What is the purpose of adding non-gameplay elements to a game?

Question

As an example, I'll reference scientists in Jetpack Joyride.

I do understand there are achievements that involve scientists, that you can kill them or you have a nerd repellent, but I am not asking about any of those.

I want to understand whether there is any very important reason to have such an element in a game, since (at least initially) it seems quite insignificant.

More precisely, does the presence of scientists (or any equivalent, apparently insignificant "actor" in a game) has any psychological effect or influence of any kind to the players? Or they are simply there as a small little feature of the game that barely makes any difference to the player's feelings & attitude whilst playing the game?

Answer 1

There are a number of reasons for this:

1. To add to the environment. By far the most likely reason. Nearly every game has components that are not essential to gameplay. From NPCs going about their daily lives to birds flying around, all of these things add to the immersion for the player and increase the visual appeal of the game. This even goes as far as, why use an animated sprite for your game character? It's not important to the gameplay for the character to look nice is it?
2. It's for something you don't know about yet. Maybe later in the game, these non-essential elements are used for something else. Where it wouldn't make sense to have them appear right when you need them.
3. It was going to be a feature, but didn't get fully implemented. Perhaps the elements were part of a planned feature, but it wasn't finished.
4. The developer has a personal reason for adding it. Maybe it's a joke, or something they really like. The game is their canvas, they can add whatever they like.

Answer 2

Easter Egg effect: Plenty of games have implemented surprises in supposedly innocent and not important elements. Players usually try to find out if there is a 'second bottom' or it is just a decoration. Anticipation of unexpected makes game more interesting and sometimes... Non-gameplay elements turn-out to be vital to your mission.

Answer 3

1. It makes the world seem more real and convincing and less planned.
2. Paying attention to non-essential details shows that the developer put effort in.
3. More details means that there is more depth to observe which help replayability.

Consider the following: You go to a restaurant to order and eat a meal. However, restaurants may include bread on the table before your meal. They may include crayons for the kids. They might have a fish tank or paintings on the wall. The walls might be painted and floors might be carpeted. They might have a musician playing. None of these things are central to the reason you are there or help you achieve the goal of eating food, but they help your overall perception of the place be more complete. Knowing that the restaurant owner didn't do ONLY what they had to do makes you feel good!