The standardization of a new Explicit Pornographic Picture Set (EPPS).

Pictures with affective content have been extensively used in scientific studies of emotion and sexuality. However, only a few standardized picture sets have been developed that offer explicit images, with most lacking pornographic pictures depicting diverse sexual practices. This study aimed to fill this gap through developing a standardized affective set of diverse pornographic pictures (masturbation, oral sex, vaginal sex, anal sex, group sex, paraphilia) of same-sex and opposite-sex content, offering dimensional affective ratings of valence, arousal, and dominance, as well as co-elicited discrete emotions (disgust, moral and ethical acceptance). In total, 192 pornographic pictures acquired from online pornography platforms and 24 control IAPS images have been rated by 319 participants (Mage = 22.66, SDage = 4.66) with self-reported same- and opposite-sex sexual attraction. Stimuli were representative of the entire affective space, including positively and negatively perceived pictures. Participants showed differential affective perception of pornographic pictures according to gender and sexual attraction. Differences in affective ratings related to participants' gender and sexual attraction, as well as stimuli content (depicted sexual practices and sexes). From the stimuli set, researchers can select explicit pornographic pictures based on the obtained affective ratings and technical parameters (i.e., pixel size, luminosity, color space, contrast, chromatic complexity, spatial frequency, entropy). The stimuli set may be considered a valid tool of diverse explicit pornographic pictures covering the affective space, in particular, for women and men with same- and opposite-sex sexual attraction. This new explicit pornographic picture set (EPPS) is available to the scientific community for non-commercial use.

Did you get the joke? Physiological, subjective and behavioral responses to mirth.

Mirth is elicited by the perception of humor, which requires the resolution of an incongruity in an unexpected and playful manner. Previous psychophysiological research using affective pictures is scarce, and did not elucidate the cognitive and affective components of the humor process. In this study, the passive viewing paradigm is applied to mirthful, incongruent, neutral and erotic pictures to characterize the emotional response of mirth. Physiological (zygomaticus major [ZM] activity, skin conductance response [SCR] and heart rate [HR]), behavioral (free viewing time) and subjective responses (mirthful ratings) were recorded from 63 participants. The presence of an inflection change in the ZM response and mirthfulness ratings were used as markers of humor comprehension. Participants showed the greatest ZM and HR in response to mirthful compared to incongruent, erotic and neutral pictures, as well as a stronger SCR response to mirthful compared to incongruent and neutral pictures. The overall results shed light on the temporal course of the humor process, suggesting that humor comprehension (cognitive component) occurred around 1000-1500 ms after picture onset, according to the ZM and SCR responses; and the humor appreciation stage (emotional component) occurred at around 3500 ms after stimulus onset, according to the HR and SCR changes. Moreover, marked interindividual variability was observed in the number of smiles, and in the pictures that provoked them. This points to the complexity of the humor process, and suggests the need to develop methods to elicit mirth and elucidate the factors potentially underlying individual differences in humor.

Exploration of Exogenous Attention to Disgust and Fear Pictures with Different Spatial Frequencies Through Event-related Potentials.

The study of the effects of fear and disgust on the capture of automatic attention is gaining interest. Most findings reveal a more efficient capture of exogenous attention by disgust than by fear stimuli, although the underlying mechanisms are not completely understood. The manipulation of their spatial frequency may provide new insight that may contribute to clarify this issue. The present study aimed to explore differential processing of disgust and fear scenes containing only low spatial frequencies (LSF) or all spatial frequencies (intact) presented as distractors in an exogenous attention task. Event-related potentials (ERPs) and behavioral responses were recorded as dependent variables from forty participants (29 women). The results showed that disgust and fear distractors captured exogenous attention equally early, as indicated by the augmented amplitude of the N2p, and later disgust distractors are the ones eliciting the highest amplitude of the LPP component. While in an initial stage, both stimuli seem to have similar preferential access to further processing allowing fast responding in both cases, disgust is more deeply processed at a later stage probably facilitating its examination. These findings suggest that exploring the temporal course of processing is relevant for the understanding of the differential capture of exogenous attention by disgust and fear distractors.

In exogenous attention, time is the clue: Brain and heart interactions to survive threatening stimuli.

