It's all coming together in-canon thanks to Star Trek: Lower Decks.
One of the oddest things about Star Trek: Strange New Worlds has been the way Spock seems to waffle back and forth from being the stoic we all know and love to a guy with a lot of emotions. This week, Strange New Worlds explained why that’s happening and put it all in context.
It happens in the episode “Those Old Scientists” (streaming early on Paramount Plus right now) when Boimler (Jack Quaid) and Mariner (Tawney Newsome) from Star Trek: Lower Decks (which takes place in Strange New Worlds‘ future) travel back in time and sho up in live-action on Star Trek: Strange New Worlds. Spock (Ethan Peck) laughs at something Boimler says, and Boimler freaks out because the Spock he knows isn’t emotional at all and he worries he has accidentally ruined the timeline.
Later, however, things get clarified for Boimler. He learns that Spock was acting like this before he arrived (which means it’s not something he’s caused) and then he talks with Spock and his new girlfriend Nurse Chapel about it.
Chapel and Spock’s discussions with Boimler make it clear that, really, this is just a phase. Spock is much younger in Strange New Worlds than he is in The Original Series. He hasn’t figured out who he is yet and is still trying to figure out his human side.
There’s some precedent for this. In the original Star Trek pilot “The Cage,” which takes place before the era of Captain Kirk, Spock can be seen smiling in several shots.
In the real world, Spock smiling in “The Cage” happens because they hadn’t figured out the character of Spock yet when they shot the pilot. Now that weirdness has been fully integrated into canon.
Yes, Spock is so emotional on Star Trek: Strange New Worlds that he has to play the Vulcan Lyre to calm himself down, but he’s young. It’s just a phase and Star Trek: Strange New Worlds isn’t trying to change the Spcok of the future we know, the Spock who buries his emotions and doesn’t shake hands at all.