Data sources and sets will be made available on this page. Data made available here were collected either directly or in collaboration with the lab. Please check back in the future for more updates. 

(Right click and select "Save Target As..." to save the files to your computer)

Replication Data for the Oxley et al. Science Article 

This is a replication data set for the results reported in Oxley et al's Science article, "Political Attitudes Vary with Physiological Traits." The SPSS syntax file can be used with the data set to replicate the Table 1 and Table 3 in the Science article. 


    Science Data Set - SPSS 

    Science Data Syntax - SPSS


Minnesota Twins Political Survey Data and Technical Note 

The Minnesota Twins Political Survey data set is publically available for download from this site. The data set is in SPSS format and contains raw survey data. This file should include descriptive variable labels and values that can be viewed in the "variable view" window of the main SPSS interface. A separate codebook with all variable labels and values is also available in an Excel file below. Missing values in the data set are labeled as either 999 or 99999999. 


    Minnesota Twins Political Survey Data Set (SPSS .sav format) 

    Codebook 


The raw data set is NOT stacked as a twin data set. To create a twin data set, the data need to be reordered so that each variable is appears twice, once for twin 1 and once for the matching twin (twin 2). An SPSS syntax file is also available for download that can serve as a template for creating these twin data sets. This file can be adapted to create smaller twin data sets containing just the variables desired for analysis; simply delete the unwanted variables from the list of variables after the save outfile command. 


    SPSS Syntax to Create Stacked Data Set 


Note that the syntax is designed to drop all non-matched twin pairs, i.e. it creates data sets that only include complete sets of twins. For some analyses it is possible that unmatched twins may be desired. These can be retained by deleting the select if match sequence NE 0 syntax. 

To run the syntax file simply open the data set, click File -> Open -> Syntax -> Syntax Template for creating twin data sets, then click Run -> All from the syntax file. This should automatically create a twin data set by separating all variables by matched twin pairs. Running this syntax file on the complete original data set should create a twins data set with an N of 596, which will include 356 MZ pairs and 240 DZ pairs. 

The variable that should be used to identify the zygosity of twins is "ZYG" (variable label "Zygosity as classified by Minn twin family registry") NOT q78 (variable label "14 - Are you and your twin identical or fraternal twins?"). ZYG (based on multiple questions by the Minnesota Twin Registry) is a considered a valid measure of zygosity. Q78 was asked in an attempt to probe misidentified zygosity (i.e. the assumption is that when ZYG and Q78 disagree, ZYG is correct and Q78 is incorrect). 


We request that all users provide appropriate acknowledgement of this data source in all papers and publications. We suggest doing so in a footnote containing the following language: 

"The data employed in this project were collected with the financial support of the National Science Foundation in the form of SES-0721378, PI: John R. Hibbing; Co-PIs: John R. Alford, Lindon J. Eaves, Carolyn L. Funk, Peter K. Hatemi, and Kevin B. Smith, and with the cooperation of the Minnesota Twin Registry at the University of Minnesota, Robert Krueger and Matthew McGue, Directors."