Desensitized gamers? Violent video game exposure and empathy for pain in adolescents - an ERP study.

This Event-Related Potential (ERP) study aimed to test how habitual and short-term violent video game exposure (VVGE) may affect empathy for pain responses in adolescents. In a within-subjects design, boys (N = 56; aged 12-16 years) performed a pain judgment task before and immediately after playing a violent video game. In this task, participants judged whether photos of hands depicted on their screen were in a painful situation or not. While both the P3 and the LPP components were not related to habitual violent video game exposure, general exposure to antisocial media content predicted lower P3 amplitudes to painful pictures. Further, 40 min of violent gameplay did not affect the P3 responses; however, it temporarily decreased LPP responses to painful pictures, suggesting a modest short-term desensitization effect. However, this latter interpretation is limited by a strong LPP pain effect - a significant amplitude difference between painful and non-painful pictures - that remained present in the post-game condition. Such persistent LPP effect may relate to the notion that adolescents are still learning how to properly regulate their emotional reactions. This study contributes to the limited literature on violent video games' desensitization in adolescents' brains, opening new avenues for media violence research.

Disgust-specific modulation of early attention processes.

Although threatening images are known to attract and keep our attention, little is known about the existence of emotion-specific attention effects. In this study (N=46), characteristics of an anticipated, disgust-specific effect were investigated by means of a covert orienting paradigm incorporating pictures that were either disgust-evoking, fear-evoking, happiness-evoking or neutral. Attention adhesion to these pictures was measured by the time necessary to identify a peripheral target, presented 100, 200, 500, or 800 ms after picture onset. Main results showed that reaction times were delayed for targets following the disgust-evoking pictures by 100 and 200 ms, suggesting that only these pictures temporarily grabbed hold of participants' attention. These delays were similar for ignore- and attend-instructions, and they were not affected by the participants' anxiety levels or disgust sensitivity. The disgust-specific influence on early attention processes thus appeared very robust, occurring in the majority of participants and without contribution of voluntary- and strategic-attention processes. In contrast, a smaller and less reliable effect of all emotional (arousing) pictures was present in the form of delayed responding in the 100 ms cue-target interval. This effect was more transitory and apparent only in participants with relatively high state-anxiety scores. Practical and theoretical consequences of these findings are discussed.

Changes in recognition memory over time: an ERP investigation into vocabulary learning.

Although it seems intuitive to assume that recognition memory fades over time when information is not reinforced, some aspects of word learning may benefit from a period of consolidation. In the present study, event-related potentials (ERP) were used to examine changes in recognition memory responses to familiar and newly learned (novel) words over time. Native English speakers were taught novel words associated with English translations, and subsequently performed a Recognition Memory task in which they made old/new decisions in response to both words (trained word vs. untrained word), and novel words (trained novel word vs. untrained novel word). The Recognition task was performed 45 minutes after training (Day 1) and then repeated the following day (Day 2) with no additional training session in between. For familiar words, the late parietal old/new effect distinguished old from new items on both Day 1 and Day 2, although response to trained items was significantly weaker on Day 2. For novel words, the LPC again distinguished old from new items on both days, but the effect became significantly larger on Day 2. These data suggest that while recognition memory for familiar items may fade over time, recognition of novel items, conscious recollection in particular may benefit from a period of consolidation.

Disgust- and not fear-evoking images hold our attention.

Even though disgust and fear are both negative emotions, they are characterized by different physiology and action tendencies. The aim of this study was to examine whether fear- and disgust-evoking images would produce different attention bias effects, specifically those related to attention (dis)engagement. Participants were asked to identify a target which was briefly presented around a central image cue, which could either be disgusting, frightening, or neutral. The interval between cue onset and target presentation varied within blocks (200, 500, 800, 1100 ms), allowing us to investigate the time course of attention engagement. Accuracy was lower and reaction times were longer when targets quickly (200 ms) followed disgust-evoking images than when they followed neutral- or fear-evoking images. For the other, longer interval conditions no significant image effects were found. These results suggest that emotion-specific attention effects can be found at very early visual processing stages and that only disgust-evoking images, and not fear-evoking ones, keep hold of our attention for longer. We speculate that this increase in early attention allocation is related to the need to perform a more comprehensive risk-assessment of the disgust-evoking images. The outcomes underline not only the importance of examining the time course of emotion induced attention effects but also the need to look beyond the dimensions of valence and arousal.

Remember to forget: ERP evidence for inhibition in an item-method directed forgetting paradigm.

