Positive Faces Research Articles

Age-related differences in the medial temporal lobe responses to emotional faces as revealed by fMRI.

Age-related differences involved in the neural substrates of emotional face perception were investigated in young and old healthy volunteers. The subjects were scanned using functional magnetic resonance imaging while they were judging the gender of faces with negative, positive, or neutral emotional valence. The results showed that both the predominant activation in young subjects and reduced activity in old subjects contributed to a significant age difference in the left amygdala during the perception of negative faces. Activity in the right parahippocampal gyrus during the perception of positive faces diminished with advancing age. Neural activity in the angular gyrus and lingual gyrus of the right hemisphere was reduced in the old subjects during the perception of positive faces. There was no region where old subjects had greater activity than young subjects during the task. In old subjects, the overall activity in the right hippocampus during the task correlated negatively with age, whereas the activity in the right parahippocampal gyrus correlated positively with neuropsychological performance. There was no significant correlation between subjects' characteristics and signal change in young subjects. These results indicate the age-associated vulnerability of the medial temporal lobe structures including the amygdala, hippocampus, and parahippocampal gyrus during face perception. The dissociation with reduced activity in the left amygdala and the right parahippocampal gyrus may suggest that aging differentially affects neural responses to faces with negative or positive emotional valence. The parieto-occipital lobe, which has been found to be involved in face processing, also showed a functional decline associated with aging.

COGNATIVE-BEHAVIORAL MODELS OF SOCIAL ANXIETY DISORDER

In 1985, Liebowitz et al labeled SAD the "neglected anxiety disorder." Clearly, times have changed. Although it took 10 years after this pronouncement for the first cognitive-behavioral model of SAD to be introduced, a great deal of research has been carried out and a great deal has been learned since then. The core features of these models seem to hold a great deal of validity. Perhaps the greatest "learning curve" has been seen in work done on the processing of the self as social object, a component of both cognitive-behavioral models of SAD. A great deal of empiric evidence now suggests that people with SAD see themselves as they believe they are seen by others. Unfortunately, their perception of how they are seen by others is often grossly distorted, likely contributing to the distress they feel about social situations and their concomitant avoidance of them. Recent work by Hirsch and Mathews has gone so far as to suggest that people with the disorder may not attend at all to social information while social events are ongoing but rather may judge them later based on preexisting notions about themselves as social beings. In Rapee and Heimberg's model, preferential allocation of attentional resources is emphasized, and this has been another great area of progress over the past few years. While people with SAD may be hypervigilant to social threat in their environments, once they find it, they tend to divert their attention away from it--as has been most clearly demonstrated in the studies of processing of facial expressions. The data suggest that both angry and happy faces may be perceived as threatening and attention is diverted as a means of avoiding them--again having important implications for social behavior and for maintenance of the disorder over time. Important strides have also been made in understanding judgment biases in SAD. Studies on this issue have suggested that individuals with the disorder see positive social outcomes as unlikely and see negative social outcomes as highly likely. When presented with ambiguous scenarios, people with SAD are more likely to select negative interpretations for them, even when they are given the option of selecting positive interpretations and neutral interpretations that they could find at least somewhat believable. Furthermore, people with SAD see both negative social outcomes and positive social outcomes as coming at a higher emotional cost than do people without the disorder. Hirsch and Mathews suggest that the core of social anxiety may be a failure to (over-)emphasize the positive. However, people with the disorder may not adequately distinguish between positive and negative cues, seeing them as equal in valence. Gilboa-Schechtman et al and Wallace and Alden, using very different approaches, have also suggested that both positive and negative outcomes in social situations come at a great emotional cost for people with SAD. Studies of facial expressions suggest that positive and negative faces are perceived as threatening, leading people with SAD to divert attention away from both. Finally, the studies on the observer perspective suggest, also in line with the research of Hirsch and Mathews, that people with SAD do not pay sufficient attention to what is going on around them in social situations. In effect, they are looking at the wrong thing (or through the wrong eyes) and missing important social cues, both positive and negative. Perhaps, as suggested by Hirsh and Mathews, people with the disorder come away from social situations with very little information at all (this notion is supported by older studies that asked socially anxious people what they remembered from social situations after they had participated in them), forcing them to draw conclusions about their performance based on blanket assumptions about themselves as social beings rather than about what actually occurred during that single event. These conclusions have very important implications for treatment. First, it is clear that clinicians need to help their patients learn to pay attention in social situations and, furthermore, to attend to the "right" things. Studies that have included that manipulations of attention suggest that this is a positive direction to pursue. Furthermore, clinicians have to help their patients to make judgments based on what really occurred in a single situation, rather than drawing blanket conclusions for all situations based on preconceived notions of the self as social being. Again, some very preliminary evidence suggests that this approach (through the use of video feedback and other techniques) could be of great benefit.

