Do sadness-primes make me work harder because they make me sad?

This experiment sought to clarify the potential role of emotional feelings in the systematic impact of implicitly processed affective stimuli on mental effort mobilisation. Participants worked on an attention task during which they were primed with suboptimally presented happiness versus sadness expressions. Before the task, half the participants received a cue for the possible affective influence of flickers to be presented during the task. This manipulation usually reduces the impact of conscious feelings on resource mobilisation. As anticipated, sadness primes resulted in higher experienced task demand and higher mental effort (stronger cardiac contractility assessed as shortened pre-ejection period) than happiness primes. Most importantly, instead of reducing the prime effects on mental effort, the cue manipulation significantly increased participants effort in general, reflecting additional cognitive demand. The results speak against the idea that affect primes influence effort mobilisation by eliciting conscious emotional feelings.