highly significantp < 0.001
The difference in negativity across the four panels was highly significant (χ 2 = 932.4, df = 3, p < 0.001) and remained so in every pairwise comparison, including those between the adjacent extremes of the gradient (ME versus GI, χ 2 = 56.6, p < 0.001; upper-respiratory versus pneumonia, χ 2 = 44.3, p < 0.001).