Implicit Anger and Effort Mobilization: Predictions

Results from the studies cited above suggest that exposure to anger primes can activate emotion knowledge about performance ease. Gendolla and Silvestrini (2011) confirmed this by showing that masked anger stimuli presented during cognitive tasks influence effort intensity. Anger and happiness primes led to lower effort than sadness primes in a “do your best” task context.

To summarize, despite clear evidence for the similarities between the effects of anger and positive affect on behavior, studies investigating the impact of implicit anger stimuli on effort mobilization during cognitive tasks are still rare.

38 Nevertheless, according to studies showing that anger stimuli share numerous motivational similarities with happiness stimuli, we can posit, according to the IAPE model (Gendolla, 2012) and Gendolla and Silvestrini’ (2011) results that implicit anger stimuli will influence effort mobilization similarly as happiness primes. Anger stimuli activate the anger emotion concept that is linked with ease, leading to reduce task demand.

39 I.6. This Present Thesis

This thesis investigates the impact of implicit affect on the intensity aspect of motivation. More specifically, this thesis aims to provide evidence for the moderating impact of implicit anger stimuli on effort intensity during cognitive tasks.

I.6.1. Objectives

Based on the IAPE model (Gendolla, 2012), implicit affective stimuli influence subjective task demand, which in turn influences effort mobilization in cognitive tasks.

Indeed, anger shares numerous motivational properties with positive affects in motivation (Harmon-Jones, 2003b). Moreover, recent studies showed a systematic influence of implicit affect primes on subjective task difficulty and effort (Gendolla & Silvestrini, 2011; Lasauskaite et al., 2012; Silvestrini & Gendolla, 2011b, 2011c). Most relevant, Silvestrini and Gendolla (2011) found that implicit anger stimuli led to lower subjective task demand than implicit sadness primes, demonstrating for the first time the moderating effect of implicit anger during task performance. This study demonstrated the facilitating effect of implicit anger stimuli on effort mobilization, but it also invite interrogations concerning the facilitating effect of implicit anger stimuli and the joint impact of task difficulty and monetary incentive on effort intensity, which will be investigated in the experimental part of this thesis.

I.6.2. Predictions

Using cardiovascular indices, and more specifically PEP as quantitative indicator of effort intensity (Kelsey, 2012), this thesis investigates the impact of implicit anger on effort-related cardiac response. Based on previous work showing that implicit affect primes can activate emotional knowledge influencing the experience of task demand, we predict that implicit anger should have a similar influence as implicit happiness on effort-related cardiac response: Implicit anger should be associated with the experience of performance ease.

Experimental Part

43

II. Experimental Part

II.1. Overview of the Studies

With the series of studies realized for this thesis, we tested the specificity of anger prime impact on effort-related cardiovascular response, compared to masked sadness stimuli. Moreover, we aimed to test the moderating effect of anger. First, we aimed to demonstrate that masked anger stimuli lead to lower effort intensity than masked neutral stimuli. Secondly, we investigated the moderating effect of implicit anger stimuli on effort intensity manipulating task difficulty and monetary incentive.

In the first two studies we tried to extend results by Gendolla and Silvestrini (2011). In order to provide evidence for the facilitating impact of masked anger stimuli on effort-related cardiac response. In this vein, we added a control condition using neutral facial expressions. Results found further support for a facilitating effect of implicit anger stimuli.

With the third study, we investigated the joint effect of implicit affect primes and objective task difficulty on effort mobilization. We compared masked anger stimuli in comparison with another negative affect (sadness). As predicted, results showed a significant interaction effect between implicit affect primes and objective task difficulty on effort mobilization.

In the fourth study, we focused on the joint impact of implicit affect primes and monetary incentive. As observed in the Study 3, in a difficult task context, sadness primes lead to disengagement and masked anger prime to an increase of effort intensity. In this study, we investigated the question if incentive in a difficult task context can eliminate the effort deficit of people primed with sadness, leading to higher effort than in the implicit anger condition.

45 II.2. Studies 1 and 2

: The Facilitating Effect of Implicit Anger: More Evidence in Terms of Effort-Related Cardiovascular Response

Freydefont, L., Gendolla, G. H. E., & Silvestrini, N. (2012). The facilitating effect of implicit anger: more evidence in terms of effort-related cardiovascular response.

