Human recognition of basic emotions from posed and animated dynamic facial expressions

Facial expressions are crucial for social communication, especially because they make it possible to express and perceive unspoken emotional and mental states. For example, neurodevelopmental disorders with social communication deficits, such as Asperger Syndrome (AS), often involve difficulties in interpreting emotional states from the facial expressions of others. Rather little is known of the role of dynamics in recognizing emotions from faces. Better recognition of dynamic rather than static facial expressions of six basic emotions has been reported with animated faces; however, this result hasn't been confirmed reliably with real human faces. This thesis evaluates the role of dynamics in recognizing basic expressions from animated and human faces. With human faces, the further interaction between dynamics and the effect of removing fine details by low-pass filtering (blurring) is studied in adult individuals with and without AS. The results confirmed that dynamics facilitates the recognition of emotional facial expressions. This effect, however, was apparent only with the facial animation stimuli lacking detailed static facial features and other emotional cues and with blurred human faces. Some dynamic emotional animations were recognized drastically better than static ones. With basic expressions posed by human actors, the advantage of dynamic vs. static displays increased as a function of the blur level. Participants with and without AS performed similarly in recognizing basic emotions from original non-filtered and from dynamic vs. static facial expressions, suggesting that AS involves intact recognition of simple emotional states and movement from faces. Participants with AS were affected more by the removal of fine details than participants without AS. This result supports a "weak central coherence" account suggesting that AS and other autistic spectrum disorders are characterized by general perceptual difficulties in processing global vs. local level features.Kasvonilmeet ovat tärkeä osa sosiaalista vuorovaikutusta, erityisesti koska ne tekevät ääneen lausumattomien tunnetilojen ilmaisemisen ja havaitsemisen mahdolliseksi. Esimerkiksi sosiaalisen vuorovaikutuksen ongelmia sisältäviin neurokehityksellisiin oireyhtymiin, kuten Aspergerin Syndroomaan (AS), liittyykin usein vaikeuksia kasvoilla näkyvien tunnetilojen tulkitsemisessa. Liikkeen roolista tunneilmausten tunnistamisessa kasvoilta on olemassa vain vähän tietoa. On osoitettu, että dynaamiset perustunneilmaukset tunnistetaan staattisia paremmin tietokoneanimoiduilta kasvoilta, vastaavaa tulosta ei ole kuitenkaan varmennettu ihmiskasvoilla. Tässä väitöskirjassa tutkitaan liikkeen roolia perustunneilmausten tunnistamisessa animoiduilta- ja ihmiskasvoilta. Ihmiskasvojen tapauksessa tutkitaan vuorovaikutusta liikkeen ja alipäästösuodatuksen (sumennuksen) kautta tapahtuvan tarkkojen yksityiskohtien poistamisen välillä. Tätä kysymystä tutkitaan lisäksi erikseen henkilöillä, joilla ei ole viitteitä AS:sta ja henkilöillä joilla on todettu AS. Tulokset vahvistivat, että liike edesauttaa tunneilmausten tunnistamista kasvoilta. Tämä tulos oli kuitenkin havaittavissa vain käytetyillä kasvoanimaatioilla, joista puuttui kasvojen tarkkoja yksityiskohtia ja muita tunteisiin liittyviä vihjeitä sekä sumennetuilla ihmiskasvoilla. Jotkin dynaamiset tunneanimaatiot tunnistettiin huomattavasti staattisia paremmin. Ihmisnäyttelijöiden esittämien perustunneilmausten tapauksessa, liikkeen tuoma lisähyöty kasvoi käytetyn sumennustason funktiona. Osallistujat, joilla oli todettu AS, tunnistivat perustunneilmauksia yhtä hyvin alkuperäisiltä ei-sumennetuilta kasvoilta ja dynaamisilta vs. staattisilta kasvoilta kuin muutkin osallistujat. Tulokset antavat viitteitä vahingoittumasta yksinkertaisten tunneilmausten ja liikkeen tunnistamisesta kasvoilta Aspergerin Syndroomassa. Osallistujat, joilla oli AS, suoriutuivat muita osallistujia heikommin, kun esitetyistä ärsykkeistä oli poistettu tarkkoja yksityiskohtia. Tämä tulos on yhdenmukainen "heikoksi keskeiseksi koherenssiksi" nimetyn näkemyksen kanssa, jonka mukaan AS:aan ja muihin autismin kirjon häiriöihin liittyy havaitsemistason vaikeuksia yleisten vs. tarkkojen piirteiden prosessoinnissa.reviewe

Intragroup Emotions : Physiological Linkage and Social Presence

We investigated how technologically mediating two different components of emotion communicative expression and physiological state to group members affects physiological linkage and self-reported feelings in a small group during video viewing. In different conditions the availability of second screen text chat (communicative expression) and visualization of group level physiological heart rates and their dyadic linkage (physiology) was varied. Within this four person group two participants formed a physically co-located dyad and the other two were individually situated in two separate rooms. We found that text chat always increased heart rate synchrony but HR visualization only with non-co-located dyads. We also found that physiological linkage was strongly connected to self-reported social presence. The results encourage further exploration of the possibilities of sharing group member's physiological components of emotion by technological means to enhance mediated communication and strengthen social presence.Peer reviewe

Virtual character facial expressions influence human brain and facial EMG activity in a decision-making game

