“…Red, blue, and green denoted an increase, decrease, and no significant difference in spectral power compared to baseline, respectively ( Pfurtscheller and Da Silva, 1999 ; Zhang and Gu, 2018 ). After obtaining the ERSP data, further research was conducted on the different frequency bands: gamma (γ, 31–100 Hz), beta (β, 14–30 Hz), alpha (α, 8–13 Hz), theta (θ, 4–7 Hz) and delta (δ, 1–3 Hz) ( Herrmann et al, 2016 ; Wang et al, 2018a , 2020 ). Paired sample t -tests were performed comparing the following experimental conditions: “high vs. low product curiosity,” “high vs. low product comprehension,” “high vs. low product preference,” “high vs. low purchase intention,” “singular vs. plural metaphorical sources,” “no vs. singular metaphorical source,” “no vs. plural metaphorical sources,” to determine whether there were significant differences in the spectral powers between the different conditions ( p < 0.05).…”