The present study examined the electrophysiological correlates of intentional forgetting using the item-method directed forgetting paradigm. Participants (N=23) studied a series of words each followed by either a "remember" cue (TBR) or a "forget" cue (TBF) and then undertook an old/new recognition memory test for which they were requested to endorse studied items regardless of original remember/forget status. Event-related potentials time locked to the cues were examined as a function of subsequent recognition-memory accuracy. Results showed that TBR and TBF cues elicited Dm or subsequent memory effects that differed in scalp distribution and polarity, suggesting activation of fundamentally different encoding operations for the respective sets of items. Additionally, analyses that examined the processes underlying successful implementations of intentions to forget (i.e., TBF-miss vs. TBR-miss) and intentions to remember (i.e., TBR-hit vs. TBF-hit) revealed that in case of unwanted information a frontal inhibition mechanism is engaged to stop processes associated with intentional memory formation. These results counter the possibility that directed forgetting reflects only the more elaborate encoding of TBR than TBF words and, instead, implicate the existence of an active inhibitory mechanism directed at TBF words once the forget cue is presented.

The wandering mind of men: ERP evidence for gender differences in attention bias towards attractive opposite sex faces.

To examine the time course and automaticity of our attention bias towards attractive opposite sex faces, event-related potentials (ERPs) were recorded from 20 males and 20 females while they carried out a covert orienting task. Faces that were high, low or average in attractiveness, were presented in focus of attention, but were unrelated to task goals. Across the entire sample larger P2 amplitudes were found in response to both attractive and unattractive opposite sex faces, presumably reflecting early implicit selective attention to distinctive faces. In male but not female participants this was followed by an increased late slow wave for the attractive faces, signifying heightened processing linked to motivated attention. This latter finding is consistent with sexual strategy theory, which suggests that men and women have evolved to pursue different mating strategies with men being more attentive to cues such as facial beauty. In general, our ERP results suggest that, in addition to threat-related stimuli, other evolutionary-relevant information is also prioritized by our attention systems.

Language representation and processing in fluent bilinguals: electrophysiological evidence for asymmetric mapping in bilingual memory.

The purpose of this investigation was to test the assumption of asymmetric mapping between words and concepts in bilingual memory as proposed by the Revised Hierarchical Model (RHM, Kroll & Stewart, 1994). Twenty four Spanish-English bilinguals (experiment 1) and twenty English-Spanish bilinguals (experiment 2) were presented with pairs of words, one in English and one in Spanish, and asked to indicate whether or not the words had the same meaning. In half the trials the Spanish word preceded the English, and in the other half the English word preceded the Spanish. In each condition half of the words had the same meaning, and the experiment included both concrete and abstract word trials. Event-related potentials (ERPs) were used to examine lexical-semantic activation during word translation. As predicted, a direction-dependent translation asymmetry was observed in the magnitude of the N400 repetition effect. Specifically, the N400 effect was larger during backward translation (L2-L1) than during forward translation (L1-L2) in both groups of bilinguals. Results are considered in the context of different models of bilingual memory.

Directed forgetting in direct and indirect tests of memory: seeking evidence of retrieval inhibition using electrophysiological measures.

We investigated whether directed forgetting as elicited by the item-cueing method results solely from differential rehearsal of to-be-remembered vs. to-be-forgotten words or, additionally, from inhibitory processes that actively impair retrieval of to-be-forgotten words. During study, participants (N=24) were instructed to remember half of a series of presented words (TBR) and to forget the other half (TBF), as indicated by an instruction cue shown shortly after each word. During test, accuracy and reaction time measures from lexical decisions (indirect memory test) followed by recognition-memory judgements (direct memory test) were supplemented with event-related potential (ERP) recordings. Results from the behavioural measures revealed directed forgetting in the recognition-memory test but not the lexical-decision test. ERPs obtained during recognition indicated that TBR words elicited a larger parietal old/new effect than TBF words overall, suggesting that remember/forget instructions impaired conscious recollection processes more severely than familiarity processes. Moreover, TBF words that were successfully forgotten elicited less parietal activity than correctly rejected new words (the reversed old/new effect; Nowicka, A., Jednorórog, K., Wypych, M., & Marchewka, A. (2009). Reversed old/new effect for intentionally forgotten words: An ERP study of directed forgetting. International Journal of Psychophysiology, 71, 97-102). This was taken to implicate that inhibitory processes likely affected these items. Enhanced negativities for successfully forgotten TBF words relative to new words were observed in the lexical-decision task at early (150-250 ms) and late (800-1000 ms) time windows, suggesting that inhibitory influences disrupt more than just conscious recollection when memory retrieval is tested indirectly.

Identifying deliberate attempts to fake memory impairment through the combined use of reaction time and event-related potential measures.

