Importantly, the size of the REA was not dependent on whether the participants chose to listen to the syllables in their native language or not.
This finding is commonly interpreted as an indicator of left hemisphere processing of language (e.g., Kimura, 1967; Pollmann, 2010).
Support for this interpretation of the REA comes from studies using functional magnetic resonance imaging (e.g., Jäncke et al., 2002; van den Noort et al., 2008), positron emission tomography (e.g., O’Leary et al., 1996; Hugdahl et al., 1999), electroencephalography (e.g., Brancucci et al., 2004), magnetoencephalography (e.g., Alho et al., 2012), Wada-test (e.g., Hugdahl et al., 1997), as well as from studies on split brain patients and patients with callosal lesion (e.g., Milner et al., 1968; Springer and Gazzaniga, 1975; for a review see Westerhausen and Hugdahl, 2008).
However, the advent of handheld mobile devices (MDs; e.g., smartphones) with processing power comparable to stationary systems has opened the door to transferring experiments from the laboratory to real-life settings while maintaining control over stimulus presentation.
In real-life, cognitive processes are executed in noisy environments.
First, we evaluated the retest reliability and concurrent validity of the DL paradigm in its MD version in two samples tested in controlled, laboratory settings (Experiment 1).
Second, we explored its ecological validity by collecting data from the general population by means of a free release of the MD version (i Dichotic) to the i Tunes App Store (Experiment 2).
The recent advent of smartphone technology provides an ideal medium for such testing.
In order to examine the feasibility of mobile devices (MD) in psychological research in general, and laterality research in particular, we developed a MD version of the widely used speech laterality test, the consonant-vowel dichotic listening (DL) paradigm, for use with i Phones/i Pods.
Second, we investigated whether the MD version produces robust results when applied to the general population as part of a “crowd sourcing” field experiment (Experiment 2), by making the paradigm publicly available on Apple’s digital application distribution platform (App Store).