Dialogue

Dialogue in Mass Effect differs from BioWare's previous titles. Instead of the traditional dialogue choices, which show you every word of your response verbatim, you are presented with paraphrases of your available dialogue options on a "conversation wheel". For example, one choice may appear as "Don't try to study me," while the actual spoken line is "I'm not some artifact you can take back to your lab, doctor."

The conversation wheel was designed to be intuitive. The left side of the wheel is normally reserved for options that will continue the conversation in depth including Charm and Intimidate options (see below); occasionally an "Investigate" option is given in the middle, which allows Shepard to ask about multiple topics. The right side of the wheel is divided into three sections, and tend to move the conversation towards quicker completion. Paragon responses, generally more selfless or cooperative, are on the top segment, the middle segment presents a more neutral option, and Renegade responses, often more aggressive and hostile, are on the bottom segment.

Characters can also be influenced by the use of Charm or Intimidate. In the conversation wheel, Charm responses are blue while Intimidate responses are red. Use of those skills is affected by Commander Shepard's morality; if the Commander does not meet the Charm or Intimidate requirements, the options are greyed out. The harder a character is to persuade, the higher a level in the respective skills are needed.

Dialogue choices impact how others react to Shepard, the rewards for completing quests, possible discounts from merchants, romance paths and, most importantly, the commander's morality. It is also possible to defuse tense situations without violence, or actually provoke it.

Mass Effect
In Mass Effect, your ability to use Charm and Intimidate options in conversations is based on the Charm and Intimidate talents. Increasing these talents will allow you to meet more difficult Charm or Intimidate requirements, as well as providing additional benefits with vendors.

Charm
Charm is used in dialogue to persuade people with compliments, clever diplomacy, or a pleasant demeanor. Using Charm often encourages people to be more forthcoming or even willingly give extra rewards for assignments. In some cases, Charm can defuse tense situations and resolve them peacefully.

Paragon points increase the available ranks in Charm; you also get extra Charm points from becoming a Spectre. As you obtain more Charm points, additional dialogue options will become available and you can unlock the 'Store Discount' which gives lower prices when buying from merchants.

Using Charm to resolve an apparently impossible situation can unlock the 'Charismatic' achievement.

Players should note that in the course of working toward 75% Paragon, four of the 12 points you can assign to Charm can be obtained simply by playing the game. So, to effectively assign skill points, a player could assign only eight points for Charm and still max out their Charm skill once their character reaches 75% Paragon. Additionally, as skills carry over from each playthrough of the game, it's possible to max Charm without spending any skill points through multiple playthroughs. (Each time you become a Spectre, you'll get a free point, as well as each time you raise your Paragon bar to a certain level, since the Paragon bar resets for each playthrough.)

Intimidate
Intimidate is used in dialogue to browbeat people with coercion, insults or threats. Using Intimidate can frighten or threaten individuals into cooperating or handing over extra rewards for assignments.

Renegade points influence Intimidate and affect its advancement. You also get extra Intimidate points from becoming a Spectre. As you obtain more Intimidate points, additional dialogue options will become available. Maxing out this ability will also unlock 'Motivated Buyer'&mdash;this increases the yield (amount of credits earned) by selling items to merchants (i.e. they give you a better deal because they're afraid of you).

Again, using Intimidate to resolve an apparently impossible situation can unlock the 'Charismatic' achievement.

Players should note that in the course of working toward 75% Renegade, four of the 12 points you can assign to Intimidate can be obtained simply by playing the game. So, to effectively assign skill points, a player could assign only eight points for Intimidate and still max out their Intimidate skill once their character reaches 75% Renegade. Additionally, as skills carry over from each playthrough of the game, it's possible to max Intimidate without spending any skill points through multiple playthroughs. (Each time you become a Spectre, you'll get a free point, as well as each time you raise your Renegade bar to a certain level, since the Renegade bar resets for each playthrough.)

There is also an Easter egg with intimidate points. If you have enough intimidate points and you are adamant enough, sometimes the game will randomly generate in dialogue cues where you can choose (in red lettering because it's renegade) to fart, causing the one you are speaking with to become angry and grossed out. Afterwards you can force them to smell it at gun point which will acquire you bonus Renegade points. It is an incredibly rare instance though and can only be acquired through constant playing of the game. There is no known way as of present to force this Easter egg.

Mass Effect 2
Due to the large amount of gameplay changes in Mass Effect 2, the reworked skill system no longer has Charm or Intimidate as individual skills. Your ability to Charm/Intimidate is now tied to your morality level, gauged by how high your Paragon and Renegade scores are, and can be increased through Commander Shepard's class passive power or certain armor pieces or suits. Whether or not you can use a particular Charm or Intimidate option is based on how many of the available Paragon or Renegade points you've earned up to that point in the game, rather than the raw values. This is why sometimes Charm or Intimidate options can be used with less of the meter filled in one play through, but the next play through the same options are grayed out, but more of the meter is filled.

Mass Effect 2 introduces interrupts, which allow Commander Shepard to make a direct action during scenes or other characters' dialogue, typically providing some sort of benefit to the situation at hand. Rather than being selected through the dialogue wheel, interrupts are triggered through button prompts when the Paragon or Renegade icon appears at the bottom of the screen. Unlike Charm and Intimidate options, interrupts do not have any Paragon or Renegade requirements and can be triggered by any character when the option becomes available. Paragon or Renegade points are usually given whenever an interrupt is used. Interrupts are entirely optional, and in most situations not using the interrupt is not considered a moral choice (i.e. not using a Paragon interrupt is usually not considered a Renegade action).

Mass Effect 3
In Mass Effect 3, your persuasive ability ties into your Reputation meter. Rather than two completely separate meters for Paragon and Renegade, there is one meter with a blue Paragon bar and a red Renegade bar stacked together. Gaining Paragon or Renegade points will increase the size of the blue or red bar respectively, therefore increasing the total size of the Reputation meter. In addition to Paragon and Renegade points, you can also gain Reputation points from completing missions and conversations that increase the size of the Reputation meter while retaining the ratio of Paragon and Renegade points. Reputation can also be increased by evolving Commander Shepard's class passive power. Whether or not Charm and Intimidate options are available is based on the total size of the Reputation meter, rather than individual Paragon or Renegade totals, meaning that a pure-Paragon Shepard can still choose an Intimidate option if they have a high enough Reputation.

Interrupts also appear, largely identical to Mass Effect 2's interrupts. In addition to affecting events and awarding Paragon or Renegade points, some interrupts will award War Assets which contribute to the outcome of the final battle.

Mass Effect 3 also introduces arguments that Commander Shepard can overhear between two people with different views. The player can choose to have Shepard voice support for one of the sides by selecting the character they wish to agree with. Most arguments will impact War Assets, either providing a minor bonus or a minor reduction of the Asset's Military Strength rating depending on who Commander Shepard sides with. Siding with a character in an argument is entirely optional, and not voicing support for any side in an argument will not impact War Assets in any way.

Known Dialogue Issues

 * In Mass Effect, there are certain NPCs (Non Player Characters) that upon trying to initiate a conversation with them, or choosing a certain dialog option, the game cannot start the conversation or action as part of the conversation. This issue has been addressed in patch 1.02.
 * Skip Dialog and Select Answer are both mapped to the space-bar (PC), X button (X360), and Square Button (PS3) which can very easily result in choosing dialog options by accident.