What if we make all of the bodies the same size?
What do you think will happen?
Here are some possibilities:
- all the brains would also be the same size
- there would be no difference in the table before
- the more "intelligent" animals would have larger brains despite controlling for body size
What is your hypothesis?
Let's think about what we're doing... We're essentially "controlling for" body size by making all body sizes the same. In other words, we make all the animals' body sizes equal so that we can see if there are "true" differences in brain sizes. For example, to compare the brains of a dolphin and a squirrel we first need to determine whether a dolphin's brain is simply larger than that of a squirrel because the dolphin's body is overall much larger.