Philosophers were given the following descriptions of two separate experiments from Livengood and Machery's "The Folk Probably Don't Think What You Think They Think: Experiments in Causation by Absence". We labeled them Experiment A and Experiement B; the first description was as follows:


Original survey question

Experiment A

Suppose subjects are presented with the following case:


The broken rope case

Susan had to climb a rope in gym class. Susan was a very good climber. She started climbing, but the rope broke before she reached the rafters. She fell on the ground.


Subjects are asked one of two questions. Some subjects are asked:


On a scale of 1 to 7, 1 indicating that you totally disagree and 7 indicating that you totally agree, how much do you agree with the following claim?

1. 'The rope breaking caused Susan to fall.'


Other subjects are asked:


On a scale of 1 to 7, 1 indicating that you totally disagree and 7 indicating that you totally agree, how much do you agree with the following claim?

2. 'Susan fell because the rope broke.'


The philosophers in our study were then asked to respond to the following question:


On average, agreement with statement 1 would be

 

 

Results

Experiment A


(Note: all numbers and percentages report the number of respondents who did not select the 'Unable to provide an unbiased answer' response.)


In the first part of the study ("study 1"), respondents were given no further information about the subjects of the original study. A total of 202 philosophers responded in study 1 (while 3 indicated that could not provide unbiased responses). The 202 responses were distributed as follows (as before, the answer which predicts the results of the original study is in bold):


total responses from study 1

% responses from study 1

significantly greater than agreement with statement 2.

9

4.5%

not significantly different than agreement with statement 2.

158

78.2%

significantly lower thanagreement with statement 2.

35

17.3%


In the second part of the study ("study 2"), respondents were given the above question, and told to suppose that the original involved 100 American undergraduate university students. A total of 97 philosophers responded in study 2 (while 4 indicated that they could not provide unbiased responses). The 97 responses were distributed as follows:


total responses from study 2

% responses from study 2

significantly greater than agreement with statement 2.

4

4.1%

not significantly different than agreement with statement 2.

70

72.2%

significantly lower thanagreement with statement 2.

23

23.8%


In all, a total of 299 philosophers answered this question:


total responses from combined study

% responses from combined study

significantly greater than agreement with statement 2.

13

4.3%

not significantly different than agreement with statement 2.

228

76.3%

significantly lower thanagreement with statement 2.

58

19.4%

 

 

Comparison with original results

Experiment A


Livengood and Machery describe the results of the original study:


In the causation condition [i.e., for the subjects given statement 1], the mean answer was 5.77 (SD = 1.37), while in the explanation condition [i.e., for the subjects given statement 2], the mean answer was 5.47 (SD = 1.82). In both conditions, the modal answer was 7. Subjects were not significantly more likely to agree with the target sentence in the explanation condition ("Susan fell because the rope broke") than with the target sentence in the causation condition ("The rope breaking caused Susan to fall").


 

We asked a second question about Livengood and Machery's "The Folk Probably Don't Think What You Think They Think: Experiments in Causation by Absence":


Original survey question

Experiment B

Suppose subjects (note: not those who participated in Experiment A) are presented with the following case:


The unsafe rope case
Susan has to climb an old, worn-out rope in gym class. She wondered if it would support her weight. Susan was a very good climber. Though nervous, she climbed all the way to the rafters.


Subjects are asked one of two questions. Roughly half of the subjects are asked:


On a scale of 1 to 7, 1 indicating that you totally disagree and 7 indicating that you totally agree, how much do you agree with the following claim?

1. 'The rope not breaking caused Susan to reach the rafters.'


Other subjects are asked:


On a scale of 1 to 7, 1 indicating that you totally disagree and 7 indicating that you totally agree, how much do you agree with the following claim?

2. 'Susan reached the rafters because the rope did not break.'


The philosophers in our study were then asked to respond to the following question:


On average, agreement with statement 1 would be

 

 

Results

Experiment B


In study 1, where respondents were given no further information about the subjects of the original study, a total of 198 philosophers responded (while 4 indicated that they could not provide unbiased responses). The 198 responses were distributed as follows (as before, the answer which predicts the results of the original study is in bold):


total responses from study 1

% responses from study 1

significantly greater than agreement with statement 2.

5

2.5%

not significantly different than agreement with statement 2.

22

11.1%

significantly lower thanagreement with statement 2.

171

86.4%


In study 2, respondents were given the above question, and told to suppose that the origial study involved 70 American undergraduate university students. A total of 97 philosophers responded in study 2 (while 4 indicated that they could not provide unbiased responses). The 97 responses were distributed as follows:


total responses from study 2

% responses from study 2

significantly greater than agreement with statement 2.

5

5.2%

not significantly different than agreement with statement 2.

15

15.5%

significantly lower thanagreement with statement 2.

77

79.4%


In all, a total of 295 philosophers answered this question:


total responses from combined study

% responses from combined study

significantly greater than agreement with statement 2.

10

3.4%

not significantly different than agreement with statement 2.

37

12.5%

significantly lower thanagreement with statement 2.

248

84.1%

 

 

Comparison with original results

Experiment B


Livengood and Machery describe the results of the original study:


In the causation condition [i.e., for the subjects given statement 1], the mean answer was 3.06 (SD = 1.84), while in the explanation condition [i.e., for the subjects given statement 2], the mean answer was 4.00 (SD = 2.14). [...] Subjects were also significantly more likely to agree with the target sentence in the explanation condition ("Susan reached the rafters because the rope did not break") than with the target sentence in the causation condition ("The rope not breaking caused Susan to reach the rafters").