In mdsteiner/ShinyPsych: An easy way to program psychology experiments using Shiny

knitr::include_graphics("../inst/pictures/screenshot_dfe.png")

Default Example

Run ShinyBandit: callApp("DfE", "run")
Show App Code: callApp("DfE", "show")

Description

The ShinyPsych - DfE Task, as in the default example, is an implementation of a decisions from experience lottery task [e.g. @hertwig2004decisions], created with the ShinyPsych package. Decisions from Experience (DfE) are choice problems in the form of lotteries in which a participant is presented different options from which he can sample and learn about the options' underlying distributions by clicking on the options. Each time she clicks on an option, an outcome is displayed. The participant can sample information for as long as she likes and and then has to indicate her preference for one option.

ShinyPsych comes with some default gamble lists that are relatively often used. Sometimes the lists contain only a subset of the gambles used in the study [e.g. @glockner2012cognitive] or are a composition of gambles from several studies (the Birnbaum gambles). Available default lists are gambles from e.g. @birnbaum2008new, @brooks2014risk, @glockner2012cognitive, @hertwig2004decisions, @loomes2002microeconometric and @rieskamp2008probabilistic.

Lottery choice problems displayed as decisions from experience have often been used in decision making research on risk taking, to investigate the dependency of decision behavior on information display, keyword: describtion-experience gap, and to investigate information sampling [e.g. @hertwig2004decisions; @frey2015role; @wulff2017meta; @phillips2014rivals]

ShinyPsych supports two to six different options with unlimited outcomes each. Most studies that used these kinds of choice problems let participants choose between two options.

Common Extensions

For a full description of the layout of the code underlying ShinyPsych - DfE Task, click here ShinyPsych - DfE Task Code Description. Here is a brief description of some ways you can easily extend ShinyPsych - DfE Task:

Define specific choice problems

If you don't want to use one of the default gamble lists but define your own choice problems, you can simply create you own file containing these gambles and load the file with the createDfeList() function. Click here for a tutorial on how exactly you can create such a file.

Change number of options

To change the number of options the participant has to choose from, simply adjust the nOpt argument in includeScriptFiles() and if your not using a default list in createDfeList().

Change number of outcomes

To change the number of outcome-probability pairs in the lotteries, change the nOutc in createDfeList() if your not using a default list.

Adjust game display

To adjust the color of the outcome values such that positive values are displayed in green, negative values in red and zeros in gray (note that when 0 are doubles, they will be floating points in javascript and thus be not exactly 0 due to floating point imprecision. This will lead to 0 sometimes being displayed in green and sometimes in red. To avoid this only use the color feature with integers), just set the signalColors in multiOptDfePage() to 1. Every other value will result in outcomes being displayed in black.