Friday, May 23, 2014

A nonverbal stroop test for children to examine the bilingual advantage

Over the past several years, I have collaborated with Alena Esposito (who was a student at NCSU at the time)  developing some PEBL tests that help measure the impact of executive control and suppression of irrelevant information on bilingual children.  This project already spurred the development of two new stroop tests that are part of PEBL (a standard color stroop and a number stroop), but it also lead to development of a new test, the Bivalent Shape Task (BST), which was published in a paper in Cognitive Development (fulltext), and we just got published as a meta-paper in the Journal of Open Research Software (JORS).



The task is pretty straight-forward, similar in structure to many stroop-like tasks, and actually fairly similar to the Oddball task which is already part of PEBL.  The task can allow responses via a mouse or keyboard, but the left response is always labeled with a red circle, and the right response with a blue square.  The task of the subject is to sort the shape in the middle of the screen based on its shape (ignoring the color).  Several consecutive blocks are measured, including congruent (where the target circle is always red and the target square is always blue), incongruent (the reverse), neutral (where the stimulus shapes are black-and-white outlines) and mixed (incorporating all of these). We developed this test to see if bilingual children were better at response inhibition even for non-linguistic materials (the stroop task has a potential confound because it is linguistic). Results showed a bilingual advantage in this task (which was not present in stroop), and suggests that there are some real developmental changes to the brain that happen for bilingual children that may transfer to skills outside language.  Some other cool aspects of this task are that it only takes about 5 minutes, and can be performed by even small children.

We published this in a new journal called the "Journal of Open Research Software".  This journal has a really interesting model that is great for people like me who develop software for research as part of our research.  Too often, software development gets discounted and ignored, because promotion and hiring committees know how to count publications, but not much else. JORS provides a way to 'publish' software in a peer-reviewed venue, and in an easily citeable format. They call this a meta-article, because it is really about something else that is the main contribution.  This is great for psychology and neuroscience, because the main venues for publishing methodology like this can be fickle.  For example, Behavior Research Methods has a policy against publishing 'software' papers like this, adding to the perception that developing research software is not an intellectual or research activity.  The irony here is that many of the papers that use PEBL tests do not cite PEBL at all or with only a footnoted URL, so that they give more citation credit to throw-away references than to the tools upon which their research was built. 



Full citations below:

Mueller, S.T. and Esposito, A.G. (2014). Computerized Testing Software for Assessing Interference Suppression in Children and Adults: The Bivalent Shape Task (BST). Journal of Open Research Software 2(1):e3, DOI: http://dx.doi.org/10.5334/jors.ak

Esposito, A. G., Baker-Ward, L., & Mueller, S. (2013). Interference Suppression vs. Response Inhibition: An Explanation for the Absence of a Bilingual Advantage in Preschoolers’ Stroop Task Performance. Cognitive Development.

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