Colonization and Development in Africa: A Natural Experiment of the Nzima in Côte d’Ivoire and Ghana

Last registered on March 15, 2022


Trial Information

General Information

Colonization and Development in Africa: A Natural Experiment of the Nzima in Côte d’Ivoire and Ghana
Initial registration date
March 11, 2022

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
March 15, 2022, 7:59 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.



Primary Investigator

Bucknell University

Other Primary Investigator(s)

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Did colonization affect the development of African countries? Existing research argues that the colonizer affected a variety of outcomes and did so in a causal way including but not limited to affecting ethnic versus national identities, views of traditional leaders, pro-social behavior, and other related outcomes. In their civilizing mission, for example, the French pushed against ethnic identities whereas the British with their emphasis on indirect rule encouraged ethnic identities. If this view is correct and colonization had long-run causal effects on identities broadly conceived then people today living in former French colonies should have less ethnic-only identities and different attitudes towards traditional leaders, their own communities (i.e., pro-social behavior), and African integration than those in British colonies. However, if colonization regardless of colonizer acted primarily as a catalyst and changed nothing from an institutional perspective then there should be no differences across these outcomes by colonizer. This paper argues that colonization in most cases acted as a catalyst and the colonizers used pre-existing institutions to accomplish their goals thus producing no appreciable long-run effects on identities and other such outcomes related to the long-run development of these places. Testing these competing claims is difficult, however, because colonization varied in many ways including by geography, timing, and other such factors thus making cross-national comparisons problematic. However, borders were in many cases arbitrarily drawn thus splitting the same people in the same place into two groups and providing a natural experiment by colonizer. The Nzima, an Akan sub-group in west Africa, is such an example as they were divided with some Nzima colonized by the French and other Nzima colonized by the British in the same part of west Africa. Building on this natural experiment, this project conducts a series of survey experiments on each side of the Ivorian-Ghanaian border examining how the Nzima respond to questions about identities related to ethnicity, traditional leaders, African integration, and their own communities (i.e., degree to which they exhibit pro-social behavior). In the context of the natural experiment, this paper also primes some of the respondents with a question about colonization while not treating others with the prime.
External Link(s)

Registration Citation

Doces, John. 2022. "Colonization and Development in Africa: A Natural Experiment of the Nzima in Côte d’Ivoire and Ghana ." AEA RCT Registry. March 15.
Experimental Details


This is a natural experiment in which the intervention is the colonizer (French versus British) amongst the Nzima an Akan ethnic group located along the border of Ghana and the Ivory Coast. Colonization was not randomly assigned in general, but some parts of Africa especially for those groups living where borders were arbitrarily made did see random assignment of colonizer. In addition to the assignment of colonizer by nature, we randomly treat some respondents with a prime about colonization while others receive no statement about colonization.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Outcomes are related to identities, pro-social behavior, and views of traditional leaders.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The experiment is a natural experiment comparing the same Akan ethnic group, the Nzima, who were randomly colonized by the French or British. In addition, respondents will be randomly treated with a prime about colonization.
Experimental Design Details
Randomization Method
Randomization of the prime will be done prior using a computer to generate random assignment.
Randomization Unit
Randomization unit is country for the colonizer and for the prime it is at the individual level.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
There are two clusters.
Sample size: planned number of observations
Total observations will be 600.
Sample size (or number of clusters) by treatment arms
Each cluster will include 300 observations.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
None available.
Supporting Documents and Materials

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Institutional Review Boards (IRBs)

IRB Name
Bucknell University Institutional Review Board
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials