No abstract

Two experiments tested the hypothesis that exposure to masked emotional expressions during the performance of cognitive tasks influences effort mobilization. In support of the predictions, participants who processed masked sad faces during task performance under "do your best" instructions showed stronger sympathetic nervous system discharge to the heart (shorter pre-ejection period, higher systolic blood pressure) than participants who were exposed to masked smiling faces or angry faces. Assessed task appraisals suggest that these effects on effort-related cardiovascular reactivity occurred because the masked emotional stimuli influenced the level of experienced task difficulty. The findings are compatible with the effects of consciously experienced affect on effort-related cardiovascular response.

Background: The higher order processes involved in self-regulation are generally thought to depend on cognitive (attentional/executive) functions with limited resources. Experimental studies further show that exerting self-control in a first task results in decreased performance in other following self-control tasks, which may be interpreted as the consequence of either effective or perceived resource depletion outlasting the first task. Given that higher order cognitive/attentional processes are also considered to be involved in pain modulatory mechanisms, we tested the idea that pain could be influenced by prior mobilization of cognitive resources. Methods: The present study investigated the consequences of performing a cognitively demanding task on subsequent pain (ratings) and spinal nociceptive responses (nociceptive flexion reflex, NFR) elicited by noxious electrical stimulations in healthy volunteers. Participants received four noxious stimulations immediately after each of six successive blocks (2 min each) of a numerical Stroop task in a neutral condition (low cognitive demand) and six successive blocks in an interference condition (high cognitive demand). Results: Results revealed that pain was rated higher following the condition requiring higher cognitive control. A similar effect was observed on the NFR. Conclusions: These findings suggest that pain regulation mechanisms including the descending pain modulatory system may be less efficient after the performance of tasks requiring high cognitive control resulting in stronger pain experience.

This experiment investigated the combined effect of masked affective stimuli and task difficulty on effort-related cardiovascular response. Cardiovascular reactivity (ICG, blood pressure) was recorded during a baseline period and performance of an easy or difficult attention task in which participants were exposed to masked sad vs. happy facial expressions. As expected, participants in the sad-faces/easy and happy-faces/difficult conditions showed stronger sympathetic nervous system discharge to the heart and vasculature--shorter preejection period, higher systolic blood pressure--indicating more effort than participants in the sad-faces/difficult and happy-faces/easy conditions. Total peripheral resistance reacted similarly as preejection period and systolic blood pressure. The findings are compatible with the effects of consciously experienced affect on effort-related cardiovascular response.

This experiment investigated the moderating effect of masked anger versus sadness primes on objective task difficulty's impact on effort-related cardiovascular response. Cardiovascular measures (ICG and blood pressure) were assessed during a habituation period and an easy versus difficult short-term memory task during which participants were exposed to masked emotional facial expressions. As expected, sadness primes led to stronger cardiac preejection period (PEP) responses than anger primes when the task was easy. When the task was difficult, we observed the reversed pattern. Here, anger primes led to stronger PEP reactivity than sadness primes. Heart rate responses described the corresponding pattern. The results demonstrate that masked anger and sadness primes have different effects on cardiac response in easy and difficult tasks. The effect of anger primes resembles the facilitating effect of happiness primes observed in previous studies.

Two experiments tested the idea that the principle of resource conservation moderates and limits automaticity effects on effort mobilization. Effort-related cardiovascular response was assessed in cognitive tasks with different levels of task difficulty (Experiment 1) and success incentive (Experiment 2) during which participants were exposed to suboptimally presented action versus inaction primes. As expected, implicit activation of the action concept resulted in stronger effort-related cardiovascular response than activation of the inaction concept-but only when the task was feasible and success incentive was sufficiently high. Effects on task performance were compatible with those on effort. The findings indicate that the automaticity effect of action/inaction primes on effort mobilization is situated, sensitive to task context, and limited by extreme task difficulty and low incentive. The findings facilitate a theoretical integration of automaticity in effort mobilization with the principle of resource conservation.

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.

We present theory and research on effort mobilization that is relevant for understanding the role of affect in cognitive control. We posit that cognitive control and effort are closely related and introduce motivational intensity theory and supporting empirical evidence mainly based on cardiovascular measures of effort. Most important, we discuss the role of affect in the context of effort mobilization and cognitive control from different perspectives. We first present theories predicting affective influences on effort, namely the mood-behavior-model and the implicit-affect-primes-effort model, and supporting empirical evidence. Second, we discuss further implications of the resource conservation principle highlighting the aversive aspect of effort and review evidence for the impact of value and its affective component on effort and cognitive control. Finally, we present a recent integration of the neural mechanisms underlying both effort and cognitive control. We conclude that affective processes are necessary and instrumental for both effort mobilization and cognitive control.