TABLE 3.
Correlation matrix for self-reported outcomes and facial muscle activation for the device-free smile manipulation.
| Comfort | Muscle fatigue | Difficulty | Positive affect | Negative affect | Aroused | Unaroused | ZMM activation change score | OOM activation change score | |
| Comfort | 1 | −0.172∗ | –0.473∗∗ | 0.327∗∗ | –0.083 | 0.163∗ | –0.147 | −0.176∗ | –0.120 |
| Muscle fatigue | – | 1 | 0.436∗∗ | –0.018 | 0.306∗∗ | –0.003 | 0.257∗∗ | 0.176∗ | 0.044 |
| Difficulty | – | – | 1 | –0.088 | 0.181 | –0.054 | 0.231∗∗ | 0.092 | –0.039 |
| Positive affect | – | – | – | 1 | –0.133 | 0.655∗∗ | −0.186∗ | 0.087 | 0.083 |
| Negative affect | – | – | – | – | 1 | 0.008 | 0.453∗∗ | –0.014 | –0.041 |
| Aroused | – | – | – | – | – | 1 | –0.353∗∗ | 0.050 | 0.053 |
| Unaroused | – | – | – | – | – | – | 1 | –0.114 | −0.208∗ |
| ZMM activation change score | – | – | – | – | – | – | – | 1 | 0.544∗∗ |
| OOM activation change score | – | – | – | – | – | – | – | – | 1 |
ZMM = zygomaticus major muscle; OOM = orbicularis oculi muscle. ∗p < 0.05, ∗∗p < 0.01.