Back to: Human Cognition – Teacher

 

 

Teacher Portal

← Back to Investigation 2
Preview Student Page

Investigation 2: Concepts

Launch Concept Slide Presentation

NAVIGATE

Once the slide presentation is launched

  • use your left and right arrows to advance or go back in the slide presentation, and
  • hover your mouse over the left edge of the presentation to get a view of the thumbnails for all the slides so that you can quickly move anywhere in the presentation.

Click on any image below to expand

Slide 1 — Human Cognition: Investigation 2

This slide introduces Investigation 2: Simple Information Processing. It reminds us that the brain is not only a physical organ but also the center of thought, memory, and decision-making. The images highlight several perspectives: a preserved brain specimen, a brain MRI, brain activity measured by fMRI, and a schematic of memory systems. Together, they emphasize that cognition is both biological and functional—what the brain is and what the brain does.

This Investigation will explore how the nervous system receives and processes information, with a focus on simple processing such as reflexes and basic sensory responses.

Discussion Questions and Answers:

  • Q1: What does this slide show?
  • A1: Different views of the human brain—an actual specimen, an MRI, an fMRI showing brain activity, and a diagram of memory systems.
  • Q2: Why do you think we are starting this unit with these images?
  • A2: To show that cognition can be studied from multiple perspectives—structure, activity, and function—all of which work together.
  • Q3: What do you notice about the difference between the specimen, scan, and diagram?
  • A3: The specimen shows the brain’s physical structure, the scans show it alive and working, and the diagram shows how scientists think the brain processes memory and information.
  • Q4: Why might the brain be the best place to start when studying human cognition?
  • A4: Because cognition—thinking, remembering, and decision-making—depends entirely on the brain’s structures and processes.

Slide 2 — The Human Brain

This image shows an actual human brain specimen. Notice its wrinkled surface, called the cerebral cortex, which provides increased surface area for billions of neurons. The folds allow for higher levels of information processing, from sensory perception to reasoning and planning. While the brain may look like a single organ, it is in fact divided into specialized regions that constantly communicate, allowing us to perform both simple reflexes and complex thought. In this investigation, we will examine how the brain’s physical design supports its extraordinary cognitive functions.

Discussion Questions and Answers:

  • Q1: What does this photo show?
  • A1: A real human brain, showing its wrinkled surface, called the cerebral cortex.
  • Q2: Why do you think the brain has so many folds and grooves?
  • A2: The folds increase the brain’s surface area, allowing far more neurons and connections to fit within the limited space of the skull and supporting more complex information processing.
  • Q3: How does this physical structure help explain human intelligence?
  • A3: More surface area and more connections between neurons allow us to think, plan, solve problems, and process information better than other animals.
  • Q4: What questions come to your mind when looking at a real human brain?
  • A4: Students might say: How does it store memories? How does it control emotions? How does thought turn into action?

Slide 3 — Nervous System

This slide introduces the two major divisions of the nervous system:

1. Central Nervous System (CNS)

  • Consists of the brain and spinal cord.
  • Acts as the body’s control center, where information is processed and decisions are made.
  • The brain handles higher functions like memory, learning, and reasoning.
  • The spinal cord coordinates simple, rapid responses like reflexes.

2. Peripheral Nervous System (PNS)

  • Includes all nerves that run to and from the CNS.
  • Nerves connect the CNS to the rest of the body — muscles, skin, and organs.
  • All peripheral nerves are attached either to the spinal cord or to the brainstem at the base of the brain.
  • Think of the PNS as the communication network that carries information back and forth between the CNS and the body.

Key Teaching Point:

This slide sets up the whole unit. Students should recognize that the CNS is the “command center,” while the PNS is the “messenger system” that links the body and the brain/spinal cord.

Discussion Questions and Answers:

  • Q1: What are the two main parts of the Central Nervous System?
  • A1: The brain and spinal cord.
  • Q2: What is the job of the CNS?
  • A2: To act as the body’s control center — processing information and making decisions.
  • Q3: What is included in the Peripheral Nervous System?
  • A3: All nerves that run to and from the CNS.
  • Q4: Where are peripheral nerves attached?
  • A4: They attach either to the spinal cord or to the brainstem at the base of the brain.
  • Q5: How could you describe the difference between the CNS and the PNS?
  • A5: The CNS is the control center, while the PNS is the communication system that connects the rest of the body to that center.

