Table 4.

Factor loadings from the omnibus principal component analysis with varimax rotation (assessments and model parameters).

	F1 29.93%	F2 14.80%	F3 13.01%	F4 12.60%	Communalities
Word repetition Del	0.89	0.17	0.20	0.09	0.87
Word repetition Imm	0.88	0.14	0.18	0.08	0.83
√p parameter weight	0.88	0.13	−0.02	−0.01	0.79
NonWord repetition Imm	0.86	0.02	0.28	0.07	0.81
NonWord repetition Del	0.80	−0.02	0.42	0.10	0.83
Cambridge Naming Test	0.75	0.55	0.24	−0.02	0.92
Boston Naming Test	0.74	0.46	0.26	−0.07	0.84
Mean length of utterance	0.70	0.12	−0.19	0.42	0.71
Words per minute	0.64	−0.02	0.01	0.37	0.55
Spoken word-picture matching	0.08	0.93	0.17	0.13	0.91
Written word-picture matching	0.05	0.85	0.03	0.33	0.84
√s parameter weight	0.13	0.59	0.44	−0.08	0.57
Word minimal pairs	0.49	0.54	0.21	0.27	0.64
96 Synonym judgement	0.36	0.44	0.33	0.42	0.61
Forward digit span	0.46	0.09	0.74	0.03	0.77
Type/token ratio	−0.06	0.25	0.67	0.02	0.51
Spoken sentence comprehension	0.31	0.23	0.65	0.44	0.76
Backward digit span	0.41	0.09	0.61	0.21	0.59
Ravens Coloured Matrices	−0.04	−0.07	0.13	0.85	0.74
Camel and cactus pictures	−0.03	0.33	0.00	0.73	0.64
Token	0.42	−0.04	−0.44	0.52	0.64
Brixton Spatial Anticipation	0.20	0.26	0.19	0.52	0.41
NonWord minimal pairs	0.31	0.28	0.34	0.38	0.43

PCA on a large neuropsychological test battery and the s and p parameter weights (square root) from the interactive two-step model (Foygel and Dell, 2000). Values ≥0.05 are indicated in bold, ≥0.04 in italics. Imm: Immediately, Del: Delayed. Numbered factors (F), with percentages showing the variance explained per factor, were termed (1) ‘phonological ability’, (2) ‘semantic ability’, (3) ‘auditory working memory’, (4) ‘executive-demand’.