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Teacher's Guide hand using a mouse

Teacher's Guide

Lesson 4—Elaborate

Outside Influence

At a Glance

Overview

In this lesson, students investigate factors that affect the important brain function of learning. In the first activity, students analyze the impact of social interaction on learning in mice. In the second activity, students design an experiment to test the impact of an enriched environment and/or exercise on learning in mice. Students analyze and share the results of their experiments with the class. In the third activity, students consider the validity of extending their conclusions from mouse experiments to humans.

Major Concepts

Learning is an important brain function. There are factors that affect learning. Laboratory animals can serve as experimental models for investigating learning. The ability of the brain to learn is not fixed.

Objectives

After completing this lesson, students will be able to

Teacher Background

Refer to the following sections in Information about the Brain:

  1. 7 Plasticity and Learning
  2. 7.1 The changing brain
  3. 7.2 Learning and memory

In Advance

Web-Based Activities
Activity Web Version?
1 Yes
2 Yes
3 No
Photocopies
Activity 1

Web Version
Master 4.1, Memo from the Director, 1 transparency
Master 4.2, Morris Water Maze Data, Research Question 1 (Web Version), 1 copy per team
Master 4.3, Morris Water Maze Results, 1 copy per team, or use own graph paper
Master 4.4, Memo to the Director on Research Question 1, 1 copy per team

Print Version
Master 4.1, Memo from the Director, 1 transparency
Master 4.3, Morris Water Maze Results, 1 copy per team, or use own graph paper
Master 4.4, Memo to the Director on Research Question 1, 1 copy per team
Master 4.5(a, b, c), Scientific Research Reference Manual, 1 copy per team
Master 4.6, Memo from Lab Technician, 1 transparency
Master 4.7, Morris Water Maze Data, Research Question 1 (Print Version), 1 transparency

Activity 2

Web Version
Master 4.3, Morris Water Maze Results, 1 copy per team plus 1 transparency
Master 4.8, Morris Water Maze Data, Research Questions 2 and 3 (Web Version), 1 copy per team
Master 4.9, Memo to the Director on Research Question 2, 1 copy for half of teams
Master 4.10, Memo to the Director on Research Question 3, 1 copy for half of teams
Master 4.11, Summary of Research Findings, 1 transparency

Print Version
Master 4.3, Morris Water Maze Results, 1 copy per team plus 1 transparency
Master 4.9, Memo to the Director on Research Question 2, 1 copy for half of teams
Master 4.10, Memo to the Director on Research Question 3, 1 copy for half of teams
Master 4.11, Summary of Research Findings, 1 transparency
Master 4.12, Next Research Assignment, 1 transparency
Master 4.13, Experimental Design, 1 copy per team
Master 4.14, Morris Water Maze Data, Research Questions 2 and 3 (Print Version), 1 transparency

Activity 3 Master 4.15, Neuron Structure Data, 1 transparency
Materials
Activity 1

Web Version
Overhead projector and screen
Computers with Internet access

Print Version
Overhead projector and screen

Activity 2

Web Version
4 colors of transparency pens
Overhead projector and screen
Computers with Internet access

Print Version
4 colors of transparency pens
Overhead projector and screen

Activity 3 Overhead projector and screen

Preparation

Activity 1, Web Version
Verify that the computer lab is reserved for your classes or that classroom computers are ready to use. Go to the Web page http://science.education.nih.gov/supplements/self/student and click on “Lesson 4—Outside Influence.” This brings up the unit’s desktop. Students then click on the link to “Outside Influence, Activity 1: Effects of Social Interaction on Learning.” Work through the lesson on the Web to familiarize yourself with the activity.

Set up overhead projector and screen.

Activity 1, Print Version
Set up overhead projector and screen.

Activity 2, Web Version
Verify that the computer lab is reserved for your classes or that classroom computers are ready to use. Go to the Web page http://science.education.nih.gov/supplements/self/student and click on “Lesson 4—Outside Influence.” This brings up the unit’s desktop. Students then click on the link to “Outside Influence, Activity 2: Effects of Enrichment and Exercise on Learning.” Work through the lesson on the Web to familiarize yourself with the activity.

