Behavioral Bias for Food Reflected in Hand Movements: A Preliminary Study with Healthy Subjects

Virtual reality assessment of a high-calorie food bias: Replication and food-specificity in healthy participants

BACKGROUND

Theoretical models and behavioural studies indicate faster approach behaviour for high-calorie food (approach bias) among healthy participants. A previous study with Virtual Reality (VR) and online motion-capture quantified this approach bias towards food and non-food cues in a controlled VR environment with hand movements. The aim of this study was to test the specificity of a manual approach bias for high-calorie food in grasp movements compared to low-calorie food and neutral objects of different complexity, namely, simple balls and geometrically more complex office tools.

METHODS

In a VR setting, healthy participants (N = 27) repeatedly grasped or pushed high-calorie food, low-calorie food, balls and office tools in randomized order with 30 item repetitions. All objects were rated for valence and arousal.

RESULTS

High-calorie food was less attractive and more arousing in subjective ratings than low-calorie food and neutral objects. Movement onset was faster for high-calorie food in push-trials, but overall push responses were comparable. In contrast, responses to high-calorie food relative to low-calorie food and to control objects were faster in grasp trials for later stages of interaction (grasp and collect). Non-parametric tests confirmed an approach bias for high-calorie food.

CONCLUSION

A behavioural bias for food was specific to high-calorie food objects. The results confirm the presence of bottom-up advantages in motor-cognitive behaviour for high-calorie food in a non-clinical population. More systematic variations of object fidelity and in clinical populations are outstanding. The utility of VR in assessing approach behaviour is confirmed in this study by exploring manual interactions in a controlled environment.

Persistent avoidance of virtual food in anorexia nervosa-restrictive type: Results from motion tracking in a virtual stopping task

OBJECTIVE

Food avoidance is central to patients with anorexia nervosa-restrictive type (AN-R). Competing accounts in experimental psychopathology research suggest that food avoidance may result from automatic, habitual responses or from elevated inhibitory control abilities. This study investigated behavioral trajectories of food avoidance in a novel virtual reality stopping task.

METHOD

Sixty patients with AN-R and 29 healthy controls with normal weight were investigated using a novel, kinematic task in virtual reality. We recorded spatial displacement in stop- and go-trials to virtual food and control objects. Inhibitory control abilities were operationalized by the VR task in stopping performance (i.e., interrupted movement in stop-trials), whereas we also measured habitual avoidance of virtual food across both go- and stop-trials (i.e., delayed movement relative to nonfood objects).

RESULTS

In patients with AN-R, hand displacements were shorter to food versus nonfood across stop- and go-trials, reflected in a Stimulus × Group interaction. Healthy controls showed no differences. Importantly, the food-specific effect in AN-R was identical across stop- and go-trials, indicating habitual food avoidance. Moreover, stop error rates (i.e., stop-trials with response) were lower in patients with AN-R.

DISCUSSION

The findings suggest food-specific habitual avoidance and heightened generalized inhibitory control in AN-R. The continuously delayed displacements during active hand movements across stop- and go-trials indicated the persistence of patients' avoidance of food.

PUBLIC SIGNIFICANCE

Experimental research investigates the mechanisms underlying mental disorders such as anorexia nervosa. In this study, we measured interrupted hand movements in response to food pictures or neutral pictures (shoes) in patients with anorexia nervosa and healthy controls. A virtual reality scenario was used. Findings indicated that patients were slower at approaching food, interrupted or not. Key mechanisms of food avoidance can be translated into habit-based treatment options in future research.

