Effects of (non)deceptive placebos on reported sleep quality and food cue reactivity.

A lack of sleep can increase appetite, particularly for high-calorie food. The current study tested the effects of an open-label placebo for improving sleep quality and reducing food cue reactivity. In open-label placebo interventions, placebo recipients are informed that they are receiving a placebo without a pharmacologically active substance. Participants (n = 150) were randomly allocated to one of three groups that received either an open-label placebo to improve sleep quality, a deceptive placebo ("melatonin"), or no placebo. The placebo was administered daily before bedtime for 1 week. Sleep quality and reactivity to high-calorie food cues (appetite, visual attention to food images) were assessed. The deceptive placebo (but not the open-label placebo) reduced reported sleep-onset latency. The open-label placebo decreased perceived sleep efficiency. The placebo interventions did not change food cue reactivity. This study demonstrated that open-label placebos do not present an alternative to deceptive placebos for improving sleep quality. The undesirable open-label placebo effects found warrant further exploration.

A differentiated look at emotions: association between gaze behaviour during the processing of affective videos and emotional granularity.

The ability to distinguish between subtle differences among emotions of similar valence is labelled emotion differentiation (ED). Previous research has demonstrated that people high in ED are less likely to use disengagement regulation strategies (i.e. avoidance/distraction) during negative affective states.The present eye-tracking study examined associations between ED and visual attention/avoidance of affective stimuli. A total of 160 participants viewed emotional video clips (positive/ negative), which were concurrently presented with a non-affective distractor image. After each video, participants verbally described their experienced emotions with adjectives in an open-response format. Moreover, they completed an ED questionnaire.The computed ED specificity index for the negative videos (the number of specific adjectives divided by all adjectives used) was positively associated with the scores on the ED questionnaire and visual revisits for the negative videos (how many times the participants gazed back and forth between video and distractor). This viewing style might reflect more active exploratory behaviour directed toward acquiring information about the negative stimulus and its context. The ED measures were not associated with the gaze behaviour for positive videos.

Voxel-based morphometry analysis of structural brain scans in skin-picking disorder.

BACKGROUND: Skin-picking disorder (SPD) is characterized by the excessive and repetitive manipulation of one's own skin resulting in tissue damage and impaired social functioning. There are only a few studies with small sample sizes that examined possible brain abnormalities in SPD, which is classified as a syndrome related to obsessive-compulsive disorders (OCD). METHOD: The current voxel-based morphometry (VBM) study compared data from 35 SPD patients and 35 control participants including both genders (mean age = 35 years, SD = 15). In addition, patients' self-reports on symptom severity, duration and impairment were correlated with grey matter volumes (GMV) in regions of interest (basal ganglia, orbitofrontal cortex (OFC), insula). RESULTS: Relative to controls, the patients showed reduced GMV in the OFC and in the insula. Basal ganglia volume did not differ between the groups. Within the SPD group, disorder-related impairment and symptom duration were negatively correlated with GMV in basal ganglia regions. DISCUSSION: This study indicated that SPD patients show GMV abnormalities in regions concerned with interoception (insula) and reinforcement of behavior (OFC). Whether the correlational findings are disorder-specific or reflect secondary processes needs to be investigated in a future longitudinal study with additional clinical control groups.

Cookie cravings - Examining the impact of sugar content information on Christmas treat preferences via mobile eye-tracking.

BACKGROUND: Diets high in added sugar can promote the development of overweight. Especially during the Holiday season, when high-sugar food is abundant, people overeat and gain more weight than during other times of the year. The present study with mobile eye-tracking glasses (Pupil Labs Invisible) investigated how sugar content information affects food preference (liking/wanting) and visual attention (where and how long one is looking) in a buffet-like situation. METHODS: Fifty-eight participants who were well acquainted with the local Christmas traditions and foods (38 female, 19 male, one diverse; mean age = 25 years, SD = 6.3 years; mean body mass index = 22.2 kg/m2, SD = 3.2 kg/m2) were presented with four cookies and two non-food items (wrapped presents) in a free viewing task. Two of the displayed cookies were 'Christmas cookies' (cookies that are traditionally eaten only during the Holiday season) and two cookies had no Christmas association. The cookies were either labeled as cookies made with or without sugar, resulting in a 3 (Category: cookies with sugar, cookies without sugar, non-food) by 2 (Christmas association: yes, no) repeated-measures design. RESULTS: Analyses of variance indicated that participants reported higher wanting and liking for cookies with sugar, particularly Christmas cookies (interaction effect for wanting: p = .047, ηp2 = .059; interaction effect for liking: p = .017, ηp2 = .084). Sugar-free cookies were fixated more often (p = .028; d = 0.35) and shorter (p < .001; d = 0.64) than sugar cookies. CONCLUSION: Assuming that cookies are sugar-free reduced the reported preference for this product, which was associated with a more detail-oriented (critical) viewing pattern. The study's findings have potential implications for public health and can aid in developing targeted interventions to promote healthier food choices during festive periods. The new strategies should not focus on the sugar content of foods.

