Processing of Internal and External Signals for Performance Monitoring in the Context of Emotional Faces

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1 Processing of Internal and External Signals for Performance Monitoring in the Context of Emotional Faces Christian Valt, Marina Palazova, and Birgit Stürmer International Psychoanalytic University, Berlin Abstract KeywordS erformance monitoring, emotional face exressions, error-related negativity (Ne/ERN), early visually-evoked otentials, N170 Performance monitoring can be based on internal or external signals. We recorded event-related otentials (ERPs) to investigate whether relating erformance to external signals affects internal erformance monitoring. Thirty articiants erformed a task in which resonses were followed by faces whose exressions were artially contingent uon erformance. Instructions given to half of the articiants mentioned a link between task erformance and the ucoming face exression. Instructed articiants showed smaller error-related negativity (Ne/ERN) to erroneous resonses and larger N170 to faces as comared to articiants in the not-instructed grou. In addition, we observed a correlation between Ne/ERN and P1-latency benefit for angry faces after errors. Taken together, rocessing of internally generated signals for erformance monitoring is reduced by instructions referring to an emotional face. Furthermore, we relate the correlation between the magnitude of internal monitoring and facilitation in rocessing angry faces to riming induced by the negative affective meaning of errors. Introduction We constantly evaluate our actions according to the goal we aim for. Performance monitoring is, therefore, one of the major demands in human information rocessing. Performance monitoring can be based on internal signals generated by the erson itself or external signals from the environment. In unambiguous situations, we generally detect our errors based on internally generated signals. In these cases, an error is detected whenever new evidence that suorts the correct resonse accumulates after the incorrect resonse was made (Yeung & Summerfield, 2012). In effect, errors are often followed by quick corrections (Rabbitt, 1966) as well as slower and more accurate resonses to the successive trial (Gehring, Goss, Coles, Meyer, & Donchin, 1993; Themanson, Rosen, Pontifex, Hillman, & McAuley, 2012). In many situations, external signals are also imortant sources of information for erformance monitoring. Among the variety of external signals resent in the environment, facial exressions are imortant means of evaluating the aroriateness of our behaviour (Blair, 2003). The inclination of infants to attend to caregivers emotional facial exressions in various situations is clear evidence of the develomental relevance of this external signal (Klinnert, Camos, Sorce, Emde, & Svejda, 1983). For examle, infants adat their references toward objects according to the emotion exressed by an exerimenter (Moses, Baldwin, Rosicky, & Tidball, 2001; Reacholi, 1998) or undertake a secific behaviour based on the facial emotion of the caregiver (Sorce, Emde, Camos, & Klinnert, 1985). With the resent study, we aimed to investigate the interlay of internal and external sources for erformance monitoring. Particiants erformed a choice-resonse task on Eriksen-Simon stimuli (Eriksen & Eriksen, 1974; Simon, 1969) and emotional face exressions were used as external signals after the articiants resonses. Faces were mainly angry after wrong resonses and neutral after correct resonses. We analysed event-related brain otentials (ERPs) to test changes in information rocessing when instructions suggested a focus on internal or external signals. A negative deflection over the midline fronto-central electrodes eaking ms after resonse execution is seen as a manifesta- Corresonding author: Dr. Christian Valt, International Psychoanalytic University, Stromstrasse, 3b, Berlin, Germany. christian.valt@ iu-berlin.de This is an oen access article under the CC BY-NC-ND license (htt://creativecommons.org/licenses/by-nc-nd/4.0/). 190 htt:// DOI /ac

2 tion of internal erformance monitoring (Falkenstein, Hohnsbein, Hoormann, & Blanke, 1991; Gehring et al., 1993). This resonse-related negativity is more robust after errors (Ne, or error-related negativity, ERN) than after correct resonses (correct-related negativity, CRN). Aart from the Ne/ERN and the CRN, a second ERP comonent is related to internal erformance evaluation. This comonent is called error ositivity (Pe, Falkenstein et al., 1991; and Pc, for the ositivity after correct resonses) and has been associated with conscious errormonitoring (Shalgi, Barkan, & Deouell, 2009), evidence accumulation (Steinhauser & Yeung, 2012), or confidence evaluation (Boldt & Yeung, 2015). A study using rincial comonent analysis reorted that the Pe consists of two subcomonents: an early fronto-central comonent that immediately follows the Ne/ERN and a late centro-arietal comonent, eaking ms after the resonse (Arbel & Donchin, 2009). The most rominent ERP comonent concerning the rocessing of external signals for erformance monitoring is the so-called feedbackrelated negativity (FRN) an ERP comonent elicited around 250 ms after the onset of informative feedback stimuli (Nieuwenhuis, Yeung, Holroyd, Schurger, & Cohen, 2004). This otential is generally evoked when internal signals fail in an accurate erformance evaluation because of low sensitivity (Heldmann, Rüsseler, & Münte, 2008; Stahl, 2010) or uncertainty of the stimulus-resonse association (Holroyd & Coles, 2002; Nieuwenhuis et al., 2002), and it is influenced by goal conduciveness (Gentsch, Grandjean, & Scherer, 2013) and goal relevance (Walentowska, Moors, Paul, & Pourtois, 2016). Notably, when faces are used as feedback stimuli, modulations of both the FRN and early visual ERP comonents of face rocessing are also observed (Aarts & Pourtois, 2012). In summary, comonents in