IQ is a system that indicates the special abilities of a Pokémon, and the set of skills varies between different Pokémon species. It is increased by eating gummis, or by drinking something from Spinda's Cafe. If a gummi is eaten inside of a dungeon, or if using Spinda's Cafe, you could get a random stat raise by 1 to 3 points.
As a Pokémon's IQ increases, they learn a number of skills to help traveling in dungeons. Some species of Pokémon require a certain IQ before evolving.
While this game mechanic is named after the intelligence quotient, there is a difference between the two. When speaking to Alakazam or Noctowl in dungeons, they will mention their high IQ, regardless of how many points they have in the stat.
While the actual IQ points of a Pokémon is a hidden number, their level of IQ is represented through the number of stars in their summary. From this, it is possible to find out the approximate range of a Pokémon's IQ number.
The number of IQ points a Pokémon gains from each gummi depends on the type of gummi. Each is said to be preferred by a particular type. The relation of that type to the type of the Pokémon being given the gummi can be used to work out the amount of IQ points the Pokémon will gain:
Relation to type
IQ points gained
Matches Pokémon's type
Strong against Pokémon's type
Neutral against Pokémon's type
Weak against Pokémon's type
Ineffective against Pokémon's type
In the case of dual-types, this is calculated for both types individually with the two totals then being added together. Because of this, Pokémon with two types will increase their IQ at a faster rate than Pokémon with just one type. The effectiveness of a type against a Pokémon of the same type does not impact as the same type automatically gains the seven points in that case.
For an example, take a dual-type Water/Ground Pokémon such as Swampert. A Blue (Water) Gummi will add 11 IQ points as it is a Water type (+7) and Water attacks are strong against Ground Pokémon (+4). A Yellow (Electric) Gummi will add 5 IQ points as Electric attacks are strong against Water Pokémon (+4) and ineffective against Ground Pokémon (+1).
A Pokémon's IQ skills can be checked in the menu under each individual team member at any time in dungeons or friend areas. While there are a total of 23 skills, it is only possible to have twelve active at a time. While the five skills without a group can be active simultaneously, there can only be one active skill from groups 1-7 at any time.
The Pokémon can catch and hold a thrown item. It can't make a catch if it is already holding an item. It also can’t catch Seeds and drink items.
If this Pokémon has a foe targeted for a move or a thrown item, it will check first for walls and other Pokémon that may get in the way. It will stop if there is an obstacle.
In the case of linked moves, Course Checker will only check the first one. So if the combination is Growl + Razor Leaf, the Razor Leaf could still be wasted as it has more terrain limitations than Growl.
The Pokémon will focus on traveling. It will use moves and items less often.
As long as moving is an option, the partner will do so and not stop to attack any nearby pokemon.
The Pokémon will use or throw its hold item.
The main benefit of this skill is that it can be turned off to provide an extra storage space.
The Pokémon will only use moves. It will not use its regular attack.
This can be used in conjunction with the move menu to get the partner to use a particular attack.
The Pokémon will stop using linked moves that are on the verge of delinking. It also stops using moves with no PP left.
As it is possible to stop partners using a particular move, this can safely be switched with Exclusive Move-User when required.
When battling several foes, the Pokémon will first target Pokémon with the lowest HP.
As the weaker foes are likely to go down in one hit, this allows the leader to focus on the stronger ones without the annoyance of the attacks from the weakest.
If its target has a status problem, the Pokémon will not use moves that cause the same status problem.
If it becomes Confused or is Cowering, the Pokémon's wildly thrown attacks will not hit friends.
The Pokémon recovers faster from status problems.
Temporary status conditions will usually not last beyond 3 turns with this skill.
The Pokémon becomes better at evading attacks and moves.
The Pokémon's critical-hit rate is boosted when attacking foes with a type disadvantage.
When battling several foes, the Pokémon will first target Pokémon that have a type disadvantage.
The Pokémon often avoids stepping on visible traps.
Switching places with the partner when standing on a trap will not count towards Trap Avoider. Partners will also avoid Wonder Tiles.
The Pokémon resists sleep from traps and the moves of foes.
When battling several foes, the Pokémon will first target the Pokémon that are worth the most Exp. Points.
While all Pokémon in the team share the experience points, this will usually make the partner attack the stronger foes.
The Pokémon's Belly empties slower.
The Pokémon will avoid fiery lava.
Any non-fire Pokémon that can travel over lava (including through later IQ skills) will get the Burn condition on stepping over it. As they would normally do it without thought, this stops the problem.
The Pokémon gains the ability to walk on water, lava, and clouds.
The Pokémon's regular attacks never miss.
If the Pokémon is on an undiscovered trap, upon taking a step it will make the trap visible without setting it off.
Stepping on an exposed trap will still have an effect. In combination with Trap Avoider, the danger of traps practically disappears.
The Pokémon avoids monster houses.
While the partner will not wander into Monster Houses on their own, the leader can still activate them.
The Pokémon gains the ability to walk on water, lava, and clouds. It can also dig its way through walls.
Digging through walls with this skill does not increase belly consumption. Partners will tend to dig their own path so are better suited to All-Terrain Hiker.
All Pokémon that evolve by happiness in the main series require an increased IQ to evolve in Mystery Dungeon. The number of IQ stars required varies between species.
The moves Frustration and Return deal set damage depending on the IQ level. With no IQ points, Return does 5 HP damage while Frustration does 45 HP damage. At maximum IQ, these values are reversed. While they are weak attacks in Mystery Dungeon, Frustration is useful in Wish Cave, Joyous Tower and Purity Forest where the Pokémon's IQ level is temporarily reduced to 0 along with their level being temporarily reduced 1.
A select few Pokémon can learn special moves if their IQ is high enough:
In Explorers of Time and Darkness, Pokémon are split into 10 IQ groups (from A to J), which affects what types of IQ skills they will learn. What follows is a list of skills and which Group they belong to. Note that some IQ skills appear in more than one group, especially those which are learnt at the start. Also, unlike in the first games, every IQ skill can be turned on.
Prioritizes moving over using attacks or items.
Refrains from attacks that would be blocked by walls or allies.
Can use the Explorer Badge to leave the dungeon. Cannot be turned off.