gallup_2003: Gallup et al. (2003) data

In profandyfield/discovr: Interactive Tutorials and Data for "Discovering Statistics Using R and RStudio"

Gallup et al. (2003) data

Description

A dataset from Field, A. P. (2023). Discovering statistics using R and RStudio (2nd ed.). London: Sage.

Usage

gallup_2003

Format

A tibble with 15 rows and 3 variables.

Details

It's something of a wonder how evolution managed to produce such a monstrosity as the human penis. One theory is sperm competition: the human penis has an unusually large glans (the 'bell-end') compared to other primates, and this may have evolved so that the penis can displace seminal fluid from other males by 'scooping it out' during intercourse. Armed with various devices from Hollywood Exotic Novelties, an artificial vagina from California Exotic Novelties, and some water and cornstarch Gallup et al. (2003) put this theory to the test. They loaded the artificial vagina with 2.6 ml of fake sperm and inserted one of three female sex toys into it before withdrawing it: a control phallus that had no coronal ridge (i.e., no bell-end), a phallus with a minimal coronal ridge (small bell-end) and a phallus with a coronal ridge. They measured sperm displacement as a percentage: 100% means that all the sperm was displaced, and 0% means that none of the sperm was displaced. If the human penis evolved as a sperm displacement device then Gallup et al. predicted: (1) that having a bell-end would displace more sperm than not; and (2) that the phallus with the larger coronal ridge would displace more sperm than the phallus with the minimal coronal ridge. The data from the study has three variables:

• id: The participant's id (these do not come from the study data file)

• phallus: the type of phallus used (No coronal ridge, minimal coronal ridge and coronal ridge)

• displace: percentage of sperm displaced by the phallus

Source

www.discovr.rocks/csv/gallup_2003.csv

References

• Gallup, G. G. J., Burch, R. L., Zappieri, M. L., Parvez, R., Stockwell, M., & Davis, J. A. (2003). The human penis as a semen displacement device. Evolution and Human Behavior, 24, 277–289. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1016/S1090-5138(03)00016-3")}

profandyfield/discovr documentation built on Oct. 29, 2023, 4:10 p.m.