1. Begin by asking students, “What is learning?”

Many responses are possible. Students will probably respond that learning is the way they know things. This answer is acceptable at this time.

2. Continue by asking, “Where does learning occur?”

Students should recognize that learning occurs in the brain.

3. Ask the class, “What affects learning?”

Student responses will vary and may include such factors as the size of the brain, the food we eat, and whether we practice. Record all responses on the board. These responses provide an opportunity for informal assessment of students’ understanding. In the discussion at the end of the lesson, students will recognize they have evidence that practice affects learning.

4. Ask students, “How can scientists determine whether these factors affect learning?”

Remind students that to conclude that a factor can affect learning, scientists need evidence obtained through observation and experimentation. Their conclusions must be verified by repeated tests. Explain to students that for the rest of the lesson, they will explore the effect of several factors on learning in mice by designing and analyzing their own experiments.

5. Organize students into pairs. Number pairs sequentially beginning with 1. Explain that the pairs are research teams at the Learning Research Laboratory.
6. Display a transparency of Master 4.1, Memo from the Director. Ask students to follow along as you read the memo to the class.

The memo from the director describes a research grant given to the fictitious Learning Research Laboratory. Students play the role of research scientists who design and analyze experiments to answer three research questions. Students investigate Research Question 1 in Activity 1 and Research Questions 2 and 3 in Activity 2.

7. Direct student attention to Research Question 1 from the director’s memo (Does social interaction affect learning in mice?). Ask students to raise their hands if they think social interaction has an effect on learning.

Students may disagree about the effect of social interaction on learning. This is acceptable; it is unlikely that students have any knowledge on which to base their opinion. This question is meant to stimulate student thinking about Research Question 1 and serves as a lead-in to, “Let’s investigate.”

8. Give each team a copy of Master 4.5(a, b, c), Scientific Research Reference Manual.

Explain that the reference manual contains essential information for conducting research on learning. Point out several sections of the manual that are important for the students’ investigations, such as the sections on the Morris Water Maze (the test of learning used in the experiment), raising mice, writing hypotheses, and drawing conclusions.

Tip from the field test: Introducing the reference manual before students start working emphasizes the importance of this resource and encourages students to use this information to help them complete the activity.

9. Tell students that a lab technician has completed an experiment to answer Research Question 1. Display a transparency of Master 4.6, Memo from Lab Technician. Ask students to follow along as you read the memo out loud.

The memo includes a model of the experimental design page students will use in Activity 2.

Tip from the field test: After reading through the memo, spend some time discussing the hypothesis. Distinguish the hypothesis from the research question. First, note that the hypothesis is a statement, not a question. Second, the hypothesis predicts a specific answer to the research question. The prediction is based on what the researcher already knows about the situation. Third, and most important, the hypothesis is testable; that is, it suggests a way to test whether the prediction is accurate. In this example, the hypothesis (Socialized mice learn more quickly than isolated mice) suggests that researchers test and compare learning in socialized mice with learning in isolated mice.

10. Display a transparency of Master 4.7, Morris Water Maze Data, Research Question 1 (Print Version). Give each team one copy each of Master 4.3, Morris Water Maze Results (or have students use their own graph paper), and Master 4.4, Memo to the Director on Research Question 1. Direct teams to

• average the data provided on Master 4.7 for each set of mice,
• construct a line graph using the data averages (on Master 4.3 or their own graph paper), and
• fill in the blanks on Master 4.4.

Encourage teams to use the Scientific Research Reference Manual as a guide as they work through their investigation.

The data on Master 4.7 represent the time it took for each mouse to reach the hidden platform in the swim tank of the Morris Water Maze. Students should calculate the average time it took each set of mice to reach the platform each day. You may want to ask students to round their answers to the nearest whole number.

Students should plot their averaged data as line graphs on Master 4.3 or their own graph paper. The averages for the Isolated mice and the Socialized mice should be plotted on the same graph, using different colors, symbols, or types of lines (unbroken and dashed, for instance) to distinguish data from the two sets of mice. Students should title their graph and create a legend by identifying which line corresponds to each data set.