the resonse-locked ERP reflect rocessing of internal signals for erformance monitoring. Evaluation of external signals, instead, is mainly evident as FRN, but modulations of early visually evoked otentials are also exected when the feedback stimulus is an emotional facial exression. Interest in contextual and goal-related factors on the dynamics of signal rocessing for erformance monitoring has recently grown (Ullserger, Danielmeier, & Jocham, 2014). Two highly relevant contextual factors for signal rocessing are (a) how certain one could be about the stimulus-resonse maing and (b) the feedback. In the absence of an established stimulus-resonse maing, as in robabilistic learning, informative feedback results in increased internal signal rocessing and reduced external signal rocessing in the course of learning (Bellebaum & Colosio, 2014; Holroyd & Coles, 2002; Müller, Möller, Rodriguez-Fornells, & Münte, 2005). External feedback signals are referentially rocessed, instead, when the stimulus-resonse maing is difficult to learn, as with random feedback (Holroyd & Coles, 2002). When instructions clearly state the stimulus-resonse maing, erformance monitoring is mostly based on internal signals and the external feedback signals are rocessed in case internal signals fail a recise erformance evaluation, as for resonse seed monitoring (Heldmann et al., 2008; Stahl, 2010). However, Olvet and Hajcak (2009a) showed that with well-established stimulus-resonse maings, a feedback related to erformance accuracy did not affect the Ne/ERN, robably because feedback is redundant (Boksem, Ruys, & Aarts, 2011). The FRN is, however, enhanced in case of ambiguous feedback (Gibbons, Schnuerch, & Stahl, 2016). Furthermore, Ogawa, Masaki, Yamazaki, and Sommer (2011) reorted reductions of the Ne/ERN amlitude when a negative admonishment is delivered as feedback. Moreover, external signals seem to acquire a secial relevance when they are informative about erformance seed. Walentowska et al. (2016) reorted that the FRN was modulated when feedback was related to resonse seed whereas the CRN was modulated with random feedback. Stahl (2010) showed that resonses that were difficult to categorise according to resonse seed were associated with a smaller CRN and a larger FRN comared to resonses that were easily categorised, because of being clearly faster or slower than a deadline (see also Heldmann et al., 2008). Taken together, internal and external signal rocessing for erformance monitoring is flexible and deends on feedback content and erson s certainty about erformance quality. With the resent exeriment, we investigated otential changes in the rocessing of internal and external signals for erformance monitoring deending on instructions. In other words, we exlored whether an exlicit instruction about a relationshi between one s own erformance and an external stimulus is sufficient to reduce internal monitoring in favour of the rocessing of an external signal. Half of the articiants (instructed grou) were instructed that the external signals were linked to their erformance, whereas for the other half of the articiants (not-instructed grou), this relationshi was not mentioned in the instructions given before the exeriment. Imortantly, the relationshi between feedback and erformance was identical for all articiants, irresective of their instructions, and articiants in both grous received clear information about the stimulus-resonse maing. Many studies have shown that instructions strongly affect the rocessing of internal signals when they invite the articiant to give riority to either seed or accuracy, affecting in this way also the imortance of errors (Gehring et al., 1993). In the resent exeriment, instead, accuracy and seed were equally imortant in both grous. By maniulating just the instructions between grous, without changing the feedback contingency on erformance, we aimed to obtain two different monitoring conditions: one that romotes the monitoring of both internal and external signals (instructed grou) and one in which internal signals should be referentially monitored (not-instructed grou). Emotional faces were used as external stimuli in order to create a context with social connotations between erformance and external stimulus: A neutral face generally followed a correct resonse while an angry face usually followed an error. In real life, we constantly monitor the reactions of eole interacting with us as feedback on our own behaviour. Therefore, the facial exressions of emotion might be an ecologically imortant external signal for erformance monitoring. With the emloyed exerimental maniulation, the Ne/ERN and later resonse-locked comonents might be altered with resect to the focus of erformance monitoring. That is, internal signals of erformance monitoring might be reduced when attention is directed by instructions towards an external signal. On the contrary, the FRN should 191 htt://

3 be enhanced in the instructed comared to the not-instructed grou. In addition, it is of articular interest whether directing the focus of erformance monitoring towards an external signal would also affect early rocessing of the signal itself. Allocating attention to a stimulus generally increases the amlitude of early visual otentials (Hillyard & Anllo-Vento, 1998; Mangun & Hillyard, 1991): In face rocessing, the amlitude of the N170 is strongly enhanced by attentional allocation to faces (Holmes, Vuilleumier, & Eimer, 2003). Therefore, early ERP comonents like the P1 and the N170 might be enhanced when instructions induce an external focus for erformance monitoring. The resent design also allows testing whether errors rime the rocessing of emotional faces, as suggested for words by Aarts, De Houwer, and Pourtois (2012, 2013). They showed that the amlitude difference between the Ne/ERN and the CRN (ΔNe/ERN) correlated with behavioural facilitation, evident as faster valence judgement, when the emotional meaning