Easy to get, difficult to avoid: Behavioral tendencies toward high-calorie and low-calorie food during a mobile approach-avoidance task interact with body mass index and hunger in a community sample

In recent years, different studies highlighted the importance of assessing behavioral tendencies toward different food stimuli in healthy and pathological samples. However, heterogeneities in experimental approaches and small sample sizes make this literature rather inconsistent. In this study, we used a mobile approach-avoidance task to investigate the behavioral tendencies toward healthy and unhealthy foods compared to neutral objects in a large community sample. The role of some contextual and stable subjective variables was also explored. The sample included 204 participants. The stimuli comprised 15 pictures of unhealthy foods, 15 pictures of healthy foods, and 15 pictures of neutral objects. Participants were required to approach or avoid stimuli by respectively pull or push the smartphone toward or away from themselves. Accuracy and reaction time of each movement were calculated. The analyses were conducted using a generalized linear mixed-effect model (GLMMs), testing the two-way interaction between the type of movement and the stimulus category and the three-way interactions between type of movement, stimulus, and specific variables (BMI, time passed since the last meal, level of perceived hunger). Our results evidenced faster approaching movement toward food stimuli but not toward neutrals. An effect of BMI was also documented: as the BMI increased, participants became slower in avoiding unhealthy compared to healthy foods, and in approaching healthy compared to unhealthy stimuli. Moreover, as hunger increased, participants became faster in approaching and slower in avoiding healthy compared to unhealthy stimuli. In conclusion, our results show an approach tendency toward food stimuli, independent from caloric content, in the general population. Furthermore, approach tendencies to healthy foods decreased with increasing BMI and increased with perceived hunger, indicating the possible influence of different mechanisms on eating-related behavioral tendencies.

Behavioural biases in the interaction with food objects in virtual reality and its clinical implication for binge eating disorder

Cognitive processes play a central role in the development, maintenance and remission in mental disorders, like in Binge Eating Disorder (BED). Insights into cognitive mechanisms reflected by embodied interaction with food and its connections to clinically relevant psychopathology offer new possibilities for translational diagnostics and interventions. We longitudinally investigated the manual interaction with food in a virtual reality (VR) in 31 patients with BED. Patients were assessed at baseline before participating in a randomized-controlled trial (RCT) investigating a computer-based inhibitory control training programme enhanced by transcranial direct current stimulation (tDCS) and at a 6-week follow-up. At both assessments, an experimental VR paradigm was conducted and patients were characterized concerning eating disorder psychopathology, eating behaviour, general impulsivity and food craving. In the experimental task, one of two simultaneously presented objects (food vs. office tools) had to be collected. Food was recognized faster than office tools and subsequent approach behaviour was initiated faster, whereas thereafter, food was collected slower than office tools. Exploratory, we could not find a modulatory effect of applied tDCS on the interaction with food. No relationship between behavioural biases and sample characterizations could be detected. Two different stages in the manual interaction with food were found: a faster first stage that comprises recognition and movement initiation and a slower second stage that comprises controlled handling and may reflect aversive motivational processes. As the behavioural patterns do not change with an ameliorated BED-psychopathology at the second assessment, the task seems insensitive in detecting translational interconnections between behavioural biases and BED-characteristics.Level of evidence: Level I, experimental study.

Improved Spatial Knowledge Acquisition through Sensory Augmentation

Sensory augmentation provides novel opportunities to broaden our knowledge of human perception through external sensors that record and transmit information beyond natural perception. To assess whether such augmented senses affect the acquisition of spatial knowledge during navigation, we trained a group of 27 participants for six weeks with an augmented sense for cardinal directions called the feelSpace belt. Then, we recruited a control group that did not receive the augmented sense and the corresponding training. All 53 participants first explored the Westbrook virtual reality environment for two and a half hours spread over five sessions before assessing their spatial knowledge in four immersive virtual reality tasks measuring cardinal, route, and survey knowledge. We found that the belt group acquired significantly more accurate cardinal and survey knowledge, which was measured in pointing accuracy, distance, and rotation estimates. Interestingly, the augmented sense also positively affected route knowledge, although to a lesser degree. Finally, the belt group reported a significant increase in the use of spatial strategies after training, while the groups' ratings were comparable at baseline. The results suggest that six weeks of training with the feelSpace belt led to improved survey and route knowledge acquisition. Moreover, the findings of our study could inform the development of assistive technologies for individuals with visual or navigational impairments, which may lead to enhanced navigation skills and quality of life.

