Costly Signaling: The Quest for a 90.0%

I remember that during my senior year of high school, there was some unofficial competition among friends to get the lowest final grade possible without ``Asian-failing." That is, to do as poorly as possible on graded assignments without getting the dreaded B+. The GPA cutoffs was set such that an A [93%, 100%] was a 4.0/4.0, A- [90%, 93%) was a 3.8/4.0, and B+ [87%, 90%) was a 3.3/4.0, so dropping from an A- to B+ is a much bigger deal than dropping from an A to A-. This game was certainly fun to play, but at that time I didn't understand the reasons that we participated.

It turns out that costly signaling could explain this phenomenon. Costly signaling, or the handicap principle, is a behavior that is costly for all groups, but more costly for the ``worse'' group than it is for the ``better'' group. In this case, better and worse are in terms of ability to do well in class and cost is the expected grade, which is related to the probability of sinking below 90% and the probability of being able to rescue a failure. I assume that the less smart kids have less control over their performance on assessments since they probably (1) can correctly answer fewer questions and (2) are more prone to make trivial errors.

Riskier variations include playing the game below senior year, during which grades are more valuable (since colleges will see them), or at MIT. I wonder how the brave souls at the Institvte would do, since the cliff between an A- (5.0/5.0) and a B+ (4.0/5.0) is massive.

In Times of Desperation

So, this morning, when I poured milk into my daily bowl of cereal, the milk ran out.

Because I can't live without milk¹, I headed toward La Verdes after my biology recitation² to buy a gallon of milk. When I finally found the milk shelf surrounded by a myriad of sodas, I saw the price. $5 for a gallon, $3 for half a gallon, and $2 for a quart. For sake of completeness, the Shaw's near Random House sells milk for approximately $4 a gallon.

Seriously?! The Costco near my house sells milk for $2.25 for a gallon. I can practically get four times the milk for the same amount of money at Costco than from here. So then I thought about the problem some more:

(Assuming that walking costs no money)

Therefore we choose La Verdes milk over Costco milk at this moment, but most definitely Costco milk over La Verdes milk when I have an entire list of food to purchase.

$$Q.E.D.$$

[1] I drink approximately 36 ounces a day; 12 ounces at each meal
[2] completely useless if you have a decent background in the subject or pay attention to the lectures and read the textbook