1 Introduction
2 Theoretical and empirical background
2.1 Psychological constructs and political extremism
2.1.1 Certainty
2.1.2 Anxiety
2.1.3 Happiness
2.2 Moral foundations and political extremism
3 Data and methods
3.1 Identifying political extremist groups in U.S. and their followers
3.2 Control groups
Liberals | Tammy Baldwin, Mazie Hirono, Edward Markey, Bernie Sanders, Elizabeth Warren |
Conservatives | Ted Cruz, Jeff Flake, Mike Lee, Rand Paul, Ben Sasse |
3.3 Preprocessing of followers
LW | RW | LWE | RWE | |
---|---|---|---|---|
No. of seed accounts | 5 | 5 | 25 | 25 |
No. of followers | 12,296,381 | 6,308,557 | 248,108 | 329,471 |
No. of unique followers | 8,489,101 | 3,849,008 | 143,759 | 173,211 |
No. of unique followers after preprocessing | 28,249 | 28,669 | 61,196 | 57,163 |
No. of unique preprocessed followers after bot exclusion | 26,594 | 27,245 | 59,709 | 55,363 |
No. of followers who follow at least 3 seed accounts | 9400 | 12,034 | 7665 | 10,983 |
No. of qualified followers | 9119 | 11,808 | 7314 | 10,609 |
Randomly sampled from qualified followers | 5000 | 5000 | 5000 | 5000 |
3.4 Preprocessing of tweets
3.5 Inferring and validating psychological indicators
Statistics | Anxiety | Certainty | Negative emotion | Positive emotion |
---|---|---|---|---|
Coefficient | 0.31 | 0.28 | 0.38 | 0.32 |
p value | 0.02 | 0.03 | 0.003 | 0.01 |
3.6 Inferring moral foundations
Statistics | Authority | Fairness | Harm avoidance/care | In-group loyalty | Purity |
---|---|---|---|---|---|
Coefficient | 0.29 | 0.51 | 0.46 | 0.28 | 0.57 |
p value | 0.035 | 0.0000 | 0.0002 | 0.05 | 0.0000 |
3.7 Confounding covariates
Name | Description |
---|---|
Tweet count | Number of tweets in the past three months |
Mention count | Number of users mentions in the past three months |
Retweet count | Number of retweets in the past three months |
Activity frequency | Average inter-event days between user’s activity |
Followers count | Number of extant followers |
Friends count | Number of extant friends |
Favorites counts | Total number of times a user favorited others’ post |
Tenure | Days since creation of an account |
Profile picture | Weather a user has a profile picture |
Tweet topics | Variables indicating the ratio of users’ tweets about a given topic |
3.8 Covariates adjustment
4 Results
4.1 Certainty
Degree of freedom | Sum of square | Mean square | F value | Pr (>F) | |
---|---|---|---|---|---|
Political orientation | 1 | 0.00000004 | 0.00000004 | 1.08 | 0.299 |
Political extremity | 1 | 0.00000019 | 0.00000019 | 5.44 | 0.020 |
Residuals | 19,997 | 0.00060811 | 0.00000003 | – | – |
Mean difference | 95% Confidence interval | Adjusted P-value | ||
---|---|---|---|---|
Lower bound | Upper bound | |||
lwe-lw | −0.0004 | −0.0012 | 0.0004 | 0.5723 |
rw-lw | 0.0003 | −0.0005 | 0.0011 | 0.7805 |
rwe-lw | −0.0003 | −0.0011 | 0.0005 | 0.835 |
rw-lwe | 0.0007 | −0.0001 | 0.0015 | 0.1112 |
rwe-lwe | 0.0001 | −0.0007 | 0.0009 | 0.9759 |
rwe-rw | −0.0005 | −0.0013 | 0.0002 | 0.2863 |
4.2 Anxiety
Degree of freedom | Sum of square | Mean square | F value | Pr (>F) | |
---|---|---|---|---|---|
Political orientation | 1 | 0.00000028 | 0.00000028 | 38.41 | <0.001∗∗∗ |
Political extremity | 1 | 0.00000001 | 0.00000001 | 0.81 | 0.367 |