Set up overhead projector and screen.

Plot the averaged data from all four sets of mice in Master 4.8, Morris Water Maze Data, Research Questions 2 and 3 (Web Version), on one transparency of Master 4.3, Morris Water Maze Results. Use different colors of transparency pens for each set of mice, and fill in the legend as you go.

Activity 2, Print Version
Set up overhead projector and screen.

Plot the averaged data from all four sets of mice in Master 4.14, Morris Water Maze Data, Research Questions 2 and 3 (Print Version), on one transparency of Master 4.3, Morris Water Maze Results. Use different colors of transparency pens for each set of mice, and fill in the legend as you go.

Activity 3
Set up overhead projector and screen.

Procedure

Teacher note: The data provided in this lesson are based on data from several original research papers. The Morris Water Maze data for each set of mice were normalized, or adjusted, to an initial time of 50 seconds for Day 1. Normalizing the data eases the interpretation of results by students while providing an acceptable data set for conveying the concepts of this lesson.

Activity 1: Effect of Social Interaction on Learning

Web activity iconFor classrooms using the Web-based version of this activity:

Teacher note: This activity uses a simulation on the Web. It will save time to have the computers online and at the correct URL: http://science.education.nih.gov/supplements/self/student. Students should click on “Lesson 4—Outside Influence.” This brings up the unit’s desktop. Students then click on the link to “Outside Influence, Activity 1: Effects of Social Interaction on Learning.”

  1. Begin by asking students, “What is learning?”
National Science Education Standards icon
Content Standard A:
Science as Inquiry. All activities in this lesson emphasize “Abilities necessary to do scientific inquiry” (identify questions and concepts that guide scientific investigations; design and conduct a scientific investigation; use appropriate tools and techniques to gather, analyze, and interpret data; develop descriptions, explanations, predictions, and models using evidence; and communicate scientific procedures and explanations) and “Understandings about scientific inquiry” (scientific explanations emphasize evidence, have logically consistent arguments, and use scientific principles, models, and theories; and asking questions and querying other scientists’ explanations is part of scientific inquiry).

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

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

Students should recognize that learning occurs in the brain.

  1. 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.

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

Remind students that to conclude whether 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 effects of several factors on learning in mice by designing and analyzing their own experiments.

  1. Organize students into pairs. Number pairs sequentially beginning with 1. Explain that the pairs are research teams at the Learning Research Laboratory.
  2. Display a transparency made from 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.

  1. 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 thinking about Research Question 1 and serves as a lead-in to, “Let’s investigate.”

  1. Direct student teams to computer stations. Ask them to click on the link to “Outside Influence, Activity 1: Effects of Social Interaction on Learning.”

Clicking on this link brings up an e-mail message from the laboratory technician. Walking the class through the Web site (Steps 8 through 11) provides an opportunity for you to explain how to navigate through the activity.

  1. Tell students to read the e-mail message from the laboratory technician.

The technician has set up an experiment to investigate Research Question 1 (Does social interaction affect learning in mice?). The e-mail message explains that the research teams will find a description of the experimental setup in the online Lab Notebook. Students will run the experiment and analyze the results.

  1. Tell students to click the “Lab Notebook” button. Review briefly the contents of the Experimental Design page that appears.

This page shows the research question, hypothesis, experimental procedure followed, and the mice used for Experiment 1. This page is the model for the experiments students will design in Activity 2.

Tip from the field test: After students have had a chance to read 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.

  1. Direct students to click the icon for the Scientific Research Reference Manual on the screen that appears, and review the Table of Contents with them.

Emphasize that consulting the reference manual will help students complete the activity more quickly and accurately. It provides information about laboratory mice, the Morris Water Maze, and, even more important for students’ work in this lesson, advice for writing hypotheses, designing experiments, analyzing data, interpreting results, 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.

