Angry faces are more resistant to forgetting than are happy faces: directed forgetting effects on the identity of emotional faces

Effects of emotion and sex difference on item-method directed forgetting

It is crucial to remember or forget others' faces in daily life. People can intentionally forget things they wish to forget, a phenomenon called directed forgetting (DF). This study examined the effects of stimuli's emotions and sex differences in participants and stimuli on DF. We used happy and angry faces as the items in a typical item-method paradigm and conducted three behavioral experiments. In Experiment 1, we recruited 60 participants to examine how emotions of stimuli and sex differences in participants and stimuli affected DF. In Experiment 2, we recruited 60 female participants and manipulated the durations of items presented during the study phase to examine whether the selective rehearsal theory was held. In Experiment 3, we recruited 50 female participants and attached recognition cues to the items presented during the test phase to examine whether the inhibitory control theory was held. We treated the sex of participants in Experiment 1, the durations of items presented during the study phase in Experiment 2 as the between-subject factors, and emotion and sex of stimuli as the with-subject factors. We conducted the mixed-design ANOVA for corrected hit rate, sensitivity, and bias based on the signal detection theory. As a result, we found that DF occurred easily for male participants, whereas not for female participants because of females' superior memorial performances and stronger sensitivities. Furthermore, we found that female participants owned the best and worst recognition rates for angry female faces and happy male faces, respectively. Our results supported the selective rehearsal theory, suggesting manipulations during the study phase had the potential to help females forget what they wished to forget. We presumed that psychologists and therapists should pay attention to the roles of sex difference in twofold, self and others, when studying people's memory and forgetting. Furthermore, the sensitivity of self and the emotion of others should be considered as well.

Different ways to forget: Electrophysiological mechanisms underlying item-method directed forgetting of angry and neutral faces

Emotional stimuli, including faces, receive preferential processing and are consequently better remembered than neutral stimuli. Therefore, they may also be more resistant to intentional forgetting. The present study investigates the behavioral and electrophysiological consequences of instructions to selectively remember or forget angry and neutral faces. In an item-method directed forgetting experiment, angry and neutral faces were randomly presented to 25 student participants (4 males). Each face was followed by an instruction to either forget or remember it and the participants’ EEG was recorded. Later, recognition memory was unexpectedly tested for all items. Behaviorally, both hit and false alarm rates were higher for angry alike than for neutral faces. Directed forgetting occurred for neutral and angry faces as reflected in a reduction of both recognition accuracy and response bias. Event-related potentials revealed a larger late positive potential (LPP, 450 – 700 ms) for angry than for neutral faces during face presentation and, in line with selective rehearsal of remember items, a larger LPP following remember than forget cues. Forget cues generally elicited a larger frontal N2 (280 – 400 ms) than remember cues, in line with the forget instruction eliciting conflict monitoring and inhibition. Selectively following angry faces, a larger cue-evoked P2 (180 – 280 ms) was observed. Notably, forget cues following angry faces elicited a larger late frontal positivity (450 - 700 ms) potentially signaling conflict resolution. Thus, whereas both angry and neutral faces are subject to directed forgetting, on a neural level, different mechanisms underlie the effect. While directed forgetting for neutral faces may be achieved primarily by selective rehearsal, directed forgetting of angry faces involves an additional late frontal positivity, likely reflecting higher cognitive demands imposed by forgetting angry faces.

Effects of Emotional Expression on Face Recognition May Be Accounted for by Image Similarity

We examined the degree to which differences in face recognition rates across emotional expression conditions varied concomitantly with differences in mean objective image similarity. Effects of emotional expression on face recognition performance were measured via an old/new recognition paradigm in which stimuli at both learning and testing had happy, neutral, and angry expressions. Results showed an advantage for faces learned with neutral expressions, as well as for angry faces at testing. Performance data was compared to three quantitative image-similarity indices. Findings showed that mean human performance was strongly correlated with mean image similarity, suggesting that the former may be at least partly explained by the latter. Our findings sound a cautionary note regarding the necessity of considering low-level stimulus properties as explanations for findings that otherwise may be prematurely attributed to higher order phenomena such as attention or emotional arousal.

Can intentional forgetting reduce the cross-race effect in memory?

Across three studies, we utilized an item-method directed forgetting (DF) procedure with faces of different races to investigate the magnitude of intentional forgetting of own-race versus other-race faces. All three experiments shared the same procedure but differed in the number of faces presented. Participants were presented with own-race and other-race faces, each followed by a remember or forget memory instruction, and subsequently received a recognition test for all studied faces. We obtained a robust cross-race effect (CRE) but did not find a DF effect in Experiment 1. Experiments 2 and 3 used shorter study and test lists and obtained a significant DF effect along with significant CRE, but no interaction between face type and memory instruction. The results suggest that own-race and other-race faces are equally susceptible to DF. The results are discussed in terms of the theoretical explanations for CRE and their implications for DF.