of a word was congruent to the negative or the ositive connotation of incorrect and correct resonses, resectively. Here, affective riming should lead to faster rocessing of angry faces after errors than after correct resonses. A correlation between the ΔNe/ERN and the P1-latency benefit for angry faces after errors might corroborate affective riming. Materials and Methods Particiants Thirty young adults (M age = 25 years, range: years, 20 women) articiated in return for a 20 reimbursement. All articiants had normal or corrected-to-normal vision. According to the Edinburgh Handedness Inventory (Oldfield, 1971), all articiants were righthanded (M = 79.8%), excet for two ambidextrous articiants. All articiants gave written informed consent according to the Declaration of Helsinki. Particiants were randomly divided in two grous (instructed, not-instructed). At the end of the exeriment, all articiants were administered the German version of the Behavioral Inhibition System/ Behavioral Aroach System (BIS/BAS) scale (Carver & White, 1994) in order to control for ossible between-grous differences in the sensitivity to unishment and reward (see Table 1). Stimuli, Design, and Procedure A combination of an Eriksen flanker task (Eriksen & Eriksen, 1974) and a Simon task (Simon, 1969) was the resonse-choice task in the resent study. A 3 3 array of the letters M, N, W, or H constituted the stimulus for the choice-resonse task. Each array was made u of a frame of flanker letters and a central target letter that could be either identical to or different from the surrounding letters (see Figure 1); letters aeared as targets or as flankers with an equal robability (i.e., 25% as target, 25% as flanker). The stimulus array was resented above or below a central fixation cross (centre-to-centre distance: 0.80 of visual angle). The arametric maniulation of two stimulus ositions, four flanker and four target letters, generated 32 stimuli, resented once in each exerimental block. Single letters and the fixation cross had each a size of and were searated by a ga of The letters and the fixation cross had a dark grey colour (RGB: 78, 78, 78) and were dislayed on a light grey background (RGB: 128, 128, 128). Particiants were requested to resond to the identity of the central target letter by ressing with their left and right index fingers one of two resonse buttons arranged vertically on the desk (see Figure 1). Two letters required a resonse with the uer button (e.g., the letters M and N) and the other two letters required a resonse with the lower button (e.g., the letters H and W). The maing of target letters to the resonse buttons was counterbalanced across articiants. Neutral and angry faces of unknown identities were used as face stimuli resented after the resonse: Eight hundred neutral faces were obtained from various databases available at Humboldt-Universität zu Table 1. Demograhic and ersonality descrition of the articiants in the two exerimental grous Instructed Not-instructed Sex 5 males 5 males Age 25 years (19-32) 26 years (21-31) Instructed Not-instructed BIS (0.76) (1.13) ns BAS (0.74) (0.96) ns Drive (0.36) (0.61) ns Fun Seeking (0.42) (0.45) ns Reward Resonsiveness (0.47) (0.54) ns Note. The reorted values reresent means (standard errors). BIS: Behavioral Inhibition System; BAS: Behavioral Aroach System; ns: value >.05. Figure 1. Schematic reresentation of the resonse-choice task, the time course of trials, and the faces used as erformance feedback. 192 htt://

4 Berlin; a hundred-sixty angry faces were selected from the FACES database (Ebner, Riediger, & Lindenberger, 2010). Faces were converted to greyscale and fitted into a vertical ellise; the colour thereof matched the background colour. All the faces were normalised on the dimensions osition, size, and luminance contrast. From the neutral faces, 775 faces were used for the exerimental trials and the remaining 25 faces were selected for a recognition task. Each trial started with the resentation of the stimulus array, dislayed for 250 ms, followed by a fixation cross dislayed for a maximum duration of 1,250 ms (see Figure 1). Particiants had 1.5 s to resond. Directly after the resonse, the fixation cross was dislayed for further 500 ms. Then, a face was resented for 1 s at the centre of the screen. After the face offset, the fixation cross was resented again for 500 ms before the next trial started with the resentation of a new stimulus array. Particiants ractised the resonse-choice task in three ractice blocks of 32 trials each. In case the articiant committed too many errors (more than 10) in the last two ractice blocks, two additional ractice blocks were erformed before the beginning of the exeriment and the articiant was encouraged to be more accurate. During the ractice blocks, incorrect resonses were signalled by the fixation cross turning red for 500 ms. The colour of the fixation cross did not change when the articiant gave a correct resonse. Faces were not dislayed during the ractice blocks. After the ractice blocks, directly before the start of the main exeriment, all articiants were instructed that each resonse was followed by a face. Half of the articiants received an additional iece of information about a relationshi between the emotion exressed by the face and their erformance in the resonse-choice task. The instruction given to articiants in the instructed grou was a face, whose exression is related to your erformance in the task, will be resented after each resonse ; the instruction given to articiants in the notinstructed grou was a face will be resented after each resonse. The main exeriment consisted of 25 exerimental blocks, each with 32 trials in random order. In addition, one to three recognition trials were resented in each block to ensure that articiants aid attention to the face stimuli. Faces were dislayed after each trial in all the exerimental blocks. Exression of faces following the resonses in the