Differential attentional guidance by unattended faces expressing positive and negative emotion.

Four experiments were conducted to evaluate whether focal attention can be guided by an analysis of the emotional expression in a face. Participants searched displays of 7, 11, 15, and 19 schematic faces for the location of a unique face expressing either a positive or a negative emotion located among distractor faces expressing a neutral emotion. The slopes of the search functions for locating the negative face were shallower than the slopes of the search functions for locating the positive face (Experiments 1A and 2A). When the faces were inverted to reduce holistic face perception, the slopes of the search functions for locating positive and negative faces were not different (Experiments 1B and 2B). The results suggest that the emotional expression in a face can be perceived outside the focus of attention and can guide focal attention to the location of the face.

Detection of Facial Expressions of Emotions in Depression

Research on perceptual and attentional processes in depression has shown that depressed as opposed to nondepressed individuals do not exhibit a positive perceptual bias in multistimulus representations. In the present study a face-in-the-crowd task was applied to examine the relationship between depression and spatial detection of facial expression of positive and negative emotions. A face-in-the-crowd task was administered to 30 subjects (15 clinically stabilized depressed inpatients and 15 normal subjects) using displays of schematic faces. Depressed subjects showed no performance differences in the detection of negative faces and no differences in decision latency for the control condition (all neutral faces) compared to normal subjects. Depressed subjects, however, were significantly slower in responding to positive faces than normal subjects. Our data suggest that depressive mood is associated with a reduced spatial attention to positive facial expression and not with an abnormal spatial processing of negative facial expression. An implication is that lowered vigilance for facial expressions of joy and happiness may affect adversely interpersonal relationships in depressed subjects.

Ratings of Emotion in Laterally Presented Faces: Sex and Handedness Effects

Sixteen right-handed participants (8 male and 8 female students) and 16 left-handed participants (8 male and 8 female students) were presented with cartoon faces expressing emotions ranging from extremely positive to extremely negative. A forced-choice paradigm was used in which the participants were asked to rate the faces as either positive or negative. Compared to men, women rated faces more positively, especially in response to right visual field presentations. Women rated neutral and mildly positive faces more positively in the right than in the left visual field, whereas men rated these faces consistently across visual fields. Handedness did not affect the ratings of emotion. The data suggest a positive emotional bias of the left hemisphere in women.

Covert and overt orienting of attention to emotional faces in anxiety

Attentional biases for emotional faces were investigated in high, medium, and low anxiety groups (N = 54) using a probe detection task. Four types of facial expression (threat, sad, happy, neutral) were used to examine the specificity of the bias. Attentional bias measures were derived from manual reaction times (RTs) to probes and the direction of initial eye movement (EM) to the faces. The RT data indicated enhanced vigilance for threat rather than neutral faces in high and medium, but not low, state anxiety. The bias for negative faces appeared to be a combined function of stimulus threat value and the individual's anxiety level. The RT bias did not seem to depend on overt orienting, as many participants made few EMs. However, those who made frequent EMs to the faces showed concordance between the RT and EM bias measures, and so the RT measure of attentional bias for negative versus positive faces at 500 ms appears to provide a valid index of the direction of initial orienting to emotional stimuli. There was no evidence of an anxiety - related bias for happy faces (predicted by the emotionality hypothesis), nor a dysphoria - related bias for sad faces. However, increased dysphoria scores were associated with reduced attentiveness to happy faces.

Lighting direction affects recognition of untextured faces in photographic positive and negative

Face recognition in photographic positive and negative was examined in a same/different matching task in five lighting direction conditions using untextured 3-D laser-scanned faces. The lighting directions were +60, +30, 0, −30 and −60°, where negative values represent bottom lighting and positive values represent top lighting. Recognition performance was better for faces in positive than in negative when lighting directions were at +60°. In one experiment, the same effect was also found at +30°. However, faces in negative were recognized better than positive when the direction was −60°. There was no difference in recognition performance when the lighting direction was 0 and −30°. These results confirm that the effect of lighting direction can be a determinant of the photographic negative effect. Positive faces, which normally appear to be top-lit, may be difficult to recognize in negative partly because of the accompanying change in apparent lighting direction to bottom-lit.

