It’s interesting, because I tend to trust a man with big ears.

Mo Rocca’s line reads as a wry, deliberately irrational “rule of thumb” about character—trusting someone based on a harmless physical trait. The humor comes from treating a superficial feature as if it were a reliable moral indicator, gently mocking the way people form snap judgments and personal superstitions about whom to believe. It also plays on the cultural association of “big ears” with attentiveness or good listening: the joke works because it half-suggests a plausible rationale (a person with big ears might “hear more,” and thus be more perceptive or honest) while remaining obviously unscientific. The effect is self-deprecating and disarming, inviting the audience to recognize their own quirky biases.