Manuscript submitted for publication.

II.2.1.Abstract

Previous studies have revealed that implicit anger leads, under “do-your-best”

instructions, to weaker effort-related cardiac response than implicit sadness (Gendolla &

Silvestrini, 2011). The present two experiments further tested whether implicit anger has a facilitating effect during task performance. Both studies assessed cardiovascular activity during a habituation period and a cognitive task during which participants were exposed to suboptimally presented facial anger vs. neutral vs. sadness expressions. In Experiment 1, cardiac pre-ejection period (PEP) reactivity was weaker in the anger-prime condition than in the neutral-prime condition, but only during the first minute of task performance.

In Experiment 2, PEP reactivity was weaker with anger primes than with both neutral and sadness primes. The findings further support the implicit-affect-primes-effort model (IAPE; Gendolla, 2012) and suggest a facilitating effect of implicit anger during task performance.

Key words: Anger, Implicit affect, priming, effort-related cardiac response.

47 II.2.2. Introduction

Recent studies from our laboratory have revealed that implicit affect priming systematically influences effort-related cardiovascular response (e.g., Freydefont &

Gendolla, 2012; Freydefont et al., 2012; Gendolla & Silvestrini, 2011). In these studies, implicit anger primes had a different impact on effort mobilization than sadness primes:

When participants performed under “do-your-best” instructions, implicit anger led to weaker cardiovascular response than implicit sadness. However, our previous studies did not involve neutral prime control conditions. Thus, it is still questionable if implicit anger really has a facilitating effect during task performance, as suggested by the implicit-affect-primes-effort model (IAPE; Gendolla, 2012)—the theoretical framework that guided this research. To investigate this issue, the present studies compared implicit anger primes’ effects on effort-related cardiovascular response with those of a neutral-prime control condition and a sadness-prime condition.

II.2.2.a. Implicit Affect and Effort Mobilization

Numerous studies have demonstrated that masked affective stimuli systematically influence evaluative judgments and human behavior (e.g., Murphy & Zajonc, 1993;

Öhman, Flykt, & Lundquist, 2000; Winkielman, Berridge, & Wilbarger, 2005). Implicit affect priming has these effects through the activation of mental representations of emotions (Zemack-Rugar, Bettman, & Fitzsimons, 2007). As masked words or objects can activate semantic knowledge in long-term memory (see Förster & Liberman, 2007 for a review), affect primes can influence evaluative judgments and behavior by activating emotion concepts in memory (see Niedenthal, 2008).

Recent studies from our laboratory tested the idea that affect primes that are processed during task performance systematically influence the level of experienced task demand and effort (Freydefont & Gendolla, 2012; Freydefont et al., 2012; Gendolla &

Silvestrini, 2011; Lasauskaite, Gendolla, & Silvestrini, in press; Silvestrini & Gendolla, 2011b, 2011c). According to the IAPE model (Gendolla, 2012), affect primes implicitly activate mental representations of the respective affective states that contain acquired information about performance ease and difficulty that is typical for the respective emotions, leading to experiences of lower or higher task demand during performance.

Task demand, in turn, determines effort intensity as long as success is possible and

48 justified, as outlined in motivational intensity theory (Brehm & Self, 1989; see Gendolla, Wright, & Richter, 2012 for a recent review). Supporting these ideas, studies based on the IAPE model have found that sadness primes indeed lead to stronger effort-related cardiac response than both happiness and anger primes, when people perform under “do-your-best” instructions (Gendolla & Silvestrini, 2011). These effects occurred because sadness primes led to higher subjective task demand and in turn to stronger effort-related cardiac response. Follow-up studies further confirmed the differential effect of implicit anger vs.

sadness on effort-related cardiac response (Freydefont & Gendolla, 2012; Freydefont et al., 2012).

