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The Challenging Concept of Change Over Time

Sharon Cohen


     One of the biggest challenges for students and teachers in world history is the concept of change over time. Of course, the concept of change over time is essential to any study of the past, but change over time in world history often takes on the added dimensions of changes over longer periods of time and usually across more places as well. These additional chronological and spatial dimensions are often next to impossible challenges for students trying to explain how larger global processes effected changes.

     The proof of these challenges is apparent in the work of students in many secondary and introductory college history courses. For example, the History Learning Project undertaken by the Indiana University History Department revealed that their college students struggled to analyze historical context and preferred to let the "'facts' speak by themselves."1 Studies of historical reasoning by fifth graders2 and ninth graders3 also demonstrate students struggling with these larger contexts for writing historical arguments. Perhaps an even greater sample of evidence is that every year the change over time essay question on the Advanced Placement World History (APWH) examination often has the lowest scores, averaging less than 30%. Over the past seven years, I have read thousands of APWH exams in which students consistently make the following types of errors on those change over time essays: 1) they misuse evidence by placing events in the wrong time period, 2) they make reference to global processes happening over a vague period of time without any anchoring dates, and/or 3) they create lists of information rather than well-structured arguments.4 Patrick Manning summarized these problems well. "One example of oversimplified global analysis is the listing of a variety of outcomes of different situations, and the assertion that they add up to a pattern. With no explanation of how the situations were selected or how they relate to each other, this would be a weak statement indeed of global patterns: one needs to identify the process, not just the linked influences and outcomes."5

     I created an intervention connected to more active student work with annotated timelines to help students see the patterns inherent in change over time in world history. This intervention emphasized students creating annotated timelines on which they have to explain the connection between events and the global processes that affect them. A 2003 article by Janet Alleman and Jere Brophy confirmed my experience that requiring students to construct and use annotated timelines generates student acceptance and analysis of the facts they put on the timeline.6 Furthermore, Denis Shemilt bolstered my observation that annotated timelines would help students write better continuity and change over time essays. He argued that timelines can be a "meaningful narrative into which present and future can be incorporated."7 Finally, I found agreement with Ian Dawson's conclusion that "pupils need to construct timelines for themselves and not just look at completed ones,"8 Dawson's work emphasized how important creating timelines can be for students to grasp the scale of changes. Once I started to require students to make annotated timelines for every time period of the world history course, they mostly stopped making the typical mistakes found on the APWH exam essays.

     However, after reading Epstein's work on how African-American students feel left out of some presentations of American history,9 I began to wonder if the historical knowledge my students were creating with these annotated timelines contradicted other knowledge they gained outside the classroom. I focused on two world history classes, of which about half were of African heritage.10 To test this question about how students learn world history, I decided to find out what students already knew Africa before we began formal study of imperialism in Africa in the nineteenth century. I asked the students to create individual lists of what they already knew about Africa (I gave the instructions orally and projected them as well). They had five minutes to create this list, and then I asked them to indicate the source for each item they listed (home/friends, school, popular culture/media). Finally, I asked them to organize their information on a timeline. I reminded them of the periodization we used for the course, but said they could create their own organization for the timeline as long as they had at least three time periods (to avoid 'now and then' vagueness). The results matched Epstein's conclusions about the source of the students' knowledge; sixty-four percent of all students of African heritage and three Latinos listed home as one of their sources of knowledge about Africa, but none of the other Latinos, or students of Asian or European heritage did. This data seemed to confirm that, in the United States, students of African heritage usually gain some knowledge of their history from home. Since that knowledge matched what we had also discussed at school (e.g. Africa as the origin of humans), I was reassured that contradictions between home and school would not impede my students' acceptance and understanding of world history.

     I then analyzed how much popular culture and the media affected the type of knowledge the students reported. It seemed likely from studies done by Seixas11 and Wineburg12 that films would be a major source of information and might affect the type of information the students claim to know. In fact, twelve students of my students listed the films Blood Diamonds (2006) and Hotel Rwanda (2004) as sources of information about forced labor in diamond mines in Sierra Leone and the genocide in Rwanda respectively. About half of the fifty students also listed learning about the HIV epidemic and poverty in Africa from television or the internet, and twenty-six cited television as a main source of geographical facts about Africa. On the other hand, all but four of the students listed school as the source of their general information about ancient Egypt, the spread of Islam, the slave trade, and colonization. I concluded that they could remember and count as knowledge what they had learned from the media as well as school. The most remarkable result from this exercise was that about a third of the students added more information to their lists once they began to make their timelines. This made me consider the possibility that all of the work we had done with annotated timelines perhaps resulted in the timeline becoming an unconscious tool to recall facts they had otherwise not remembered in the initial five minutes I gave them to write their lists.

