Listening to Andy Weir talk about eridians is so funny because fans are always talking about Rocky and Adrian as these “soft” adorable aliens but Weir won’t ever let us forget that their species are apex predators on their planet. Not like humans who became apex predators by inventing weapons, but natural top of the foodchain like lions or polar bears. So far I haven’t found an interview where Weir explains who ate eridians in the ancient past that caused them to watch over each other while they slept; another predator species or rivaling eridians.
Grace is joking around with a selectively violent creature that can rip his soft squishy body apart in an instant!
But it’s also a lot of fun to hear Weir talk about all the stuff he wants to include in a possible sequel, like the fact that eridians can have several conversations at once even with the same eridian. He imagine Rocky and Adrian bickering in one conversation while having a nice conversation at the same time that slowly turns into a fight and all of a sudden they’re yelling at each other in two conversations about different things.
He also says they have terrible spacial memory because they can see everything around them all the time thanks to their echo location so to them it’s crazy that humans can only see in one direction but still remember what’s behind them and even what the last room they were in looks like. Apparently eridians mostly just remember that the room exists and that it has the computer in it but if you asked them where the computer is placed in the room they’ll struggle to give a precise answer.
And Rocky got scared when Grace hugged him because eridians don’t have a concept of expressing affection with physical touch. To them it’s only neutral or violent because thanks to their hard shell they can’t really feel much. They only use it to move each other around or to break through their prey’s shell to get to the soft insides. So in their inter-species friendship only Grace would feel any desire to touch Rocky. It makes it very cute that Rocky joins in on Grace’s hugging ritual. It’s purely for Grace’s sake.
According to Weir eridians never had a reason to develop spacial memory because as soon as they enter a place they know where everything is, even if it’s behind something else, unlike humans who have to look for it. It reminds me of this video by a guy who has facial blindness.
He explains that humans have a part of our brain dedicated to remembering faces because we’re social creatures who need to remember friends and foes, but that part can be damaged despite our memory being perfect otherwise. The way Weir explains eridians memory it almost sounds like something akin to aphantasia but for spaces specifically. They never forget info but visuals are more wishy-washy. Thats why they know what’s in a room but they don’t know where it is if they’re not “looking” at it.
There’s definitely an argument to be made that eridians might feel differently about physical touch in the movie canon, especially because eridians lie on top of each other while watching each other sleep in the movie but watch from a distance in the book. But Weir explained in an interview that hugging is part of an exchange between Grace and Rocky. They do things for each other that makes the other happy despite not enjoying it themselves. Rocky let Grace hug him but would never ask Grace to do it, and Grace let Rocky watch him sleep but would prefer if he didn’t. They both know these things make the other happy and are an expression of care, trust and affection so they do it for each other.
Fist bumping is a different matter. It’s a lot less intimate and eridians touch hands all the time when passing objects between them. This is me speculating, but Rocky probably worked out pretty quickly that Grace use it to show friendship, teamwork and a job well done and who doesn’t want to be told they did well/let a friend know you appreciate their work? I used to have a coworker who, for some reason, would snap his fingers once in place of praising you. Snapping is usually an unpleasant sound to me, especially if someone is snapping at me, but I quickly came to appreciate it and would snap my fingers at him when he did well and it would put the biggest smile on his face. Intentions make all the difference.
