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The effect of fear of violence on cognition and productivity: An experiment in Kenya
Last registered on October 09, 2015


Trial Information
General Information
The effect of fear of violence on cognition and productivity: An experiment in Kenya
Initial registration date
October 09, 2015
Last updated
October 09, 2015 5:40 PM EDT
Primary Investigator
University of Chicago
Other Primary Investigator(s)
PI Affiliation
Columbia University
PI Affiliation
Columbia University
PI Affiliation
Princeton University
PI Affiliation
Columbia University
Additional Trial Information
In development
Start date
End date
Secondary IDs
Is there a psychological mechanism through which persistent fears of crime and violence weigh on productivity? We aim to study the effects of insecurity on cognition and productivity in a lab experiment in Kenya. In this study, we will experimentally induce feelings of insecurity with a reflection task, and then assess changes in performance on several tasks that require a varying mixture of cognitive skills and effort. The primary purpose of this study is to assess the effectiveness of our prime and to make sure our outcomes are measuring what we seek to measure. We will use this information to inform the design of a larger experiment concerning insecurity and productivity.
External Link(s)
Registration Citation
Blattman, Christopher et al. 2015. "The effect of fear of violence on cognition and productivity: An experiment in Kenya." AEA RCT Registry. October 09. https://doi.org/10.1257/rct.907-2.0.
Former Citation
Blattman, Christopher et al. 2015. "The effect of fear of violence on cognition and productivity: An experiment in Kenya." AEA RCT Registry. October 09. https://www.socialscienceregistry.org/trials/907/history/5556.
Experimental Details
At the beginning of the experiment, the treatment group is asked to list beliefs or experiences that make them worried about violence in their neighborhoods. They are then asked to write a detailed description of the most worrying item on the list. To reactivate the prime, about halfway through the session, participants are asked to pick another item from their list and describe it. The control group complete similar tasks, but their list is of beliefs or experiences that relax them.
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
To assess the effect of these primes on outcomes, we collect data in 4 different games. First, to measure fluid intelligence, participants complete a set of 12 Raven's progressive matrices. Second, to measure effort provision, participants complete a slider task, where they are asked to slide a series of markers to some target point on a number line. Third, to measure executive control, participants complete a stroop-style task, where they see a series of blue and white arrows and are instructed to touch the side of the screen that the white arrows point to, but touch the opposite side for the blue arrows. Finally, as a cognitive measure of effort provision, participants complete a puzzle game called "Flow Free", where the objective is to connect pairs of colored dots in non-overlapping paths.
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
Participants complete a demographic questionnaire and then learn the rules to each game. Practice rounds are part of the instructions phase. Then participants complete the priming exercise, followed by the Raven's matrices and slider tasks in random order. Participants complete a second reflection task and then complete the Stroop and Flow Free tasks (also in random order). Finally, participants are asked a number of questions about their mood, concerns about security, and their past exposure to violence. The entire session takes about 2 hours. In all games, participants are incentivized.
Experimental Design Details
Randomization Method
Participants are randomly assigned to their seats in each session. Using Stata, we randomly assign each seat-session to treatment or control. We also randomly assign orderings of the game so as to be balanced across treatments. Our randomization is such that for our first 8 participants, we have 4 in treatment, 4 in control, and 1 treatment participant and 1 control participant assigned to each game ordering. Each block of 8 participants is balanced in this way.
Randomization Unit
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
Sample size: planned number of observations
Sample size (or number of clusters) by treatment arms
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
0.23-0.32 Standard Deviations (Bounded by conservative and liberal assumptions)
IRB Name
Columbia University
IRB Approval Date
IRB Approval Number
IRB Name
Kenya Medical Research Institute
IRB Approval Date
IRB Approval Number
Analysis Plan

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Study Withdrawal
Is the intervention completed?
Is data collection complete?
Data Publication
Data Publication
Is public data available?
Program Files
Program Files
Reports and Papers
Preliminary Reports
Relevant Papers