Eating, Smelling, and Seeing: Investigating Multisensory Integration and (In)congruent Stimuli while Eating in VR

Integrating taste in AR/VR applications has various promising use cases - from social eating to the treatment of disorders. Despite many successful AR/VR applications that alter the taste of beverages and food, the relationship between olfaction, gustation, and vision during the process of multisensory integration (MSI) has not been fully explored yet. Thus, we present the results of a study in which participants were confronted with congruent and incongruent visual and olfactory stimuli while eating a tasteless food product in VR. We were interested (1) if participants integrate bi-modal congruent stimuli and (2) if vision guides MSI during congruent/incongruent conditions. Our results contain three main findings: First, and surprisingly, participants were not always able to detect congruent visual-olfactory stimuli when eating a portion of tasteless food. Second, when confronted with tri-modal incongruent cues, a majority of participants did not rely on any of the presented cues when forced to identify what they eat; this includes vision which has previously been shown to dominate MSI. Third, although research has shown that basic taste qualities like sweetness, saltiness, or sourness can be influenced by congruent cues, doing so with more complex flavors (e.g., zucchini or carrot) proved to be harder to achieve. We discuss our results in the context of multimodal integration, and within the domain of multisensory AR/VR. Our results are a necessary building block for future human-food interaction in XR that relies on smell, taste, and vision and are foundational for applied applications such as affective AR/VR.

Playing with temptation: Stopping abilities to chocolate are superior, but also more extensive

Cue-specific inhibitory control is assumed to support balanced food intake, but previous studies with established measures showed inconsistent results. We developed a novel kinematic stop task in virtual reality (VR) and report results from trajectory recordings. The primary objective of this explorative study was to assess the interrelationships between validated measures of food-related inhibitory control and novel measures from the VR task. We hypothesized that healthy female participants show worse inhibitory control when grasping attractive virtual chocolate, compared to non-edible color-and-shape matched objects. We further aimed to quantify the construct validity of kinematic measures (e.g., reaching extent/spatial displacement, movement time after stop-signal, velocity) with established measures of inhibitory control in a keyboard-based adaptive stop-signal task (SST). In total, 79 females with varying levels of chocolate craving participated in an experimental study consisting of self-report questionnaires, subjective chocolate craving, the conventional SST and the kinematic task in VR. Results showed superior stopping ability to chocolate in both tasks. In VR, participants successfully interrupted an initiated approach trajectory but terminated slightly closer to chocolate targets. Stop-signal delay (SSD) was adapted relative to movement onset and appeared later in chocolate trials, during which participants still stopped faster, as was also confirmed by shorter stop-signal reaction time (SSRT) in the conventional task. Yet, SSRT did not correlate with stopping in VR. Moreover, SSRT was related to depressive symptoms whereas measures from VR were related to chocolate craving and subjective hunger. Thus, VR stopping can provide deeper insights into healthy weight individuals' capacity to inhibit cue-specific approach behavior towards appetitive stimuli in simulated interactions. Furthermore, the results support a multi-faceted view of food-specific inhibitory control and behavioral impulsivity.

Evidence for the embodiment of the automatic approach bias

Tendencies of approach and avoidance seem to be a universal characteristic of humans. Specifically, individuals are faster in avoiding than in approaching negative stimuli and they are faster in approaching than in avoiding positive stimuli. The existence of this automatic approach-avoidance bias has been demonstrated in many studies. Furthermore, this bias is thought to play a key role in psychiatric disorders like drug addiction and phobias. However, its mechanisms are far from clear. Theories of embodied cognition postulate that the nature of gestures plays a key role in this process. To shed light on the role of the involved gesture we employed a 2 × 2 factorial design with two types of stimuli. Participants had either to approach positive and avoid negative stimuli (congruent conditions) or to avoid positive stimuli and approach negative stimuli (incongruent conditions). Further, they responded either with a joystick or a button press on a response pad. Participants reacted faster in congruent conditions, i.e., avoiding negative stimuli and approaching positive stimuli, than in incongruent conditions. This replicates the known approach and avoidance bias. However, direct analysis of the button press condition revealed no reaction time advantage for congruent trials compared to incongruent trials. In contrast, in the joystick condition participants were significantly faster performing congruent reactions than incongruent reactions. This interaction, a significant reaction time advantage, when the response is enacted by moving a joystick towards or away from the body provides evidence that approach-avoidance tendencies have a crucial bodily component.

