Tommy Hanusa's Game Design Blog: 2019

Voices of F.E.A.R.

Chances are if you are reading this article you already have a passing interest in the AI of Monolith Productions 2005 classic F.E.A.R. First Encounter Assault Recon. While FEAR is best described as a mid 2000s video game love-letter to imported asian cinema, it's mostly remembered for its horror thematics and Artificial Intelligence (although, I think there are other interesting things happening in this game too). Most of video game AI itself is about building the actions and reactions that an AI agent or NPC has and telegraphing those actions to the player. One of the most common ways to do this is through the sounds and ‘barks’ of the AI agent.

This blog post will take a look at sounds and barks used by AI agents to communicate with the player with a particular focus on FEAR, but comparing with other games as well.

Basic trends

There are some commonalities in most AI barks (including FEAR). They are short, often less than 3 seconds. They are often recurring; used/reused as reactions to the player often including whenever the AI agent changes state. They often contain multiple versions of the same line (3-5 seems most common) or they only play on a random roll (50% of the time when all conditions are met). Later systems tend to have ‘call and response’ barks. They don’t contain ‘plot’ information or critical narrative information (such as changes in the objective or an increase of dramatic steaks).

Essentially the barks are encounter oriented; and based on what an agent could say in a variety of likely situations. They are also targeted at human depicting AI agents, humans have a lot of different things to say while animals or aliens would not. However these other AI agents may not be expected to behave intelligently as more ‘human-like’ AI Agents.

Numbers

Agents in different games have different numbers of audio barks, FEAR (2005 - fps) has around 300-400 barks for their AI agents. Deus Ex (2000 - fps/rpg/is), Bioshock Infinite (2013 - fps/rpg), Splintercell: Blacklist (2013 - stealth action) has about 75-100 per agent, although it’s a little hard to determine due to the extraction method used. Neverwinter Nights has a little less than 50 barks (2002 - crpg) on its more advanced agents but leverages UI and other systems to communicate states. Doom 3 (2004 - fps) is on the extreme low end with ~30 or less audio barks for many of its AI agents.

An interesting point a reference is that there are ~35 hand signals for dismount operations in Training Circular (TC) 3-21.60, which is military manual on the proper hand signals to be used in wartime scenarios by the United States Armed forces. As this is information deemed critical enough to be communicated through hand signals, I think it’s worthy of study for anyone looking for a communication model. It should be noted that this TC was not available during the release of FEAR.

Differences in FEAR

FEAR distinguishes itself from the audio barks most obviously by number of barks it has, however the specificity of certain audio barks is also important. Most games use general terms in audio barks to denote location, but FEAR has a long list of very situational places terms. They also respond to possible player tactics and weapon with very specific terms. When the AI agents search for the player, they again have very specific location terms they can use. In addition to these specifics FEAR calls out player and agent tactics as most other games do. There seem to be general fall back audio barks for the specific instances as well, which are similar to what is seen in most games. However one difference is that the AI agents in FEAR also have some interaction options that other games don’t always give their agents.

It's important to note that one of the criticisms of FEAR was that its environments were very similar. It almost entirely took place in office blocks and warehouses. This meant that a lot of audio cues could be reused and certain locations like labs and offices were very common. Also, since the soldiers are ‘clones’ they can all sound the same with no variation in their voices. As far as enemy types involved in FEAR, there are only Replica Troopers (the AI agent analysed), Heavy Armor, Powered Armor, Assassins, Turrets, UAVs, Assassins, and Spectres appear in the game. This seems to be a little sparser than some games, but not by much.

But the counter point is that other games (and even FEAR itself) have enough space for voice lines with multiple characters using a large amount of audio barks. Bioshock:Infinite has 10 possible voice sets for some variations of it’s basic AI agents. So while 3-400 audio lines may seem excessive, it is likely no different as a size consideration as long as there are lines to say.

Voices of Fear Spreadsheet

I have collected and transcribed every general voice file used by the basic AI Agent in F.E.A.R. for analysis. I also made up some categories roughly based on how common I felt these audio barks would be played. The rough categories are (in order of possible frequency) interjection, multi, command, situational, specific item, armor*, turret* and hurt/death. Interjections are generally an audio bark of the AI Agent swearing. Multi are audio barks that likely fit a wide variety of situations, or those situations are going to be common. Commands are likely to be said the the AI agent and can be said at almost any time with little context. Situational audio barks are generally a response to a possible situation. Specific item is an audio bark that calls out something specific, generally a detail that keeps the audio bark from being used in many different scenarios. Armor and turret audio barks didn’t seem to fit well into the model and are related specifically to the Powered Armor and Turret enemy types (They could be categorized as Specific Items). Hurt/death are noises the AI agent makes when they die. Asterisks (*) generally denote me being unable to transcribe what is being said.

spreadsheet

Individual notes (appendix)

I don’t have time to break down of every title I looked at but I do want to make some comments about some particularly interesting facts that I found about the content of the audio barks. I think there are a lot of interesting things to take away.

Almost every game has some sort of vocalization to communicate the awareness that the AI agent has of the player. There is almost always an unaware and an aware state and audio barks that play during the transition between those.
Every game has particular callouts around mechanics, especially if those are specific states the the ai agent, the player, or objects. A notable example of this in Dishonored, where AI Agents patrolling a ‘wall of light’ will notice and mention if someone tampered with it. They may even notice if a player steals or otherwise moves their weapons.
Not many games do this but there is an audio bark for protecting ‘your commander’ in Dishonored. Some AI Agents organize into squads or have commanders or similar units. This is especially true if destroying these units can cause the squad to panic.
The AI Agents of Half-life 2 are known for being hard to understand, with heavily ‘radio filtered’ voices and coded terms. This is often cited as a reason the AI is lackluster.
All AI agents say something before they throw a grenade, but in Splinter Cell: Blacklist they tend to also say why type of grenade they will throw.
Splintercell: Blacklist has lots of non-specific dialog for its AI agents, however it does make some exceptions for the player being in vents or for the player being above the AI agents.
Bioshock infinite’s AI Agents and Audio barks seemed to follow the following states as per their files (* denotes optional). The method of extraction has made it difficult to get named audio files from most games.