The role of subjective frequency in language switching: an ERP investigation using masked priming

Abstract

Two experiments examined the nature of language-switching effects in a priming paradigm with event-related brain potential (ERP) recordings. primes and targets were always unrelated words but could be either from the same or different languages (Experiment 1) or from the same or a different frequency range (Experiment 2). Effects of switching language across prime and target differed as a function of the direction of the switch and prime duration in Experiment 1. Effects tended to be stronger with 100-ms prime durations than with 50-ms durations, and the expected pattern of greater negativity in the switch condition appeared earlier when primes were in L1 and targets in L2 than vice versa. Experiment 2 examined whether these language-switching effects could be due to differences in the subjective frequency of words in a bilingual's two languages, by testing a frequency-switching manipulation within the L1. Effects of frequency switching were evident in the ERP waveforms, but the pattern did not resemble the language-switching effects, therefore suggesting that different mechanisms are at play.

Fig. 1

Electrode montage and sites analyzed in ANOVAs of ERP data in both experiments

Fig. 2

A typical trial in Experiment 1

Fig. 3

a Target ERPs from selected sites in Experiment 1 in the 50-ms prime condition, showing L1 (English) targets preceded by either L1 (English) primes (solid) or L2 (French) primes (dashed). The vertical calibration bar and the arrow on the time legend marks the point of target onset. Negative values plotted upward and x-axis scale in milliseconds in this and all the following figures. b Target ERPs in the 100-ms prime duration condition; all else as in Fig. 3a

Fig. 4

a Voltage maps of difference waves (between-language trials minus within-language trials) at three latencies in Experiment 1 for L1 targets in the top row and L2 targets in the bottom row, averaged across the two prime durations. b Voltage maps of difference waves (switch trials minus nonswitch trials) in Experiment 2 for high-frequency targets in the top row and low-frequency targets in the bottom row

Fig. 5

a Target ERPs at selected sites in the 50-ms condition of Experiment 1, showing L2 (French) targets preceded by L2 (French) primes (solid) over-plotted with L2 (French) targets preceded by L1 (English) primes (dashed). b Target ERPs in the 100-ms condition of Experiment 1 showing L2 (French) targets preceded by either L2 primes (solid), or L1 (English) primes (dashed)

Fig. 6

Difference waves formed by subtracting the voltage values at one representative electrode site (Cz). On the left, the nonswitch condition is subtracted from the switch condition for L1 and L2 targets at the 50-ms (solid) and 100-ms (dashed) prime durations of Experiment 1. On the right are subtractions of the high-frequency targets when preceded by a low-versus high-frequency prime word (solid) and low-frequency targets when preceded by high-versus low-frequency primes (dashed) in Experiment 2

Fig. 7

ERPs to selected sites in Experiment 2, showing high-frequency primes (analogous to L1 words) followed by high-frequency targets (solid) and low-frequency primes (analogous to L2 words) followed by high-frequency targets (dashed)

Fig. 8

ERPs to selected sites in Experiment 2, showing low-frequency primes (analogous to L2 words) followed by low-frequency targets (solid) and high-frequency primes (analogous to L1 words) followed by low-frequency targets (dashed)