We examined the effects of the emotional facial expressions of a virtual character (VC) on human frontal electroencephalographic (EEG) asymmetry (putatively indexing approach/withdrawal motivation), facial electromyographic (EMG) activity (emotional expressions), and social decision making (cooperation/defection). In a within-subjects design, the participants played the Iterated Prisoner's Dilemma game with VCs with different dynamic facial expressions (predefined or dependent on the participant's electrodermal and facial EMG activity). In general, VC facial expressions elicited congruent facial muscle activity. However, both frontal EEG asymmetry and facial EMG activity elicited by an angry VC facial expression varied as a function of preceding interactional events (human collaboration/defection). Pre-decision inner emotional-motivational processes and emotional facial expressions were dissociated, suggesting that human goals influence pre-decision frontal asymmetry, whereas display rules may affect (pre-decision) emotional expressions in human-VC interaction. An angry VC facial expression, high pre-decision corrugator EMG activity, and relatively greater left frontal activation predicted the participant's decision to defect. Both post-decision frontal asymmetry and facial EMG activity were related to reciprocal cooperation. The results suggest that the justifiability of VC emotional expressions and the perceived fairness of VC actions influence human emotional responses.Peer reviewe

Perception of stereoscopic direct gaze : The effects of interaxial distance and emotional facial expressions

Peer reviewe

Gender Differences in Emotional Responses to Cooperative and Competitive Game Play

Peer reviewe

Negativity Bias in Media Multitasking : The Effects of Negative Social Media Messages on Attention to Television News Broadcasts

Peer reviewe

Those Virtual People all Look the Same to me: Computer-Rendered Faces Elicit a Higher False Alarm Rate Than Real Human Faces in a Recognition Memory Task

Virtual as compared with real human characters can elicit a sense of uneasiness in human observers, characterized by lack of familiarity and even feelings of eeriness (the “uncanny valley” hypothesis). Here we test the possibility that this alleged lack of familiarity is literal in the sense that people have lesser perceptual expertise in processing virtual as compared with real human faces. Sixty-four participants took part in a recognition memory study in which they first learned a set of faces and were then asked to recognize them in a testing session. We used real and virtual (computer-rendered) versions of the same faces, presented in either upright or inverted orientation. Real and virtual faces were matched for low-level visual features such as global luminosity and spatial frequency contents. Our results demonstrated a higher response bias toward responding “seen before” for virtual as compared with real faces, which was further explained by a higher false alarm rate for the former. This finding resembles a similar effect for recognizing human faces from other than one's own ethnic groups (the “other race effect”). Virtual faces received clearly higher subjective eeriness ratings than real faces. Our results did not provide evidence of poorer overall recognition memory or lesser inversion effect for virtual faces, however. The higher false alarm rate finding supports the notion that lesser perceptual expertise may contribute to the lack of subjective familiarity with virtual faces. We discuss alternative interpretations and provide suggestions for future research

Stereoskooppinen esittäminen vahvistaa kasvonilmeiden aiheuttamia tunteita

Peer reviewe

Perception of basic emotion blends from facial expressions of virtual characters: pure, mixed, or complex?

As animated virtual characters in games, movies and other applications become more humanlike, it becomes more and more important to be able to imitate the complicated facial behaviour of a real human. So far, facial expression animation and research have been dominated by the basic emotions view, limited to the six universal expressions: anger, disgust, fear, joy, sadness and surprise. More complex facial expressions can be created by blending these basic emotions, but it is not clear how these blends are perceived. Are they still perceived as basic emotions or combinations of basic emotions, or are they perceived as expressions of more complex emotions? We used a series of online questionnaires to study the perception of all pairwise blends of basic emotions. The blends were produced as a sum of facial muscle activations in the two basic emotions, using a physically-based, animated face model. Our main finding is that several basic emotion blends with an opposite valence are perceived as complex emotions that are neither pure emotions nor their blends. Blends of basic emotions with a similar valence are typically perceived as pure basic emotions (e.g., a blend of anger and disgust is perceived as pure anger). Only one of the blends (joy+surprise) was perceived as a blend of two different basic emotions

Testing the ‘uncanny valley’ hypothesis in semirealistic computer-animated film characters

The uncanny valley (UV) hypothesis, which predicts that almost but not fully humanlike artificial characters elicit negative evaluations, has become increasingly influential. At the same time, the hypothesis has become associated with many computer-animated films that have aimed at high realism. In the present investigation, we tested whether semirealistic animated film characters do in fact elicit negative evaluations. Fifty-four participants were asked to evaluate five matched film excerpts from each of cartoonish, semirealistic, and human-acted films. Mixed model analyses were conducted to reduce the effects of participant and stimulus related confounds. Explicit selections made after the experiment confirmed that participants associated semirealistic film characters correctly with the UV. Semirealistic animated characters also received higher eeriness ratings than the other film characters. In particular, two semirealistic films ‘Beowulf’ and ‘The Polar Express’ were selected the most often explicitly, and ‘Beowulf’ also received higher eeriness ratings than any other film. Somewhat unexpectedly, cartoonish characters received the highest strangeness ratings and (after confound correction) the lowest likability ratings. Taken together, the present findings demonstrate that semirealistic animated film characters are more eerie than cartoonish characters or real actors, and hence provide evidence for the existence of the UV in animated film characters.Peer reviewe