II.2.2.b. Anger Effects

Additionally to our research on the systematic impact of implicit anger on effort-related cardiac response discussed above, there is more evidence that anger stimuli influence evaluative judgments (Smits & Kuppens, 2005), behavior (Wacker, Hedmann,

& Stemmler, 2003), and attention (van Honk, Tuiten, de Haan, van den Hout, & Stam, 2001). Although anger has negative valence, numerous studies have shown that it shares motivational properties with positive affect (Carver & Jones, 2009; Jones, 2003a). Anger is associated with an approach orientation (Carver & Harmon-Jones, 2009; Harmon-Harmon-Jones, 2003b) and, most relevant, anger is linked to high optimism and experiences of high control (Lerner & Keltner, 2001). Moreover, Putman, Hermans, and van Honk, (2004) found a facilitating effect of angry faces on selective attention. In this study, participants with low trait anger faster identified colors in a Stroop task when they were exposed to angry faces than when neutral faces were presented. Altogether, this suggests that anger should have a facilitating effect on behavior: Anger should be associated with ease.

II.2.2.c. Effort-Related Cardiovascular Response

According to Wright’s (1996) integration of motivational intensity theory (Brehm

& Self, 1989) with Obrist’s (1981) active coping approach, beta-adrenergic sympathetic impact on the heart responds proportionally to the level of experienced task demand as long as success is possible and justified. Noninvasively, beta-adrenergic impact is best assessed as increased cardiac contractility and thus shortened cardiac pre-ejection-period

49 (PEP)—the time interval between the beginning of left ventricular excitation and the opening of the aortic valve (Berntson, Lozano, Chen, & Cacioppo, 2004). In support of Wright’s integrative model, PEP sensitively responds to variations in experienced task demand (Richter, Friedrich, & Gendolla, 2008), incentive value (Richter & Gendolla, 2009), and combinations of both (Richter, 2010b; Silvestrini & Gendolla, 2011a).

Numerous studies have also quantified effort as reactivity of systolic blood pressure (SBP), which is systematically influenced by cardiac contractility through its impact on cardiac output (see Gendolla & Richter, 2010; Wright & Kirby, 2001).

However, both systolic and diastolic blood pressure (DBP) are also influenced by peripheral vascular resistance, which is not systematically influenced by ß-adrenergic impact (Levick, 2003) and can mask contractility effects on SBP and DBP. Still other studies (e.g., Eubanks & Wright, 2002) have quantified effort as responses in heart rate (HR). However, HR is influenced by both sympathetic and parasympathetic impact and should only reflect effort mobilization if the sympathetic impact is stronger (Berntson, Lozano, Chen, & Cacioppo, 2004). Consequently, PEP is the most reliable and valid indicator of effort intensity among these parameters (Kelsey, 2012). Nevertheless, PEP should always be assessed together with blood pressure and HR to control for possible pre-load (ventricular filling) or after-load (arterial pressure) effects (Sherwood et al., 1990).

II.2.2.d. Overview Over the Present Studies

Our primary goal was to test the facilitating effect of implicit anger during task performance using cardiovascular measures. Moreover, we aimed to provide additional evidence for the IAPE model (Gendolla, 2012) idea that the effects of affect primes on effort-related cardiovascular response are emotion category-specific rather than valence-specific. If the effect is emotion category-specific, anger primes should have different effects than primes of other negative emotions that are associated with difficulty.

Therefore, we contrasted the effects of anger primes not only against a neutral prime control condition, but also against a sadness-prime condition.

According to the IAPE model, anger primes should lead to weaker PEP response than sadness primes, because anger is associated with ease whereas sadness is associated with difficulty. Previous studies were interpreted as lending support to this effect (Freydefont & Gendolla, 2012; Freydefont et al., 2012; Gendolla & Silvestrini, 2011), but

50 the absence of neutral prime control conditions left some ambiguity regarding the question if implicit anger has really a facilitating effect. In order to provide a more conclusive test, we ran two experiments, added a neutral-prime control condition, and used affect primes taken from two different databases of emotional faces in order to facilitate generalization of our findings. In accordance with the IAPE model, both studies tested the prediction of a linear affect prime effect on PEP response: PEP reactivity was expected to be weaker in the anger-prime condition than in the sadness-prime condition, with the neutral-prime control condition falling in between.

