Browsing by Author "Gomes, Nuno"
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- Beware the serpent: The advantage of ecologically-relevant stimuli in accessing visual awarenessPublication . Gomes, Nuno; Silva, Samuel; Silva, Carlos Fernandes da; Soares, Sandra Cristina de OliveiraSnakes and spiders constitute fear-relevant stimuli for humans, as many species have deleterious and even fatal effects. However, snakes provoked an older and thus stronger evolutionary pressure than spiders, shaping the vision of earliest primates toward preferential visual processing, mainly in the most complex perceptual conditions. To the best of our knowledge, no study has yet directly assessed the role of ecologically-relevant stimuli in preferentially accessing visual awareness. Using continuous flash suppression (CFS), the present study assessed the role of evolutionary pressure in gaining a preferential access to visual awareness. For this purpose, we measured the time needed for three types of stimuli - snakes, spiders (matched with snakes for rated fear levels, but for which an influence on humans but not other primates is well grounded) and birds - to break the suppression and enter visual awareness in two different suppression intensity conditions. The results showed that in the less demanding awareness access condition (stimuli presented to the participants' dominant eye) both evolutionarily relevant stimuli (snakes and spiders) showed a faster entry into visual awareness than birds, whereas in the most demanding awareness access condition (stimuli presented to the participants' non-dominant eye) only snakes showed this privileged access. Our data suggest that the privileged unconscious processing of snakes in the most complex perceptual conditions extends to visual awareness, corroborating the proposed influence of snakes in primate visual evolution.
- Can Humans Discriminate Horse ‘Fear’ Chemosignals from Control Chemosignals? Comment on Sabiniewicz et al. A Preliminary Investigation of Interspecific Chemosensory Communication of Emotions: Can Humans (Homo sapiens) Recognise Fear- and Non-Fear Body Odour from Horses (Equus ferus caballus). Animals 2021, 11, 3499Publication . Semin, Gün R.; Gomes, Nuno; D'Aniello, Biagio; Sabiniewicz, AgnieszkaWe illustrate the problematic nature of different assumptions guiding the examination of whether humans can detect the source of fear chemosignals (i.e., body odors) emitted by horses—a research question examined in an article recently published in Animals. A central issue is that the formulation of the question itself contains the answer to it. In this paper, we parse the problematic assumptions on which the analysis and methodology rely, leading to conclusions that are difficult to support. These assumptions constitute examples of methodological problems that should be avoided in research with animals and odors. The unique aspect of this paper is that it is a collaborative product, including the original contributor, in the pursuit of transparency in science.
- Comparing fear and anxiety chemosignals: Do they modulate facial muscle activity and facilitate identifying facial expressions?Publication . Gomes, Nuno; Pause, Bettina; Smeets, Monique; Semin, G. R.Fear and anxiety are the most frequently studied emotional states in chemosignal research. Despite differences between these two emotional states, findings from research using fear and anxiety body odors (BOs) are often treated as part of a similar phenomenon. In this article, we examine possible similarities and differences between participants exposed to fear and anxiety BOs on 2 dependent variables commonly used in chemosignals’ research: (1) the activation of facial muscles in displays of fear expressions (i.e. the medial frontalis and the corrugator supercilii); and (2) the time required to discriminate between negative emotional expressions (fear, anger, and disgust) and neutral ones. Our results show that fear (vs. rest) and anxiety (vs. exercise) BOs activate the medial frontalis, suggesting that both have a similar impact on receivers’ facial muscles. However, we could not replicate previous findings regarding the influence of fear BOs in discriminating negative emotional faces from neutral ones. Two additional replication attempts failed to replicate the earlier results, indicating that the results reported in the literature with this specific paradigm should be interpreted cautiously. Suggestions for future research examining possible differences between fear and anxiety BOs are advanced.