Evidence for Holistic Processing of Faces Viewed as Photographic Negatives

Inversion and photographic negation both impair face recognition. Inversion seems to disrupt processing of the spatial relationship between facial features ('relational' processing) which normally occurs with upright faces and which facilitates their recognition. It remains unclear why negation affects recognition. To find out if negation impairs relational processing, we investigated whether negative faces are subject to the 'chimeric-face effect'. Recognition of the top half of a composite face (constructed from top and bottom halves of different faces) is difficult when the face is upright, but not when it is inverted. To perform this task successfully, the bottom half of the face has to be disregarded, but the relational processing which normally occurs with upright faces makes this difficult. Inversion reduces relational processing and thus facilitates performance on this particular task. In our experiments, subjects saw pairs of chimeric faces and had to decide whether or not the top halves were identical. On half the trials the two chimeras had identical tops; on the remaining trials the top halves were different. (The bottom halves were always different.) All permutations of orientation (upright or inverted) and luminance (normal or negative) were used. In experiment 1, each pair of 'identical' top halves were the same in all respects. Experiment 2 used differently oriented views of the same person, to preclude matches being based on incidental features of the images rather than the faces displayed within them. In both experiments, similar chimeric-face effects were obtained with both positive and negative faces, implying that negative faces evoke some form of relational processing. It is argued that there may be more than one kind of relational processing involved in face recognition: the 'chimeric-face effect' may reflect an initial 'holistic' processing which binds facial features into a 'Gestalt', rather than being a demonstration of the configurational processing involved in individual recognition.

Comparison of Hematite Coagulation by Charge Screening and Phosphate Adsorption: Differences in Aggregate Structure

AbstractThe formation and structure of hematite aggregates were examined by dynamic and static light scattering techniques. A large range in coagulation kinetics was studied by varying either indifferent electrolyte (KCl) concentration or surface complexing anion (H2PO4-) concentration, PT, at pH 6.0 ± 0.1. Diffusion limited aggregation (DLA) was induced by counterion screening at [KCl] > 80 mM or by surface charge neutralization at PT = 31 μM (and ionic strength =1.0 mM). In DLA, the fractal dimension, df, of aggregates formed by either surface charge neutralization or counterion screening was 1.7 ± 0.1. A reduction in the rate of coagulation in KCl for [KCl] > critical coagulation concentration (CCC) produced an increase in df to 2.1 ± 0.1. For aggregation induced by phosphate adsorption at constant ionic strength, there was no apparent trend in df with coagulation rate. The value of df was consistently less than 1.8 when reaction limited aggregation (RLA) resulted from surface charge neutralization rather than counterion screening. TEM observations of aggregates formed in the presence or absence of phosphate confirm that, when RLA is induced by phosphate adsorption, resulting aggregates are much looser in structure than those formed by counterion screening. The results suggest that the high-affinity binding of phosphate to hematite may result in a nonrandom distribution of surface charge that facilitates the coalescence of positive and negative charge crystal faces.

Line-focus acoustic microscopy measurements of acoustic properties of LiTaO3 crystal plates with an inversion layer

Inversion layers of 2 μm and 30 μm thickness were formed at the negative dipole-end (−c) face of a Z-cut LiTaO3 crystal plate by proton exchange followed by heat treatment. The phase velocities of leaky surface acoustic waves (LSAWs) on both the positive (+c) and negative (−c) faces of the plate were measured by line-focus acoustic microscopy versus the angle of propagation, at a frequency of 225 MHz, and the results were compared with theoretical predictions. It is shown that for an inversion layer of 30 μm thickness the phase velocities of LSAWs on the +c and −c faces are the same, and almost equal to the velocities of the virgin plate. This suggests that the material constants, which are decreased due to the proton exchange, are restored to the original values by the heat treatment.

Understanding and Controlling the Morphology of ZnO Crystallites under Hydrothermal Conditions

AbstractThe morphological features of ZnO crystallites influenced by solution basicity under hydrothermal conditions have been studied from the standpoint of the incorporation of the growth units. A crystal chemistry approach is developed to understand and thus to control a desirable morphology of the crystallites. The effects of the additive OH− on the crystal morphology of ZnO crystallites are qualitatively but satisfactorily explained by a mechanism considering two aspects: (1) solution structures and the structural forms of growth units under a certain growth condition, i.e. the interactions between the solvent molecules and the growth units; and (2) the influence of the solvent molecules or additives on growth interfaces, particularly on two polar faces of ZnO crystallites in terms of the inhibition or promotion of the incorporation of various growth units depending on the solution basicity. Since the incorporation rates of the growth units are different on positive and negative polar faces, the relative growth rates of these faces are different and thus lead to the habit modifications. The approach clearly demonstrates that the hindrance of crystal growth is a consequence of surface adsorption processes.