Assessment:
Listening to student presentations allows you to assess students’ abilities to analyze data, create graphs, and draw conclusions. You can collect students’ completed Masters 4.3 and 4.4 for a more formal assessment.

Allow about 25 minutes for students to calculate averages, create graphs, and complete the memo to the director.

11. Reconvene the class. Ask different student teams to share their graphs, their answers to the questions on the memo, and their conclusion(s) about learning.

Encourage teams to challenge the graphs, answers, and conclusions of their classmates based on the results of the experiment. Students should interpret a decrease in times to platform on the Morris Water Maze test to mean that learning occurred. Since all mice decreased their times to platform over the three days of the experiment, all the mice learned. However, the mice raised in social conditions learned more rapidly than the mice raised in isolated conditions. Therefore, students should conclude that the data support the hypothesis: Socialized mice learn more quickly than isolated mice.

1. Organize students into their research teams from Activity 1. Display a transparency of Master 4.12, Next Research Assignment. Read this memo to the class.

Master 4.12 is a memo from the director assigning even-numbered teams to conduct an experiment to answer Research Question 2 (Does an enriched environment affect learning in mice?) and odd-numbered teams to conduct an experiment to answer Research Question 3 (Does exercise affect learning in mice?).

2. Give each team a copy of Master 4.13, Experimental Design. Make sure each team has a copy of Master 4.5(a, b, c), Scientific Research Reference Manual.
3. Instruct teams to complete Master 4.13 by writing their research question, writing a hypothesis, and selecting two sets of mice that are appropriate for testing their hypothesis.

Remind students that the reference manual provides advice for developing a hypothesis and selecting research subjects. Also remind them of the discussion about hypotheses in Activity 1. Hypotheses are statements that predict an answer to the research question. In addition, hypotheses are testable; that is, the statement of a hypothesis suggests a way to test whether the prediction is accurate.

Four sets of mice (Standard Cage, Standard Cage with Running Wheel, Enriched Cage, and Enriched Cage with Running Wheel) are available to students. Students should select the two sets they believe to be appropriate for testing their hypothesis.

Assessment:
Circulate among student groups. Ask questions to assess students’ understanding of control and experimental groups and their ability to select two appropriate conditions to test their hypotheses.

Examples of hypotheses for Research Question 2 (Does an enriched environment affect learning in mice?) include Enriched cage mice learn faster than standard cage mice and Mice in standard cages with running wheels learn faster than mice in enriched cages with running wheels. Encourage students to develop specific hypotheses that predict a result they can test through their experiments.

Two combinations of mouse data sets can be used to test hypotheses for Research Question 2. Students may either

• compare data from Standard Cage mice with data from Enriched Cage mice or
• compare data from Standard Cage with Running Wheel mice with data from Enriched Cage with Running Wheel mice.

Either of these combinations will allow students to evaluate enrichment as the only variable.

Examples of hypotheses for Research Question 3 (Does exercise affect learning in mice?) include Mice who exercise learn faster than mice who do not exercise and Mice in standard cages with running wheels learn faster than mice in standard cages without running wheels. Encourage students to develop specific hypotheses that predict a result they can test through their experiments.

Two combinations of mouse data sets can be used to test hypotheses for Research Question 3. Students may either

• compare data from Standard Cage mice with data from Standard Cage with Running Wheel mice or
• compare data from Enriched Cage mice with data from Enriched Cage with Running Wheel mice.

Either of these combinations will allow students to evaluate exercise as the only variable.

4. Display a transparency of Master 4.14, Morris Water Maze Data, Research Questions 2 and 3 (Print Version), which contains data for all four sets of mice.

Instruct students to average the data for the two sets of mice they chose on Master 4.13, Experimental Design. You may want to ask students to round their answers to the nearest whole number.

5. Give each team a new copy of Master 4.3, Morris Water Maze Results, or ask students to take out a new sheet of graph paper. Ask teams to graph their averaged data following the same procedure as they did in Activity 1.

