Trace Decay

In an interview, composer Ramin Djawadi spoke about the song "Reverie" by Debussy, that was used by Ford to calm a Host, when she was not responding to verbal commands. He said, "The music is being controlled, and it's being chosen for a reason".[2] Djawadi continued, saying, "The great power of music is that something subconsciously happens when you listen to a piece of music, even if you don't pay full attention to it. It just does something to us that nothing else can do, other than music."[2]

Amy Winehouse's "Back to Black" and The Animals's "House of the Rising Sun" are also featured in the episode.[2]

"Trace Decay" was viewed by 1.78 million American households on its initial viewing.[3] The episode also acquired a 0.8 rating in the 18–49 demographic.[3] In the United Kingdom, the episode was seen by 1.03 million viewers on Sky Atlantic.[4]

Thandiwe Newton received widespread acclaim for her performance and was nominated for Outstanding Supporting Actress in a Drama Series.

"Trace Decay" received highly positive reviews from critics. The episode has a 94% score on Rotten Tomatoes and has an average rating of 8.2 out of 10, based on 18 reviews. The site's consensus reads: "Providing its major characters rich layers of context, Westworld's 'Trace Decay' begins pulling together the elements of the park's origins and setting the stage for what is sure to be a thrilling conclusion."[5]

Terri Schwartz of IGN reviewed the episode positively, saying, "While Westworld didn't offer any true resolutions to some of its biggest questions, it teased them out in an interesting way and offered a lot more context to major characters like Maeve and the Man in Black."[6] She gave it a score of 8.7 out of 10.[6] Scott Tobias of The New York Times wrote in his review of the episode; "Thandie Newton has become Yul Brynner in the original Westworld, a robot hellbent on destruction, only infinitely smarter and more devious. Her liberation is the show's, too."[7] Zack Handlen of The A.V. Club wrote in his review, "With two episodes left in the first season, the action is pulling together and the stakes are rising, and yet elements crucial to our understanding remain withheld."[8] He gave the episode a B.[8]

Liz Shannon Miller of IndieWire wrote in her review, "We can't expect major twists every week, but while 'Trace Decay' didn't feel like it was stalling, it perhaps could have pushed things further. It's a minor complaint, though — a bump in the ride we're still enjoying."[9] She gave the episode a B+.[9] James Hibberd of Entertainment Weekly wrote in his review, "There are only two more episodes left, almost everybody has been captured, or in the process of being captured, and poor Bernard doesn't remember anything! How will it end?"[10] Ed Power of The Daily Telegraph wrote in his review, "For once it was worth paying attention as Westworld dropped further breadcrumbs regarding the park's origins and Bernard's role in its creation."[11] David Crow of Den of Geek said in his review, "The hour felt like a comedown, a slowing and re-calibration before the final two episodes presumably blow us all away as if we're a poor, dull-eyed sheriff walking away from Armistice while she has a rifle trained on our backside."[12] He gave the episode a 3.5 out of 5.[12] Erik Kain of Forbes also reviewed the episode, saying, "Where does it all go from here? I don't know, honestly. What I do know is that I can't wait to find out. Without doubt, Westworld is the best thing on TV right now."[13]