51 II.2.3. Study 1

This experiment investigated the facilitating effect of anger primes (vs. neutral and sadness primes) in the context of an attention-related mental concentration task, using facial expressions from the Radboud Faces Database (Langner et al., 2010) to manipulate implicit affect.

II.2.3.a. Method

Participants and Design

Sixty-two healthy undergraduate students from various disciplines of the University of Geneva (37 women, 24 men, mean age 21.67 years, SD = 0.43) were randomly assigned to a three-cell between-persons design (Prime: anger vs. neutral vs.

sadness)¹. Two participants were excluded from the statistical analyses because of incomplete data. Moreover, 6 participants were excluded because of extreme PEP reactivity scores, exceeding the grant mean of the entire sample for more than 2 SDs. The final sample included therefore N = 54 participants. Participation was voluntary and remunerated with a small amount of money (10 Swiss Francs, approximately 11 USD).

Affect Primes

Pictures of facial expressions from the Radboud Faces Database (Langner et al., 2010) were used as affect primes. The pictures were presented in black and white. Facial expressions of the same 4 individuals (2 women and 2 men) showing 3 different expressions (anger, neutral, or sadness) were used in the anger, neutral, and sadness experimental conditions, respectively (picture codes: Rafd090_01, Rafd090_02, Rafd090_03, Rafd090_04, Rafd090_07, Rafd090_08, Rafd090_09, Rafd090_10, Rafd090_14, Rafd090_19, Rafd090_36, Rafd090_38, Rafd090_57, Rafd090_58, Rafd090_71).

1 The distribution of women and men was balanced between the experimental conditions.

52 Apparatus and Physiological Measures

A Cardioscreen 1000 system (medis, Ilmenau, Germany) assessed electrocardiogram (ECG) and thoracic impedance signals (ICG) (see Scherhag et al., 2005 for a validation of the system). Four pairs of disposable spot electrodes were placed on the right and left sides of the base of the participant’s neck and on the right and left middle axillary lines at the height of the xiphoid. The signals were assessed with a sampling rate of 1000 Hz and analyzed with BlueBox 2.V1.21 software (Richter, 2010a).

The first derivative of the change in thoracic impedance was calculated and the resulting dZ/dt-signal was ensemble averaged over periods of 1 min using the detected R-peaks (Kelsey & Guethlein, 1990). To obtain PEP values (time interval in ms between R-onset and B-point, as defined by Berntson et al., 2004), B-point location was estimated based on the RZ interval as proposed by Lozano et al. (2007). If necessary, the B-point location was manually corrected as recommended by Sherwood et al. (1990). Additionally, we assessed systolic and diastolic blood pressure (in millimeters of mercury [mm Hg]) with a Vasotrac APM205A monitor (MEDWAVE^®, St. Paul, MN). This system uses applanation tonometry with a pressure sensor placed on the top of the radial artery on the wrist (see Belani et al., 1999 for a validation study). Systolic and diastolic pressure values were recorded each 10-15 heart beats, i.e. 4-5 measures per minute. Values were offline averaged over 1 min periods.

Procedure

The study procedure had been approved by the local ethical committee. The experiment was run in individual sessions. After having signed informed consent, participants were seated in a comfortable chair in front of a computer screen. The experimenter attached the blood pressure cuff and the electrodes and left the participant alone. The procedure started with some biographical questions. Then participants indicated their affective state with 2 items of the positive (happy, joyful) and 2 items of the negative (sad, depressed) scales of the UWIST mood check list (Matthews, Jones &

Chamberlain, 1990). As in previous studies (Freydefont et al., 2012; Freydefont &

Gendolla, 2012), 2 adjectives assessing anger (angry, irritated) were added. Participants responded to the 6 items (“Right now, I’m feeling) on 7- point scales (1 - “not at all”, 7 -

53

“very much”). These ratings were made to monitor participants’ affective states before the affect priming procedure.

