Table 3.

Bivariate correlations between item-level predictor variables

	Words	Syllables	Avg. word frequency	Avg. age of acquisition	Avg. imageability
Item psycholinguistic characteristics
Words
Syllables	0.91 [0.89, 0.93]
Average word frequency	− 0.15 [− 0.29, − 0.01]	− 0.28 [− 0.41, − 0.14]
Average age of acquisition	− 0.12 [− 0.26, − 0.03]	0.10 [− 0.04, 0.24]	− 0.13 [− 0.27, 0.01]
Average imageability	− 0.42 [− 0.53, − 0.29]	− 0.47 [− 0.58, − 0.35]	0.30 [0.17, 0.43]	− 0.05 [− 0.19, 0.10]
Response format (difficulty vs. frequency)	0.04 [− 0.11, 0.19]	0.05 [− 0.09, 0.20]	− 0.44 [− 0.55, − 0.31]	0.13 [− 0.01, 0.28]	− 0.06 [− 0.21, 0.09]

Correlations based on 1% trimmed sample (i.e., scores retained at or below 99th percentile)

Correlation coefficients and 95% confidence intervals based on Fisher’s z transformation