24 arachnophobes were used in all. 12 were asked to play with a big hairy tarantula spider with big fangs and an evil look. Their subsequent anxiety was measured. The remaining 12 were shown only picture of the same hairy tarantula. Again, the anxiety was measured.
Usage
viagra
Arguments
Details
Dataset from Field et al. book (p. 362).
References
Field, A., Miles, J, & Field, Z. (2012). Discovering Statistics Using R. Sage.