I think memories keep them emotionally stable as they are basically born adult...

Its so they dont go crazy and go on a killing spree. After all whats the point of living if you arent even real and have no clue what will happen after you die. They cant be brainwashed or programed for to long. Once they have contact with humans and other replicants they start to develop their own personalities and behaviors. False memories help them cope with everyday things.

@Invidia said:

Without MEMORIES they can't function as well.

TYRELL also explains that's the reason why he gives RACHEL the memories of his niece.

https://en.wikipedia.org/wiki/Blade_Runner

Bryant has Deckard meet with Eldon Tyrell so he can administer the test on a Nexus-6 to see if it works. Tyrell expresses his interest in seeing the test fail first, and asks him to administer it on his assistant Rachael. After a much longer than normal test, Deckard concludes Rachael is a replicant who believes she is human. Tyrell explains she is an experiment who has been given false memories to provide an emotional "cushion".

It's to keep her from freaking out by thinking that she's already HUMAN.

Without FEELINGS they have NO FEELINGS for others which also makes them DANGEROUS.

Without personalities the humans also can't relate to them ...

and whenever they hire someone like PRIS as a PLEASURE MODEL for HIRE ...

then they'd also essentially be having sexual relations with what amounts to a LIFE LESS BLOW UP DOLL ...

which would also not achieve the goal of getting PLEASURE from the OBJECT that you've HIRED to give you PLEASURE ...

which would most likely also not be a very PLEASUREABLE experience for you if the OBJECT that you hired has no personality.

Of course PRIS having a PERSONALITY also doesn't guarantee that you'd have a PLEASUREABLE experience with her either.

And K's HOLOGRAPHIC girlfriend also ends up needing the help of the other girl as a way to give PLEASURE to K.

OK, fair enough, I accept that emotions can be useful in certain situations - but it's not really a... solution, if you know what I mean - now they run the risk of becoming rogue.

Also, in the TV series - Humans the robots are depicted more realistically. As in they can follow orders, have directives (not to harm humans, etc.) but don't have feelings (by default - of course a scientist experiments with a certain code which eventually gives some of them self-awareness).

The replicants have emotions intrinsically, as they are bio-engineered humans... it's the memories which are implanted, in order to keep them emotionally stable and give them a desired context... Look at humans who have troubled childhoods and few good memories, it generally doesn't end well... They'll have emotions whether or not they have memories implanted.

On a related note, The Island, yes, the Michael Bay movie, [Spoilers] also explores a related concept where implanted memories and the story of the island are used to make the clones subservient...

They didn't build the replicants to have emotions on purpose. It was more like a design flaw they couldn't fix. So they tried to at least work around that flaw by giving them false memories to make them more stable.

@Invidia said:

Saw that movie a long time ago ...

and then read the WIKIPEDIA PLOT summary of it ...

but it doesn't mention anything about implanted memories.

[The Island SPOILERS] I think there is a brainwashing sequence where they project various images into the clones eyes... I can't remmber exactly so might be mistaken...