Residuals | 19,997 | 0.00012607 | 0.00000001 | – | – |
Mean difference | 95% Confidence interval | Adjusted P-value | ||
---|---|---|---|---|
Lower bound | Upper bound | |||
lwe-lw | 0.0005 | 0.0002 | 0.0009 | <0.001∗∗∗ |
rw-lw | −0.0001 | −0.0005 | 0.0002 | 0.73 |
rwe-lw | −0.0005 | −0.0008 | −0.0001 | <0.001∗∗∗ |
rw-lwe | −0.0007 | −0.001 | −0.0003 | <0.001∗∗∗ |
rwe-lwe | −0.001 | −0.0014 | −0.0006 | <0.001∗∗∗ |
rwe-rw | −0.0003 | −0.0007 | 0 | 0.07 |
4.3 Happiness
Degree of freedom | Sum of square | Mean square | F value | Pr (>F) | |
---|---|---|---|---|---|
Positive emotion: | |||||
Political orientation | 1 | 0.000003 | 0.0000026 | 11.24 | 0.001∗∗ |
Political extremity | 1 | 0.000017 | 0.0000167 | 73.11 | <0.001∗∗∗ |
Residuals | 19,997 | 0.003962 | 0.0000002 | – | – |
Negative emotion: | |||||
Political orientation | 1 | 0.000001 | 0.0000012 | 12.08 | 0.001∗∗ |
Political extremity | 1 | 0.000007 | 0.0000074 | 73.17 | <0.001∗∗∗ |
Residuals | 19,997 | 0.001757 | 0.0000001 | – | – |
Mean difference | 95% Confidence interval | Adjusted P-values | ||
---|---|---|---|---|
Lower bound | Upper bound | |||
Positive emotion: | ||||
lwe-lw | −0.0065 | −0.0084 | −0.0047 | <0.001∗∗∗ |
rw-lw | −0.0004 | −0.0023 | 0.0014 | 0.9381 |
rwe-lw | −0.0027 | −0.0046 | −0.0008 | 0.0016∗ |
rw-lwe | 0.0061 | 0.0043 | 0.008 | <0.001∗∗∗ |
rwe-lwe | 0.0038 | 0.0019 | 0.0058 | <0.001∗∗∗ |
rwe-rw | −0.0023 | −0.0042 | −0.0004 | 0.0104 |
Negative emotion: | ||||
lwe-lw | 0.0038 | 0.0026 | 0.005 | <0.001∗∗∗ |
rw-lw | −0.0003 | −0.0015 | 0.0008 | 0.9026 |
rwe-lw | 0.0018 | 0.0006 | 0.003 | 0.0009∗∗∗ |
rw-lwe | −0.0041 | −0.0053 | −0.003 | <0.001∗∗∗ |
rwe-lwe | −0.002 | −0.0032 | −0.0008 | 0.0001∗∗∗ |
rwe-rw | 0.0021 | 0.0009 | 0.0033 | <0.001∗∗∗ |
4.4 Moral foundations theory
4.4.1 Fairness
Degree of freedom | Sum of square | Mean square | F value | Pr (>F) | |
---|---|---|---|---|---|
Political orientation | 1 | 0.00000003 | 0.000000030 | 16.41 | <0.001∗∗∗ |
Political extremity | 1 | 0.00000001 | 0.000000010 | 5.21 | 0.022 |
Residuals | 19,997 | 0.00003219 | 0.000000002 | – | – |
Mean difference | 95% Confidence interval | Adjusted P-value | ||
---|---|---|---|---|
Lower bound | Upper bound | |||
lwe-lw | 0.0001 | −0.0001 | 0.0002 | 0.8738 |
rw-lw | −0.0001 | −0.0002 | 0.0002 | 0.9749 |
rwe-lw | −0.0003 | −0.0005 | −0.0001 | 0.0003∗∗∗ |
rw-lwe | −0.0001 | −0.0003 | 0.0001 | 0.6353 |
rwe-lwe | −0.0003 | −0.0005 | −0.0002 | <0.001∗∗∗ |
rwe-rw | −0.0003 | −0.0004 | −0.0001 | 0.0014∗ |
4.4.2 Harm avoidance/care
Degree of freedom | Sum of square | Mean square | F value | Pr (>F) | |
---|---|---|---|---|---|
Political orientation | 1 | 0.00000011 | 0.00000011 | 4.50 | 0.034 |
Political extremity | 1 | 0.00000002 | 0.00000002 | 0.91 | 0.34 |
Residuals | 19,997 | 0.00043226 | 0.00000002 | – | – |
Mean difference | 95% Confidence interval | Adjusted P-value | ||
---|---|---|---|---|
Lower bound | Upper bound | |||
lwe-lw | −0.0001 | −0.0006 | 0.0004 | 0.9453 |
rw-lw | −0.0003 | −0.0008 | 0.0002 | 0.4058 |
rwe-lw | −0.0005 | −0.0011 | 0 | 0.0576 |
rw-lwe | −0.0002 | −0.0007 | 0.0003 | 0.7547 |
rwe-lwe | −0.0004 | −0.0009 | 0.0001 | 0.1985 |
rwe-rw | −0.0002 | −0.0007 | 0.0003 | 0.7327 |
4.4.3 Ingroup loyalty
Degree of freedom | Sum of square | Mean square | F value | Pr (>F) | |
