This is not my work, just copy/pasted from https://techraptor.net/gaming/guides/sapiens-investigation-and-breakthrough-guide for ease of use for myself, thought maybe others might find it usefull so here we are.


Fire Lighting Unlocks

Campfire
Torch

How to Unlock Rock Knapping in Sapiens

You can unlock Rock Knapping by Investigating a Rock.
Rock Knapping Unlocks

Small Rock
Stone Hand Axe
Stone Knife
Stone Spear Head
Stone Pickaxe Head

How to Unlock Basic Hunting in Sapiens

You can unlock Basic Hunting by Investigating a Chicken with a Small Rock Tool.
Basic Hunting Unlocks

Allows you to hunt small prey like Chickens.

How to Unlock Thatch Building in Sapiens

You can unlock Thatch Building by Investigating Hay.
Thatch Building Unlocks

Thatch Hut/Roof
Thatch Square Wall
Thatch Roof Wall
Thatch Wall with Door
Large Thatch Roof Corner
Thatch Wall
Thatch Wall Single Window
Large Thatch Roof
Thatch Short Wall"

How to Unlock Pottery in Sapiens

You can unlock Pottery by Investigating Clay.


Pottery Unlocks

Mud Brick
Unfired Urn

How to Unlock Butchery in Sapiens

You can unlock Butchery by Investigating a dead Animal with a Knife.
Butchery Unlocks

Butcher Alpaca
Butcher Chicken
Butcher Mammoth

How to Unlock Flax Spinning in Sapiens

You can unlock Flax Spinning by Investigating Dry Flax.
Flax Spinning Unlocks

Flax Twine

How to Unlock Tree Felling in Sapiens

You can unlock Tree Feeling by Investigating a Tree with a Hand Axe.
Tree Felling Unlocks

Allows you to cut down Trees.

How to Unlock Digging in Sapiens

You can unlock Digging by Investigating the ground with a Hand Axe.


Digging Unlocks

Ability to dig up the ground.
Clay Path
Rock Path
Sand Path
Soil Path

How to Unlock Bone Carving in Sapiens

You can unlock Bone Carving by Investigating a Bone with a Knife.
Bone Carving Unlocks

Bone Knife
Bone Spear Head
Bone Flute

How to Unlock Flint Knapping in Sapiens

You can unlock Flint Knapping by Investigating a piece of Flint.
Flint Knapping Unlocks

Flint Spear Head
Flint Hand Axe
Flint Knife
Flint Pickaxe Head

How to Unlock Wood Working in Sapiens

You can unlock Wood Working by Investigating a Log after you've felled a Tree.
Wood Working Unlocks

Split Log
Log Drum

How to Unlock Threshing in Sapiens

You can unlock Threshing by Investigating a piece of Wheat.
Threshing Unlocks

Quern Stone
Hulled Wheat

How to Unlock Basic Cooking in Sapiens

You can unlock Basic Cooking by Investigating a Beetroot, Pumpkin, Chicken Meat, Alpaca Meat, or Mammoth Meat with a lit Campfire.
Basic Cooking Unlocks

Campfire Roasted Beetroot
Campfire Roasted Pumpkin
Cooked Mammoth Meat
Cooked Alpaca Meat
Cooked Chicken Meat

How to Unlock Tool Assembly in Sapiens

You can unlock Tool Assembly by Investigating either a Branch, Flax Twine, or a Tool Head (Hand Axe, Spear Head, etc.) after having Investigated Flax Spinning.
Tool Assembly Unlocks

Stone Hatchet
Balafon
Stone Spear
Stone Pickaxe
Flint Spear
Bone Spear
Flint Pickaxe
Flint Hatchet

How to Unlock Wood Building in Sapiens

You can unlock Wood Building by Investigating a Split Log.
Wood Building Unlocks

Split Log Hut/Roof
Split Log Bench
Split Log Wall with Door
Split Log Floor 4x4
Split Log Wall with Large Window
Split Log Wall
Split Log Steps 2x2 Half Floor
Split Log Roof Wall
Split Log Square Wall
Split Log Floor 2x2
Split Log Steps 2x3 Single Floor
Split Log Short Wall

How to Unlock Planting in Sapiens

You can unlock Planting by Investigating any Farming Crop with a Hand Axe.
Planting Unlocks

Allows planting of Crops.

How to Unlock Music in Sapiens

You can unlock Music by Investigating a Log Drum, Bone Flute, or Balafon.
Music Unlocks

Ability for Sapiens to play Music.

How to Unlock Grinding in Sapiens

You can unlock Grinding by Investigating Hulled Wheat with a Quern-Stone.
Grinding Unlocks

Flour

How to Unlock Mud Brick Building in Sapiens

You can unlock Mud Brick Building by Investigating a Dry Mud Brick.
Mud Brick Building Unlocks

Mudbrick Floor 4x4
Mudbrick Floor 2x2
Kiln
Mudbrick Column
Mudbrick Wall
Mudbrick Square Wall
Mudbrick Wall With Door
Mudbrick Half Wall
Mudbrick Wall with Large Window

How to Unlock Spear Hunting in Sapiens

You can unlock Spear Hunting by Investigating an Alpaca or Mammoth using a Spear.
Spear Hunting Unlocks

Ability to hunt large Animals like Alpaca and Mammoth.

How to Unlock Mining in Sapiens

You can unlock Mining by Investigating a Boulder with a Pickaxe.
Mining Unlocks

Allows you to Mine Boulders.

How to Unlock Baking in Sapiens

You can unlock Baking by Investigating Flour with a lit Campfire.
Baking Unlocks

Flatbread
Bread Dough

How to Unlock Ceramics in Sapiens

You can unlock Ceramics by Investigating an Unfired Urn with a lit Kiln.
Ceramics Unlocks

Fired Urn
Unfired Tile
Brick
Tile

How to Unlock Brick Building in Sapiens

You can unlock Brick Building by Investigating a Fired Brick.
Brick Building Unlocks

Brick Half Wall
Brick Wall
Brick Square Wall
Brick Wall with Door
Brick Wall with Large Window

How to Unlock Tiling in Sapiens

You can unlock Tiling by Investigating a Tile.
Tiling Unlocks

Tile Floor 2x2
Tile Hut/Roof
Tile Path
Tile Floor 4x4