exerimental blocks was determined by an algorithm that roduced an angry face after 66.6% of incorrect resonses and a neutral face in the remaining 33.3% of incorrect resonses (see Figure 1). Presentation of an angry face after an error triggered the resentation of another angry face after a correct resonse in one of the next 24 trials, allowing an equal number of angry faces after incorrect and correct resonses throughout the exeriment. All other correct resonses, and miss resonses, were followed by a neutral face exression. In recognition trials, a face followed a mask dislayed for 500 ms and the articiant had to judge whether the face was identical or different to the one resented in the receding trial. This was erformed as an attention-check to ensure that articiants in both grous rocessed the face stimuli. Half of the faces resented in the recognition task were reeated from the receding trial, while half were faces never resented before. The Y and N buttons on a German keyboard were used in this task to exress a ositive or a negative answer; no time limit was imosed for resonding. In case of an error in recognition, a feedback recommended the articiant to ay more attention to the face stimuli. To obtain an error rate of 10% throughout the exeriment, written feedback of the average resonse time (RT) was dislayed at the end of each third block (excet the second to last block). In case the articiant committed fewer than four errors in the receding three blocks, the feedback encouraged the articiant to be faster. In case of more than 15 errors in the last three blocks, the articiant was asked to resond more accurately. Additionally, written within-block feedback suggested the articiant to be more accurate if five errors were committed in the receding 10 trials. In order to control for between-grous ersonality differences, articiants filled out the BIS/BAS (Carver & White, 1994) scale at the end of the exeriment. In fact, a ositive correlation between the individual unishment and reward sensitivity and the magnitude of the Ne/ERN has been shown in an exerimental context of unishment and reward omission (Boksem, Tos, Kostermans, & De Cremer, 2008). Particiants also answered the question whether they had noticed any relationshi between their erformance and the emotion exressed by the faces and, in case they did, they had to describe the relationshi. Electrohysiological Recording and Event-Related Potential Calculation The electroencehalogram (EEG) was recorded during the whole exeriment from 28 Ag/AgCl electrodes embedded in an elastic ca (Easy-Ca, EASYCAP GmbH, Herrsching, Germany; URL htt:// The locations of electrodes were based on the International system and corresonded to the ositions: F1/2, F7/8, F3/4, Fz, FC3/4, FCz, T7/8, C3/4, Cz, CPz, P7/8, P3/4, Pz, PO9/10, PO7/8, O1/2, and Oz. Two electrodes were alied directly on the skin over the left and right mastoids, M1 and M2. Initial common reference was M1 and AFz served as ground. The electrooculogram (EOG) was recorded from three electrodes, one laced below the right eye (VEOG) and two on the outer canthi of both eyes (HEOG). All signals were digitised with a frequency of 250 Hz and a band-ass of 0.05 to 70 Hz. The electrodes imedance was ket below 5 kω for EEG and below 10 kω for EOG. Offline, the influence of blinks and eye movements on the EEG was corrected by indeendent comonent analysis based on 20 calibration trials for each artifact (left, right, u, down, and blink) obtained after the exeriment roer. A band-ass filter with cut-off frequencies of 0.1 Hz and 30 Hz and a sloe of 48 db/octave was alied. Resonse-locked eochs started 200 ms re-resonse and lasted until 600 ms ost-resonse. Stimulus-locked eochs started 200 ms before the face stimulus was dislayed and lasted for 1 s after the onset of the stimulus. The 200 ms re-resonse and re-stimulus intervals were used as baseline. Trials were first automatically checked for artifacts (maximum allowed voltage ste of 50 µv/ms, maximum allowed absolute difference of 200 µv in a 200 ms interval, minimal and maximal 193 htt://

5 allowed amlitude of 200 µv and 200 µv, lowest allowed activity of 0.5 µv/ms in a 100 ms interval) and then visually insected. Trials with artifacts were discarded from further analyses. All ERPs were recalculated to average reference based on the electrodes F1/2, F7/8, F3/4, Fz, FCz, M1/2, T7/8, C3/4, Cz, CPz, P7/8, P3/4, Pz, and O1/2. Resonse-locked eochs were averaged searately according to the correctness of the resonse in order to obtain resonse-locked ERPs for correct and incorrect resonses. The CRN and the Ne/ERN were calculated as mean amlitudes at the medial fronto-central electrodes between 0 and 100 ms after resonse. Early and late Pc and Pe were calculated as the mean amlitude at the medial fronto-central electrodes in the time-window of ms (Arbel & Donchin, 2009) and as the mean amlitude at the medial arietal electrodes in the timewindow of ms (Olvet & Hajcak, 2009b; Pontifex et al., 2010), resectively. The electrodes showing the largest effect of grou were then selected for statistical analysis based on visual insection. The amlitudes of these negative and ositive deflections at the selected electrodes were entered into searate reeated-measures analyses of variance (ANOVAs), with Resonse Correctness (correct resonses vs. incorrect resonses) as a within-subject factor and Grou (instructed vs. not-instructed) as a between-subjects factor. To exlore grou effects, follow-u indeendent-samles two-tailed t tests with Grou as a between-subjects factor were run. The significance level of α =.05 was adjusted according to Bonferroni s correction for multile airwise tests (α/2 =.025). Face-locked eochs were averaged searately according to resonse correctness and exression of the face. The P1 and the N170 were extracted from the face-locked ERP waves as the ositive and the negative eak over left and right arieto-occiital electrodes between 50 and 