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Dive into the research topics where Jacqueline Ferreira is active.

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Featured researches published by Jacqueline Ferreira.


PLOS ONE | 2015

Nosewitness Identification: Effects of Negative Emotion

Laura Alho; Sandra C. Soares; Jacqueline Ferreira; Marta Rocha; Carlos Fernandes da Silva; Mats J. Olsson

Every individual has a unique body odor (BO), similar to a fingerprint. In forensic research, identification of culprit BOs has been performed by trained dogs, but not by humans. We introduce the concept of nosewitness identification and present the first experimental results on BO memory in witness situations involving violent crimes. Two experiments indicated that BO associated with male characters in authentic videos could later be identified in BO lineup tests well above chance. Moreover, culprit BO in emotional crime videos could be identified considerably better than the BO of a male person in neutral videos. This indicates that nosewitness identification benefits from emotional encoding. Altogether, the study testifies to the virtue of body odor as a cue to identify individuals observed under negative emotion.


Psychophysiology | 2017

An automatic classifier of emotions built from entropy of noise

Jacqueline Ferreira; Susana Brás; Carlos Fernandes da Silva; Sandra C. Soares

The electrocardiogram (ECG) signal has been widely used to study the physiological substrates of emotion. However, searching for better filtering techniques in order to obtain a signal with better quality and with the maximum relevant information remains an important issue for researchers in this field. Signal processing is largely performed for ECG analysis and interpretation, but this process can be susceptible to error in the delineation phase. In addition, it can lead to the loss of important information that is usually considered as noise and, consequently, discarded from the analysis. The goal of this study was to evaluate if the ECG noise allows for the classification of emotions, while using its entropy as an input in a decision tree classifier. We collected the ECG signal from 25 healthy participants while they were presented with videos eliciting negative (fear and disgust) and neutral emotions. The results indicated that the neutral condition showed a perfect identification (100%), whereas the classification of negative emotions indicated good identification performances (60% of sensitivity and 80% of specificity). These results suggest that the entropy of noise contains relevant information that can be useful to improve the analysis of the physiological correlates of emotion.


Frontiers in Psychology | 2018

Biometric and Emotion Identification: An ECG Compression Based Method

Susana Brás; Jacqueline Ferreira; Sandra C. Soares; Armando J. Pinho

We present an innovative and robust solution to both biometric and emotion identification using the electrocardiogram (ECG). The ECG represents the electrical signal that comes from the contraction of the heart muscles, indirectly representing the flow of blood inside the heart, it is known to convey a key that allows biometric identification. Moreover, due to its relationship with the nervous system, it also varies as a function of the emotional state. The use of information-theoretic data models, associated with data compression algorithms, allowed to effectively compare ECG records and infer the person identity, as well as emotional state at the time of data collection. The proposed method does not require ECG wave delineation or alignment, which reduces preprocessing error. The method is divided into three steps: (1) conversion of the real-valued ECG record into a symbolic time-series, using a quantization process; (2) conditional compression of the symbolic representation of the ECG, using the symbolic ECG records stored in the database as reference; (3) identification of the ECG record class, using a 1-NN (nearest neighbor) classifier. We obtained over 98% of accuracy in biometric identification, whereas in emotion recognition we attained over 90%. Therefore, the method adequately identify the person, and his/her emotion. Also, the proposed method is flexible and may be adapted to different problems, by the alteration of the templates for training the model.


iberian conference on pattern recognition and image analysis | 2017

Impact of the Acquisition Time on ECG Compression-Based Biometric Identification Systems

João M. Carvalho; Susana Brás; Jacqueline Ferreira; Sandra C. Soares; Armando J. Pinho

The ECG signal conveys desirable characteristics for biometric identification (universality, uniqueness, measurability, acceptability and circumvention avoidance). However, based on the current literature review, there are no results that evaluate the number of heartbeats needed for personal identification. This information is undoubtedly useful when building a biometric identification system – any system should ask participants to provide data for identification, using the smallest time interval that is possible, for practical reasons. In this paper, we aim at exploring this topic using a measure of similarity based on the Kolmogorov Complexity, called the Normalized Relative Compression (NRC). To attain the goal, we built finite-context models to represent each individual – a compression-based approach that has been shown successful for several other pattern recognition applications like image similarity, DNA sequences or authorship attribution.