Students should plot the averages as line graphs on Master 4.3 or their own graph paper. The averages for both sets of mice should be plotted on the same graph, using different colors, symbols, or types of lines (unbroken and dashed, for instance) to distinguish data from the two sets of mice. Students should title their graph and create a legend by identifying which line corresponds to each data set.

6. While teams prepare their graphs, give each even-numbered team a copy of Master 4.9, Memo to the Director on Research Question 2, and each odd-numbered team a copy of Master 4.10, Memo to the Director on Research Question 3. Ask teams to complete the memos by using the results of their experiment.

Move among the teams during this time, answering questions and making suggestions as necessary. Point out that the reference manual provides guidance for analyzing data and drawing conclusions from graphs. Allow about 25 minutes for students to calculate averages, create graphs, and complete the memo to the director.

7. When students have completed their data tables, graphs, and memos, pair odd- and even-numbered teams and tell them to share their results with each other. Encourage teams to challenge their partner team’s conclusions if those conclusions are not supported by the data.
8. Reconvene the class and display Master 4.11, Summary of Research Findings. Ask students to summarize their conclusions about learning from the three experiments by providing evidence-based answers to the three research questions.

Use this as an opportunity to assess student understanding of experimental results.

For Research Question 1, students should explain that the data from the experiment indicate that mice from a social environment learn more quickly than do mice from an isolated environment. Thus, the data support the hypothesis: Socialized mice learn more quickly than isolated mice.

Assessment:
Listening to student presentations allows you to assess students’ abilities to analyze data, create graphs, and draw conclusions. You can collect students’ completed memos and graphs for a more formal assessment.

For Research Question 2, the data gave mixed results. Teams that compared Standard Cage mice with Enriched Cage mice found that on Day 2, Standard Cage mice appear to be learning more quickly than Enriched Cage mice. By Day 3, Enriched Cage mice appear to be learning more quickly than Standard Cage mice. Teams that compared Standard Cage with Running Wheel mice with Enriched Cage with Running Wheel mice found that the Standard Cage with Running Wheel mice outperformed the Enriched Cage with Running Wheel mice on both Day 2 and Day 3. Encourage students to identify whether their team’s data support or do not support the team hypothesis.

For Research Question 3, students should explain that the data from the experiment indicate that mice from a cage with a running wheel learn more quickly than do mice from a cage without a running wheel. Encourage students to identify whether these data support or do not support their team’s hypothesis.

9. Display the transparency of Master 4.3, Morris Water Maze Results, that you prepared with averaged results from all four sets of mice plotted on one graph. Ask students to interpret their results in the context of data from all four sets of mice.

For ease of student interpretation of results, clearly label each line of the graph and use different colors for each line. You may need to ask guiding questions, such as, “How does the performance of mice from an enriched cage compare with that of mice from a cage with a running wheel?” or “Does having a running wheel improve the performance of mice raised in an enriched cage?”

Students should notice that mice from a standard cage with a running wheel learn more quickly than mice from either an enriched cage or an enriched cage with a running wheel. These results are somewhat unexpected, since it might seem that the stimulation of an enriched environment would do more to improve learning ability than wheel running would. In addition, it may seem strange that mice in a standard cage with a running wheel would perform better than mice in an enriched cage with a running wheel, since there seems to be less stimulation for the mice in the standard cage.

10. Ask students to propose explanations for these findings. How would they test their explanations?

Student explanations will vary; any reasonable explanation is acceptable. Some possible explanations include that the mice were distracted by the enriched environment instead of stimulated by it; playing in the enriched cage kept mice from learning; since socialized mice learned better than isolated mice, perhaps wheel running is more of a social than an enrichment activity for mice.

The important point is that students recognize that their explanations must be tested through additional experimentation to determine whether they are valid. Students may suggest experiments to test their explanations. Make sure students understand that their new experiments must have appropriate cage conditions and controls. For instance, if a student suggests that wheel-running mice learned better because wheel running is a more social activity for mice than is enrichment, they might test this by comparing isolated mice in cages with running wheels with isolated mice in enriched cages.

1. Ask students, “If mice are a good model system for humans, what do your mouse experiment results mean for humans?”

Factors that improve learning in mice should also improve learning in humans.