  1. Give to each team one copy each of Master 4.2, Morris Water Maze Data, Research Question 1 (Web Version), 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
  • run the experiment and collect data for each mouse on Master 4.2,
  • average the data for each set of mice on Master 4.2,
  • construct a line graph of the data averages on Master 4.3 or their own graph paper, and
  • fill in the blanks on Master 4.4, Memo to the Director.

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

Students run three trials for each set of mice; each trial represents a different day. The Morris Water Maze data, appearing in a “timer” to the RIGHT of each swim tank, represents the time it takes for each mouse to reach the hidden platform in the Morris Water Maze. Students should record the data in the appropriate boxes of Master 4.2, Morris Water Maze Data, Research Question 1 (Web Version). Students should then 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 enter their results in the appropriate sections of the Morris Water Maze data tables on Master 4.2.

assessment icon
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.

Next, students should plot the averages 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.

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

  1. 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 of the mice learned. However, the mice raised in social conditions learned more rapidly than the mice raised in isolated conditions. Thus, students should conclude that the data support the hypothesis: Socialized mice learn more quickly than isolated mice.

print activity iconFor classrooms using the print version of this activity:

  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.

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

Students should recognize that learning occurs in the brain.

  1. 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.

  1. 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.

  1. Organize students into pairs. Number pairs sequentially beginning with 1. Explain that the pairs are research teams at the Learning Research Laboratory.
  2. 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.

  1. 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.”

  1. 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.

  1. 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.

  1. 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

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 icon
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.

  1. 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.

Activity 2: Effects of Enrichment and Exercise on Learning

Web activity iconFor classrooms using the Web-based version of this activity:

  1. Organize students into their research teams from Activity 1.
  2. Direct student teams to computer stations. Ask them to click on “Outside Influence, Activity 2: Effects of Enrichment and Exercise on Learning” on the unit’s desktop.
  3. Tell students to read the e-mail message from the director.

The e-mail message from the director assigns 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?).

  1. Tell students to click on their team’s assigned research question within the director’s e-mail. Review briefly the contents of the Experimental Design page that appears.

The Experimental Design page displays either Research Question 2 or Research Question 3 (based on the links students followed from the director’s e-mail) and a box in which they can type a hypothesis. Instructions for the student are at the bottom of the page.

  1. Instruct teams to write a hypothesis for their research question, then click on the “Animal Care Laboratory” icon to select mice for their experiment.

Student teams may ask for assistance in writing their hypothesis. Remind students that the reference manual provides advice for developing a hypothesis. Also remind them of the discussion about hypotheses in Activity 1. Hypotheses are statements that predict a specific answer to the research question. In addition, hypotheses are testable; that is, a hypothesis suggests a way to test whether the prediction is accurate.

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.

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.

  1. At the Animal Care Laboratory, instruct student teams to select two sets of mice to use in testing their hypothesis.

Remind students that the reference manual provides advice for selecting appropriate research subjects. Four sets of mice (Standard Cage, Standard Cage with Running Wheel, Enriched Cage, and Enriched Cage with Running Wheel) are available to students, and they may select any two sets for their experiment. Students should select the two sets they believe to be appropriate for testing their hypothesis.

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.

assessment icon
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.

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.

  1. Tell students to click on the “To Experimental Design Page” button when they have finished selecting the sets of mice they will use. After confirming the experiment they have designed, students should click the “Run Experiment” button and proceed with collecting their data as they did in Activity 1.

The Experimental Design page summarizes the students’ experiment. It looks the same as in Activity 1, but with the appropriate research question. The program will automatically display the hypothesis students wrote and the sets of mice they selected.

Clicking the “Run Experiment” button takes students to a page with the Morris Water Maze setup, as in Activity 1. Students can return to the Animal Care Laboratory from this page if they decide they need to select a different pair of mouse sets to use in testing their hypothesis.