How immersive virtual reality can become a key tool to advance research and psychotherapy of eating and weight disorders

Immersive virtual reality technology (VR) still waits for its wide dissemination in research and psychotherapy of eating and weight disorders. Given the comparably high efforts in producing a VR setup, we outline that the technology's breakthrough needs tailored exploitation of specific features of VR and user-centered design of setups. In this paper, we introduce VR hardware and review the specific properties of immersive VR versus real-world setups providing examples how they improved existing setups. We then summarize current approaches to make VR a tool for psychotherapy of eating and weight disorders and introduce user-centered design of VR environments as a solution to support their further development. Overall, we argue that exploitation of the specific properties of VR can substantially improve existing approaches for research and therapy of eating and weight disorders. To produce more than pilot setups, iterative development of VR setups within a user-centered design approach is needed.

Grab it or not? Measuring avoidance of spiders with touchscreen-based hand movements

BACKGROUND AND OBJECTIVES

Previous studies have shown that humans, particularly those with high levels of spider fear, show automatic avoidance of spiders. However, most tasks used in these studies employ symbolic approach-avoidance movements instead of naturalistic movements.

METHODS

The current study employed a touchscreen-based approach-avoidance task in which 86 female participants made hand and arm movements that mimic the real-life touching, grasping, and moving of spiders. Using a large touchscreen, they had to reach for pictures of spiders and neutral objects (leaves), touch them, and drag them either away from themselves or towards themselves. To draw attention to stimulus content, pictures of butterflies were used in additional NoGo trials, they required participants to not move their hand.

RESULTS

Avoidance of spiders was observed in both the pre-movement times (time to lift the hand from a starting position) and the grabbing times (time to reach the picture), and this avoidance was larger for more spider-fearful participants. The dragging times (time to swipe the picture), however, revealed a relative spider-approach tendency: Compared to leaves, participants were faster to drag spiders closer than to swipe them away.

LIMITATIONS

We discuss potential reasons for this mixed pattern of results, including the low reliability of the dragging times.

CONCLUSIONS

We recommend the use of touchscreens for the assessment of approach-avoidance tendencies, and we suggest avenues for further research.

Comparison of different response devices to assess behavioral tendencies towards chocolate in the approach-avoidance task

Behavioral tendencies in the Approach-Avoidance Task (AAT) have mostly been assessed using a joystick as a response device. In recent years, other hardware devices such as tablets, smartphones, and computer mice have also been used. However, it remains unclear whether different response devices yield similar results and show comparable psychometric properties. The aim of the present study was to assess approach biases towards chocolate with different response devices and to compare their reliability and validity. Forty-five individuals with regular chocolate consumption completed three different AATs (joystick, computer mouse, touchscreen), each comprised of two blocks. In the compatible block of trials, chocolate-related pictures had to be pulled near while object-related pictures had to be pushed away. In the incompatible block of trials, instructions were reversed. Preregistered analyses revealed that participants were faster to pull than to push chocolate-related pictures relative to object-related pictures, indicating an approach bias for chocolate with no significant differences between response devices. Correlations among the three response devices were low to medium. Exploratory analyses revealed that approach biases were moderated by block order such that biases were only present and associated with craving (joystick AAT only) when the incongruent block was completed first. Internal consistencies of the bias score ranged between r_SB = 0.67-0.76. Results of the present study point to the existence of an approach bias to chocolate regardless of response device, albeit each task seems to measure a different aspect of it. Order effects point to specific temporal dynamics in the acquisition of stimulus response (e.g., chocolate-pull) mappings that require further study.