Analysis of growth habits of polar organic crystal N-4-nitrophenyl-(L)-prolinol (NPP) based on the incorporation of growth units

The growth habits of the polar organic crystal N-4-nitrophenyl-(L)-prolinol (NPP) in organic solvents have been studied from the standpoint of the incorporation of growth units. Qualitative explanations of the observed growth forms are based on (1) the interaction between the solvent molecules and the growth units, and (2) the influence of the solvent molecules on growth interfaces, particularly on two polar faces of the polar organic crystal. Since the incorporation rates of the growth units are different on positive and negative polar faces, a variety of growth habits appear. The surface structures of the grown crystal have been investigated through ex-situ observations of atomic force microscopy (AFM).

Hemispheric asymmetry as a function of handedness: perception of facial affect stimuli.

Hemispheric asymmetry in 14 left- and 14 right-handed persons shown tachistoscopically presented emotional stimuli to left and right visual fields was examined using a forced-choice, reaction-time paradigm in which subjects were asked to identify positive and negative faces. Neutral faces were included within the two-alternative forced-choice paradigm. Reaction time and response-bias measures were recorded. Analysis indicated differential lateralization for left-handed and right-handed subjects with respect to neutral affective stimuli. While right-handed subjects' perceptions of neutral stimuli remained consistent across visual fields, left-handed ones identified neutral stimuli as more positive (happy) when presented to the left visual field and negative (angry) when presented to the right visual field. Implications for differential lateralization patterns among left- and right-handed adults are discussed.

Effect of unilateral contraction of hand muscles on perceiver biases in the perception of chimeric and neutral faces

Judgements of chimeric faces (half sad, half happy) showed a strong negative bias when the left face was negative. Contractions of the right hand reduced this bias but left hand contractions had no effect. The left positive faces elicited weak positive response biases that were not strongly affected by either contraction. Faces that were drawn to be neutral elicited negative or positive response biases depending on the method of presentation. When this bias was negative under control conditions left contraction had no effect, but the bias became positive following right contractions. Similarly, when the control bias was positive the right contraction had no effect, but the bias became negative following left contractions. The results are interpreted as reflecting emotional changes and shifts in lateral attention resulting from activation of the hemisphere contralateral to the contraction.

The influence of face on person perception

The purpose is to examine the influence of three factors on person perception, (a) the degree of facial attractiveness, (b) the order of presentation of the faces and the verbal information of the same stimulus person and (c) the sex of the perceivers. Seventy-one male undergraduates and 89 female undergraduates were asked to rate the personalities of the two positive and two negative stimulus persons of the opposite sex, who were selected by each subject in preliminary experiment, and asked to choose what kind of relation they would have with them. Positive or negative face was presented either before or after verbal information. The main results were as follows. (a) Generally, positive faces exerted greater influence than negative faces. (b) Faces presented after verbal information were more influential than those presented before it (recency effect). (c) The influence of face on male subjects was greater than that on female subjects.

A technique for the fine longitude control of a geostationary satellite as demonstrated on insat‐1B

AbstractThe possibilities of finer longitude control of a geostationary satellite are studied with a view to providing insight into the problem of co‐location of satellites. It is shown that for a three‐axis stabilized satellite such as INSAT‐1B, placed close to an equilibrium longitude, the propellant expenditure for satellite attitude control is considerably larger than that required for longitude drift control. An experiment was conducted on INSAT‐1B in which the forces arising from the attitude control thrusters are optimally used to counteract the force due to the solar radiation pressure thereby reducing the perturbations on the orbital eccentricity vector. This is accomplished by suitably switching between the redundant attitude control thrusters located in the positive and negative roll faces of the satellite. The extent to which the effects of the solar radiation pressure are nullified is quantitatively estimated from the observed behaviour of the eccentricity vector. Without any recurrent propellant expenditure it is shown that it is possible to restrict the longitudinal excursions to nearly half of the normally allocated ±0·1° longitude band.

