Short answers, pulled from the story.
The practice of awarding bronze medals for third place began at the 1904 Olympic Games in St. Louis, Missouri. Before 1904, only first and second place were recognized with medals.
The obverse design used on Olympic medals from 1928 to 1968 was created by Florentine artist Giuseppe Cassioli. His design, which included text naming the host city, remained on the obverse in some form through the 2000 Games, when Athens commissioned a new design for 2004.
In those sports, two bronze medals are given per event, one for each eliminated semi-finalist or for winners of repechage brackets. The tournament structure means two athletes can legitimately claim third place without competing against each other.
The study found that bronze medalists were significantly happier with their result than silver medalists. Silver medalists felt more frustrated because they compared themselves to the gold medalist they had narrowly missed, while bronze medalists felt relief at receiving any honor over finishing fourth.
Bronze is traditionally the most common metal used for all types of high-quality medals, including artistic ones, not only competitive awards.
Jerry Seinfeld parodied the phenomenon in his special I'm Telling You for the Last Time, riffing on the counterfactual thinking study showing bronze medalists are often happier than silver medalists.