  1. Give each team a copy of Master 4.8, Morris Water Maze Data, Research Questions 2 and 3 (Web Version), and a new copy of Master 4.3, Morris Water Maze Results. Direct teams to
  • run the experiment and collect data for the sets of mice they selected for their experiment on Master 4.8,
  • average the data for each of their chosen sets of mice on Master 4.8, and
  • construct a line graph of their data averages on Master 4.3 or their own graph paper.

Encourage teams to use the reference manual as a guide as they work through their investigation.

Students run three trials for each set of mice; trials represent three consecutive days of testing. The Morris Water Maze data, appearing in a “timer” to the RIGHT of each swim tank, represents the time it takes for each mouse to reach the hidden platform in the Morris Water Maze. Students should record the data in the appropriate boxes of Master 4.8, Morris Water Maze Data, Research Questions 2 and 3 (Web Version). Students should then 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 enter their results in the appropriate sections of the Morris Water Maze data tables on Master 4.8.

Next, students should plot the averages as line graphs on Master 4.3. 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.

  1. 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 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.

  1. 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.
  2. 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. Therefore, the data support the hypothesis that Socialized mice learn more quickly than isolated mice.

assessment icon
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.

  1. Display the transparency of Master 4.3, Morris Water Maze Results, you have 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 is less stimulation available for the mice in the standard cage.

  1. 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 here 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 than is enrichment, they might test this by comparing isolated mice in cages with running wheels with isolated mice in enriched cages.

Teacher note: Your students may feel that after analyzing their data, they ended up with more questions than answers. You may find this an appropriate time to talk to your students about the nature of scientific inquiry. Help students understand that science is an ongoing process. Remind students that experimental results present scientists with new questions, explanations, and experiments. New explanations refine or replace old ones, and experimental results lead to new questions that must be tested through new experiments. Scientific knowledge is constantly evolving through the critical examination of new ideas and results.

print activity iconFor classrooms using the print version of this activity:

  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?).

  1. 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.
  2. 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 icon
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

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

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

  1. 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.

  1. 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.

  1. 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.

  1. 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.
  2. 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 icon
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.

  1. 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.

  1. 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.

Teacher note: Your students may feel that after analyzing their data, they ended up with more questions than answers. You may find this an appropriate time to talk to your students about the nature of scientific inquiry. Help students understand that science is an ongoing process. Remind students that experimental results present scientists with new questions, explanations, and experiments. New explanations refine or replace old ones, and experimental results lead to new questions that must be tested through new experiments. Scientific knowledge is constantly evolving through the critical examination of new ideas and results.

Activity 3: A Human Perspective (for Print and Web)

Teacher note: Ethical treatment is a concern for animal subjects as well as for human subjects. However, try to avoid emotional issues by pointing out that scientists who use laboratory animals comply with stringent guidelines for humane treatment of the animals. Where necessary, focus discussion on the limitations of using human subjects and the advantages and limitations of animal models.

Tip from the field test: After completing the mouse experiments, students often wonder or ask, “What does this have to do with me?” Completing Activity 3 provides an opportunity for students to relate their newly developed understandings about learning in mice to humans.

  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.

  1. 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.

  1. 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.

  1. 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.

  1. 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.”

  1. 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.

  1. 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.

  1. 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 icon
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.

  1. 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.

  1. 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.


Web activity icon Lesson 4 Organizer: Web Version
Activity 1: Effects of Social Interaction on Learning
What the Teacher Does Procedure Reference

Ask students,

  • “What is learning?”
  • “Where does learning occur?”
  • “What affects learning?”
  • “How can scientists determine whether these factors affect learning?”

Steps 1–4

Organize students into pairs.

  • Number groups sequentially starting with 1.
  • Explain that pairs are research teams at the Learning Research Laboratory.
  • Display transparency of Master 4.1, Memo from the Director and read it to class.
  • Direct attention to Research Question 1 and ask students to raise their hands if they think social interaction has an effect on learning.
transparency iconSteps 5–7

Send students to computer stations and have them click on the link to this activity.