Mind the food: behavioural characteristics and imaging signatures of the specific handling of food objects

In our world with nearly omnipresent availability of attractive and palatable high-calorie food, the struggle against overweight and obesity is a major individual and public health challenge. Preference for unhealthy food and eating-related habits have a strong influence on health, suggesting that high-calorie food triggers fast and near-automatic reaching and grasping movements. Therefore, it is important to better understand the specific neural mechanisms that control the handling of food involving a coordinated interplay between sensoric, motoric, and cognitive subsystems. To this end, 30 healthy participants (Ø BMI: 22.86 kg/m2; BMI range: 19-30 kg/m2; 23 females) were instructed to collect one of two concurrently presented objects (food vs. office tools) by manual movement in virtual reality (VR) and on a touchscreen. Parallel to the task in VR, regional brain activity was measured by functional near-infrared spectroscopy (fNIRS). In the VR and on the touchscreen, stimulus recognition and selection were faster for food than for office tools. Yet, food was collected more slowly than office tools when measured in VR. On the background of increased brain activity in the right dorsolateral prefrontal cortex (dlPFC) during food trials, this suggests more behavioural control activity during handling foods. In sum, this study emphasizes the role of the right dlPFC in faster recognition and selection of food as part of a food-valuation network, more controlled handling of food in the VR which highlights the relevance of medium for modelling food-specific embodied cognitions.

LEAP Motion Technology and Psychology: A Mini-Review on Hand Movements Sensing for Neurodevelopmental and Neurocognitive Disorders

Technological advancement is constantly evolving, and it is also developing in the mental health field. Various applications, often based on virtual reality, have been implemented to carry out psychological assessments and interventions, using innovative human-machine interaction systems. In this context, the LEAP Motion sensing technology has raised interest, since it allows for more natural interactions with digital contents, via an optical tracking of hand and finger movements. Recent research has considered LEAP Motion features in virtual-reality-based systems, to meet specific needs of different clinical populations, varying in age and type of disorder. The present paper carried out a systematic mini-review of the available literature using Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. The inclusion criteria were (i) publication date between 2013 and 2020, (ii) being an empirical study or project report, (iii) written in English or Italian languages, (iv) published in a scholarly peer-reviewed journal and/or conference proceedings, and (v) assessing LEAP Motion intervention for four specific psychological domains (i.e., autism spectrum disorder, attention-deficit/hyperactivity disorder, dementia, and mild cognitive impairment), objectively. Nineteen eligible empirical studies were included. Overall, results show that protocols for attention-deficit hyperactivity disorder and autism spectrum disorder can promote psychomotor and psychosocial rehabilitation in contexts that stimulate learning. Moreover, virtual reality and LEAP Motion seem promising for the assessment and screening of functional abilities in dementia and mild cognitive impairment. As evidence is, however, still limited, deeper investigations are needed to assess the full potential of the LEAP Motion technology, possibly extending its applications. This is relevant, considering the role that virtual reality could have in overcoming barriers to access assessment, therapies, and smart monitoring.

Approach bias retraining through virtual reality in smokers willing to quit smoking: A randomized-controlled study

Automatic approach biases toward smoking-related cues have been implicated in the development and maintenance of addictive behaviors. Studies aiming at modifying such biases have shown promise in changing maladaptive approach tendencies for smoking cues and reducing smoking behavior. However, training effects tend to be small and partly inconsistent. The present randomized-controlled trial incorporated virtual reality (VR) technology into Approach Bias Modification (ABM) to improve efficacy. One-hundred-eight smokers attended behavioral counseling for smoking cessation and were thereafter randomized to receive VR-ABM or VR-control training. During VR-ABM, participants trained to implicitly avoid smoking-related objects and to approach alternative objects, while no such contingency existed in the VR-control condition. Trainings were administered in six sessions within a two-week period. Assessments were conducted at baseline, post-intervention (three weeks after baseline), and at follow-up (seven weeks after baseline). VR-ABM did not change approach biases, nor other cognitive biases, but it was superior in reducing daily smoking. However, this effect was limited to the two-week training period. Both groups improved in other smoking- and health-related variables across time. Future work should continue to investigate working mechanisms of ABM, in particular crucial training ingredients. VR could prove valuable for public health as the potential of VR-based treatments is large and not fully explored.

