How does one determine the effects of an aspect mask?

Question

Is the special ability granted by an aspect mask determined by the wearer's level or the creator's caster level?

The face-slot item aspect mask (6,500 gp; 2 lbs.) says that

This leather mask is vaguely animalistic, and is inlaid with various primitive designs. Three times per day on command, the wearer gains the benefit of a single aspect of an animal attuned to the mask, as if by the hunter's animal focus class feature. Each mask is attuned to one type of animal from the animal focus list, chosen when the mask is created.

Thus the the magic item aspect mask as a standard action for 1 min. can provide, chosen when the mask is made, but 1 of the following bonuses. These bonuses aren't listed in the aspect mask's description, and, instead, listed among the class features of the hunter.

• Bat: The creature gains darkvision to a range of 60 feet. At 8th level, the range increases by 30 feet. At 15th level, the creature also gains blindsense to a range of 10 feet.
• Bear: The creature gains a +2 enhancement bonus to Constitution. This bonus increases to +4 at 8th level and +6 at 15th level.
• Bull: The creature gains a +2 enhancement bonus to Strength. This bonus increases to +4 at 8th level and +6 at 15th level.
• Falcon: The creature gains a +4 competence bonus on Perception checks. This bonus increases to +6 at 8th level and +8 at 15th level.
• Frog: The creature gains a +4 competence bonus on Swim checks and on Acrobatics checks to jump. These bonuses increase to +6 at 8th level and +8 at 15th level.
• Monkey: The creature gains a +4 competence bonus on Climb checks. This bonus increases to +6 at 8th level and +8 at 15th level.
• Mouse: The creature gains evasion, as the rogue class feature. At 12th level, this increases to improved evasion, as the rogue advanced talent.
• Owl: The creature gains a +4 competence bonus on Stealth checks. This bonus increases to +6 at 8th level and +8 at 15th level.
• Snake: The creature gains a +2 bonus on attack rolls when making attacks of opportunity and a +2 dodge bonus to AC against attacks of opportunity. These bonuses increase to +4 at 8th level and +6 at 15th level.
• Stag: The creature gains a 5-foot enhancement bonus to its base land speed. This bonus increases to 10 feet at 8th level and 20 feet at 15th level.
• Tiger: The creature gains a +2 enhancement bonus to Dexterity. This bonus increases to +4 at 8th level and +6 at 15th level.
• Wolf: The creature gains the scent ability with a range of 10 feet. The range of this sense increases to 20 feet at 8th level and 30 feet at 15th level. The range doubles if the opponent is upwind, and is halved if the opponent is downwind.

Note that, if the effect of the aspect mask is creator-dependent rather than wearer-dependent, in at least 2/3 of these cases it's cheaper to buy an item granting a constant similar effect than it is to buy an aspect mask that provides an occasional, action-depleting effect.

Also note that I am well aware that some magic items are just terrible.

(The aspect mask is created at caster level 3rd--the minimum level at which a caster can take the feat Craft Wondrous Item--instead of 1st (the level at which the hunter gets the special ability animal focus) or 4th (the minimum level at which the druid gets wild shape, the alternative prerequisite for the aspect mask's creation), which seems a little weird. There's no price given for a greater aspect mask.)

Answer 1

It says the bonus “increases,” so I am pretty sure that is what it does

You do not typically see the word “increases” when referring to the effects of an item made at different caster levels. There is also, typically, a cost associated with that (as you say, a greater aspect mask would be what you would typically expect). Thus, I feel that “increases” is only appropriate if it is something that will change after the item has been made (otherwise it would never “increase” it would be just made at that bonus), and the only relevant “level” that’s going to change is the wearer’s character level.

That said, it’s hard to say for sure. It certainly doesn’t seem to come out and say so.

Answer 2

The bonuses depend on the CL of the mask and do not change.

Level-dependent powers of a magic item always depend on the caster level of the item, never the level of their wielder.

From Magic Item Descriptions:

Caster Level (CL): The next item in a notational entry gives the caster level of the item, indicating its relative power. The caster level determines the item's saving throw bonus, as well as range or other level-dependent aspects of the powers of the item (if variable). It also determines the level that must be contended with should the item come under the effect of a dispel magic spell or similar situation.

The only exception is staves, which use the caster level of the person holding them for spells cast from them. An aspect mask grants bonuses depending on the CL it was created at, which is 3 by default. A hunter of 8th level or above could craft a mask that grants the second tier of bonuses, and one of 15th level or higher could craft one that gives the highest bonuses, but a normal aspect mask is created at CL 3 and thus only gives the lowest tier.

There's no price for a greater aspect mask- that is, one that grants bigger bonuses- because such a mask is just a regular aspect mask at higher CL. You could estimate one using the table Estimating Magic Item Gold Piece Values, but it would vary widely depending on which animal the mask was attuned to; a face-slot enhancement to a physical ability score (from Bear, Bull, or Tiger) is obviously stronger than a bonus to Climb checks (from Monkey), and should be priced as such.