Consequences of positive vs. negative information concerning the amount of sugar consumption on appetite, mood, and visual food cue attention: Findings from two online interventions.

BACKGROUND: Eating too much sugar is associated with many negative health effects. Two brief online interventions were carried out to investigate whether information about the negative consequences of eating high-sugar food vs. positive consequences of eating low-sugar food can change reported appetite, mood, and visual food cue attention. METHOD: For Study I, participants (n = 201) were allocated to one of three groups: Two groups were asked to list either the negative consequences of high-sugar consumption (negative focus) or the positive consequences of low-sugar consumption (positive focus). The third group carried out a control task (writing a shopping list). For Study II, 200 participants took part in a quiz with questions focusing on either positive, negative, or neutral consequences of high vs. low sugar consumption. Participants evaluated their appetite and mood before and after all interventions (list, quiz) and additionally completed a visual probe task with images depicting high vs. low-sugar food. RESULTS: In Study I, the positive focus increased appetite for low-sugar food. The negative focus reduced participants' positive mood but did not change reported appetite. In Study II, all quiz conditions decreased appetite for high-sugar foods but did not affect mood. None of the interventions influenced visual attention to the food images. CONCLUSION: Focusing on negative consequences of a high-sugar diet is less pleasant and is less effective in changing people's appetite than considering the positive aspects of a low-sugar diet. Thus, future interventions should instead spotlight the positive outcomes of a healthy diet.

(No) Effects of a Self-Kindness Intervention on Self-Esteem and Visual Self-Perception: An Eye-Tracking Investigation on the Time-Course of Self-Face Viewing.

Previous research has suggested a favorable impact of self-kindness on subjective well-being. The present experiment investigated the effects of an app-assisted self-kindness intervention for increasing self-esteem and self-face gaze, and for decreasing depression. We explored self-face processing via a time-course analysis of eye-tracking data. Eighty participants (56 female, 24 male; mean age: 23.2 years) were randomly allocated to one of two intervention groups, each receiving daily instructions to enhance either self-kindness or relaxation (active control). Following a one-week intervention period, both groups reported improved self-esteem (p = .035, ηpart2 = .068) and reduced depression (p < .001, ηpart2 = .17). The duration of self-face gaze increased in both groups (p < .001, ηpart2 = .21). Self-face processing was characterized by an early automatic attention bias toward the self-face, with a subsequent reduction in self-face bias, followed in turn by an attentional self-face reapproach, and then a stable self-face bias. We thus identified a complex temporal pattern of self-face inspection, which was not specifically altered by the intervention. This research sheds light on the potential for app-assisted interventions to positively impact psychological well-being, while also highlighting the complexity of self-face processing dynamics in this context. In the future, we propose the inclusion of personalized self-kindness statements, which may amplify the benefits of these interventions.

Sadness-associated eating styles and visual food cue reactivity: An eye-tracking investigation.