The central aim of this study was to evaluate the value of reaction time (RT) measures and event-related potentials (ERPs) for the assessment of simulated memory impairment. In two identical experiments (N=24), healthy volunteers carried out an adapted version of the Amsterdam Short-Term Memory (ASTM) test. In half of the cases participants were instructed to perform to their best of abilities (control condition) while in the other half participants were asked to feign a believable memory deficit (simulation condition). Compared to controls, simulating participants were found to produce longer and more variable RTs. In addition, they took longer to respond to new words than to old words, while control participants showed the opposite pattern. Both early (300-500 ms) and late (500-800 ms) ERP old/new effects were similar in magnitude and scalp distribution for both groups of participants, regardless of the fact that simulating participants had significantly lower recognition accuracy than controls. The ERP old/new effect was assumed to reflect unaffected retrieval mechanisms and thus the discrepancy between this measure and recognition performance was interpreted as evidence for intentional underperformance. Results are discussed in relation to clinical observations and deception detection studies. It was concluded that the combined use of RT and ERP measures could be useful to detect and evaluate simulation of memory impairment but that future studies should include patient groups to test some of our assumptions.

Neural correlates of intrusion of emotion words in a modified Stroop task.

Behavioural studies have demonstrated that the emotional Stroop task is a valuable tool for investigating emotion-attention interactions in a variety of healthy and clinical populations, showing that participants are typically more distracted by negative stimuli as compared to neutral or positive stimuli. The main aim of this study was to find and examine the neural correlates of this greater intrusion from negative emotional stimuli. Reliable reaction time (RT) and event-related potential (ERP) data were collected from 23 participants who performed a manual emotional Stroop task with short (40 ms) and long (500 ms) inter-trial intervals. In the short interval condition, participants were found to produce longer RTs for negative than neutral words, suggesting that these stimuli were more difficult to ignore. This RT effect disappeared in the long interval condition, although larger P1 amplitudes were found for the negative words. This suggests that differences in early attention allocation may be unrelated to the degree of intrusion at the behavioural level. In addition, a larger negative slow wave around 300-700 ms post-stimulus was observed in the long interval condition, but only for those negative words that produced prolonged RTs as compared to their matched controls. This late and broadly distributed effect is believed to reflect suppression of meaning representations.

Assessing subjective sleep reports in the first-degree relatives of antidepressant-treated depressed outpatients.

This study sought to investigate whether first-degree relatives of depressed patients report, and react to, sleep perceptions in the same way as the depressed group. Our previous research suggested that depressed individuals may experience greater sleep 'distress' than healthy individuals; we wished to explore whether this was also apparent in their nearest relatives. A sample was recruited of 18 antidepressant-treated patients with a current DSM-IV diagnosis of major depressive disorder, 18 healthy controls, and a group of 10 first-degree relatives for each study group. In accordance with previous findings, poorer sleep perceptions corresponded with poorer life-quality and mood perceptions, and depressed individuals reported poorer sleep perceptions and poorer life-quality/mood perceptions than controls. Additionally, there was evidence of similar sleep reporting between depressed patients and their relatives, and for a difference between these relatives and other non-depressed groups. There was a non-significant trend for depressed patients, and their relatives, to report total sleep time in the same manner as each other, and differently to other non-depressed groups. Reports of poor sleep may be associated with reports of poor mood in depression, but in non-depressed individuals the association may be with a feeling of weariness.

Quantifying subjective assessment of sleep and life-quality in antidepressant-treated depressed patients.

This study sought to establish a method of quantifying subjective perceptions of sleep against perceptions of life-quality and mood, using amended versions of the Pittsburgh sleep diary (PghSD) and quality of life of insomniacs (QOLI) questionnaire. Diaries and questionnaires were self-completed in participants' homes. Outpatients with a DSM-IV diagnosis of major depressive disorder were compared with a healthy control group (with no history, or family history, of depression). Poorer sleepers, as determined by the sleep diary, were significantly more likely to report poorer life-quality and mood perceptions on the subsequent questionnaire. Furthermore, the depressed group reported significantly poorer perceptions of sleep quality and poorer perceptions of life-quality and mood than the control group, even though estimates of sleep disturbance were similar. This may indicate that depressed individuals experience more 'sleep distress' than healthy individuals. These results confirm the extent of subjectively reported sleep disruption in depression and demonstrate the merit of combining the amended PghSD and QOLI to quantify sleep perceptions.

A systematic investigation of same and cross modality priming using written and spoken responses.

Effects of presentation modality and response format were investigated using visual and auditory versions of the word stem completion task. Study presentation conditions (visual, auditory, non-studied) were manipulated within participants, while test conditions (visual/written, visual/spoken, auditory/written, auditory/spoken, recall-only) were manipulated between participants. Results showed evidence for same modality and cross modality priming on all four word stem completion tasks. Words from the visual study list led to comparable levels of priming across all test conditions. In contrast, words from the auditory study list led to relatively low levels of priming in the visual/written test condition and high levels of priming in the auditory/spoken test condition. Response format was found to influence priming performance following auditory study in particular. The findings confirm and extend previous research and suggest that, for implicit memory studies that require auditory presentation, it may be especially beneficial to use spoken rather than written responses.