Data and Analysis Unit: liv001

Citation: Lawson et al. (2017)

Description

Free sorting experiments reported by Lawson et al. (2016). This DAU contains raw freesort data, stimulus lists, and analysis scripts. The following materials are covered by a Creative Commons Share-Alike 4.0 license.

Resources

• data.csv - Trial-level raw data, column headings are as follows:
  • Expt.PSYC. : Experiment code. Relative to Lawson et al. (2016), exp.1 = 28, exp.2 = 9, exp.3 = 58, exp.4 = 25. The file also contains experiment code 23. Experiment code 23 is an experiment not reported in Lawson et al. (2016) due to space limitations.
  • ExptGroup : Experimental condition; meaning is dependent on experiment:
    • PSYC28 : 1 = pictures, 2 = words
    • PSYC9: 2 = tax primed, 3 = them primed, 4 = not primed
    • PSYC58: 2 = them instructed, 3 = tax instructed
    • PSYC25: 2 = them instructed, 3 = tax instructed
  • SjNo : Participant number (unique within an experiment)
  • CategoryNo : For each participant, CategoryNo ranges from 1 to the number of groups that participant created. Within a given participant, items with the same category number were put into the same group. Where a classification decision was not recorded due to human error, or where the participant placed the item into a 'junk' category (an option only available in PSYC25), an 'NA' is recorded.
  • ItemIndex : For each category for each participant, ItemIndex ranges from 1 to the number of items in the category. Where a classification decision was not recorded due to human error, an 'NA' is recorded. Hence 'junk' decisions and missing data can be distinguished because the former have NA for both CategoryNo and ItemIndex, while the latter have NA only for CategoryNo.
  • ItemNo : A number identifying the classified stimulus. stim_names.csv maps these numbers on to object names.
• stim_names.csv - Mapping of ItemNo in data.csv to the names of the objects presented. The mapping was different for PSYC28 ('E1') than for the remaining studies PSYC9, PSYC23, PSYC58, PSYC25 ('E234').
• analysis.R - R script for analyses reported in Tables 1 and 2 of Lawson et al. (2016). In addition to data.csv, it requires the following to run:
  • Installation of R package freesortphi. Within R, type: install.packages("freesortphi", repos="http://R-Forge.R-project.org")
  • mcout.rda - Archived results of Monte Carlo simulations of the chance levels (see montecarlo.R)
• montecarlo.R - R script to produce mcout.rda. Currently, it takes about 12 hours to run on an Intel i7 '8 core' (4 cores with hyperthreading) machine using package freesortphi version 0.1.3. Requires R packages: 'freesortphi', 'snowfall', and 'rlecuyer'. The last two of these packages are available from CRAN (i.e. are a standard install from within R). For the first, see above. In the R script, set cpus appropriate to your machine.

References

• Lawson, R., Chang, F. & Wills, A.J. (2017). Free classification of large sets of everyday objects is more thematic than taxonomic. Manuscript accepted by Acta Psychologica.