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Table 3 Mean number of regions (out of a possible 12) containing manipulation and results of Monte Carlo simulation to determine chance performance in location task by manipulation type and overall

From: Can people identify original and manipulated photos of real-world scenes?

Manipulation type Number of regions Percentage correct by chance
M M 95% CI
Airbrushing 1.50 12 [12, 13]
Add/sub 1.33 11 [11, 11]
Geometry 1.33 11 [11, 11]
Shadow 1.33 11 [11, 11]
Super-additive 4.67 39 [39, 39]
Overall 2.03 17 [17, 17]
  1. CI confidence interval. For each manipulation type, we show the mean number of regions that contained the manipulation across all six images. The manipulation type “Overall” is the mean number of manipulated regions across all six images and all five manipulation types. To determine chance performance in the location task, we ran a Monte Carlo simulation of one million responses based on the number of regions manipulated for each image and manipulation type