Emotional memories are (usually) harder to forget: A meta-analysis of the item-method directed forgetting literature

The current meta-analysis explored whether emotional memories are less susceptible to item-method directed forgetting than neutral memories. Basic analyses revealed superior memory for remember (R) than forget (F) items in both the neutral, M = 19.6%, CI_95% [16.1, 23.1], and the emotional, M = 15.1%, CI_95% [12.4, 17.7], conditions. Directed forgetting in either valence condition was larger for (a) words than for other stimuli; (b) recall than recognition tests; (c) studies that used recall prior to recognition testing; (d) shorter lists; and (e) studies that included buffer items. Direct comparison of the magnitude of the directed forgetting effect across neutral and emotional conditions within studies revealed relatively diminished directed forgetting of emotional items compared to neutral items, with an average difference of 4.2%, CI_95% [2.0, 6.4]. However, the nature of this finding varied broadly across studies, meaning that whether - and to what degree - emotional memories are more resilient than neutral memories likely depends on the methodological features of the study in question. Moderator analyses revealed larger differences (a) in studies for which the emotional items were more arousing than the neutral items, and (b) when buffer items were included. Together, these findings suggest that emotional memories are often more resilient to intentional forgetting than neutral memories, although further research is necessary to characterize the circumstances under which these differences emerge.

Metamemory and Memory Discrepancies in Directed Forgetting of Emotional Information

Directed Forgetting (DF) studies show that it is possible to exert cognitive control to intentionally forget information. The aim of the present study was to investigate how aware individuals are of the control they have over what they remember and forget when the information is emotional. Participants were presented with positive, negative and neutral photographs, and each photograph was followed by either a Remember or a Forget instruction. Then, for each photograph, participants provided Judgments of Learning (JOLs) by indicating their likelihood of recognizing that item on a subsequent test. In the recognition phase, participants were asked to indicate all old items, irrespective of instruction. Remember items had higher JOLs than Forget items for all item types, indicating that participants believe they can intentionally forget even emotional information—which is not the case based on the actual recognition results. DF effect, which was calculated by subtracting recognition for Forget items from Remember ones was only significant for neutral items. Emotional information disrupted cognitive control, eliminating the DF effect. Response times for JOLs showed that evaluation of emotional information, especially negatively emotional information takes longer, and thus is more difficult. For both Remember and Forget items, JOLs reflected sensitivity to emotionality of the items, with emotional items receiving higher JOLs than the neutral ones. Actual recognition confirmed better recognition for only negative items but not for positive ones. JOLs also reflected underestimation of actual recognition performance. Discrepancies in metacognitive judgments due to emotional valence as well as the reasons for underestimation are discussed.

Directed forgetting of emotionally valenced faces

An item-method directed forgetting task was used in three studies to present photographs of happy, neutral and sad faces to participants who had been induced to adopt a happy, neutral or sad mood. At test remember, forget or new judgments of old and new photographs of happy, neutral or sad faces were collected. According to the affect-as-cognitive-feedback hypothesis positively valenced stimuli serve as 'go signals' validating the use of currently accessible cognitions to process task demands whereas negatively valenced stimuli serve as 'stop signals' inhibiting or reversing the use of those cognitions. Since directed forgetting tasks entail the cognitions (among others) that some stimuli should be remembered and others should be forgotten, happy faces should facilitate task demands whereas sad faces should not. As predicted, directed forgetting effects were found for happy but not sad faces in Experiments 1 and 3, and directed forgetting effects were found neutral valenced faces in Experiment 2. Across all three studies mood state did not influence directed forgetting. Findings are discussed in terms of the effects of facial valence cues on directed forgetting and some directions for future research.

The impact of visual working memory capacity on the filtering efficiency of emotional face distractors

Emotional faces can serve as distractors for visual working memory (VWM) tasks. An event-related potential called contralateral delay activity (CDA) can measure the filtering efficiency of face distractors. Previous studies have investigated the influence of VWM capacity on filtering efficiency of simple neutral distractors but not of face distractors. We measured the CDA indicative of emotional face filtering during a VWM task related to facial identity. VWM capacity was measured in a separate colour change detection task, and participants were divided to high- and low-capacity groups. The high-capacity group was able to filter out distractors similarly irrespective of its facial emotion. In contrast, the low-capacity group failed in filtering the neutral and angry face distractors, while the filtering was efficient for the happy face distractors. The results indicate that potentially threatening faces are particularly difficult to filter if VWM capacity is limited.

KDEF-PT: Valence, Emotional Intensity, Familiarity and Attractiveness Ratings of Angry, Neutral, and Happy Faces

The Karolinska Directed Emotional Faces (KDEF) is one of the most widely used human facial expressions database. Almost a decade after the original validation study (Goeleven et al., 2008), we present subjective rating norms for a sub-set of 210 pictures which depict 70 models (half female) each displaying an angry, happy and neutral facial expressions. Our main goals were to provide an additional and updated validation to this database, using a sample from a different nationality (N = 155 Portuguese students, M = 23.73 years old, SD = 7.24) and to extend the number of subjective dimensions used to evaluate each image. Specifically, participants reported emotional labeling (forced-choice task) and evaluated the emotional intensity and valence of the expression, as well as the attractiveness and familiarity of the model (7-points rating scales). Overall, results show that happy faces obtained the highest ratings across evaluative dimensions and emotion labeling accuracy. Female (vs. male) models were perceived as more attractive, familiar and positive. The sex of the model also moderated the accuracy of emotional labeling and ratings of different facial expressions. Each picture of the set was categorized as low, moderate, or high for each dimension. Normative data for each stimulus (hits proportion, means, standard deviations, and confidence intervals per evaluative dimension) is available as supplementary material (available at https://osf.io/fvc4m/).