Touchscreen-based assessment of food approach biases: Investigating reliability and item-specific preferences

Strong cravings for unhealthy foods and implicit tendencies to approach them threaten the physical and mental health of vulnerable populations. Yet, implicit measures of food approach tendencies have methodological limitations, as existing approach-avoidance tasks (AAT) are often unreliable and require specialized hardware. We propose a novel method to measure approach biases: on a touchscreen, participants slide their hand either toward a food item (and away from control images) or away from it (and toward control images) in separate blocks. Adequate attention to the stimuli is ensured by the coupling of stimulus category to the required response. We found that this touchscreen-variant of the AAT yielded reliable bias scores when approach and avoidance were defined as movements relative to the stimulus rather than to the body. Compared to control images, we found an approach bias for low-calorie foods but not for high-calorie foods. This bias additionally varied on a food-by-food basis depending on the participant's desire to eat individual food items. Correlations with state and trait cravings were inconclusive. Future research needs to address the order effects that were found, in which participants avoiding foods in the first block showed larger biases than participants approaching food in the first block, likely due to insufficient opportunity to practice the task. Our findings highlight the need for approach bias retraining paradigms to use personalized stimulus sets. The task can enrich the methodological repertoire of research on eating disorders, obesity and cognitive bias modification.

Using virtual reality to train inhibitory control and reduce binge eating: A proof-of-concept study

OBJECTIVE

One reason for limited efficacy of treatments for binge eating disorder (BED) and bulimia nervosa (BN) is a failure to directly target deficits in inhibitory control (i.e., the ability to withhold a pre-potent response). Inhibitory control trainings (ICTs; computerized tasks meant to improve inhibitory control) have shown promise but appear not to be powerful enough to generalize to real-word eating behavior or engaging enough for to sustain long-term compliance. Delivering an ICT through virtual reality (VR) technology should increase intervention power because 3D imagery and actual real hand/arm movements are lifelike and may improve compliance because the VR environment is highly engaging. Thus, we created the first-ever VR-based ICT to test its initial feasibility, acceptability, and impact on binge eating.

METHOD

We recruited participants (N = 14) with once-weekly loss-of-control (LOC) eating to use the VR ICT daily, at home, for two weeks, and measured feasibility, acceptability and change in LOC eating at post-intervention and 2-week follow-up.

RESULTS

The VR ICT was feasible to construct and deploy, and demonstrated high acceptability and compliance (i.e., 86.8% of daily trainings completed). Users of the VR ICT experienced large decreases in LOC eating at post-intervention and 2-week follow-up.

DISCUSSION

Results from this initial pilot indicate that delivering ICT through VR is feasible, acceptable, and is associated with reductions in binge eating. Future study is warranted and should examine whether a VR ICT can serve as a useful adjunct to standard treatment for BN and BED.

Promoting smoking abstinence in smokers willing to quit smoking through virtual reality-approach bias retraining: a study protocol for a randomized controlled trial

Background

Automatic processes to approach smoking-related cues have been repeatedly linked to smoking status, intensity of smoking, and cigarette craving. Moreover, recent findings suggest that targeting those tendencies directly by means of approach bias modification (ABM) has merit in changing maladaptive approach tendencies for drug cues and reducing drug consumption. However, training effects tend to be small. Embedding the training into virtual reality (VR) technology could be a promising way to improve training efficacy. The present protocol describes a randomized controlled trial that aims to assess the efficacy of a newly developed VR-ABM as a means of reducing smoking-related approach biases or nicotine consumption in smokers seeking abstinence.

