I love data-driven analyses like this one Harvard Business Review did on logos. The top-level takeaway:

our research demonstrates (albeit with certain qualifications and under certain conditions), descriptive logos more favorably impact consumers’ brand perceptions than nondescriptive ones, and are more likely to improve brand performance.

Read the whole thing to understand exactly what they mean by “descriptive logos” and why they’re more effective. If you’re into this stuff, they’ve done similar surveys on simplicity vs complexity and symmetry vs asymmetry.