     The concept of change over time is extremely challenging for students to display fully in their writing about world history. This brief survey of some of the scholarship on teaching the concept of change over time along with the small research I did in my own classroom seem to point to two possible solutions. First, as teachers we should help students reveal their prior knowledge of topics to acknowledge that our students enter our classrooms with some ideas learned at home or through various media. Second, to encourage recall and analysis of key changes, we should expand our use of annotated timelines, so that students have some schema or method to incorporate new knowledge about historical topics. Perhaps, using these two pedagogical approaches we can guide our students toward more achievement and fewer errors in their historical writing.

Appendix I

Directions for the Annotated Timeline Assignment:

Give students a time period or several time periods to focus their analysis. They should then select a theme common to world history (political, social, economic, cultural, environmental, demographic, etc.) and the ten events they think show the largest changes related to that theme for the time period and place each event on a timeline they create. The annotations go below the timeline and explain why each event was significant to world history. At the very bottom of the page, they write a thesis statement about how the events related to the "theme" in this time period show continuity and change over time.

     For some students, making the timeline into an unusual shape that conveys the main idea of the theme or the thesis can help them express and remember the main points on the timeline.

Appendix II

Figure 1

Sharon Cohen is World History Connected's editor for scholarship on teaching and learning in world history. She teaches Advanced Placement World History at Springbrook High School in suburban Maryland. From 2002 – 2006, she was on the AP World History Test Development Committee. She has produced several publications for the College Board, including the Teacher's Guide for AP World History (2007) and Special Focus on Teaching About Latin America and Africa in the Twentieth Century (2008). As a College Board consultant, she has conducted AP World History workshops and summer institutes since 2001. She can be reached at



1 A. Diaz, J. Middendorf,, D. Pace, and L. Shopkow, L. "The History Learning Project: A department "decodes" its students," Journal of American History, 94, no. 4, (2008), 1213.

2 P. Afflerbach, and Bruce VanSledright, "Hath! Doth! What? Middle graders reading innovative history text," Journal of Adolescent & Adult Literacy, 44 no. 8 (2001), 696-707.

3 Robert Bain, "Into the Breach: Using research and theory to shape history instruction," in Peter N. Stearns, Peter Seixas and Sam Wineberg, (eds)., Knowing, Teaching, and Learning History (New York: New York University Press, 2000), 331-53.

4 The Advanced Placement World History Chief Readers' reports available on also report these same types of errors.

5 Patrick Manning, "Interactions and connections: Locating and managing historical complexity," The History Teacher. 39, no. 2 (2006), 189.

6 Janet Alleman and Jere Brophy, "History is Alive; Teaching young children about changes over time," The Social Studies. 94, no. 3 (2003), 107-114.

7 Denis Shemilt, "The Caliph's Coin: The Currency of Narrative Frameworks in History Teaching," in Peter N. Stearns, Peter Seixas, Sam Wineburg, eds., Knowing Teaching and Learning History, National and International Perspectives (New York: New York University Press, 2000), 87.

8 Ian Dawson, "Time for Chronology? Ideas for developing chronological understanding," in Teaching History, 117 (2004), 21.

9 Terry Epstein, "Adolescents' Perspectives on Racial Diversity in U. S. history: Case Studies from an Urban Classroom," American Educational Research Journal, 37, no. 1, (2000), 185-214.

10 The term "of African heritage" refers to students who themselves or their parents were born in Africa, the Caribbean, or mark 'African-American' on official school forms.

11 Peter Seixas, "Popular Film and Young People's Understanding of Native American-White Relations," The History Teacher, 26, no. 3 (1993), 351-370.

12 See Sam Wineburg, Historical Thinking and Other Unnatural Acts: Charting the Future of Teaching the Past. (Philadelphia: Temple University Press, 2001).



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