Source credibility and plausibility are considered in the validation of textual information: evidence from a social media context

Figures & data

Table 1. Overview of all hypothesised effects of Experiment 1 and 2.

		Experiment 1		Experiment 2
Effect	Dependent Measure	Hypothesis	Prediction	Hypothesis	Prediction
Plausibility Effect	Reading Times	1.1	belief-consistent texts < belief-inconsistent texts	2.1	plausible texts < implausible texts
	Plausibility Ratings	1.3	belief-consistent texts > belief-inconsistent texts	2.3	plausible texts > implausible texts
Trustworthiness Effect	Reading Times	1.2	trustworthy source < untrustworthy source	-	-
	Plausibility Ratings	1.4	trustworthy source > untrustworthy source	-	-
Open Research Question/ Interaction Effect	Reading Times	Open Research Question 1	trustworthy source & belief-inconsistent text <untrustworthy source & belief-inconsistent text	2.2	trustworthy source & implausible text > untrustworthy source & implausible text
	Plausibility Ratings	Open Research Question 2	trustworthy source & belief-inconsistent text > untrustworthy source & belief-inconsistent text	2.4	trustworthy source & implausible < untrustworthy source & implausible
			trustworthy source & belief-consistent text > untrustworthy source & belief-consistent text		trustworthy source & plausible text > untrustworthy source & plausible text
Manipulation Check	Source Credibility Ratings	1.5	trustworthy source > untrustworthy source	2.5	trustworthy source > untrustworthy source

Figure 1. Translated example tweets from filler and experimental trials from Experiment 1.

Table 2. Estimated coefficients, standard errors, degrees of freedom, and t values for the linear mixed model of the reading times in Experiment 1.

	Est.	SE	df	t	p
(Intercept)	9.124	0.037	54.75	246.54	< .001
Item Position	−0.096	0.006	2626	−15.90	< .001
Text Length	0.038	0.016	62.83	3.26	< .001
Trustworthiness	−0.019	0.006	2636	−3.18	.001
Text-belief Consistency	−0.027	0.012	61.57	−2.30	.025
Trustworthiness x Text-belief Consistency	0.003	0.006	2638	0.48	.630

Note. Trustworthiness (contrast coded: trustworthy = 1, untrustworthy = −1). Text-belief consistency (contrast coded: belief-consistent = 1, belief-inconsistent = −1).

Figure 2. Mean reading times with ±1 standard error of Experiment 1 and 2 by experimental condition.

Table 3. Estimated coefficients, standard errors, degrees of freedom, and t values for the linear mixed model of the plausibility ratings in Experiment 1.

	Est.	SE	df	t	p
(Intercept)	4.13	0.09	69.57	43.99	< .001
Trustworthiness	0.12	0.03	1797	3.32	< .001
Text-belief Consistency	1.10	0.08	61.36	14.410	< .001
Trustworthiness x Text-belief Consistency	0.12	0.03	1797	2.57	.010

Note. Trustworthiness (contrast coded: trustworthy = 1, untrustworthy = −1). Text-belief consistency (contrast coded: belief-consistent = 1, belief-inconsistent = −1).

Figure 3. Mean plausibility ratings with ±1 standard error of Experiment 1 and 2 by experimental condition.

Figure 4. Mean source credibility ratings with ±1 standard error of Experiment 1 and 2 by experimental condition.

Figure 5. Translated example tweets from experimental trials from Experiment 2.

Table 4. Estimated coefficients, standard errors, degrees of freedom, and t values for the linear mixed model of the reading times in Experiment 2.

	Est.	SE	df	t	p
(Intercept)	8.693	0.035	74.41	250.72	< .001
Text Length	0.129	0.017	66.33	7.48	< .001
Item Position	−0.100	0.007	1910	−13.68	< .001
Trustworthiness	−0.011	0.007	1904	−1.47	.142
Plausibility	0.011	0.007	1923	1.57	.116
Trustworthiness x Plausibility	0.015	0.007	1901	2.04	.041

Note. Trustworthiness (contrast coded: trustworthy = 1, untrustworthy = −1). Plausibility (contrast coded: plausible = 1, implausible = −1).

Table 5. Estimated coefficients, standard errors, degrees of freedom, and t values for the linear mixed model of the plausibility ratings in Experiment 2.

	Est.	SE	df	t	p
(Intercept)	3.70	0.07	49.62	54.66	< .001
Trustworthiness	0.11	0.03	2727.22	65.33	< .001
Plausibility	1.86	0.03	2728.98	3.76	< .001
Trustworthiness x Plausibility	0.02	0.03	2727.22	0.81	.419

Note. Trustworthiness (contrast coded: trustworthy = 1, untrustworthy = −1). Plausibility (contrast coded: plausible = 1, implausible = −1).

Data availability statement

The experimental texts, data files, and R-scripts for the full and additional analyses are available (https://osf.io/r5bgx/). The reported experiments were not preregistered.