Subconsciously means happening below the level of awareness while you are awake and functioning — a subconscious bias. Unconsciously covers that too, but also means literally not conscious, as in knocked out. Only one of them can describe someone who has fainted.
The core difference
Overlapping in one sense, and only one has the medical meaning.
- subconsciously — below awareness, while awake: subconsciously copying her accent.
- unconsciously — the same sense, and also: not conscious at all: lying unconscious.
The clinical note
Unconscious has a precise medical meaning, which is why "unconscious bias" occasionally confuses people meeting the phrase for the first time. In psychology, Freud's unconscious is a specific theoretical concept, while subconscious is a popular term he largely avoided — so the words carry different weight depending on which tradition you are in.
Choosing
For influences below awareness, both work and unconscious bias is the established phrase. Where the reader might think of loss of consciousness, subconsciously avoids the ambiguity.
Frequently asked questions
Is subconscious the same as unconscious?
In everyday use, nearly. But unconscious also means not conscious at all, and in psychoanalysis the unconscious is a specific theoretical term.
Did Freud use the word subconscious?
He largely avoided it, preferring the unconscious. Subconscious is more a popular term than a technical one.
Which should I use for bias?
Unconscious bias is the established phrase, though subconscious would be understood.