150 ms and between 100 and 200 ms, resectively. The FRN was calculated as the mean amlitude of the face-locked ERP at the medial fronto-central electrodes between 210 and 310 ms after onset of the face stimulus (Nieuwenhuis et al., 2004). The electrodes showing the largest effect of grou were then selected for statistical analysis based on visual insection. The activity of the FRN and the amlitude and latency of the P1 and the N170 eaks at the selected electrodes were entered into searate reeated-measures ANOVAs with Resonse Correctness (correct resonse vs. incorrect resonse) and Emotion (neutral vs. angry) as within-subject factors and Grou (instructed vs. not-instructed) as a between-subjects factor. Follow-u related-samles two-tailed t tests were run to exlore the meaning of significant interactions. The significance level of α =.05 was adjusted according to Bonferroni s correction for multile airwise tests (α/4 =.0125). Results Mann-Whitney s U tests for indeendent-samles erformed on the BIS/BAS scores indicated that the two grous did not significantly differ neither in the BIS-scale score, U = 82.5, =.217, nor in any of the BAS-subscale scores, Us > 81.5, s >.202 (see Table 1). At the end of the exeriment, 19 articiants correctly reorted the general relationshi between angry faces and errors. Six articiants in the instructed grou and five articiants in the not-instructed grou did not notice any relation. Behavioural Performance Mean error rate in the resonse-choice task was 8.79% (SE = 0.85%) and ranged from 2.38% to 24.50% across articiants. Grou did not significantly affect articiants mean error rate (t[28] < 1.00; instructed: M = 9.41%, SE = 1.57%; not-instructed: M = 8.18%, SE = 0.67%) and RTs for correct (t[28] < 1.00; instructed: M = 743 ms, SE = 18 ms; not-instructed: M = 723 ms, SE = 19 ms) or incorrect (t[28] < 1.00; instructed: M = 714 ms, SE = 28 ms; not-instructed: M = 706 ms, SE = 29 ms) resonses. Accuracy in the recognition task was 91.38% (SE = 3.16%) for the instructed grou and 95.71% (SE = 0.88%) for the not-instructed grou. Recognition erformances in the two grous did not differ significantly, t(28) = 1.32, =.20, r =.24. Processing of Internal Signals The average number of trials for the ERP calculation of incorrect and correct resonses was 66.2 (SE = 5.1, range: ) and (SE = 7.1, range: ), resectively. The amlitude of the negative deflection at electrode Fz was used to investigate the Ne/ERN and CRN activity in the two grous; the activities at electrode FCz and at electrode Pz were used to exlore effects of instructions on the early and the late ositivity. The ANOVA erformed on activity at electrodes Fz showed a significant effect of resonse correctness, F(1, 28) = 56.00, <.001, η 2 =.67, indicating larger negativity after errors (Ne/ERN) than after correct resonses (CRN), but no main effect of grou, F(1, 28) = 1.55, =.22, η 2 =.05. Imortantly, grou significantly interacted with resonse correctness, F(1, 28) = 8.87, =.006, η 2 =.24, indicating that the difference between Ne/ERN and CRN (ΔNe/ERN) was larger in the not-instructed grou than in the instructed grou. Follow-u t tests, with adjusted α levels of.025, showed that grou significantly modulated the amlitude of the Ne/ERN, t(28) = 2.73, =.011, r =.46, but not the amlitude of the CRN, t < The Ne/ERN in the notinstructed grou was more negative than the Ne/ERN in the instructed grou (see Figure 2). The amlitude of the ositive deflection at FCz resented a significantly different amlitude, F(1, 28) = 35.22, <.001, η 2 =.56, with larger ositivity for the early Pe than the early Pc. Grou did not have any significant effect on the amlitude of this ositivity F(1, 28) = 1.41, =.24, η 2 =.05, and did not significantly interact with resonse correctness, F < These results suggest that grou did not affect the amlitude of the early ositive otential and did not affect the difference between early Pc and early Pe (see Figure 2). A similar attern of results was obtained for the late ositive otential. The difference between late Pc and late Pe was significant, F(1, 28) = 71.42, <.001, η 2 =.72, but grou was not significant as a main effect, F < 1.00, and did not interact with resonse correctness, F < 1.00 (see Figure 2). 194 htt://

6 Processing of External Signals The average number of trials in the four conditions was 42.4 (SE = 3.6, range: 12 80) for angry faces after errors, 42.3 (SE = 2.6, range: 12 78) for angry faces after correct resonses, 27.6 (SE = 2.6, range: 10 41) for neutral faces after errors, and (SE = 10.6, range: ) for neutral faces after correct resonses. Overall, the P1 and the N170 amlitudes were larger over the arieto-occiital electrodes, with a maximum effect of grou at PO10 (see Figure 3). The electrode Fz was used for FRN analyses. P1 and N170 Resonse correctness had a significant effect on the amlitude of the P1, F(1, 28) = 21.05, <.001, η 2 =.43, with a larger P1 after incorrect resonses than after correct resonses, but the amlitude of the P1 was not significantly affected by emotion, F(1, 28) = 1.24, =.28, η 2 =.04 (see Figure 3). The factor grou was not significant in the analysis of the P1 amlitude, F < The interaction between emotion and resonse correctness was not significant, F(1, 28) = 2.66, =.11, η 2 =.09, and grou did not interact with any effect on the P1 amlitude, Fs < The two within-subject factors, emotion and resonse correctness, had both a significant main effect on P1 latency: emotion, F(1, 28) = 48.65, <.001, η 2 =.63, and resonse correctness, F(1, 28) = , <.001, η 2 =.82; but, the between-subjects factor did not show a significant main effect, F < 1.00 (see Figure 3). The two main effects of emotion and resonse correctness were further defined by a significant interaction, F(1, 28) = 48.45, <.001, η 2 =.64. Follow-u comarisons, with adjusted α levels of.0125, were erformed to exlore the meaning of the interaction. The latencies of the P1 were slower for angry faces after