>>5137902>>5149341>>5149612>>5142876It's best to know the rules so you know when and HOW to break them.
For the OP: While the OP is showing graphic design interpretations of shapes, there is some crossover in the psychology of character design. The description on the shapes is broad, but it helps to handle clients who want the graphic to mean more to themselves.
To pseudoscience: You're not wrong, but there is psychology in how we react to and perceive shapes on a basic level because of the characteristics of other things with similar shapes. Our brains are constantly trying to contrast and compare things to better define what we perceive and we end up making a bunch of connections that on the surface doesn't make any sense. Knife sharp. Knife hurt. Be careful of knife. Bad man say bad word. Bad word hurt. Bad word hurts like knife. Bad word sharp.
To discussion in general:
Subverting an expectation is a great way to make a memorable character, but that means their has to be an expectation to start with, and most expectations are visual since that communicates first.
Knowing psychology and how we interpret shapes, colors, words, and how they can stack in new and interesting ways is a useful tool.
TL:DR; Psychology is awesome. Shapes communicate more than you think. Know the rules and know when and how to break them. Remember that its all guidelines more than rules. Yar!