morse: Rothkopf's Morse Code Data

Description

Rothkopf's (1957) Morse code data of discrimination probabilities among $36$ auditory Morse code signals for the letters $A$, $B$, ..., $Z$ and the digits $0$, $1$, ..., $9$.

Usage

morse

Arguments

Format

The morse data frame consists of $36$ rows and $36$ columns, representing the Morse code signals for the letters and digits $A$, ..., $Z$, $0$, ..., $9$ presented first and second, respectively. Each number, an integer, in the data frame gives the percentage of subjects who responded ‘same’ to the row signal followed by the column signal.

Source

Rothkopf, E. Z. (1957) A measure of stimulus similarity and errors in some paired-associate learning tasks. Journal of Experimental Psychology, 53, 94--101.

Details

Each signal consists of a sequence of dots and dashes. A chart of the Morse code letters and digits can be found at http://en.wikipedia.org/wiki/Morse_code.

Rothkopf's (1957) $36x36$ Morse code data gives the same-different judgements of $598$ subjects in response to the $36x36$ auditorily presented pairs of Morse codes. Subjects who were not familiar with Morse code listened to a pair of signals constructed mechanically and separated by a pause of approximately $1.4$ seconds. Each subject was required to state whether the two signals presented were the same or different. Each number in the morse data frame is the percentage of roughly $150$ subjects.

References

Dzhafarov, E. N. and Colonius, H. (2006) Reconstructing distances among objects from their discriminability. Psychometrika, 71, 365--386.

Dzhafarov, E. N. and Colonius, H. (2007) Dissimilarity cumulation theory and subjective metrics. Journal of Mathematical Psychology, 51, 290--304.

Uenlue, A. and Kiefer, T. and Dzhafarov, E. N. (2009) Fechnerian scaling in R: The package fechner. Journal of Statistical Software, 31(6), 1--24. URL http://www.jstatsoft.org/v31/i06/.