a correct resonse (124 ms) than after an incorrect resonse (110 ms), t(29) = 14.39, <.001, r =.94. For neutral faces, the P1 latency after a correct resonse (123 ms) did not differ from that after an incor- Figure 2. Resonse-locked grand average ERPs at medial electrodes for correct and incorrect resonses in the instructed and the not-instructed grou. Toograhical mas of the subtracted brain activity in the Ne/ERN-CRN (0 100 ms), the early Pe-Pc ( ms) and the late Pe-Pc ( ms) timewindows. Box lots of the mean activity in the two grous (ins: instructed vs. not-ins: not-instructed) searately for the CRN and the Ne/ERN, for the early Pc and the early Pe, and for the late Pc and the late Pe. Figure 3. Face-locked grand average ERPs at arieto-occiital electrodes for correct and incorrect trials in the instructed and not-instructed grou, searately for angry and neutral faces. Toograhical mas of the brain activity in the P1 ( ms) and the N170 ( ms) time-windows. Box lots of the mean amlitude of the N170 eak in the two instruction grous (ins: instructed vs. not-ins: not-instructed), searately for angry and neutral faces after correct or incorrect resonses. 195 htt://

7 rect resonse (121 ms), t(29) = 1.51, =.14, r =.27. Furthermore, emotion had a significant effect on the P1 latency for errors, t(29) = 7.87, <.001, r =.82, but not for correct resonses, t(29) < The effects of emotion and resonse correctness were not modulated by grou, Fs(1, 28) < 3.11, s >.09, η 2 <.10, and the three-way interaction also failed to reach significance, F(1, 28) = 2.67, =.11, η 2 =.09. The N170 amlitude showed a significant main effect of resonse correctness, F(1, 28) = 8.41, =.007, η 2 =.23, with a larger amlitude for correct than for incorrect resonses, and a significant main effect of emotion, F(1, 28) = 8.26, =.008, η 2 =.23, with a more negative N170 for angry than for neutral faces (see Figure 3). Notably, the betweensubjects main effect of grou was significant for N170 amlitude, F(1, 28) = 4.18, =.05, η 2 =.13, indicating larger N170 amlitudes in the instructed grou as comared to the not-instructed grou. The interactions between factors were all short of significance in the N170 analyses, Fs < The N170 latency showed a significant main effect of resonse correctness, F(1, 28) = 58.83, <.001, η 2 =.68, and of emotion, F(1, 28) = 10.00, =.004, η 2 =.26, but no main effect of grou, F < These two significant main effects were further defined by a significant interaction, F(1, 28) = 26.46, <.001, η 2 =.49. Follow-u comarisons, with adjusted α levels of.0125, were erformed to exlore the meaning of the interaction. The N170 for angry faces eaked earlier after an incorrect resonse (160 ms) than after a correct resonse (174 ms), t(29) = 9.12, <.001, r =.86. For neutral faces, the N170 latency after a correct resonse (172 ms) did not differ from that after an incorrect resonse (169 ms), t(29) = 1.77, =.09, r =.31. Furthermore, emotion altered the N170 latency after errors, t(29) = 5.34, <.001, r =.70, but not after correct resonses, t(29) = 1.52, =.14, r =.27. No other interaction was significant, Fs < Feedback-Related Negativity The FRN comonent was significantly modulated by the emotion exressed by the face, F(1, 28) = 12.43, <.001, η 2 =.30: It was smaller for angry than for neutral faces (see Figure 4). However, the FRN was not modulated by resonse correctness, F(1, 28) = 2.24, =.15, η 2 =.07, and by grou, F < All the interactions between factors failed to reach significance, Fs(1, 28) < 2.37, s >.13, η 2 <.08. Affective Priming The P1-latency benefit, comuted as the latency difference between the P1 eak for angry faces resented after errors and the P1 eak for angry faces resented after correct resonses, correlated significantly with the amlitude difference between the Ne/ERN and the CRN, r =.41, =.03. That is, the larger the ΔNe/ERN, the earlier the latency of the P1 for angry faces (see Figure 5). Discussion The resent exeriment investigated the effect of instructing a focus of attention towards external signals on the neural correlates of erformance monitoring. Angry and neutral faces were resented after each resonse in a resonse-choice task. The exression of the faces was linked to the accuracy of the resonse, but only half of the articiants were exlicitly instructed about a ossible relationshi. When the instruction indicated a relationshi between task erformance and face stimulus, the Ne/ERN to erroneous resonses was reduced. This reduction could reflect an instruction-deendent reallocation of monitoring resources from internal to external signals. In agreement with such an interretation, the N170 to subsequent face stimuli was enhanced in the instructed comared to the not-instructed grou, but instructions did not affect the amlitude of the FRN. The resent results, hence, oint to the ossibility that the rocessing of internal signals can be reduced by focusing on external signals for erformance evaluation. Interestingly, we also found a correlation between ΔNe/ERN and P1-latency benefit for angry faces resented after errors comared to angry faces resented after a correct resonse. This result corroborates Figure 4. Face-locked grand average ERPs at medial fronto-central electrodes for correct and incorrect trials in the instructed and not-instructed grou, searately for angry and neutral faces. Toograhical mas of subtracted brain activity in the FRN ( ms) time-windows. Figure 5. Linear correlation between amlitude of the Ne/ERN-CRN difference and P1 benefit in latency for angry faces after errors comared to angry faces resented after a correct resonse. 196 htt://