The capture of exogenous attention by negative stimuli has been interpreted as adaptive for survival in a diverse and changing environment. In the present paper, we investigate the neural responses towards two discrete negative emotions with different biological meanings, disgust and fear, and its potential relationships with heart rate variability (HRV) as an index of emotional regulation. With that aim, 30 participants performed a digit categorization task while fear, disgust and neutral distractor pictures were presented. Resting HRV at baseline, behavioral responses, and event-related potentials were recorded. Whereas P1 amplitudes were highest to fear distractors, the disgust stimulation led to augmented P2 amplitudes compared to the rest of distractors. Interestingly, increased N2 amplitudes were also found to disgust distractors, but only in high HRV participants. Neural source estimation data point to the involvement of the insula in this exogenous attentional response to disgust. Additionally, disgust distractors provoked longer reaction times than fear and neutral distractors in the high HRV group. Present findings are interpreted in evolutionary terms suggesting that exogenous attention is captured by negative stimuli following a different time course for fear and disgust. Possible HRV influences on neural mechanisms underlying exogenous attention are discussed considering the potential important role of this variable in emotional regulation processes.

MATTER in emotion research: Spanish standardization of an affective image set.

Pictures with affective content have been widely used in the scientific study of emotions, from two main perspectives: on the one hand, dimensional theories claiming that affective experiences can be described according to a few fundamental dimensions such as valence and arousal, and on the other hand, discrete-category theories proposing the presence of a number of basic and universal emotions. Although it has been demonstrated that these two approaches are not mutually exclusive, the existing standardized affective picture databases have been created from the dimensional perspective, which has led to important gaps for research focused on discrete emotions. The present work introduces MATTER, a new database comprising 540 pictures depicting disgusting, fearful, neutral, erotic, mirthful and incongruent content, which provides normative values (total N = 368, mean = 120.47 ratings/picture) in valence and arousal dimensions, as well as in discrete affective (disgust, fear, erotica and mirth) and cognitive (incongruence and interest) features. A tentative classification into discrete categories is presented, and the physical properties of each picture are reported. Our findings suggest that MATTER constitutes a modern and suitable set of affective images including, for the first time, both mirth- and incongruence-related pictures. Additionally, it will enable the examination of affective and cognitive processes in fear/disgust and humor/incongruence fields.

Understanding the capture of exogenous attention by disgusting and fearful stimuli: The role of interoceptive accuracy.

The aim of the study was to explore the role of interoceptive accuracy (IA) on exogenous attention to disgusting and fearful distractors of a main concurrent task. Participants were thirty university students previously identified as high (N = 16) or normal IA according their performance in a heartbeat detection task. Event-related potentials and behavioural responses were recorded. The results showed that disgusting stimuli capture exogenous attention in a first stage as reflected by the augmented amplitude of the P100 component of the ERPs in high IA participants. Fearful distractors may capture attention in a later moment in all participants as revealed by a marginally significant effect on the amplitude of N200. At behavioural level, disgusting distractors provoked a higher number of errors than neutral in normal IA participants. The time course of the effect of disgust and fearful eliciting distractors on exogenous attention appeared to depend on the individual characteristic of participants.

Fractal dimension of EEG signals and heart dynamics in discrete emotional states.

In this study, we explored the fractal dimension (FD; a measure of signal complexity) of 28 EEG channels with positive and negative emotional states. The EEG of participants and their ECG were registered while watching short video clips that induced fear, disgust, humour, or neutral emotions. In order to better understand the nature of these emotions, the Higuchi FD of EEG segments and the heart rate variability (HRV) of the ECG associated with each emotion were obtained. Our results exhibited similar patterns of results with both measures. Humour elicited the highest FD scores in most EEG channels and the highest HRV, while fear, among all emotions, produced the lowest scores in both measures. These results may contribute to the understanding of the relationship between cortical and heart dynamics and their role on emotion perception.

Ambient Light Modulation of Exogenous Attention to Threat.

Planet Earth's motion yields a 50 % day-50 % night yearly balance in every latitude or longitude, so survival must be guaranteed in very different light conditions in many species, including human. Cone- and rod-dominant vision, respectively specialized in light and darkness, present several processing differences, which are-at least partially-reflected in event-related potentials (ERPs). The present experiment aimed at characterizing exogenous attention to threatening (spiders) and neutral (wheels) distractors in two environmental light conditions, low mesopic (L, 0.03 lx) and high mesopic (H, 6.5 lx), yielding a differential photoreceptor activity balance: rod > cone and rod < cone, respectively. These distractors were presented in the lower visual hemifield while the 40 participants were involved in a digit categorization task. Stimuli, both targets (digits) and distractors, were exactly the same in L and H. Both ERPs and behavioral performance in the task were recorded. Enhanced attentional capture by salient distractors was observed regardless of ambient light level. However, ERPs showed a differential pattern as a function of ambient light. Thus, significantly enhanced amplitude to salient distractors was observed in posterior P1 and early anterior P2 (P2a) only during the H context, in late P2a during the L context, and in occipital P3 during both H and L contexts. In other words, while exogenous attention to threat was equally efficient in light and darkness, cone-dominant exogenous attention was faster than rod-dominant, in line with previous data indicating slower processing times for rod- than for cone-dominant vision.