- Comparing fear and anxiety chemosignals: Do they modulate facial muscle activity and facilitate identifying facial expressions?Publication . Gomes, Nuno; Pause, Bettina; Smeets, Monique; Semin, G. R.Fear and anxiety are the most frequently studied emotional states in chemosignal research. Despite differences between these two emotional states, findings from research using fear and anxiety body odors (BOs) are often treated as part of a similar phenomenon. In this article, we examine possible similarities and differences between participants exposed to fear and anxiety BOs on 2 dependent variables commonly used in chemosignals’ research: (1) the activation of facial muscles in displays of fear expressions (i.e. the medial frontalis and the corrugator supercilii); and (2) the time required to discriminate between negative emotional expressions (fear, anger, and disgust) and neutral ones. Our results show that fear (vs. rest) and anxiety (vs. exercise) BOs activate the medial frontalis, suggesting that both have a similar impact on receivers’ facial muscles. However, we could not replicate previous findings regarding the influence of fear BOs in discriminating negative emotional faces from neutral ones. Two additional replication attempts failed to replicate the earlier results, indicating that the results reported in the literature with this specific paradigm should be interpreted cautiously. Suggestions for future research examining possible differences between fear and anxiety BOs are advanced.
- Exogenous attention to fear: Differential behavioral and neural responses to snakes and spidersPublication . Soares, Sandra Cristina de Oliveira; Kessel, Dominique; Lorca, María Hernández; Rubio, María J. García; Rodrigues, Paulo; Gomes, Nuno; Carretié, LuisResearch has consistently shown that threat stimuli automatically attract attention in order to activate the defensive response systems. Recent findings have provided evidence that snakes tuned the visual system of evolving primates for their astute detection, particularly under challenging perceptual conditions. The goal of the present study was to measure behavioral and electrophysiological indices of exogenous attention to snakes, compared with spiders - matched for rated fear levels but for which sources of natural selection are less well grounded, and to innocuous animals (birds), which were presented as distracters, while participants were engaged in a letter discrimination task. Duration of stimuli, consisting in a letter string and a concurrent distracter, was either presented for 180 or 360ms to explore if the stimulus duration was a modulating effect of snakes in capturing attention. Results showed a specific early (P1) exogenous attention-related brain potential with maximal amplitude to snakes in both durations, which was followed by an enhanced late attention-related potential (LPP) showing enhanced amplitudes to spiders, particularly under the longer exposure durations. These results suggest that exogenous attention to different classes of threat stimuli follows a gradual process, with the most evolutionary-driven stimulus, i.e., snakes, being more efficient at attracting early exogenous attention, thus more dependent on bottom-up processes.
- Investigating inattentional blindness through the lens of fear chemosignalsPublication . Semin, Gün R.; DePhillips, Michael; Gomes, NunoInattentional blindness is a phenomenon wherein people fail to perceive obvious stimuli within their vision, sometimes leading to dramatic consequences. Research on the effects of fear chemosignals suggests that they facilitate receivers’ sensory acquisition. We aimed to examine the interplay between these phenomena, investigating whether exposure to fear chemosignals (vs. rest body odors) can reduce the inattentional-blindness handicap. Utilizing a virtual-reality aquarium,we asked participants to count how many morsels a school of fish consumedwhile two unexpected stimuli swam by. We predicted that participants exposed to fear chemosignals (N =131) would detect unexpected stimuli significantly more often than participants exposed to rest body odors (N =125). All participants were adult Portuguese university students aged 18 to 40 years. The results confirmed our hypothesis, χ2 (1) = 6.10,p = .014, revealing that exposure to fear chemosignals significantly increased the detection of unexpected stimuli by about 10%. The implications of our findings open a novel avenue for reducing the adverse consequences of inattentional blindness
- Mapping human vigilance: The influence of conspecificsPublication . Gomes, Nuno; Semin, Gün R.A considerable volume of animal research on detecting threat and foraging reveals that the co-presence of conspecifics reduces vigilance and enhances foraging. Monitoring threat is an adaptive process and is of considerable relevance to humans. It is therefore important to understand how the presence of others influences threat monitoring - namely vigilance - and consequently the capacity to detect threats. We examine this with a novel paradigm, that simulates a “foraging under threat” situation, with an eye-tracker (allowing the examination of the allocation of attention). Our results show, as predicted, that participants in the individual condition (versus co-presence) allocated more attentional resources to scanning the environment and thereby sacrificing foraging, which increased their likelihood of detecting threatening events. Thus, the presence or absence of others modulates vigilance strategies in humans. These findings highlight the heuristic value of animal vigilance models to understand humans threat monitoring with considerable applied relevance.
