad i could be happy but its just how my face is. u shouldnt need technology to tell someone if your happy ot sad all they gotta do is look at your face and they should already know if your mad or sad.

if the person isnt sure they should ask and see wether if your mad or sad. mona lisa smiling is just showing that shes happy or that she was happy while taking the picture. to be honest i think u can smile and feel something other than happiness. like when someone is mad and they smile just to seem like there happy.

i really dont get how u can calculate emotions like its an emoiton not a math question u either ask if the person is mad or sad or u just guess off the facial expressions. thats how i see it in my eyes itll be much easier to just ask then to do reasurch.

i think the smile should be used to show happiness people can be happy for just a moment then change there face which i understand i do it all the time. mad face should show if your mad. sad face should show that your sad. it shouldnt have to involve technology to find out how the person feels. mona lisa is a wonderful painting but i think she was happy in the picture because she smiled.