Table 2. Correlation coefficients of Low-level Image Features and Ratings.

	Mean ratings				Individual ratings
	Arousal		Time ref.		Arousal		Time ref.
	r	P	r	P	Mean r z *	SE	Mean r z *	SE
Luminance
Mean	.307	.157	−.022	.917	.156	0.041	−.011	0.039
SD	.001	.996	−.151	.484	−.001	0.047	−.109	0.036
Median	.322	.139	−.025	.909	.163	0.046	−.011	0.042
Colour
R-value	.371	.089	−.146	.498	.190	0.046	−.092	0.037
G-value	.278	.200	.009	.967	.140	0.041	.008	0.040
B-value	.032	.881	.295	.174	.018	0.031	.195	0.040
R/G-ratio	.143	.509	−.425	.052	.083	0.053	−.272	0.049
R/B ratio	.273	.209	−.405	.063	.128	0.039	−.263	0.047
G/B ratio	.242	.263	−.315	.148	.112	0.038	−.206	0.046
Mean	.254	.242	.050	.818	.131	0.037	.037	0.038
Spatial frequency	.174	.420	−.026	.904	.070	0.057	−.033	0.045

Note: r =  Pearson correlation coefficients; P =  uncorrected significance level; SD  =  Standard Deviation of the Mean; ‘Mean ratings’ refers to tests between the average ratings (across all participants) and the low-level image feature parameters; ‘Individual ratings’ refers to the averaged correlation coefficients between the individual participants' ratings and the low-level image features (SE  =  Standard Error of the Mean; Mean r _z  =  Fisher-Z-transformed r; *the critical value for P<.05, df  = 23) was r _crit  = .553.