Archives of Sexual Behavior | 2018

Influence of Body Odors and Gender on Perceived Genital Arousal

Patrícia Alves-Oliveira; Joana Carvalho; Jacqueline Ferreira; Laura Alho; Pedro Nobre; Mats J. Olsson; Sandra C. Soares

Olfaction is often linked to mating behavior in nonhumans. Additionally, studies in mating behavior have shown that women seem to be more affected by odor cues than men. However, the relationship between odor cues and sexual response—specifically, sexual arousal—has not been studied yet. The aim of this study was to evaluate the impact of the exposure to human body odors (from individuals of the opposite gender) on perceived genital arousal, while these were presented concomitantly to sexually explicit video clips. Eighty university students (40 women) rated their perceived genital arousal (perceived degree of erection/genital lubrication) in response to an audiovisual sexual stimulus, while simultaneously exposed to a body odor from an opposite-gender donor or no odor. Participants also rated each odor sample’s (body odor and no odor) perceived pleasantness, intensity, and familiarity. Findings indicated that odor condition had an effect on women’s (but not men’s) perceived genital arousal, with women showing higher levels of perceived genital arousal in the no odor condition. Also, results showed that women rated body odors as less pleasant than no odor. Notwithstanding, the odor ratings do not seem to explain the association between body odor and perceived genital arousal. The current results support the hypothesis that women, rather than men, are sensitive to odors in the context of sexual response. The findings of this study have relevance for the understanding of human sexuality with respect to chemosensory communication.


Chemical Senses | 2017

Do Masculine Men Smell Better? An Association Between Skin Color Masculinity and Female Preferences for Body Odor

Mariana de Lurdes Carrito; Isabel M. Santos; Laura Alho; Jacqueline Ferreira; Sandra C. Soares; Pedro Bem-Haja; Carlos Fernandes da Silva; David I. Perrett

A recent study claimed face skin color as a sexually dimorphic variable that influences attractiveness preferences in mate choice. Thereby, skin color may assume the role of a mate quality signal influencing attractiveness preferences. As body odor is linked to attractiveness, this study aimed to explore whether the odors of men with more masculine facial skin color would be evaluated more positively than odors from less masculine men. Female raters were presented with body odors of 18 men and were asked to rate them in various characteristics. Multilevel modeling revealed that the odors of the donors with more masculine color were rated not only as more attractive, more pleasant, and sexier, but also healthier. This indicates that odor associated with men with more masculine skin color is attractive, just as other sexually dimorphic traits. Furthermore, we found a negative relation between skin color masculinity and perceived odor maleness. Regarding this last finding, a new discussion is introduced with respect to the influence of cognitive stereotypes in odor judgments. Altogether, the study supports the possibility that chemosensory signals may be communicating signs of mate quality associated with masculinity.


Frontiers in Psychology | 2016

Nosewitness Identification: Effects of Lineup Size and Retention Interval.

Laura Alho; Sandra C. Soares; Liliana P. Costa; Elisa Pinto; Jacqueline Ferreira; Kimmo Sorjonen; Carlos Fernandes da Silva; Mats J. Olsson