Methods

One hundred daily smokers who are motivated to quit smoking will be recruited into the randomized controlled trial. All participants will attend a brief smoking cessation intervention (TAU) and will be randomly assigned either to the experimental (VR-avoidance training) or the placebo-control group (VR-placebo training). During the VR-avoidance training, participants are implicitly instructed to make an avoidance movement in response to smoking-related objects (e.g., cigarettes) and an approach movement in response to alternative objects (e.g., healthy food). During the VR-placebo training, no such contingency between arm movement and item content exists. Trainings are administered in six sessions within two weeks. Training effects on automatic approach tendencies and smoking behavior are measured immediately after training and at a 7-week follow-up.

Discussion

Embedding the training into virtual reality (VR) technology could be a promising new way to improve ecological validity, realism, and immersion and thereby increase ABM training effects. The results of this study can inform future research in the optimization and advancement of treatment for addiction.

Trial registration

Registered with Current Controlled Trials: study ID ISRCTN16006023. Registered on 28 March 2019.

Measuring approach-avoidance tendencies towards food with touchscreen-based arm movements

Most tasks for measuring automatic approach-avoidance tendencies do not resemble naturalistic approach-avoidance behaviors. Therefore, we developed a paradigm for the assessment of approach-avoidance tendencies towards palatable food, which is based on arm and hand movements on a touchscreen, thereby mimicking real-life grasping or warding movements. In Study 1 (n = 85), an approach bias towards chocolate-containing foods was found when participants reached towards the stimuli, but not when these stimuli had to be moved on the touchscreen. This approach bias towards food observed in grab movements was replicated in Study 2 (n = 60) and Study 3 (n = 94). Adding task features to disambiguate distance change through either corresponding image zooming (Study 2) or emphasized self-reference (Study 3) did not moderate this effect. Associations between approach bias scores and trait and state chocolate craving were inconsistent across studies. Future studies need to examine whether touchscreen-based approach-avoidance tasks reveal biases towards other stimuli in the appetitive or aversive valence domain and relate to relevant interindividual difference variables.

Promising technological innovations in cognitive training to treat eating-related behavior

One potential reason for the suboptimal outcomes of treatments targeting appetitive behavior, such as eating and alcohol consumption, is that they do not target the implicit cognitive processes that may be driving these behaviors. Two groups of related neurocognitive processes that are robustly associated with dysregulated eating and drinking are attention bias (AB; selective attention to specific stimuli) and executive function (EF; a set of cognitive control processes such as inhibitory control, working memory, set shifting, that govern goal-directed behaviors). An increasing body of work suggests that EF and AB training programs improve regulation of appetitive behaviors, especially if trainings are frequent and sustained. However, several key challenges, such as adherence to the trainings in the long term, and overall potency of the training, remain. The current manuscript describes five technological innovations that have the potential to address difficulties related to the effectiveness and feasibility of EF and AB trainings: (1) deployment of training in the home, (2) training via smartphone, (3) gamification, (4) virtual reality, and (5) personalization. The drawbacks of these innovations, as well as areas for future research, are also discussed. The above-mentioned innovations are likely to be instrumental in the future empirical work to develop and evaluate effective EF and AB trainings for appetitive behaviors.

