Irwin & Mandel's (2023) expert analysts inferred higher confidence from probability intervals located above 50% than from equally-wide intervals below 50%

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In a second task within the same study, the 41 expert intelligence analysts were shown two numeric probability intervals with an identical 20-point spread (20%–40% and 60%–80%, equidistant from the scale's midpoint) and asked what confidence level — low, moderate, or high — each communicated. If confidence genuinely tracked only interval width, the two should read identically. They did not: "experts did not separate the location of the probabilities from the width of the intervals. Specifically, they judged the range below 50% as indicating mainly low or moderate confidence, whereas they judged the range above 50% as indicating mainly moderate or high confidence" (Wilcoxon signed-rank test, Z = −4.69, p < .001). Non-expert samples showed the identical pattern at larger scale (n = 440, Z = −14.56, p < .001; independent n = 624 sample, Z = −15.17, p < .001).

Together with the forward-direction finding — that stated confidence shifts inferred probability — this establishes the conflation runs both ways: confidence functions as a de facto probability cue, and probability level functions as a de facto confidence cue. This is the specific mechanism behind Kelly et al.'s summary that "analysts and nonexperts alike do treat probability and confidence as related constructs," and the second half of what resolves question-verify-irwin-mandel-2023-probability-confidence-cue.