Materials, data and code for the manuscript titled "Blurring the lines between cognition and metacognition: the case of meta-metacognition". Here is a guideline to the uploaded files: "all_subjects_data.csv" contains the raw data for all the subjects. "pre-processing.m" is the MATLAB file in which we excluded potential inattentive subjects and trials, and estimated each subjects' behavioral indexes including decision accuracy, RT and Signal Detection Theory (SDT) parameters (e.g., d', confidence criterion and Mratio, etc). The functions used for estimating the SDT parameters are in the "helperFunctions" folder. This MATLAB file should be run first to generate the data for further analyses in R. "analysis & plot.R" is the R file in which we performed the statistical analysis and made the corresponding plots on the pre-processed data. "task code" folder contains the JavaScript files for presenting the stimuli and running the experiment. "typ2only_typ2typ3" folder is the code for the experiment starting with Type-2-only condition, while "typ2typ3_typ2only" is for the experiment starting with Type-2/Type-3 condition. The experiment can also be accessed here: https://perception-expts.gatech.edu/type3_index.html (But please note that the link might not be supported for a very long time due to technical issues including browser compatibility and server updates).