Sign linguists routinely parse ASL sentences using the category ‘topic’, by which is meant a constituent on the left edge of the main clause, structurally separate from it, and marked by a discrete formal symbolic event, more fully brow raise + backward head tilt + pause, although brow raise is sometimes considered sufficient. This paper provides evidence confirming suspicions that these left-detached constituents need not be marked by brow raise, and suggests that brow raise is better regarded as signaling a type of momentary focus — thus explaining why sign languages tend to employ it as they do — and that it belongs to a larger set of ‘topic-marking’ devices whose iconicity remains active in day-to-day signing.