But behavior in the human being is sometimes a defense, a way of concealing motives and thoughts, as language can be a way of hiding your thoughts and preventing communication.

Maslow is warning against taking outward conduct—or even speech—at face value. Actions can function defensively: instead of expressing genuine needs, fears, or intentions, a person may adopt behaviors that protect the self from anxiety, shame, or vulnerability. By pairing behavior with language, Maslow extends the point beyond “body language” to everyday discourse: words can be used not to communicate but to obscure, rationalize, or misdirect. The implication is methodological as well as moral: anyone trying to understand people (therapists, teachers, researchers) must look past surface performances and attend to underlying motives, conflicts, and unmet needs that may be masked by socially acceptable behavior or fluent talk.