Sorcerer: Learning Lower Level Spell Rather Than Higher Level Spell?

[Balkoth]

Let's say you're a level 7 Sorcerer who gets three level 2 spells known and two level 3 spells known.

You can clearly cast a level 2 spell by using a level 3 slot.

Could you instead choose to learn four level 2 spells and one level 3 spell upon level up, though?

[Azothath]

Not in PFS or by CRB RAW.

Sorcerers CAN get a Page of Spell Knowledge to increase their daily selection of castable spells buuttt it gets expensive fast. Choose something non-combatish if possible to avoid some negative GM creative interpretation.

Sorcerers CAN change a spell known when they gain an even level at level 4 or above.

[Faenor]

If your sorcerer is human, the alternate favoured class bonus allows you to pick additional lower level spells each level. Not exactly what you're asking but could be handy.

[Dragonchess Player]

There is also the Expanded Arcana feat:

Advanced Player's Guide wrote:

Prerequisites: Caster level 1st, see Special.

Benefit: Add one spell from your class’s spell list to your list of spells known. This is in addition to the number of spells normally gained at each new level in your class. You may instead add two spells from your class’s spell list to your list of spells known, but both of these spells must be at least one level lower than the highest level spell you can cast in that class. Once made, these choices cannot be changed.

Special: You can only take this feat if you possess levels in a class whose spellcasting relies on a limited list of spells known, such as the bard, oracle, and sorcerer.

You can gain Expanded Arcana multiple times.

[Azothath]

Dragonchess Player wrote:

There is also the Expanded Arcana feat...

Expanded Arcana feat

for a feat you can get two lower level spells instead.

I think it is of academic interest as IMO it's a bad idea. Consider that you adding a first(1000GP) or second(4000GP) level spell through Page of Spell Knowledge, and a useful feat is worth about 5000-10000GP (based on ioun stones and Rods of Metamagic). There are also spells that can mimic the effects of lower level spells, those would be a better option.

Faenor wrote:

If your sorcerer is human, the alternate favoured class bonus allows you to pick additional lower level spells each level.

that's 1 hit point/skill point for an extra known lower level spell and that's a good deal.