8 revious studies on affective riming and suggests a ossible negative affective connotation of errors that rimes the rocessing of subsequent negative exressions. Directing the focus of erformance monitoring to an external signal by instruction significantly reduced the amlitude of the Ne/ ERN, but it did not affect the magnitude of the other resonse-related ERP comonents of erformance evaluation, like different Pe/Pc subcomonents. Imortantly, articiants in the two exerimental grous did not differ in their erformance, both in the resonse-choice task and the recognition task, and in their unishment/reward sensitivity, as measured by the BIS/BAS scales. This limits the interretations of the obtained Ne/ERN modulations in terms of between-grous differences in erformance (Gehring et al., 1993; Luu, Flaisch, & Tucker, 2000) and ersonality (Boksem et al., 2008). Moreover, the relationshi between feedback and erformance was similar for all articiants and the stimulus-resonse maing was clearly stated. Hence, the smaller Ne/ERN in the instructed grou can be seen as a secific instructiondeendent modulation of erformance monitoring. In other words, linking an emotional face to erformance is sufficient to reduce the monitoring of internal signals, irresective of the validity of the feedback for accurate erformance evaluation. The observed modulation of the Ne/ERN between grous fits well with the assumtion that the rocessing of internally generated information is reduced when the instruction suggests that an external signal can be used to evaluate the accuracy of the resonse. Ogawa et al. (2011) found a reduced Ne/ERN in a context of verbal admonishment and suggested that the focus of erformance monitoring is reallocated from internal to external signals when an external signal is offered for erformance evaluation. In line with this argument, we also found a larger N170 to face stimuli in the instructed grou, indicating that articiants in this grou might have allocated enhanced attention to the external face feedback (Holmes et al., 2003). Taken together, the modulations of the Ne/ERN and the N170 in oosite directions are in line with the assumtion that the instructed grou reallocated the focus of erformance monitoring from internal to external signals. The resent findings suggest that the focus of erformance monitoring can be shifted from internal to external signals by exlicit instruction even when the information content of the external signal is the same for all articiants. Most of the studies in the field of erformance monitoring reorted switches from an internal to an external focus deendent on feedback information content (Holroyd & Coles, 2002; Nieuwenhuis et al., 2002) or feedback reliability (Walentowska et al., 2016). In the resent design, however, the external signal was a correct feedback to erformance for only 66.6% of the errors and the criteria for resonse evaluation were clearly defined and easily evaluable. Consequently, internal signals should have been rioritised, regardless of any ossible relationshi between external signals and erformance. In contrast, more imact seems to be given to the external signal according to the instruction. We argue that articiants in the instructed grou could have referentially attended to face stimuli in order to understand the before-hand instructed relationshi, whereas articiants in the not-instructed grou simly acceted the absence of a clear relationshi between erformance and face stimuli and referentially focused on internal signals. Unfortunately, a erformance at ceiling in the recognition task did not allow us to further exlore whether the allocation of erformance monitoring on the external stimulus determined any behavioural benefit. In addition, being instructed about a relationshi between erformance and external signal, or looking for such relationshi, did not boost articiants awareness of it. This suggests that exlicit instructions about a relationshi affect the dynamics in signal rocessing for erformance monitoring but do not bias the subjective consideration of a 66.6% contingency between errors and angry faces as valid feedback. In contrast to the Ne/ERN, the CRN was not modulated by instructions, indicating that instructions affected only those rocesses that are secific to the monitoring of errors, and not those general monitoring rocesses that are common for both correct and incorrect resonses. This result constitutes further evidence for different underlying rocesses of Ne/ERN and CRN (Yordanova, Falkenstein, Hohnsbein, & Kolev, 2004). Moreover, the absence of any significant effect of instruction on the early and the late Pe suggests that instructions influence early, and robably automatic, information rocessing, but not those late stages of erformance monitoring that generally involve error awareness. On the other hand, instruction-deendent modulations of the N170, in the absence of corresondent FRN modulations, suggest the ossibility that face stimuli acquire a articular saliency in the instructed grou, even when they are not necessary for aroriate erformance monitoring, but this saliency does not affect their interretation. However, FRN analyses in the resent exeriment should be treated cautiously because of the concurrent activity of higher emotional rocesses usually eliciting an early osterior negativity (Rellecke, Sommer, & Schacht, 2012) in the same time window. Similarly, rocesses underlying modulations of the ositive eak receding the FRN are debatable (Potts, Martin, Burton, & Montague, 2006). In fact, face rocessing evokes both an occiito-temoral negativity, the N170, and a frontal ositivity (Jeffreys, 1989), the vertex ositive otential (VPP). These two otentials seem associated with the activity of the same neural generator (Joyce & Rossion, 2005). Therefore, the significant N170 effect might hinder an accurate analysis of FRN effects. Imortantly, only the N170 amlitude was significantly enlarged in the grou exlicitly instructed about the relationshi between erformance and facial exression. Looking for such a relationshi or a more general tendency to ay attention to the face stimuli, hence, altered only the attention-related rocesses secific to the structural encoding of the face. Strikingly, while main effects of emotion were observed for both the latency of P1 and N170 comonents, no Emotion Grou interactions were resent. Two imortant imlications ensue from such findings. First, emotion effects can be considered indeendent of to-down influences like the grou instructions in the resent exeriment. Second, since modulations of P1 and N170 by emotional exressions can be considered to be a consequence of secific attentional mechanisms (i.e., emotional attention, for a review see Pourtois, Schettino, & Vuilleumier, 2013), this study suggests that instruction influenced secific face rocessing stages (e.g., structural encoding), 197 htt://

