Pre-pandemic electrodermal activity predicts current COVID-related fears: household size during lockdown as a moderating factor

Figures & data

Figure 1. Individuals’ COVID-19 related fears as a function of their pre-pandemic Tonic SCL scores. A scatter plot of pre-pandemic Tonic SCL in microsiemens and COVID-related fears with a linear regression line and its corresponding 95% confidence interval. On the margins we display density plots of each of the plotted variables.

Figure 2. Individuals’ COVID-19 related fears as a function of their pre-pandemic NS-SCRs score. A scatter plot of pre-pandemic NS-SCRs and COVID-related fears with a linear regression line and its corresponding 95% confidence interval. On the margins we display density plots of each of the plotted variables.

Table 1. Correlation matrix for the three specific fears comprising our COVID-19 fear score and pre-pandemic tonic SCL and number of SCRs.

Variable	1	2	3	4
1. Tonic SCL in microsiemens	–	–	–	–
2. # of NS-SCRs	.55**	–	–	–
3. Fear of family member infected	.13	.16*	–	–
4. Fear of unknown sickness	.18*	.17*	.53**	–
5. Fear of infecting others	.09	.17*	.50**	.52**

*p < .05; **p < .01; SCL: skin conductance level; NS-SCRs: number of nonspecific skin conductance responses. N = 176.

Table 2. Means and SD’s of the main variables and correlations between them.

Variable	Mean/%	SD	1	2	3	4	5	6	7
1. Female^a	71%		–	–	–	–	–	–	–
2. Age	23.12	3.02	−.10	–	–	–	–	–	–
3. High decrease in income^b	20%		.26**	−.12	–	–	–	–	–
4. Days elapsed since BL	762	221	−.20**	.24**	−.17*	–	–	–	–
5. Tonic SCL in microsiemens	10.48	6.13	−.03	.00	.09	−.13	–	–	–
6. # of NS-SCRs	26.21	16.42	−.08	.01	−.01	.01	.55**	–	–
7. # of people in household	2.94	1.95	−.05	−.18*	.01	.04	−.03	−.12	–
8. COVID-related fears	3.17	1.05	.27**	.01	.27**	−.09	.16*	.20**	−.03

*p < .05; **p < .01 ^a = (Dummy coded: 0 = male; 1= female); ^b = Dummy coded (0 = no reduction; 1 = partial reduction; 2 = large reduction); BL: baseline; SCL: skin conductance level; NS-SCRs: nonspecific skin conductance responses. N = 176.

Table 3. Hierarchical regression analysis predicting COVID-19 related fears with NS-SCRs as a predictor.

Variable	Step 1	Step2
Gender^a	.23**	.24**
Age	.08	.07
Income decrease^b	.23**	.22**
Days elapsed since BL	−.03	−.01
Number of NS-SCRs^c	.21**	.23**
# of people in household^c	.03	.05
# of people in household X # of NS-SCRs		.16*
R^2	.14	.16
F(df)	5.50 (6,162)**	5.43 (7,161)**
Fchange	4.03*	4.82*

^a = (Dummy coded: 0 = male; 1= female); ^b = Dummy coded (0 = no reduction or partial reduction; 1 = large reduction); ^c = men centered; BL: baseline; NS-SCRs: nonspecific skin conductance responses. N = 168; coefficients are standardized. *p < .05; **p < .01.

Figure 3. Effects of pre-pandemic number of NS-SCRs on COVID-related fears among individuals who inhabited with a low, average, and high number of people in their household during the lockdown. A simple slope plot depicting the relationship between standardized pre-pandemic number of NS-SCRs and COVID fears in three subgroups in the sample – those reporting a low (-1SD; two people), an average (four people), and a high (+1SD; six people) number of people in their household during the lockdown.

Table 4. Moderation analysis of the interaction between number of NS-SCRs and household size on covid-19 fears.

Simple Slope Estimates
	Estimate	SE	95% Confidence Interval		T	p Value
			Lower	Upper
Low (-1SD; two people)	0.004	0.006	−0.009	0.016	0.583	.561
Average (four people)	0.015	0.005	0.006	0.024	3.213	0.002
High (+1SD; six people)	0.026	0.008	0.011	0.011	3.490	<.001

In the Table we show the effect of the predictor (Pre-pandemic # of NS-SCRs) on the dependent variable (COVID-19 fears) at different levels of the moderator (# of people in household). Estimates are unstandardized; SE: standard error.

Table 5. Hierarchical regression analysis predicting COVID-19 related fears with tonic SCL, in microsiemens, as a predictor.

Variable	Step 1	Step 2
Gender^a	.22**	.22**
Age	.07	.07
Income decrease^b	.22**	.22**
Days elapsed since BL	−.01	−.001
Tonic SCL in microsiemens^c	.14*	.14*
# of people in household^c	.01	.01
# of people in household X SCL in microsiemens		.04
R^2	.11	.10
F(df)	4.59 (6.162)**	3.93 (7.161)**
Fchange	1.98	0.30

^a = (Dummy coded: 0 = male; 1= female); ^b = Dummy coded (0 = no reduction or = partial reduction; 1 = large reduction); ^c = men centered; BL: baseline; SCL: skin conductance level. N = 168; coefficients are standardized. * = p < .05; ** = p < .01. We also computed this analysis without control variables or outliers in number of NSSCRs – results remained similar – See Tables S2 and S3 in the supplementary digital results file.