Slide 4 — Information Processing

This slide introduces two categories of information processing in the nervous system: Simple Processing and Complex Processing.

Left Side – Simple Processing

Examples include reflexes like the knee-jerk reflex or blinking, automatic responses such as sneezing or pulling your hand away from a hot stove, pupil dilation reflex, and basic sensory discrimination like detecting two touches on the skin during the two-point discrimination test.

  • Simple processing is fast, automatic, and often protects us by allowing rapid responses before conscious thought occurs.
  • They don’t require conscious thought.
  • This will be the focus of Investigation 2, where students will study reflexes and basic neurological exams.

Right Side – Complex Processing

Examples include decision-making (choosing how to solve a math problem), memory tasks (recalling what you studied), problem-solving and planning (deciding a strategy in a game), and higher-order sensory processing (interpreting a story, understanding language, recognizing faces).

  • These involve the cerebral cortex, require more time, attention, and prior knowledge.
  • This type of processing will be the subject of Investigations 3 and 4, where students will explore memory, learning, and higher-level cognition.

Key Contrast for Students:

Point out how simple processing keeps us safe through immediate, automatic responses, while complex processing allows us to think, learn, and plan at a higher level.

This distinction sets the stage for the rest of the Human Cognition Unit, moving from quick, protective responses in Investigation 2 to the deeper functions of the brain in Investigations 3 and 4.

Discussion Questions and Answers:

  • Q1: What is the main difference between simple and complex information processing?
  • A1: Simple processing is fast, automatic, and often handled by the spinal cord or brainstem. Complex processing involves the cerebral cortex, takes longer, and requires attention and prior knowledge.
  • Q2: Can you give an example of simple processing?
  • A2: Yes — reflexes like the knee-jerk reflex, blinking when something comes close to the eye, or pulling your hand away from a hot stove.
  • Q3: What about an example of complex processing?
  • A3: Deciding how to solve a math problem, recalling information for a test, or interpreting a story are all examples of complex processing.
  • Q4: Which type of processing will we focus on in Investigation 2?
  • A4: Investigation 2 will focus on simple processing — reflexes and basic sensory discrimination.
  • Q5: Which type of processing will we study in Investigations 3 and 4?
  • A5: Investigations 3 and 4 will focus on complex processing — memory, decision-making, problem-solving, and higher-level cognition.

Slide 5 — The Reflex Arc: Knee-Jerk Reflex

This slide shows the classic patellar (knee-jerk) reflex, an example of simple information processing. We can identify each of the five components of the reflex arc:

  • Receptor: The muscle spindle in the quadriceps detects when the tendon is tapped and stretched.
  • Sensory Neuron: The stretch signal travels from the receptor to the spinal cord through a sensory neuron (green).
  • Integration Center (Spinal Cord): In the spinal cord, the sensory neuron synapses directly with a motor neuron (red) — this is a monosynaptic reflex. At the same time, an interneuron (purple) sends an inhibitory signal to the neuron (blue) that normally activates the hamstrings.
  • Motor Neuron: The motor neuron (red) sends the return signal back to the quadriceps muscle.
  • Effector: The quadriceps muscle contracts, producing the lower leg “kick.”
  • Inhibitory Effect on the Hamstrings: To make the movement smooth, the spinal cord also inhibits the hamstrings (blue neuron). This is called reciprocal inhibition — while the quadriceps contract, the hamstrings relax, preventing them from resisting the motion.

👉 Teacher Note: Highlight how this reflex never needs to “wait” for the brain. The signal loop stays within the spinal cord, allowing the body to respond before conscious awareness occurs. The nervous system values speed when protection is more important than analysis. Then connect to the larger point: this is an example of simple processing in the nervous system.

Discussion Questions and Answers:

  • Q1: What part of the body detects the stretch when the knee is tapped?
  • A1: The muscle spindle in the quadriceps muscle acts as the receptor, sensing the stretch.
  • Q2: Where does the sensory signal travel first?
  • A2: The signal travels along a sensory neuron into the spinal cord.
  • Q3: Does the brain have to process this signal before the leg kicks?
  • A3: No — the signal is handled in the spinal cord integration center, making it a very fast reflex.
  • Q4: Which muscle contracts to cause the kick?
  • A4: The quadriceps muscle contracts, causing the lower leg to extend.
  • Q5: Why don’t the hamstrings resist this movement?
  • A5: At the same time, an inhibitory signal is sent to the hamstrings (the opposing muscles), making them relax. This is called reciprocal inhibition, and it ensures the reflex is smooth and effective.