9 whereas emotional attention influences remain unaffected. Notably, P1 and N170 latencies were earlier for angry faces after an error and, again, both were not affected by instruction. We therefore ascribe the N170 latency effect to a carry-over from the latency modulation of the P1. Privileged rocessing of an angry facial exression after an error was evident already at early levels of visual stimulus rocessing, receding the N170. The P1, reflecting early endogenous allocation of attention, eaked earlier and was larger in amlitude for angry faces that followed an incorrect resonse as comared to all other conditions. This rocessing benefit could reflect affective riming following erroneous resonses (Aarts et al., 2012, 2013). Interestingly, the correlation between P1-latency benefit and ΔNe/ERN further suorts affective riming. Processing of angry faces after errors was faster when the difference between Ne/ERN and CRN was larger. The ΔNe/ERN is often associated with the exerience of negative affect (Hajcak & Foti, 2008; Hajcak, McDonald, & Simons, 2004; Luu et al., 2000), and it is enhanced in sychological disorders characterized by dee distress for errors, as in anxiety disorder (Proudfit, Inzlicht, & Mennin, 2013). Thus, the correlation between P1 latency and ΔNe/ERN might indicate that an erroneous resonse rimes negative affect so that the rocessing of angry faces got a latency benefit. Potential limits of the resent exeriment may include the use of a between-subjects design, with the consequent ossibility of Tye-I or Tye-II errors, and the unequal number of trials between conditions due to the high number of correct resonses. Regarding the first limitation, questionnaires and behavioural erformance measures did not indicate any significant differences between grous in the resent study and the oosite effects of Ne/ERN and N170 amlitudes were redicted between-subjects effects, emhasising the robustness of the resent findings. Potential differences in signal-to-noise ratios across conditions might affect within-subject contrasts but not the contrasts between grous. Therefore, the reorted effects of instruction on the amlitude of the Ne/ERN and the N170 are both reliable, whereas contrasts between conditions should be considered with caution. The issues of unequal trial numbers between conditions and the consequent otential differences in signal-to-noise ratios do not aly to the correlation, because an equal number of angry faces followed correct and incorrect resonses. The significant correlation between internal erformance monitoring and facilitated ercetual rocesses for angry faces is an electrohysiological corroboration of the behavioural finding that errors rime the rocessing of subsequent negative material. The outcome of the resent investigation oens a wide field for future research on erformance monitoring dynamics. In addition, the resent findings might offer a new aroach to sychological disorders characterized by athological internal erformance monitoring (Olvet & Hajcak, 2008). Internalisation disorders are characterised by the inclination to an inward exression of distress and a hyeractive monitoring system. An increased Ne/ERN is resent in sychological disorders characterised by internalisation, like obsessive-comulsive disorder (Gehring, Himle, & Nisenson, 2000; Johannes et al., 2001; Ruchsow et al., 2005), general anxiety disorder (Weinberg, Olvet, & Hajcak, 2010), and deression (Chiu & Deldin, 2007; Holmes & Pizzagalli, 2008). Whether atients with internalisation disorders show a normal flexibility to move from internal to external signals according to instruction, like articiants in the resent exeriment, should be addressed by future research. To conclude, this study shows that (a) internal monitoring can be reduced by instruction suggesting the rocessing of external stimuli, leading to enhanced rocessing of the feedback, and (b) that the negative feelings associated with errors, indexed by the ΔNe/ERN, determine facilitation in rocessing feedback stimuli with a negative valence. In addition, the observed instruction-deendent effects on erformance monitoring reresent a romising oortunity for the study of erformance monitoring dynamics both in healthy and clinical oulations. Acknowledgments This research was suorted by funding of the Deutsche Forschungsgemeinschaft (STU 248/3-2). We are grateful to Dorit Wenke and Anne Löffler for their cooeration in develoing a highly demanding interference task and to Werner Sommer and Andrea Hildebrandt for suorting us with numerous well-controlled face stimuli. We thank Christoher Saville for roofreading. Moreover, we thank Anna Weber for her assistance in data collection. References Aarts, K., De Houwer, J., & Pourtois, G. (2012). Evidence for the automatic evaluation of self-generated actions. Cognition, 124, doi: /j.cognition Aarts, K., De Houwer, J., & Pourtois, G. (2013). Erroneous and correct actions have a different affective valence: Evidence from ERPs. Emotion, 13, doi: /a Aarts, K., & Pourtois, G. (2012). Anxiety disruts the evaluative comonent of erformance monitoring: An ERP study. Neurosychologia, 50, doi: /j. neurosychologia Arbel, Y., & Donchin, E. (2009). Parsing the comonential structure of ost-error ERPs: A rincial comonent analysis of ERPs following errors. 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