BACKGROUND: Emotional eating has been associated with biases of attention and memory for visual food cues. This eye-tracking study investigated whether the tendency to overeat in response to sadness is associated with the inspection and recall of visual food cues. METHOD: Participants (n = 115, mean age = 26 years, 70 females, 45 males) viewed images depicting food and non-food. We compared gaze duration, 'hyperscanning' parameters (fixation duration, saccadic angle, scan path length), and recall performance between different image categories (high-calorie, low-calorie food, non-food) and groups with different sadness-associated eating styles (increased, decreased, unchanged food consumption during states of sadness). RESULTS: The group with sadness-related overeating reported a higher body mass index than the other groups, but neither displayed a visual attention bias nor memory bias for food cues. We observed a prolonged gaze duration for low-calorie food cues, which were rated as more appetizing than high-calorie cues. All participants recalled more food cues (low- and high-calorie) than non-food cues independent of gaze duration. CONCLUSION: This study expanded previous research designs by groups that decrease vs. increase the amount eaten when feeling sad, and food/non-food images that were carefully matched for visual properties. Based on this approach, we were not able to show that self-disclosed sadness eating is associated with visual/memory biases for food images.

Effects of Self-Esteem on Self-Viewing: An Eye-Tracking Investigation on Mirror Gazing.

While some people enjoy looking at their faces in the mirror, others experience emotional distress. Despite these individual differences concerning self-viewing in the mirror, systematic investigations on this topic have not been conducted so far. The present eye-tracking study examined whether personality traits (self-esteem, narcissism propensity, self-disgust) are associated with gaze behavior (gaze duration, fixation count) during free mirror viewing of one's face. Sixty-eight adults (mean age = 23.5 years; 39 females, 29 males) viewed their faces in the mirror and watched a video of an unknown person matched for gender and age (control condition) for 90 s each. The computed regression analysis showed that higher self-esteem was associated with a shorter gaze duration for both self-face and other-face. This effect may reflect a less critical evaluation of the faces.

Disgust-Related Memory Bias in Children and Adults.

Studies with adults found a memory bias for disgust, such that memory for disgusting stimuli was enhanced compared to neutral and frightening stimuli. We investigated whether this bias is more pronounced in females and whether it is already present in children. Moreover, we analyzed whether the visual exploration of disgust stimuli during encoding is associated with memory retrieval. In a first recognition experiment with intentional learning, 50 adults (mean age; M = 23 years) and 52 children (M = 11 years) were presented with disgusting, frightening, and neutral pictures. Both children and adults showed a better recognition performance for disgusting images compared to the other image categories. Males and females did not differ in their memory performance. In a second free recall experiment with eye-tracking, 50 adults (M = 22 years) viewed images from the categories disgust, fear, and neutral. Disgusting and neutral images were matched for color, complexity, brightness, and contrast. The participants, who were not instructed to remember the stimuli, showed a disgust memory bias as well as shorter fixation durations and longer scan paths for disgusting images compared to neutral images. This "hyperscanning pattern" correlated with the number of correctly recalled disgust images. In conclusion, we found a disgust-related memory bias in both children and adults regardless of sex and independently of the memorization method used (recognition/free recall; intentional/incidental).

The Color Nutrition Information Paradox: Effects of Suggested Sugar Content on Food Cue Reactivity in Healthy Young Women.

Color nutrition information (CNI) based on a traffic light system conveys information about food quality with a glance. The color red typically indicates detrimental food characteristics (e.g., very high sugar content) and aims at inhibiting food shopping and consumption. Red may, however, also elicit cross-modal associations with sweet taste, which is a preferable food characteristic. We conducted two experiments. An eye-tracking study investigated whether CNI has an effect on cue reactivity (dwell time, saccadic latency, wanting/liking) for sweet foods. The participants were presented with images depicting sweets (e.g., cake). Each image was preceded by a colored circle that informed about the sugar content of the food (red = high, green = low, gray = unknown). It was tested whether the red circle would help the participants to direct their gaze away from the 'high sugar' item. A second experiment investigated whether colored prime circles (red, green, gray) without nutrition information would influence the assumed sweetness of a food. In Experiment 1, CNI had the opposite of the intended effect. Dwell time and saccadic latency were higher for food items preceded by a red compared to a green circle. This unintended response was positively associated with participants' liking of sweet foods. CNI did not change the wanting/liking of the displayed foods. In Experiment 2, we found no evidence for color priming on the assumed sweetness of food. Our results question whether CNI is helpful to influence initial cue reactivity toward sweet foods.

A Direct Comparison of Placebo and Nocebo Effects on Visuospatial Attention: An Eye-Tracking Experiment.