  • Have students read the e-mail message from the laboratory technician.
  • Ask them to click on the “Lab Notebook” button and review with them the contents of the Experimental Design page.
  • Have students click on the link to the “Scientific Research Reference Manual” and review this resource with them.
Web activity iconSteps 8–11

Give each team one copy each of Master 4.2, Morris Water Maze Data, Research Question 1 (Web Version), 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.

master iconStep 12

Direct teams to

  • run the experiment and collect data for each mouse on Master 4.2,
  • average the data for each set of mice on Master 4.2,
  • construct a line graph of the data averages on Master 4.3 or their own graph paper, and
  • fill in the blanks on Master 4.4, Memo to the Director.
Web activity iconStep 12

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.

Step 13
Activity 2: Effects of Enrichment and Exercise on Learning
What the Teacher Does Procedure Reference
  • Organize students into their research teams from Activity 1.
  • Direct teams to computer stations and have students click on the link to this activity.
  • Ask students to read the e-mail message from the director.
  • Have students click on the link to their team’s assigned research question.
  • Briefly review the contents of the Experimental Design page that appears.
Web activity iconSteps 1–4
  • Instruct teams to write a hypothesis for their research question and then click on the “Animal Care Laboratory” icon.
  • Instruct teams to select two sets of mice to use in testing their hypothesis.
  • Ask students to click on the “To Experimental Design Page” button to review the experiment they have designed.
  • Students should then click the “Run Experiment” button and collect their data as they did in Activity 1.
Web activity iconSteps 5–7

Give each team a copy of Master 4.8, Morris Water Maze Data, Research Questions 2 and 3 (Web Version), and a new copy of Master 4.3, Morris Water Maze Results. Direct teams to

  • run the experiment and collect data for the sets of mice they selected for their experiment on Master 4.8,
  • average the data for each of their chosen sets of mice on Master 4.8, and
  • construct a line graph of their data averages on Master 4.3 or their own graph paper.
master iconStep 8

Web activity icon

While teams are preparing 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 one a copy of Master 4.10, Memo to the Director on Research Question 3. Ask teams to complete the memos using the results of their experiment.

master iconStep 9

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.

Step 10

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.

transparency iconStep 11

Display the transparency of Master 4.3, Morris Water Maze Results, you have 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.
  • Ask students to propose explanations for these findings. How would they test their explanations?
transparency iconSteps 12–13
Activity 3: A Human Perspective
What the Teacher Does Procedure Reference

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

Step 1

Display the transparency of Master 4.3, Morris Water Maze Results, that you prepared with averaged results for all four sets of mice plotted on one graph.

  • Ask students to make observations about the similarities in results among all four sets of mice.
  • Ask, “Why do you think the time it took to find the platform over the three days of testing decreased for all mice?”
transparency iconSteps 2–3

Encourage students to share their own experiences with practice and learning. Ask,

  • “Has practice helped them learn tasks?”
  • “What does this say about the mouse as a model system for learning research?”
  • “Do you think the brain changes as a result of learning?”
Steps 4–5

Display a transparency of Master 4.15, Neuron Structure Data.

  • Explain that these pictures show neurons from the brains of four adult mice, each with different experiences.
  • Ask students to make observations about the neurons of the mice.
  • Ask whether these results, combined with the results of the Morris Water Maze tests, support the hypothesis that learning results in changes in the brain.
  • Ask, “If the mouse is a good model system for humans, what do these results predict about humans?”
  • Remind students that a hypothesis is a testable statement. Ask students to suggest ways to test their hypothesis.
transparency iconSteps 6–10
transparency icon= Involves using a transparency.
Web activity icon= Involves using the Internet.
master icon= Involves copying a master.

print activity icon Lesson 4 Organizer: Print Version
Activity 1: Effects of Social Interaction on Learning
What the Teacher Does Procedure Reference

Ask students,

  • “What is learning?”
  • “Where does learning occur?”
  • “What affects learning?”
  • “How can scientists determine whether these factors affect learning?”

