4-LS1-2: Senses, the Brain and Responses
Also called NGSS 4-LS1-2 · Topic: Structure, Function, and Information Processing · Life Science
The Official Wording
Use a model to describe that animals receive different types of information through their senses, process the information in their brain, and respond to the information in different ways.
Clarification statement: Emphasis is on systems of information transfer.
Assessment boundary: Assessment does not include the mechanisms by which the brain stores and recalls information or the mechanisms of how sensory receptors function.
NGSS Lead States, 2013 · Read it on nextgenscience.org · checked October 15, 2026
What 4-LS1-2 Means in Plain English
Fourth graders use a model, like a flowchart, to show how animals handle information. A sense organ picks up a signal such as light, sound or touch, nerves carry the message to the brain, the brain makes sense of it, and the body responds.
Students trace the path of the message without learning how memory works or how eyes and ears detect signals. This builds on structures and their jobs (4-LS1-1) and leads to how sensory messages shape behavior and memory (MS-LS1-8).
4-LS1-2 I Can Statements
- I can trace a message from a sense to the brain.
- I can explain how the brain decides on a response.
- I can give examples of animals responding to what they sense.
4-LS1-2 Worked Example
A partner test a class can run with one ruler to follow a message from the senses to the brain to the hand.
How quickly does a message travel from your senses to your brain to your fingers?
Set It Up: A 30-centimeter ruler for each pair and a recording sheet.
- One partner holds the ruler at the top. The catcher holds thumb and finger open at the zero mark.Fingers ready, not touching
- Without warning, the holder lets go and the catcher grabs the ruler.Caught at about 18 cm
- Repeat five times and record the centimeter mark at each catch.18, 16, 15, 14, 14 cm
- Now the catcher closes their eyes and the holder says “go” as the ruler drops.Catches using hearing instead of sight
- Draw the path for each test: sense, nerves, brain, nerves, hand.Eye or ear, brain, fingers
Every catch came after a short delay, so the ruler always fell a bit before the fingers closed.
Why it works: The eyes or ears sense the drop, nerves carry the message to the brain, and the brain sends a message to the hand to close.
Common Mistakes with 4-LS1-2
Skipping the brain
“My eyes told my hand to grab.”
Try this: The eyes only sense. Messages travel to the brain first, and the brain sends the signal that makes the hand move.
Thinking one sense works alone
Saying a dog finds food only by smell
Try this: Animals often combine senses. A dog may smell food, hear the bag rustle and see the bowl, and the brain puts these together.
Thinking every response is the same
“Animals always run away when they sense something.”
Try this: The brain picks a response to fit the message. An animal may run, freeze, eat, hide or come closer, depending on what it senses.
Where 4-LS1-2 Fits
Practice 4-LS1-2
Quick Check
- You hear your name and turn around. What happens in between?
- Which body part decides how to respond?
- Why does the ruler fall a little before you catch it?