The role of sedimentary and tectonic brines in the Damara Orogen, Namibia

Along the southern margin of the Upper Proterozoic Damara Orogen, Namibia, an accumulation of extraordinarily large megacrystalline quartz-dolomite bodies occur. They were emplaced in tectonically controlled positions during an early deformational phase of the Damara Orogeny, where hot nappes were thrust over a fluvial-lacustrine and evaporitic metaplaya sequence (Kamtsas and Duruchaus Formations) which was deposited on the faulted EW-trending continental margin of the Kalahari craton. Individual occurrences of the quartz-dolomite bodies often cover several hundred square meters. Characteristic for the quartz-dolomite bodies is zoning with an outer shell of giant milky quartz crystals, some more than 15 m long along the c-axis, tightly intergrown or twinned (Brazilian twins) with a perfect cleavage parallel to the positive rhombohedral faces {1011}; there is an inner shell of crystalline dolomite and a central pipe of dolomitic breccia. Based on fluid inclusions studies the formation fluids of quartz-dolomite bodies can be related to the mobilization of interstitial fluids and to dehydration and leaching of evaporitic hydrate minerals of the metaplaya sequence. The fluids are characterized by extremely high salinities of up to 68 wt % total salt content. Minimum temperatures of formation, as determined in fluid inclusion studies, ranged from 150 to 250°C. At a later stage CO 2 derived from decarbonatization reactions was dissolved in the fluids. Changes in pressure and temperature led to effervescence and the formation of a quartz stockwork in the surrounding country rock. During the main phase of the progressive Damara Orogeny, the southward advancing accretionary nappe pile of the Khomas trough drove ahead large amounts of tectonometamorphic fluids, characterized by intermediate salinity and high CO 2 contents. When these fluids met with the previously established hypersaline fluid system, large amounts of CO 2 were released due to the mixing of the two fluids; if there is no mixing, each fluid then maintains its salinity and there is no CO 2 degassing. The CO 2 from this mixing is now present as secondary, high-density inclusions not only in the quartz-dolomite bodies but also in the surrounding country rock. Pressure estimations indicate at least 100–600 MPa as a minimum pressure of formation for these inclusions. The remaining aqueous fluid phase has produced local alterations and Cu, Pb, and Au mineralization.

Radiation therapy for lung cancer: Nursing considerations

During the early postpartum period, mothers exhibit increased amygdala responses to positive infant expressions, which are important for positive mother-infant relationships. Socioeconomic disadvantage is associated with altered amygdala response to emotional stimuli as well as more negative mother-infant relationships. However, little is known about the role of socioeconomic disadvantage in neural responses specifically to infants. Thus, we examined whether socioeconomic disadvantage (indexed by lower income-to-needs ratio) is associated with neural responses to infant emotions and parenting behaviors among new mothers. Using fMRI, neural responses to infants’ emotional expressions (positive, negative, and neutral faces) were assessed among 39 low- and middle-income first-time mothers during 0–6 postpartum months. Lower income-to-needs ratio was associated with dampened amygdala responses to positive infant faces, but increased amygdala responses to negative infant faces. An indirect effect of socioeconomic disadvantage on emotional availability via amygdala activation suggests that socioeconomic disadvantage is associated with heightened neural sensitivity to infants’ negative emotions, which is further associated with mothers’ intrusiveness observed during interactions with their own infant. The findings suggest that low-income mothers may be more vulnerable to altered neural processing of infants’ emotional expressions which may further influence mothers’ emotional availability during interactions with their own infants.

Recognition of emotion in hemifaces presented to the left and right visual fields.

Thirty-two right-handed subjects (16 males and 16 females) participated in a choice reaction time experiment replicating two previous studies which demonstrated the superiority of the left hemisphere in rapidly identifying facial emotion as either positive or negative. Slides of hemifaces split along the vertical axis, showing either positive (happiness, surprise) or negative (anger, disgust, or sadness) affect were presented tachistoscopically to either the left or right visual field. A 2 X 2 X 2 mixed ANOVA revealed main effects for visual field and type of affect. In contrast to earlier studies which presented full face stimuli, presentation of hemifaces produced a strong left visual field advantage and, as expected, positive faces produced faster reaction times than negative faces.

Hemispheric differences in the perception of positive and negative faces.

Thirty-two right-handed subjects (15 males and 17 females) participated in a study investigating the effects of the perception of positive and negative emotional stimuli on choice reaction time. Slides of faces showing positive (happy, surprise) or negative (anger, disgust, sadness) affect were presented via a tachistoscope to either the right or left visual field. A 2 X 2 X 2 X 2 mixed analysis of variance with repeated measures over the factors of hand used by visual field by affect across sex of subject revealed a main effect for visual field (with slightly faster responses to stimuli presented in the right visual field) and a strong affect by visual field interaction with positive facial slides identified more quickly than negative facial slides when presented to the right visual field.