Next, we recorded cardiovascular baseline activity (8 min). During this period participants watched a hedonically neutral documentary film about Lithuania. Then participants received instructions (“Please respond as quickly and accurately as possible”) for an adapted version of the d2 mental concentration test (Brickenkamp & Zillmer, 1998). Task trials started with a fixation cross (1000 ms) followed by pictures of facial expression from the Radboud Faces Database (13 ms). In each condition, half of the pictures showed emotional expressions (according to the experimental condition), while the other half showed neutral expressions. Pictures were immediately backward masked (133 ms) with a grey-scale random dot pattern, which was followed by a stimulus of the d2-task. Participants had to indicate by pressing “yes” or “no” keys if the presented stimulus was a “d” with exactly 2 apostrophes. Distracters (“d” with 1, 3 or 4 apostrophes or “p” with 1 to 4 apostrophes) appeared randomly during the task. The stimuli appeared on the screen until the response was entered, but maximally for 2000 ms. Responses were followed by the message “response entered”. In case of no response, the message “please answer more quickly” appeared. To keep performance time and the number of presented primes constant between the conditions, these messages were presented for 4000 ms minus participant’s reaction time. The inter-trial interval was 2000 - 5000 ms (random) to prevent habituation effects. Participants worked on 48 experimental trials. Before the experimental trials, participants had performed 10 training trials with correctness feedback and only neutral facial expressions. No correctness feedback was given during the task to avoid affective reactions (e.g., Kreibig, Gendolla, & Scherer, in press) that could interfere with the affect primes’ effects.

After the task, participants rated experienced task difficulty, mobilized effort, subjective value of success, their felt capability, and the importance of success on 7-point scales (1 - not at all, 7 - very much). Moreover, the same affect items that had been assessed at the beginning of the experiment were rated to control for possible affect prime effects on participants’ affective state. Finally, a funnel debriefing procedure was run, asking to the participants to describe the study’s purpose and what they had seen during the trials. Participants who mentioned “flickers” were asked about their content.

54 II.2.3.b. Results

Cardiovascular Baselines

Baseline values were calculated by averaging cardiovascular values of the last two minutes of the habituation period (Cronbach’s αs > .96)². Cell means and standard errors appear in Table 1. One-way ANOVAs found no significant differences between the three experimental conditions for any cardiovascular index (ps > .09). Preliminary statistical analyses found also no gender effect on any cardiovascular baseline values (ps > .12).

Table 1: Means and Standard Errors (in Parentheses) of the Cardiovascular Baselines Values for the Experiment 1.

Anger primes Neutral primes Sadness primes

PEP 101.72

Note: PEP = pre-ejection period (in ms), SBP = systolic blood pressure (in mmHg), DBP

= diastolic blood pressure (in mmHg), HR= heart rate (beats/min).

2 We calculated the cardiovascular baseline values from the 5 last min of the habituation period, because there was a decline in assessed values over the first 3 min. For the last 5 min of the habituation period, the values were stable and did not differ significantly from one another (ps .78).

55 Cardiovascular Reactivity

Cardiovascular reactivity scores for PEP, SBP, DBP, and HR were determined by subtracting cardiovascular baseline values from the averaged 1-min scores of cardiovascular activity during task performance. Preliminary analyses found no significant gender effects on any cardiovascular index (ps > .06). Also, ANCOVAs found no significant associations between baseline values and reactivity scores (all ps > .08).

However, preliminary repeated measures ANOVAs found a highly significant time main effect on PEP reactivity, F(4, 51) = 5.79, p < .001, η² =.10, our main dependent variable.

Focused comparisons revealed a significant decrease in PEP reactivity between the first (M = -1.96, SE = 0.49) and the second minute of task performance (M = -0.98, SE = 0.38), t(53) = 3.02, p > .01, while no significant differences emerged between the last 4 minutes (ps > .16). This suggests that participants disengaged after the first minute of the task—an effect that was already observed in a previous study (Silvestrini & Gendolla, 2007).

Considering this finding, we restricted our further analyses of cardiovascular reactivity (and performance indices) to the first minute of task performance. We tested our predictions about a linear increase in effort-related cardiovascular response with a priori contrast analyses, which are the most powerful statistical tool for this (Rosenthal &

Considering this finding, we restricted our further analyses of cardiovascular reactivity (and performance indices) to the first minute of task performance. We tested our predictions about a linear increase in effort-related cardiovascular response with a priori contrast analyses, which are the most powerful statistical tool for this (Rosenthal &