Slide 6 — Other Examples of Simple Processing

This slide shows that not all reflexes look the same, but they all share the same feature: they are automatic, protective, and fast.

  • Shivery Reflex: The body’s automatic response to cold. Muscles contract rapidly to generate heat without conscious control.
  • Sneeze Reflex: A powerful, automatic clearing of the nasal passages. This protects the lungs from dust or irritants.
  • Withdrawal Reflex: Pulling the hand away from something hot or sharp. The spinal cord directs the action before the brain is even aware of the danger.

Key Point for Students:

Simple processing doesn’t need the brain to act first — the spinal cord and brainstem handle these responses quickly.

However, the brain does join in afterward. For example, if you touch a hot stove, your hand jerks back automatically, but your brain catches up and interprets it (“That was dumb!”). This helps students see the partnership between spinal reflexes and brain interpretation.

Discussion Questions and Answers:

  • Q1: What is the purpose of shivering when we are cold?
  • A1: Shivering causes rapid muscle contractions that generate heat, helping the body stay warm without conscious thought.
  • Q2: Why is sneezing considered a reflex?
  • A2: Because it’s an automatic response to irritants — it clears the nasal passages without us deciding to do it.
  • Q3: What makes the withdrawal reflex so important?
  • A3: It protects us from injury by pulling our hand away from something hot or sharp before we even realize the danger.
  • Q4: If the spinal cord can make your hand pull back from a hot stove, what role does the brain play?
  • A4: The brain notices what happened, interprets it, and uses the experience to guide future decisions and behavior.
  • Q5: How are all of these reflexes similar?
  • A5: They are all automatic, protective, and fast responses controlled by simple processing in the spinal cord or brainstem.

Slide 7 — Skin Receptors

This slide shows the different types of receptors in the skin that allow us to sense our environment. Notice that there are many kinds, each tuned to different signals:

  • Free nerve endings
  • Merkel disks
  • Meissner’s corpuscles
  • Ruffini endings
  • Pacinian corpuscles
  • Root hair plexus

You don’t need to go into detail about each one here — the main point is that the skin contains a variety of specialized nerve endings.

Also notice the compass at the top of the slide. Students will use a compass in Investigation 2 to perform the two-point discrimination test. This lab will help them see that receptor density is different across body regions, which explains why some areas (like fingertips) are more sensitive than others (like the back).

Key Idea: The skin is filled with specialized receptors, and we’ll use the compass to explore how their distribution affects sensitivity.

Discussion Questions and Answers:

  • Q1: What do all the receptors shown in the skin diagram have in common?
  • A1: They are all specialized nerve endings that detect different types of touch, pressure, pain, or temperature.
  • Q2: Why will we be using a compass in the lab?
  • A2: To test two-point discrimination — how close two touches can be before they feel like one, which depends on receptor density in that area of skin.
  • Q3: Why are fingertips more sensitive than the back?
  • A3: Because fingertips have many more receptors packed closely together, while the back has fewer receptors spread farther apart.
  • Q4: Why might some parts of the body need more detailed information about touch than others?
  • A4: Areas used for exploring, manipulating objects, communicating, and protecting ourselves often require more detailed sensory information.

Slide 8 — Sensory Homunculus

This slide shows the sensory homunculus, a map of how much brain area in the sensory cortex is devoted to different parts of the body.

Notice that the homunculus figure looks distorted: the hands, lips, and tongue appear very large compared to the arms, legs, or back.

This distortion shows that areas with high receptor density (lots of nerve endings, like fingertips and lips) take up more space in the brain.

Areas with low receptor density (like the back or thighs) take up much less space.

Key Idea: Sensitivity doesn’t match body size — it matches the importance of the body part for survival and interaction. Hands are crucial for tool use, lips and tongue for eating and speech, so they are represented as oversized.

This slide connects directly to the two-point discrimination test in Investigation 2. Students will discover that what they experience in the lab matches the homunculus map of the brain.

