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

Cognitive Research: Principles and Implications

Table 4 Chance performance in location task by manipulation type and overall based on mean number of subjects choosing the manipulated region in the original version of the image

Manipulation type	Percentage correct by chance
	Image
	A	B	C	D	E	F	Overall
Airbrushing	19	31	28	28	23	20	25
Add/sub	24	5	15	3	3	1	9
Geometry	11	12	17	2	26	12	13
Shadow	20	16	28	39	4	5	19
Super-additive	74	63	44	72	33	26	53
Overall image	30	25	27	29	18	13	23

For each of the six critical images and each of the five manipulation types, we show the probability that the manipulated region of the image was selected by chance in the original version of the image. The “Overall” column denotes the mean probability of selecting the manipulated regions for that manipulation type across all 6 images A-F. The “Overall image” is the mean probability of selecting the manipulated regions for that image across all manipulation types. Each image had a minimum of 101 responses