An Event-related Potential Study on the Interaction between Lighting Level and Stimulus Spatial Location.

Due to heterogeneous photoreceptor distribution, spatial location of stimulation is crucial to study visual brain activity in different light environments. This unexplored issue was studied through occipital event-related potentials (ERPs) recorded from 40 participants in response to discrete visual stimuli presented at different locations and in two environmental light conditions, low mesopic (L, 0.03 lux) and high mesopic (H, 6.5 lux), characterized by a differential photoreceptor activity balance: rod > cone and rod < cone, respectively. Stimuli, which were exactly the same in L and H, consisted of squares presented at fixation, at the vertical periphery (above or below fixation) or at the horizontal periphery (left or right). Analyses showed that occipital ERPs presented important L vs. H differences in the 100 to 450 ms window, which were significantly modulated by spatial location of stimulation: differences were greater in response to peripheral stimuli than to stimuli presented at fixation. Moreover, in the former case, significance of L vs. H differences was even stronger in response to stimuli presented at the horizontal than at the vertical periphery. These low vs. high mesopic differences may be explained by photoreceptor activation and their retinal distribution, and confirm that ERPs discriminate between rod- and cone-originated visual processing.

Resting heart rate variability and the startle reflex to briefly presented affective pictures.

We have previously shown that persons with low HRV showed potentiated startle responses to neutral stimuli. In the present study we replicated our prior findings and extended them to examine the effects of HRV on the startle magnitude to pictures that were presented outside of conscious awareness. A total of 85 male and female students were stratified via median split on their resting HRV. They were presented pictures for 6 s or for 30 ms. Results indicated that the high HRV group showed the context appropriate startle magnitude increase to unpleasant foreground. The low HRV group showed startle magnitude increase from pleasant to neutral pictures but no difference between the neutral and unpleasant pictures. This pattern of results was similar for the 30 ms and the 6 s conditions. These results suggest that having high HRV may allow persons to more efficiently process emotional stimuli and to better recognize threat and safety signals.

The effect of conscious and non-conscious presentation of biologically relevant emotion pictures on emotion modulated startle and phasic heart rate.

Many researchers have proposed an emotion regulation circuit that includes the prefrontal cortex and the amygdala. LeDoux (1996) has proposed that there are two pathways by which emotion information is processed. A fast route that bypasses the prefrontal cortex to allow rapid response to potential threat, and a slower route that includes the prefrontal cortex and allows modulation of bottom-up inputs. We investigated these pathways and their peripheral manifestations using emotional pictures presented for either 30 milliseconds or 6 seconds. 36 female participants were randomly assigned to view pleasant, unpleasant, and neutral pictures that varied in viewing time while the eyeblink startle magnitude and phasic heart rate (HR) responses were recorded. Significant Group by Valence interactions were found for both startle and heart rate responses. For the 6 second condition the expected emotion modulated startle effect was found with a larger startle for unpleasant and smaller startles for pleasant foregrounds relative to neutral pictures. For HR, the D1 component was larger for pleasant and unpleasant foregrounds compared to the neutral and the A1 component was larger for the unpleasant compared to the pleasant and the neutral. For the 30 millisecond condition, startle magnitudes were larger for the pleasant and unpleasant compared to the neutral. Whereas the HR response showed the expected tri-phasic profile there were no significant between valence differences. These results suggest that briefly presented emotion stimuli access the fast route of emotion recognition perhaps via the amygdala. The 6 second presentations allow the prefrontal cortex to modulate the bottom up inputs and thus produce a context appropriate response.

Habituation and sensitization of protective reflexes: dissociation between cardiac defense and eye-blink startle.

We examined the habituation and recovery of two protective reflexes, cardiac defense and eye-blink startle, simultaneously elicited by a white noise of 500ms as a function of the time interval between stimulus presentations. Participants were 90 volunteers (54 women) randomly distributed into 6 inter-trial interval (ITI) conditions. They all received three presentations of the stimulus with a time interval of 30min between the first and third noise. The timing of the second noise was manipulated in six steps, using a between-group design, in order to increase the ITI between Trials 1 and 2 and symmetrically decrease the ITI between Trials 2 and 3. Cardiac defense showed fast habituation at the shortest ITI (2.5min), but reduced habituation and increased recovery at the longest ITI (27.5min). In contrast, eye-blink startle showed sensitization irrespective of the ITI. This pattern of findings highlights dissociations between protective reflexes when simultaneously examined. The results are discussed in the context of the cascade model of defense reactions.