Although canine identification of body odor (BO) has been widely used as forensic evidence, the concept of nosewitness identification by human observers was only recently put to the test. The results indicated that BOs associated with male characters in authentic crime videos could later be identified in BO lineup tests well above chance. To further evaluate nosewitness memory, we assessed the effects of lineup size (Experiment 1) and retention interval (Experiment 2), using a forced-choice memory test. The results showed that nosewitness identification works for all lineup sizes (3, 5, and 8 BOs), but that larger lineups compromise identification performance in similarity to observations from eye- and earwitness studies. Also in line with previous eye- and earwitness studies, but in disagreement with some studies on odor memory, Experiment 2 showed significant forgetting between shorter retention intervals (15 min) and longer retention intervals (1-week) using lineups of five BOs. Altogether this study shows that identification of BO in a forensic setting is possible and has limits and characteristics in line with witness identification through other sensory modalities.


international conference of the ieee engineering in medicine and biology society | 2015

Psychophysiology of disgust: ECG noise entropy as a biomarker.

Susana Brás; Jacqueline Ferreira; Sandra C. Soares; Carlos Fernandes da Silva

The identification or classification of emotions allows the description of the persons state and, therefore, the inference of their preferences. The basic emotion of disgust, in particular, allows the organism to protect itself against diseases. Usually, the decrease in heart rate is associated with this emotion. As an avoidance behavior, when facing with disgust stimuli, the body reacts with movements, such as muscle contraction, etc. These reactions are evidenced in the electrocardiogram (ECG) as noise responses. In this paper, we propose the amount of ECG noise measured by the noise entropy as a new biomarker in emotion identification, which has been neglected in the literature. Our results showed that the noise entropy was able to discriminate between disgust, fear and neutral conditions in 88% (p<;0.05). It was also evidenced in this dataset that the median noise entropy in disgust was higher than in neutral and in fear conditions.


Perception | 2018

The Effects of Emotional Visual Context on the Encoding and Retrieval of Body Odor Information

Valentina Parma; Stephanie Macedo; Marta Rocha; Laura Alho; Jacqueline Ferreira; Sandra C. Soares

Conditions during information encoding and retrieval are known to influence the sensory material stored and its recapitulation. However, little is known about such processes in olfaction. Here, we capitalized on the uniqueness of body odors (BOs) which, similar to fingerprints, allow for the identification of a specific person, by associating their presentation to a negative or a neutral emotional context. One hundred twenty-five receivers (68 F) were exposed to a male BO while watching either criminal or neutral videos (encoding phase) and were subsequently asked to recognize the target BO within either a congruent or an incongruent visual context (retrieval phase). The results showed that criminal videos were rated as more vivid, unpleasant, and arousing than neutral videos both at encoding and retrieval. Moreover, in terms of BO ratings, we found that odor intensity and arousal allow to distinguish the target from the foils when congruent criminal information is presented at encoding and retrieval. Finally, the accuracy performance was not significantly different from chance level for either condition. These findings provide insights on how olfactory memories are processed in emotional situations.


Pattern Recognition Letters | 2018

Extended-Alphabet Finite-Context Models

João M. Carvalho; Susana Brás; Diogo Pratas; Jacqueline Ferreira; Sandra C. Soares; Armando J. Pinho

Abstract The normalized relative compression (NRC) is a recent dissimilarity measure, related to the Kolmogorov complexity. It has been successfully used in different applications, like DNA sequences, images or even ECG (electrocardiographic) signal. It uses a compressor that compresses a target string using exclusively the information contained in a reference string. One possible approach is to use finite-context models (FCMs) to represent the strings. A finite-context model calculates the probability distribution of the next symbol, given the previous k symbols. In this paper, we introduce a generalization of the FCMs, called extended-alphabet finite-context models (xaFCM), that calculates the probability of occurrence of the next d symbols, given the previous k symbols. We perform experiments on two different sample applications using the xaFCMs and the NRC measure: ECG biometric identification, using a publicly available database; estimation of the similarity between DNA sequences of two different, but related, species – chromosome by chromosome. In both applications, we compare the results against those obtained by the FCMs. The results show that the xaFCMs use less memory and computational time to achieve the same or, in some cases, even more accurate results.

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Laura Alho

Universidade Lusófona

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