Steps 1–4

Organize students into pairs.

  • Number groups sequentially starting with 1.
  • Explain that pairs are research teams at the Learning Research Laboratory.
Step 5

Display a transparency of Master 4.1, Memo from the Director, and read it with the class.

  • Direct students’ attention to Research Question 1
  • Ask students to raise their hands if they think social interaction has an effect on learning.
  • Give each team a copy of Master 4.5(a, b, c), Scientific Research Reference Manual.
transparency iconSteps 6–8

master icon

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, and read it with the class.

transparency iconStep 9

Display a transparency of Master 4.7, Morris Water Maze Data, Research Question 1 (Print Version). Give each team one copy of Master 4.3, Morris Water Maze Results, and one copy of Master 4.4, Memo to the Director on Research Question 1.

master iconStep 10

transparency icon

Direct teams to

  • average the data on Master 4.7 for each set of mice,
  • construct a line graph using the data averages, and
  • fill in the blanks on Master 4.4.
Step 10

Reconvene the class. Ask different student teams to share their graphs, answers to the questions on Master 4.4, and their conclusions about learning.

Step 11
Activity 2: Effects of Enrichment and Exercise on Learning
What the Teacher Does Procedure Reference

Organize students into their research teams from Activity 1.

  • Display a transparency of Master 4.12, Next Research Assignment, and read it with the class.
  • Give each team a copy of Master 4.13, Experimental Design.
  • Make sure each team has its copy of Master 4.5(a, b, c), Scientific Research Reference Manual.
transparency iconSteps 1–2

master icon

Instruct teams to complete Master 4.13 by

  • writing their research question,
  • writing a hypothesis, and
  • selecting two sets of mice appropriate for testing their hypothesis.
Step 3
  • Display a transparency of Master 4.14, Morris Water Maze Data, Research Questions 2 and 3 (Print Version).
  • Give each team a copy of Master 4.3, Morris Water Maze Results.
  • Ask teams to graph their averaged data as they did in Activity 1.
transparency iconSteps 4–5

master icon
  • Give even-numbered teams a copy of Master 4.9, Memo to the Director on Research Question 2.
  • Give odd-numbered teams a copy of Master 4.10, Memo to the Director on Research Question 3.
  • Ask teams to complete their master.
master iconStep 6

Pair odd-numbered teams with even-numbered teams and ask them to share and discuss their results with one another.

Step 7

Reconvene the class.

  • Display a transparency of 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.
transparency iconStep 8

Display the transparency of Master 4.3, Morris Water Maze Results, that you have 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.
  • Ask students to propose explanations for these findings.
  • Ask, “How would you test your explanations?”
transparency iconSteps 9–10
Activity 3: A Human Perspective
What the Teacher Does Procedure Reference

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

Step 1

Display the transparency of Master 4.3, Morris Water Maze Results, that you prepared with averaged results for all four sets of mice plotted on one graph.

  • Ask students to make observations about the similarities in results among all four sets of mice.
  • Ask, “Why do you think the time it took to find the platform over the three days of testing decreased for all mice?”
transparency iconSteps 2–3

Encourage students to share their own experiences with practice and learning.

  • Has practice helped them learn tasks?
  • What does this say about the mouse as a model system for learning research?
  • Ask students whether they think the brain changes as a result of learning.
Steps 4–5

Display a transparency of Master 4.15, Neuron Structure Data.

  • Explain that these pictures show neurons from the brains of four adult mice, each with different experiences.
  • Ask students to make observations about the neurons of the mice.
  • Ask whether these results, combined with the results of the Morris Water Maze tests, support the hypothesis that learning results in changes in the brain.
  • Ask, “If the mouse is a good model system for humans, what do these results predict about humans?”
  • Remind students that a hypothesis is a testable statement. Ask students to suggest ways to test their hypothesis.
transparency iconSteps 6–10
transparency icon= Involves using a transparency.
master icon= Involves copying a master.

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