---|---|---|---|---|---|
Political orientation | 1 | 0.00000004 | 0.00000004 | 3.651 | 0.056 |
Political extremity | 1 | 0.00000006 | 0.00000006 | 6.056 | 0.014∗ |
Residuals | 19,997 | 0.00018303 | 0.00000001 | – | – |
Mean difference | 95% Confidence interval | Adjusted P-value | ||
---|---|---|---|---|
Lower bound | Upper bound | |||
lwe-lw | 0.0001 | −0.0004 | 0.0005 | 0.9834 |
rw-lw | 0.0005 | 0.0001 | 0.001 | 0.0052∗ |
rwe-lw | −0.0001 | −0.0005 | 0.0004 | 0.9854 |
rw-lwe | 0.0005 | 0.0001 | 0.0009 | 0.0195 |
rwe-lwe | −0.0001 | −0.0006 | 0.0003 | 0.8949 |
rwe-rw | −0.0006 | −0.001 | −0.0002 | 0.0022∗ |
4.4.4 Obedience to authority
Degree of freedom | Sum of square | Mean square | F value | Pr (>F) | |
---|---|---|---|---|---|
Political orientation | 1 | 0.00000089 | 0.00000089 | 56.05 | <0.001∗∗∗ |
Political extremity | 1 | 0.00000004 | 0.00000004 | 2.38 | 0.123 |
Residuals | 19,997 | 0.00027571 | 0.00000002 | – | – |
Mean difference | 95% Confidence interval | Adjusted P-value | ||
---|---|---|---|---|
Lower bound | Upper bound | |||
lwe-lw | −0.0005 | −0.0009 | −0.0001 | 0.0051∗ |
rw-lw | 0.0003 | −0.0001 | 0.0007 | 0.18 |
rwe-lw | 0.0012 | 0.0008 | 0.0016 | <0.001∗∗∗ |
rw-lwe | 0.0008 | 0.0004 | 0.0012 | <0.001∗∗∗ |
rwe-lwe | 0.0017 | 0.0013 | 0.0021 | <0.001∗∗∗ |
rwe-rw | 0.0009 | 0.0005 | 0.0013 | <0.001∗∗∗ |
4.4.5 Purity
Degree of freedom | Sum of square | Mean square | F value | Pr (>F) | |
---|---|---|---|---|---|
Political orientation | 1 | 0.00000006 | 0.00000006 | 8.54 | 0.003∗ |
Political extremity | 1 | 0 | 0.000000002 | 0.34 | 0.561 |
Residuals | 19,997 | 0.0001138 | 0.000000007 | – | – |
Mean difference | 95% Confidence interval | Adjusted P-value | ||
---|---|---|---|---|
Lower bound | Upper bound | |||
lwe-lw | 0.0001 | −0.0002 | 0.0004 | 0.9193 |
rw-lw | 0.0003 | 0.0001 | 0.0006 | 0.0857 |
rwe-lw | 0.0003 | 0.0001 | 0.0006 | 0.0645 |
rw-lwe | 0.0002 | −0.0001 | 0.0005 | 0.3195 |
rwe-lwe | 0.0002 | −0.0001 | 0.0005 | 0.2522 |
rwe-rw | 0.0001 | −0.0003 | 0.0003 | 0.9972 |
4.5 Effect sizes
5 Discussion
Variable | Hypothesis | Test | Direction | Significant |
---|---|---|---|---|
Certainty | Extremists > Non-extremists | ANOVA | ✗ | ✗ |
Extremists < Non-extremists | ANOVA | ✓ | ✗ | |
RWE > LWE | Tukey’s HSD | ✓ | ✗ | |
Anxiety | RWE > Others | Tukey’s HSD | ✗✗✗ | ✗✗✗ |
RWE < Others | Tukey’s HSD | ✓✓✓ | ✓✓✗ | |
Positive emotion | RW > LW | Tukey’s HSD | ✗ | ✗ |
RW < LW | Tukey’s HSD | ✓ | ✗ | |
Extremists > Non-extremists | ANOVA | ✗ | ✗ | |
Extremists < Non-extremists | ANOVA | ✓ | ✓ | |
RWE > LWE | Tukey’s HSD | ✓ | ✓ | |
RWE < LWE | Tukey’s HSD | ✗ | ✗ | |
Negative emotion | RW > LW | Tukey’s HSD | ✗ | ✗ |
RW < LW | Tukey’s HSD | ✓ | ✗ | |
Extremists > Non-extremists | ANOVA | ✓ | ✓ | |
Extremists < Non-extremists | ANOVA | ✗ | ✗ | |
RWE > LWE | Tukey’s HSD | ✗ | ✗ | |
RWE < LWE | Tukey’s HSD | ✓ | ✓ | |
Fairness | LWE > RWE | Tukey’s HSD | ✓ | ✓ |
LWE > LW | Tukey’s HSD | ✓ | ✗ | |
Harm avoidance | LWE > RWE | Tukey’s HSD | ✓ | ✗ |
LWE > LW | Tukey’s HSD | ✗ | ✗ | |
Obedience to authority | RWE > LWE | Tukey’s HSD | ✓ | ✓ |
RWE > RW | Tukey’s HSD | ✓ | ✓ | |
Ingroup loyalty | RWE > LWE | Tukey’s HSD | ✗ | ✗ |
RWE > RW | Tukey’s HSD | ✗ | ✓ | |
Purity | RWE > LWE | Tukey’s HSD | ✓ | ✗ |
RWE > RW | Tukey’s HSD | ✓ | ✗ |