The dissemination of divination in roman republican times

Dendrologist/INT/AD - Dendrologist/RIT/AD -6,761 47 < 0.001
Banban/INT/AC - Banban/RIT/AC -7,189 43 < 0.001
Banban/INT/AD - Banban/RIT/AD -6,113 42 < 0.001
Table 4.5. Paired t-test for Intentional vs. Ritual conditions
Table 4.5. gives clear evidence that there is a significant difference in the participants rating
of the credibility of the information produced by the diviner in the Intentional compared to
the Ritual condition. In order to asses the effect size Cohen's d was calculated. The results are
shown on table 4.6.
Pairs Cohen's d
Kurabi/INT/AC - Kurabi/RIT/AC 0,74
Kurabi/INT/AD - Kurabi/RIT/AD 0,98
Dendrologist/INT/AC - Dendrologist/RIT/AC 1,37
Dendrologist/INT/AD - Dendrologist/RIT/AD 1,45
Banban/INT/AC - Banban/RIT/AC 1,61
Banban/INT/AD - Banban/RIT/AD 1,40
Table 4.6. Effect size of difference between intentional and ritual
conditions
These are quite sizeable effects, since Cohen's rule of thumb is that effects around .80 are
large effects.
If the results were confounded with a primitivist stereotype we would expect differences
between the Kurabi and Banban story on one hand and the dendrologist on the other. If the
results were confounded with racial stereotypes, we would expect a difference between any
of the stories. No such differences in the response pattern between the stories can be
observed. This indicates that effects are not attributable to a primitivist or racial stereotype.
The difference in rating could also possibly be attributed to participants who already
believed in divination and therefore already had experience of divination ritual. To test for
this the second part of the questionnaire was used. It contained a series of questions about
how likely different persons in the participants’ own culture were to predict the future. The
list included normal persons such as doctors, engineers and 6 th graders, as well as diviners.
Believers in divination were taken to be people who rated the ability to predict the future high
for the following persons: Shaman, Numerologist, Tarot Card Reader, Cheiromantic,
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