Exploring the Influence of Haptic and Olfactory Cues of a Virtual Donut on Satiation and Eating Behavior

Olfactory research in immersive virtual environments (IVEs) have often examined the addition of scent as part of the environment or atmosphere that act as experimental stimuli. There appears to be a lack of research on the influence of virtual foods in IVEs on human satiation. Studies based on situational cues or self-perception theory provide support for the hypothesis that touching and smelling a virtual food item may lead to increased consumption as a result of modeling expected behavior. On the other hand, studies grounded in embodied cognition suggest that satiation may take place as a result of mental simulation that resembles actual consumption behavior. In this preliminary study, we sought to explore the effects of haptic and olfactory cues through virtual food on human satiation and eating behavior. In our study, 101 participants took part in a 2 (touch: present vs absent) × 2 (scent: present vs absent) experiment where they interacted with a donut in an IVE. Findings showed that participants in the touch and scent present conditions ate significantly fewer donuts than those who were not exposed to these cues, and reported higher satiation as compared to their counterparts. However, findings were less clear with respect to participants who received both haptic and olfactory cues. As a whole, results provide preliminary support for satiation effects as a result of sensory simulation.

How Deep Is Your SNARC? Interactions Between Numerical Magnitude, Response Hands, and Reachability in Peripersonal Space

Spatial, physical, and semantic magnitude dimensions can influence action decisions in human cognitive processing and interact with each other. For example, in the spatial-numerical associations of response code (SNARC) effect, semantic numerical magnitude facilitates left-hand or right-hand responding dependent on the small or large magnitude of number symbols. SNARC-like interactions of numerical magnitudes with the radial spatial dimension (depth) were postulated from early on. Usually, the SNARC effect in any direction is investigated using fronto-parallel computer monitors for presentation of stimuli. In such 2D setups, however, the metaphorical and literal interpretation of the radial depth axis with seemingly close/far stimuli or responses are not distinct. Hence, it is difficult to draw clear conclusions with respect to the contribution of different spatial mappings to the SNARC effect. In order to disentangle the different mappings in a natural way, we studied parametrical interactions between semantic numerical magnitude, horizontal directional responses, and perceptual distance by means of stereoscopic depth in an immersive virtual reality (VR). Two VR experiments show horizontal SNARC effects across all spatial displacements in traditional latency measures and kinematic response parameters. No indications of a SNARC effect along the depth axis, as it would be predicted by a direct mapping account, were observed, but the results show a non-linear relationship between horizontal SNARC slopes and physical distance. Steepest SNARC slopes were observed for digits presented close to the hands. We conclude that spatial-numerical processing is susceptible to effector-based processes but relatively resilient to task-irrelevant variations of radial-spatial magnitudes.

Multisensory Technology for Flavor Augmentation: A Mini Review

There is growing interest in the development of new technologies that capitalize on our emerging understanding of the multisensory influences on flavor perception in order to enhance human–food interaction design. This review focuses on the role of (extrinsic) visual, auditory, and haptic/tactile elements in modulating flavor perception and more generally, our food and drink experiences. We review some of the most exciting examples of recent multisensory technologies for augmenting such experiences. Here, we discuss applications for these technologies, for example, in the field of food experience design, in the support of healthy eating, and in the rapidly growing world of sensory marketing. However, as the review makes clear, while there are many opportunities for novel human–food interaction design, there are also a number of challenges that will need to be tackled before new technologies can be meaningfully integrated into our everyday food and drink experiences.

Lost in space: multisensory conflict yields adaptation in spatial representations across frames of reference

According to embodied cognition, bodily interactions with our environment shape the perception and representation of our body and the surrounding space, that is, peripersonal space. To investigate the adaptive nature of these spatial representations, we introduced a multisensory conflict between vision and proprioception in an immersive virtual reality. During individual bimanual interaction trials, we gradually shifted the visual hand representation. As a result, participants unknowingly shifted their actual hands to compensate for the visual shift. We then measured the adaptation to the invoked multisensory conflict by means of a self-localization and an external localization task. While effects of the conflict were observed in both tasks, the effects systematically interacted with the type of localization task and the available visual information while performing the localization task (i.e., the visibility of the virtual hands). The results imply that the localization of one's own hands is based on a multisensory integration process, which is modulated by the saliency of the currently most relevant sensory modality and the involved frame of reference. Moreover, the results suggest that our brain strives for consistency between its body and spatial estimates, thereby adapting multiple, related frames of reference, and the spatial estimates within, due to a sensory conflict in one of them.