Appendix
Deoxyhemoglobin deoxyHb Results
Neural responses to speech-like stimuli across all trials. All effects are reported as significant at p<0.05 unless otherwise stated. The 2 (syllabic sequence type: ABB, ABC) x 4 (region: left posterior, left anterior, right posterior, right anterior) x 2 (risk group: HRA, LRC) x 2 (gender: male, female) mixed-design ANOVA revealed a main effect of risk group (F(1, 33) = 11.925, p = 0.002), whereby deoxyHb changes to language stimuli of both syllable sequence types across all regions and both genders were significantly stronger in HRA compared to LRC 3 month olds (i.e. LRC showed a positive deoxyHb concentration change whereas HRA showed a negative deoxyHb concentration change). No other significant main or interaction effects were detected.
Neural responses to speech-like stimuli across exposure. The 2 (syllabic sequence type: ABB, ABC) x 4 (region: left posterior, left anterior, right posterior, right anterior) x 2 (risk group: HRA, LRC) x 2 (gender: male, female) x 2 (exposure: first vs. last stimuli blocks) mixed-design ANOVA also revealed a main effect of risk group (F(1, 33) = 6.755, p = 0.014), whereby deoxyHb changes to language stimuli were stronger in HRA than LRC 3 month olds (i.e. LRC showed positive deoxyHb values whereas HRA showed negative deoxyHb values). This ANOVA also revealed an interaction between exposure and gender (F(1,33) = 6.096, p = 0.019), which indicates that deoxyHb responses differed over the course of infants’ exposure to these stimuli, depending on infants’ genders. Follow up t-tests reveal that female infants’ deoxyHb responses became weaker (i.e. less negative), whereas males’ neural responses showed no significant change, over exposure to both syllabic sequence types (Figures 5 and 6).
Fig. 5
Interaction between exposure and gender in deoxyhemoglobin responses (F(1,33) = 6.096, p = 0.019)
Fig. 6
Average deoxyHb concentration at each time point across the 16 second time window for (a) first four ABB, (b) last four ABB, (c) first four ABC, and (d) last four ABC stimulus trials heard, broken down by gender and risk group, and collapsed across all ROIs.