Examples of the four experimental conditions in a two-choice go/nogo design.

<p>In each trial two pictures were presented one after the other on screen. The first picture, the target, consisted of a colored circle in front of or behind a gray, horizontal oblong. The second picture, the probe, comprised a colored object in front of or behind a gray lattice of iron bars. In the go/color condition the probe color deviated determinably from the target color. In the go/position condition it was the probe position determinably deviating from the target position. In the nogo/color condition the deviated probe color was indeterminable. In the nogo/position condition the probe object was stuck between the iron bars, giving rise to an indeterminable position. Participants were instructed to respond to each condition accordingly with button pressing and speaking.</p

Mean Reaction Times (RT) in ms and Error Rates in Percentage (Standard Deviations in Parentheses).

<p>Mean Reaction Times (RT) in ms and Error Rates in Percentage (Standard Deviations in Parentheses).</p

Difference waves between go- and nogo-LRP in position conditions.

<p>The difference waves were derived for the three speaker groups, respectively, by subtracting the LRP elicited in the nogo/position condition from the LRP elicited in the go/position condition: the dotted line for the Chinese speaker group, the solid line for the German speaker group, and the dashed line for the Polish speaker group.</p

Mean lateralized readiness potentials (LRP) in the color (left charts) and the position (right charts) conditions.

<p>The three panels from top to bottom are results of the nogo-LRP, the stimulus-locked go-LRP, and the response-locked go-LRP, respectively. In the bottom of each chart the electromyogram is shown for the hand that executed the response or that would have executed the reponse which was inhibited in nogo trials. The four groups of participants were separately designated in each chart: the dotted black line for the Chinese speaker group, the solid black line for the German speaker group, the dashed black line for the Polish speaker group, and the solid gray line for the control group.</p

A simplified diagrammatic depiction of incremental speech production [1], [2].

<p>As soon as the encoding of an utterance constituent is finished at one processing level, it triggers its processing at the ensuing level. Meanwhile, the next constituent is processed at the foregoing level. Different constituents are hence encoded parallel at several processing levels, one constituent at each level, respectively.</p

Regression coefficients of dRT over number and dRT over magnitude bins.

<p>Regression coefficients of dRT over number and dRT over magnitude bins.</p

Left-handed and right-handed responses to each number in each notation, magnitude judgement.

<p><b>SNARC effect</b>: Right-handed responses slower than left-handed responses for small numbers, faster for large numbers. <b>Distance effect</b>: Increased responses times for numbers closer to the middle. Bottom right: Participants who reported using visual categorisation (per our questionnaire; plotted in grey) vs. those who did not. Note the slightly compressed y-axis in this plot. Error bars indicate within-subject SEMs for each number, pooled across each contrast of numbers [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163897#pone.0163897.ref052" target="_blank">52</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163897#pone.0163897.ref053" target="_blank">53</a>]. Horizontal dashed lines indicate grand means of RTs for each notation.</p

Left-handed and right-handed responses to each number in each notation, parity judgement task.

<p><b>SNARC effect</b>: Right-handed responses slower than left-handed responses for small numbers, faster for large numbers. Error bars indicate within-subject SEMs for each number, pooled across each contrast of numbers [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163897#pone.0163897.ref052" target="_blank">52</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163897#pone.0163897.ref053" target="_blank">53</a>]. Horizontal dashed lines indicate grand means of RTs for each notation.</p

The stimuli used in our experiments.

<p>(a) Arabic digits, (b) simple-form Chinese characters, (c) Chinese hand signs as used in Chinese Sign Language. Stimuli in each column represent identical numbers. Note that the number 5 is omitted in all notations. This enabled us to use it as the standard for the magnitude judgement task. Hand signs images retrieved from <a href="https://en.wikipedia.org/wiki/Chinese_number_gestures" target="_blank">https://en.wikipedia.org/wiki/Chinese_number_gestures</a>, created by Wikipedia user Ningling, and used under the terms of the GNU Free Documentation License.</p