Fearful and sexual pictures not consciously seen modulate the startle reflex in human beings.

BACKGROUND: Animal and human studies consistently have demonstrated that the startle reflex elicited by intense auditory stimulation is enhanced by the previous presentation of fear-evoking stimuli. There is also growing and varied evidence of the nonconscious processing of fear stimuli in human beings eliciting brain and autonomic fear responses. METHODS: We report two studies using the startle probe paradigm and the backward-masking procedure to examine the modulation of the eye-blink component of the startle reflex by consciously and nonconsciously presented emotional pictures. RESULTS: Conscious and nonconscious presentation of fearful pictures amplified the magnitude of the startle reflex in both studies. The opposite tendency was observed for conscious and nonconscious presentation of sexually attractive pictures in the second study. CONCLUSIONS: These findings support the notion that negative (and possibly positive) biologically relevant stimuli can be nonconsciously processed, presumably via amygdala activation, and can affect behavioral responding.

Non-conscious modulation of cardiac defense by masked phobic pictures.

The present study investigated the modulation of cardiac defense by presenting emotional pictures under both effective and non-effective masking procedures. The aim was to test Ohman's model of pre-attentive processing of fear. Participants were 48 women volunteers with intense fear of spiders. The stimulus to elicit cardiac defense was a white noise of 105 dB, 500 ms duration and instantaneous risetime. Subjects had two trials of picture-noise presentation-one with a picture of a spider and one with a picture of a flower-, either under an effective masking procedure (30 ms duration) or a non-effective masking procedure (500 ms duration). Order of presentation was counterbalanced. Dependent variables were heart rate and subjective assessment of the noise. Results showed an increased cardiac response in the first trial and a less reduced cardiac response in the second trial when the noise was preceded by the phobic picture under both masking procedures. The response was accompanied by an increase in the subjective unpleasantness of the noise. These results provide support to Ohman's theoretical model.

The rhythm of the heart in the blink of an eye: emotion-modulated startle magnitude covaries with heart rate variability.

Emotion-modulated startle is a robust phenomenon that has been demonstrated in a wide range of experimental situations. Similarly, heart rate variability (HRV) has been associated with a diverse range of processes including affective and attentional regulation. The present study sought to examine the relationship between these two important measures of affective behavior. Ninety female participants viewed pleasant, neutral, and unpleasant pictures while exposed to acoustic startle stimuli. The eyeblink startle was recorded both during the affective foregrounds and during intertrial intervals. HRV was assessed during a resting baseline and relationships between HRV and startle magnitudes examined. Results indicated that resting HRV was inversely related to startle magnitude during both intertrial intervals and affective foregrounds. In addition, the participants with the highest HRV showed the most differentiated emotion-modulated startle effects, whereas those with the lowest HRV, compared to those with the highest HRV, showed significantly potentiated startle to neutral foregrounds and marginally potentiated startle to pleasant foregrounds. The findings are consistent with models that posit that prefrontal cortical activity modulates subcortical motivation circuits. These results have important implications for the use of startle probe methodology and for HRV in the study of emotional regulation and dysregulation.

A new look at cardiac defense: attention or emotion?

The study of cardiac defense has a long tradition in psychological research both within the cognitive approach--linked to Pavlov, Sokolov, and Graham's work on sensory reflexes--and within the motivational one--linked to the work of Cannon and subsequent researchers on the concepts of activation and stress. These two approaches have been difficult to reconcile in the past. We summarize a series of studies on cardiac defense from a different perspective, which allows integration of the traditional approaches. This new perspective emphasizes a sequential process interpretation of the cardiac defense response. Results of descriptive and parametric studies, as well as those of studies examining the physiological and psychological mechanisms underlying the response, show a complex response pattern with both accelerative and decelerative components, with both sympathetic and parasympathetic influences, and with both attentional and emotional significance. The implications of this new look at cardiac defense are discussed in relation to defensive reactions in natural settings, the brain mechanisms controlling such reactions, and their effects on health and illness.

