4. Studies 3 and 4

4.5. General discussion

The three present experimental studies and the meta-analysis support the idea that moods’

effect on effort intensity, operationalized as cardiovascular response, is moderated by the type of judgment people use for effort mobilization. That is, the present studies brought additional evidence for the idea that moods’ impact on resource mobilization is context dependent (see Martin, 2000; Richter et al., 2006 for reviews). Moreover, none of the studies found any evidence that mood had an impact on resource mobilization before participants were confronted with a task and could use their feelings as task relevant information. Together, this lends further support to the idea that moods per se are not motivational states and thus do not have stable effects on resource mobilization. Rather, moods’

motivational effects depend on a context-dependent informational mood impact, as conceptualized in the MBM (Gendolla, 2000).

Departing from seminal studies by Martin and colleagues on mood-as-input effects on persistence (Martin et al., 1993; Martin, 2000), we tested our hypotheses about the context-dependency of mood effects on effort intensity by manipulating effort mobilization rules participants applied during their performance on a mental concentration or a memory task. In accordance with the psychophysiological literature, we operationalized effort intensity as cardiovascular reactivity, especially SBP reactivity (see Obrist, 1981; Wright, 1996; Wright & Kirby, 2001). The results showed that the

cardiovascular response of participants who asked themselves—during task performance—if they mobilized enough effort was stronger in a negative mood than in a positive mood (Studies 1-2). The same effect occurred when no explicit rule was manipulated. This latter “no-rule” effect replicated previous studies (e.g., Gendolla et al., 2001; Gendolla & Krüsken, 2001, 2002) and suggests that the default judgment for mobilizing resources is based on a “have I done enough” evaluation. This interpretation is in accordance with the idea of motivational intensity theory (Brehm & Self, 1989) that resource mobilization follows an energy conservation principle according to which people invest only as much effort as necessary to carry out instrumental behavior. However, the most relevant finding of the present studies is that effort intensity was higher in a positive mood than in a negative mood when participants asked themselves if they enjoyed their performance (Studies 1-3). Together with the replicated finding that mood had no effect on cardiovascular arousal before task performance this clearly demonstrates the context-dependency of mood effects on effort intensity. The “default” effect of adjusting effort intensity to task demand (“Have I mobilized enough resources”) was turned on its head by changing the effort-rule—i.e. the judgment for which participants used their mood as diagnostic information. Martin and colleagues have obtained similar effects on persistence (e.g., Erber & Erber, 2000; Hirt, Levine, et al., 1997; Hirt, McDonald et al., 1999; Martin & Davies, 1998; Sanna et al., 1996).

However, the present studies are the first that demonstrate those effects on objective measures of effort intensity (rather than the duration of performance) in terms of an objective energetic measure—

cardiovascular response.

Obviously, the present findings oppose to notions suggesting that moods have relatively stable effects on motivation, like the assumption that effort is higher in a negative mood than in a positive mood (e.g., Frijda, 1986; Morris, 1992; Schwarz, 1990). The present replicated evidence that resource mobilization according to an “enjoy-rule” results in higher effort intensity in a positive mood than in a negative mood contradicts the hypothesis that positive affect has typically an effort-reducing or energy saving function (e.g., Carver, 2003; Fredrickson, Mancuso, Branigan & Tugade, 2000; Morris, 1999;

Schwarz, 1990). As demonstrated in the present research, under certain situations positive mood can lead to a higher effort than negative mood.

Interestingly, the present evidence for higher effort intensity in a positive mood when individuals focus on the pleasantness of performance points to research on mood effects on problem solving and creativity. For such tasks, which are usually experienced as interesting and relatively pleasant, the typical effect is that a positive mood fosters creativity performance (see Abele, 1995; Baas,

de Dreu, & Nijstad, 2008). The present findings suggest that this effect could be caused by an implicit application of an “enjoy-rule” for resource mobilization for interesting tasks. Support for this idea stems from studies by Krüsken (2002, discussed in Richter et al., 2006). In those experiments cardiovascular response was stronger in a positive mood than in a negative mood when participants worked on verbal creativity tasks without a fixed performance standard (“do your best”). However, when fixed performance standards were provided (e.g., easy vs. difficult) cardiovascular reactivity was stronger in a negative mood than in a positive mood and increased with the standard (“create 3 vs. 5 vs. 7 ideas”).

This suggests that participants used an “enjoy-rule” as long as they worked without a performance standard, but that they used an “enough-rule” when they were confronted with a performance standard that made task difficulty rather than performance pleasure salient.

Regarding the cardiovascular indices DBP and HR reactivity only described a general increase during task performance, while SBP reactivity was, as expected, affected by both mood and effort-rule.

However, the lower sensitivity of DBP and HR for the manipulations is not surprising, because these cardiovascular measures are a less reliable index of effort than SBP (Wright, 1996; Wright & Kirby, 2001).

Both systolic and diastolic blood pressure are influenced by myocardial contractility that is potentiated by β-adrenergic sympathetic discharge, but effects on DBP are more likely to be masked by changes in total peripheral resistance than effects on SBP (Levick, 2003). Moreover, HR is determined by both sympathetic and parasympathetic arousal and should thus only respond to effort mobilization when the sympathetic impact is stronger, which is not always the case (Berntson, Cacioppo, & Quigley, 1993;

Brownley et al., 2000; Obrist, 1981).

It might be astonishing for some readers that the measures of task performance did not mirror the effects on SBP reactivity—our primary variable reflecting effort intensity. None of the three present studies found Mood x Effort interaction effects on any performance index. However, it is of note that effort and achievement are not the same and that variations in effort mobilization do not automatically result in variations of performance indices. Achievement is not determined by effort alone. It depends on additional variables, such as ability (e.g., Locke & Latham, 1990), type of task (Abele, 1995), or individual differences (such as having an exceptional memory or having an Attention-Deficit Hyperactivity Disorder, e.g., Frazier, Youngstrom, Glutting, & Watkins, 2007). The relationship between these variables is complex and only sometimes produces associations between effort and achievement (e.g., Gendolla & Krüsken, 2002c; Gendolla & Richter, 2005).

In summary, the main conclusion that can be drawn from our studies is that mood effects on effort intensity depend on the type of judgment that is used for the self-regulation of resource mobilization and for which they are thus used as information. Moreover, our findings also show that mood has no effect on resource mobilization until it is experienced in a context in which it can be used as task-relevant information. Taken together with the evidence for the context-dependency of moods’

effect on effort during task performance, this provides further support to the assumption that moods themselves are not motivational states but that they systematically influence resource mobilization due to their context-dependent informational impact, as conceptualized in the MBM (Gendolla, 2000).


The present chapter introduces the summary of our main results, followed by their integration into a broader discussion. The results’ discussion intends to connect the present findings with other related theories. Implications of the current research in applied domains, such as health, education and creativity will also be addressed. Finally, some limitations of the present studies and suggestions for future research are outlined.

Dans le document Mood and mental effort : informational mood impact on cardiovascular reactivity and the context-dependency of moods (Page 134-139)