Researchers had students listen to brief audio clips of popular songs for only four-tenths of a second. Most participants were able to recognize the artist and song more than percent of the time.

50%

Explanation:

Most researchers have done various studies or research on a person's meditation. It depends entirely on the listening ability of the person who understands the specific audio. However, sound takes another part to reach a person’s auditory nerves and that person responds to it. A person notices is that after a few minutes there is a tendency to overreact to that particular scenario.  so in given competitors were able to identify the song and artist by more than 50%.

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

producing or giving rise torelating to or engaged in the production of goods, crops, or other commodities.

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.