Background: Placebo and nocebo effects on visual attention are still poorly understood. This eye-tracking study directly compared effects of sham transcranial magnetic stimulation (sTMS) that was administered along with the verbal suggestion that the treatment would either increase (placebo) or decrease (nocebo) left-sided visual attention. Method: Twenty women who had reported decreased attention (nocebo responders) and 20 women who had reported increased attention (placebo responders) following sTMS completed a visual search task with three visual load levels. The task was conducted once with and once without the placebo or the nocebo (sTMS). Left-sided fixations and reaction times for left-sided targets (in comparison with right-sided targets) were analyzed. Results: Contrary to the verbal suggestion, the nocebo responders showed more left-sided fixations in the nocebo condition (compared with the control condition) and responded faster to left-sided targets in the high-load condition. The placebo had no effect on fixations and reaction times. Conclusion: These results indicate a more beneficial effect of a nocebo compared with a placebo for the first time. Limits and possibilities of placebo and nocebo interventions are discussed.

Placebo Effects on Visual Food Cue Reactivity: An Eye-Tracking Investigation.

Background: Enhanced visual food cue reactivity has been associated with overeating and weight gain. Due to the increasing prevalence of high-fat food images that we are constantly exposed to in both the real and the virtual world, methods that are able to reduce the reactivity to these types of cues are urgently needed. This eye-tracking study investigated whether food cue reactivity, especially toward high-caloric food, can be reduced with a placebo intervention. Method: Fifty-two women [mean body mass index (BMI) = 23.5] were presented with pictures depicting combinations of food (high-caloric, low-caloric) and non-food items, which were shown once with and once without a placebo in a repeated-measures design. The placebo was a pill introduced as a medication targeting peptide YY that is able to reduce appetite specifically for high-caloric food. Gaze data (dwell time, fixations) and self-reported appetite were assessed during the two eye-tracking sessions (with/without placebo). Results: The placebo reduced general appetite as well as specific appetite for the depicted food items. Additionally, the placebo decreased the percentage of fixations and dwell time on the food images. The placebo was not able to specifically change visual food cue reactivity to high-caloric stimuli but reduced responses to both high-caloric and low-caloric food. Reported appetite reduction and weight concerns were positively associated with the placebo-related decrease in visual attention for food. Conclusions: The placebo was able to reduce visual food cue reactivity. This finding demonstrates that placebos are able to alter early visual-attentional processes.

Imagine There Is No Plegia. Mental Motor Imagery Difficulties in Patients with Traumatic Spinal Cord Injury.

In rehabilitation of patients with spinal cord injury (SCI), imagination of movement is a candidate tool to promote long-term recovery or to control futuristic neuroprostheses. However, little is known about the ability of patients with spinal cord injury to perform this task. It is likely that without the ability to effectively perform the movement, the imagination of movement is also problematic. We therefore examined, whether patients with SCI experience increased difficulties in motor imagery (MI) compared to healthy controls. We examined 7 male patients with traumatic spinal cord injury (aged 23-70 years, median 53) and 20 healthy controls (aged 21-54 years, median 30). All patients had incomplete SCI, with AIS (ASIA Impairment Scale) grades of C or D. All had cervical lesions, except one who had a thoracic injury level. Duration after injury ranged from 3 to 314 months. We performed the Movement Imagery Questionnaire Revised as well as the Beck Depression Inventory in all participants. The self-assessed ability of patients to visually imagine movements ranged from 7 to 36 (Md = 30) and tended to be decreased in comparison to healthy controls (ranged 16-49, Md = 42.5; W = 326.5, p = 0.055). Also, the self-assessed ability of patients to kinesthetically imagine movements (range = 7-35, Md = 31) differed significantly from the control group (range = 23-49, Md = 41; W = 337.5, p = 0.0047). Two patients yielded tendencies for depressive mood and they also reported most problems with movement imagination. Statistical analysis however did not confirm a general relationship between depressive mood and increased difficulty in MI across both groups. Patients with spinal cord injury seem to experience difficulties in imagining movements compared to healthy controls. This result might not only have implications for training and rehabilitation programs, but also for applications like brain-computer interfaces used to control neuroprostheses, which are often based on the brain signals exhibited during the imagination of movements.