- Not all emotions are equal:Fear chemosignals lower awareness thresholds only for fearful facesPublication . Semin, Gün R.; Korb, Sebastian; Gomes, Nuno; Silva, FábioExposure to body odors (chemosignals) collected under different emotional states (i.e., emotional chemosignals) can modulate our visual system, biasing visual perception. Recent research has suggested that exposure to fear body odors, results in a generalized faster access to visual awareness of different emotional facial expressions (i.e., fear, happy, and neutral). In the present study, we aimed at replicating and extending these findings by exploring if these effects are limited to fear odor, by introducing a second negative body odor - i.e., disgust. We compared the time that three different emotional facial expressions (i.e., fear, disgust, and neutral) took to reach visual awareness, during a breaking continuous flash suppression paradigm, across three body odor conditions (i.e., fear, disgust and neutral). We found that fear body odors do not trigger an overall faster access to visual awareness, but instead sped-up access to awareness specifically for facial expressions of fear. Disgust odor, on the other hand, had no effects on awareness thresholds of facial expressions. These findings contrast with prior results, suggesting that the potential of fear body odors to induce visual processing adjustments is specific to fear cues. Furthermore, our results support a unique ability of fear body odors in inducing such visual processing changes, compared to other negative emotional chemosignals (i.e., disgust). These conclusions raise interesting questions as to how fear odor might interact with the visual processing stream, whilst simultaneously giving rise to future avenues of research.
- Revisiting “The Malicious Serpent”: Phylogenetically threatening stimulus marked in the human brainPublication . Biondi, Luiz; Gomes, Nuno; Maior, Rafael S.; Soares, Sandra C.Twenty years ago, Öhman and Mineka's publication “The Malicious Serpent” emphasized the selective pressure ancestral reptiles would have on early mammals’ visual system, specifically the development of a set of subcortical structures that would provide snake-like images privileged access to the amygdala. This process would occur automatically and allows for quick defensive reactions. Based on criticisms directed to the snake detection research, we created five questions that guided the discussion in this review. Evidence suggests the existence of a set of subcortical structures that promote prompt detection of snakes and sustained attention, but difficulties arise due to the complex interconnectivity of cortical and subcortical structures and multiple threat responses. Gaps in the research are identified as potential for future investigation.
- The function of fear chemosignals: Preparing for dangerPublication . Gomes, Nuno; Semin, Gün R.It has been shown that the presence of conspecifics modulates human's vigilance strategies as is the case with animal species. Mere presence has been found to reduce vigilance. However, animal research has also shown that chemosignals (e.g., sweat) produced during fear-inducing situations modulates individuals' threat detection strategies. In the case of humans, little is known about how exposure to conspecifics' fear chemosignals modulates vigilance and threat detection effectiveness. The present study (N= 59) examined how human fear chemosignals affect vigilance strategies and threat avoidance in its receivers. We relied on a paradigm that simulates a "foraging under threat" situation in the lab, integrated with an eye-tracker to examine the attention allocation. Our results showed that the exposure to fear chemosignals (vs. rest chemosignals and a no-sweat condition) while not changing vigilance behavior leads to faster answers to threatening events. In conclusion, fear chemosignals seem to constitute an important warning signal for human beings, possibly leading its receiver to a readiness state that allows faster reactions to threat-related events.