2. Display the transparency of Master 4.3, Morris Water Maze Results, that you prepared with averaged results from all four sets of mice plotted on one graph. This time, ask students to make observations about the similarities in results among all four sets of mice.

The time to platform for all mice decreased over the three days of testing. Students should interpret the improved performance as evidence that all mice learned.

3. Ask students, “Why do you think the time it took to find the platform over the three days of testing decreased for all mice?”

Each trial allowed mice to practice finding the platform. By following the visual cues on the wall, mice learned to find the platform more easily with each trial.

If students listed practice as a factor that affects learning in the initial discussion of this lesson, remind them of this. Point out that they now have evidence, based on a mouse animal model, that supports their idea that practice affects learning.

4. Encourage students to share their own experiences with practice and learning. Has practicing helped them learn tasks? What does this say about the mouse as a model system for learning research?

Students will likely share a variety of examples where practice helped them learn a task. Some possible examples of such tasks include learning a sport, learning to play a musical instrument, and playing computer games. This variety of examples helps make the point that practice improves learning in humans. Since practice also improves learning in mice, the mouse appears to be a good model system for learning research.

5. Ask students whether they think the brain changes as a result of learning.

Students probably do not have knowledge on which to base their opinion. This question is meant to stimulate thinking and serves as a lead-in to, “Let’s investigate.”

6. Display a transparency of Master 4.15, Neuron Structure Data. Explain to students that these pictures show neurons from the brains of four adult mice, each with different experiences.

Explain the following to your class.

• Mouse 1 and Mouse 2 are both from a standard cage. However, Mouse 1 never experienced the Morris Water Maze, while Mouse 2 was allowed to practice finding the platform on the Morris Water Maze.
• Mouse 3 and Mouse 4 are both from an enriched cage. However, Mouse 3 never experienced the Morris Water Maze, while Mouse 4 was allowed to practice finding the platform on the Morris Water Maze.

7. Ask students to make observations about the neurons of the mice.

The mice that practiced on the Morris Water Maze (Mouse 2 and Mouse 4) have more branches on their neurons than do their counterparts that did not practice (Mouse 1 and Mouse 3, respectively). The increase in neuron branching with practice occurs in mice from both enriched and standard cages. Students should also notice that both mice from the enriched cage (Mouse 3 and Mouse 4) have greater neuron branching than the mice from the standard cage (Mouse 1 and Mouse 2) do.

Tip from the field test: A brief review of the parts of a neuron is sometimes helpful to ensure that students use the language of neuroscience to describe what they see.

8. Ask students whether these results, combined with the results of the Morris Water Maze tests, support the hypothesis that learning results in changes in the brain.

The results from the Morris Water Maze test and the neuron structure data indicate that there is a correlation between learning and changes in the brain. This does not prove the hypothesis that Learning results in changes in the brain. However, combining the Morris Water Maze test data and the neuron structure data provides support for this hypothesis.

Assessment:
As a formal assessment of students’ understanding, you can direct them to summarize their responses to the questions in Steps 7 to 10 after the class discussion.

Tip from the field test: You may want to add a discussion of the difference between association and causation. Results from the mouse experiments show an association between certain factors and learning; that is, increases or decreases in the rates at which mice learn coincided with the presence or absence of certain factors, such as an exercise wheel or toys. However, from these experiments alone, one cannot determine whether these factors actually caused the changes in learning.

9. Ask, “If the mouse is a good model system for humans, what do these results predict about humans?”

Ask students to state their answer as a hypothesis. Try to get the class to come up with a general, consensus hypothesis such as, Learning leads to changes in the human brain.

10. Remind students that a hypothesis is a testable statement. Ask students to suggest ways to test their hypothesis.

Remind students that to look for changes in the human brain, they will need a noninvasive method of examining the brain. Students should recall PET scans from Lesson 2 and suggest this as a method for testing their hypothesis. If PET scans of the same individual before and after learning demonstrate changes in brain activity compared with scans taken before and after the same time period but with no learning, the data would support the hypothesis that Learning leads to changes in the human brain. If the PET scans show no changes in brain activity, the data would not support the hypothesis.