Discussion Questions and Answers:

  • Q1: Why does the homunculus have such big lips and hands?
  • A1: Because those body parts have many more sensory receptors, so they take up more brain area for processing touch.
  • Q2: Why are the arms, legs, and back much smaller in the homunculus?
  • A2: They have fewer receptors spread out over larger areas, so they are less sensitive and need less brain space.
  • Q3: What is the main message of the homunculus?
  • A3: Sensitivity is not about body size — it’s about the importance of a body part for survival, communication, and interacting with the world.
  • Q4: How does this connect to the two-point discrimination test you’ll do in lab?
  • A4: In areas with high sensitivity (like fingertips), students will feel two points very close together. In areas with low sensitivity (like the back), the two points must be farther apart.
  • Q5: What does the homunculus tell us about the way the brain processes information?
  • A5: The homunculus shows that the brain does not treat all information equally. It devotes more resources to the parts of the body that are most important for interacting with and understanding the world.
  • Q6: If the brain gives more attention to what matters most for survival and interaction, what kinds of things deserve our attention in everyday life?
  • A6: Students may give many answers. The key idea is that attention is limited, so choosing what deserves our attention is an important part of learning and good decision-making.

Slide 9 — Pupillary Reflex

This slide shows the pupillary light reflex, another example of a simple, automatic processing pathway.

When light shines into the eye, the pupil constricts to limit how much light enters.

In darkness, the pupil dilates to let in more light.

This reflex happens automatically and very quickly to protect the eye and help vision adjust to changing light.

Key Point: Even though it feels automatic, the pathway still involves both the peripheral nervous system (the sensory input from the eye and the motor signal to the iris muscles) and the central nervous system (the signal passes through the brainstem where it is processed before the motor command is sent back).

In the Lab: Students will perform this reflex test in Investigation 2 using a small flashlight, just as doctors do in a routine eye exam. They’ll observe the pupil’s quick response to light and notice how the reflex does not require conscious thought.

Discussion Questions and Answers:

  • Q1: What happens to the pupil when light shines into the eye?
  • A1: It constricts (gets smaller) to limit the amount of light entering the eye.
  • Q2: Which parts of the nervous system are involved in this reflex?
  • A2: Both the peripheral nervous system (eye receptors and iris muscles) and the central nervous system (the brainstem processes the signal).
  • Q3: Why is this reflex important for vision?
  • A3: It protects the eye from too much light and helps vision adjust quickly to different lighting conditions.
  • Q4: How will students test this reflex in lab?
  • A4: By shining a flashlight briefly into a partner’s eye and observing the pupil constrict.
  • Q5: Why would it be dangerous if the pupil did not respond automatically to light?
  • A5: Bright light could damage the retina, and vision would not adjust quickly enough when moving between bright and dark environments.

Slide 10 — Pupil Dilation: Pupillary Reflex

This slide shows how the pupils respond automatically to changes in light. In bright light (left), the pupil constricts to limit the amount of light entering the eye. In dim light (right), the pupil dilates to allow more light in. This is an example of an involuntary reflex controlled by the autonomic nervous system. The response travels from the eye to the brain and back, protecting vision and ensuring that the right amount of light reaches the retina.

Discussion Question and Answer:

  • Q1: Why would it be difficult to function if your pupils could not change size?
  • A1: Your eyes would not adjust properly to changing light conditions, making it difficult to see in bright sunlight or in dim environments.

Slide 11 — From Simple to Complex Processing

This cartoon is a great reminder that reflexes can protect us in the short term, but they don’t replace critical thinking. Cutting off the branch you’re sitting on is not something a reflex can fix — it’s a mistake of poor planning. That’s why the human brain’s ability for complex processing — problem-solving, memory, reasoning — is so important. Investigations 3, 4, and 5 will help us explore those higher-level abilities.

Discussion Questions and Answers:

  • Q1: Why wouldn’t a reflex save this person?
  • A1: Because this problem isn’t about an immediate danger — it’s about a failure to think ahead.
  • Q2: What kind of processing is needed to avoid this mistake?
  • A2: Complex processing — planning, reasoning, and thinking about the future.
  • Q3: Why is complex processing just as important as reflexes?
  • A3: Reflexes protect us in the moment, but complex processing helps us avoid dangers before they even happen.