Modulación no consciente de la respuesta cardiaca de defensa por imágenes fóbicas / Non-conscious modulation of the cardiac defense response by phobic pictures

El presente estudio examina el efecto de visualizar una imagen fóbica frente a una imagen no fóbica en la modulación de la respuesta cardiaca de defensa provocada por un estímulo auditivo intenso. 48 mujeres con miedo a las arañas fueron examinadas siguiendo un diseño factorial de dos grupos independientes (grupo de enmascaramiento hacia atrás no efectivo y grupo de enmascaramiento hacia atrás efectivo) y dos presentaciones del estímulo auditivo precedido de una imagen visual (una fóbica y otra no fóbica). La variable dependiente fue la frecuencia cardiaca segundo a segundo analizada durante los 80 segundos posteriores al estímulo auditivo. 6 sujetos del grupo de enmascaramiento efectivo fueron excluidos del análisis por haber reconocido alguno de los dos estímulos visuales. Los resultados del análisis con los sujetos restantes muestran el efecto esperado de la modulación emocional: la imagen fóbica, en comparación con la imagen no fóbica, potencia la respuesta cardiaca de defensa. Los mismos efectos se observan en los grupos conscientes y no consciente. Se discuten los resultados en el contexto de las teorías del priming motivacional de Peter Lang y del procesamiento preatencional del miedo fóbico de Arne Öhman (AU)

This study examined the effect of viewing a phobic versus a non phobic picture on the modulation of the cardiac defense response elicited by an intense auditory stimulus. 48 women with fear of spiders were examined using a factorial design with two independent groups (non-effective backward masking and effective backward masking) and two presentations of the auditory stimulus preceded by a visual image (one phobic and one non phobic). The dependent variable was second-by-second heart rate analyzed for 80 seconds after the auditory stimulus. 6 subjects of the effective masking group were able to identify one of the two visual stimuli and were excluded from the statistical analysis. The results of the analysis with the remaining subjects showed the expected emotional modulation: the phobic picture, as compared to the non phobic picture, potentiated the cardiac defense response. The same effects were observed in both the conscious and the non-conscious groups. The results are discussed in the context of Peter Lang’s motivational priming and Arne Öhman’s preattentional fear processing theories (AU)

Modulación emocional de los reflejos defensivos mediante visualización de imágenes afectivas / Emotional modulation of defensive reflexes by viewing affective pictures

Se presentan los resultados de un estudio en el que se examinó la modulación de la respuesta cardiaca de defensa y del reflejo motor de sobresalto (parpadeo), evocados por estímulos acústicos, mediante la visualización simultánea de imágenes afectivas seleccionadas de la adaptación española del International Affective Picture System. 60 mujeres estudiantes voluntarias participaron en el estudio. El test psicofisiológico consistió en 9 ensayos en los que se presentaron durante 9 segundos 3 diapositivas agradables, 3 desagradables y 3 neutrales, balanceadas según el orden de presentación, con un intervalo entre ensayos de 95-120 segundos. Cada ensayo de visualización iba acompañado de la presentación, a través de auriculares, de un ruido blanco de 105 dB de intensidad, 500 milisegundos de duración y tiempo de subida instantáneo, que se iniciaba 3,5 segundos después de iniciada la diapositiva. Las variables dependientes fueron la frecuencia cardiaca segundo a segundo y la electromiografía integrada del músculo orbicular del ojo. Los resultados muestran una potenciación tanto de la respuesta cardiaca de defensa como del reflejo motor de sobresalto ante la visualización de las imágenes desagradables. La visualización de imágenes agradables produjo inhibición, en comparación con la visualización de imágenes neutrales, sólo en el caso del reflejo motor de sobresalto. Estos resultados dan apoyo empírico a la teoría del priming motivacional de los reflejos propuesta por Lang y confirman el carácter dinámico y secuencial de la respuesta cardiaca de defensa (AU)

We present the results of a study aimed to examine the modulation of the cardiac defense response and the startle reflex (eyeblink), elicited by acoustic stimuli, by simultaneous visualization of affective pictures selected from the Spanish adaptation of the International Affective Picture System. 60 volunteer student women participated in the study. The psychophysiological test consisted of 9 trials in which 3 pleasant, 3 unpleasant and 3 neutral pictures were presented, in counterbalanced order, during 6 seconds, with an inter-trial interval between 95 and 120 seconds. Each visualization trial was accompanied by the presentation, through headphones, of a white noise of 105 dB intensity, 500 ms duration and instantaneous risetime. The noise was initiated 3.5 s after initiation of the picture. Dependent variables were second-by-second heart rate and integrated electromyography of the orbicularis oculi muscle. Results show a potentiation of both the cardiac defense response and the startle reflex by visualization of unpleasant pictures. Visualization of pleasant pictures showed inhibition, as compared to neutral pictures, only of the startle reflex. These results give support to the motivational priming theory of defensive reflexes proposed by Lang and confirm the dynamic and sequential character of the cardiac defense response (AU)