Masked emotional priming beyond global valence activations

Abstract

An immense body of research demonstrates that emotional facial expressions can be processed unconsciously. However, it has been assumed that such processing takes place solely on a global valence-based level, allowing individuals to disentangle positive from negative emotions but not the specific emotion. In three studies, we investigated the specificity of emotion processing under conditions of limited awareness using a modified variant of an affective priming task. Faces with happy, angry, sad, fearful, and neutral expressions were presented as masked primes for 33 ms (Study 1) or 14 ms (Studies 2 and 3) followed by emotional target faces (Studies 1 and 2) or emotional adjectives (Study 3). Participants’ task was to categorise the target emotion. In all three studies, discrimination of targets was significantly affected by the emotional primes beyond a simple positive versus negative distinction. Results indicate that specific aspects of emotions might be automatically disentangled in addition to valence, even under conditions of subjective unawareness.

Keywords:

• Affective priming
• Emotion perception
• Facial expression
• Automatic
• Unconscious

Acknowledgements

The research reported in this article was supported by a grant from the Deutsche Forschungsgemeinschaft (DFG) to DW and from the Netherlands Organisation for Scientific Research (NWO) to JD. Experiment 1 was conducted while the first author was at Oxford University. We thank Gwenda Simons for her help in providing laboratory facilities and support in getting the approval of the local ethics commission.

Notes

¹Because of high error rates, all analyses were repeated with error rates as dependent variables to control for speed–accuracy trade-offs. These analyses yielded no significant prime–target interactions in all three experiments, albeit non-significant trends towards reduced error rates in congruent as compared to incongruent trials.

²One might argue that the lack of an emotional priming effect can be explained by assuming that sad and fearful primes are not processed with regard to any evaluative aspects at all and are thus perceived as neutral. However, an additional analysis shows this to be implausible. After adjusting cell means of Table 1 for main effects of primes and targets, we calculated a priming difference mean RT (sad/fearful primes followed by happy targets) minus mean RT (sad/fearful primes followed by sad/fearful targets) to see whether these primes are at least processed with regard to valence. The mean of this difference is M=26 ms (SE=7 ms); it is significantly above zero, t(80) = 3.43, p<.001. In a related note one could assume that the significant C2[prime]×C2[target] interaction contrasting negative type-congruent trials (i.e., angry–angry and fearful/sad–sad/fearful) and negative type-incongruent trials (i.e., angry–fearful/sad and fearful/sad–angry) was (partly) due to main effects of prime and targets. Rerunning the analysis with means adjusted for main effects of prime and target emotion, however, yielded essentially the same result as with unadjusted means, F(1, 80) = 6.68, p<.05.

³Each df corresponds to a specific difference variable that can be tested on deviance from zero (see, e.g., the test for the contrasts C1×C1, C2×C2, and C3×C3 given above). The multivariate test for a set of three or six difference variables, respectively, corresponds to the test whether the set vector of means deviates from the corresponding zero vector.

⁴Likewise, the prime by target interaction remained significant after exclusion of the four “emotion aware” participants, F(9, 68) = 33.46, p<.001, η²=.816, and also after exclusion of the 24 “face aware” participants, F(9, 48) = 23.13, p<.001, η²=.813.

⁵Analyses using adjusted means (see Footnote 2) documented a global valence priming effect for sad and fearful primes with M=18 ms (SD=83), t(27) = 1.13, p=.13 (one-tailed), thereby roughly replicating results from Experiment 1, without sufficient test power.

⁶Analyses using adjusted means (see Footnote 2) could not replicated earlier findings of significant global valence priming effect for sad and fearful primes with M=7 ms, t(51) = 0.48, ns.