Computer-based Impulsive Process Interventions in Dietary Behavior

Unhealthy foods are often appetizing and thus hard to resist, despite knowledge about their detrimental effects on health. The psychological processes underlying choices between immediately rewarding but health-harming and potentially less rewarding but health-promoting options have been described in dual-process models such as the Reflective-Impulsive Model. These models assume two interacting kinds of processes: one impulsive, association-based, fast, and effortless; the other reflective, based on syllogistic reasoning, slow, and dependent on cognitive resources. While most interventions on eating behavior aim to alter reflective reasoning and increase its influence on behavior, some relatively new computer-based interventions aim to directly change impulsive aspects of food intake. They do so by presenting users images of unhealthy food while asking them to show a behavior that is inconsistent with their impulse to approach, i.e. inhibit a response or show an avoidance reaction. This way, the association between unhealthy foods and approach behavior is broken up, reducing the strength of elicited impulses in the future. Evidence has mounted that particularly the Go/No-Go task can reduce intake of unhealthy foods. In this task, participants need to inhibit their impulse to react when seeing unhealthy food images, creating an “unhealthy-stop” association. Two important questions have remained unanswered in this research line: (1) What are the psychological mechanisms of behavioral effects in these interventions? (2) How well do laboratory-based demonstrations of efficacy translate to real-world behavior change? This thesis aims to produce evidence that helps answer those questions and enhance understanding of impulsive process interventions by (1) meta-analyzing the scientific literature with a specific focus on implicit bias change as a potential psychological mechanism (Study I), (2) examining a potential neural marker of the psychological mechanisms involved (Study II), and (3) investigating relevant aspects of such an intervention in the field (Study III). Study I thereby lays the foundation for the main research questions and study design in Studies II and III. The specific aims of Study I were to provide an overview of the literature on different kinds of computer-based impulsive process interventions by meta-analyzing their effects on eating behavior. In addition, it aimed to identify study-level moderators of effects, to investigate implicit bias change in the included studies as a potential mechanism of behavioral effects, and thus to identify ways forward for the research area. Study II followed up on the results of Study I and aimed to identify the role of a neural marker of the involved psychological processes, the N2 event-related potential (ERP), by measuring neural activity during the performance of an impulsive process intervention. Study III then used data from a field trial to investigate dose-response relationships in an impulsive process intervention in order to provide best-practice guidance for future intervention users. The studies in this thesis used a range of methods to answer the specific research questions. In Study I, I conducted a systematic literature review with meta-analysis. Meta-regressions with categorical and continuous predictors tested potential moderating variables and the relationship between behavioral effects and a hypothesized psychological mechanism of effects. In Study II, a specific neural marker, the N2 ERP , was analyzed during food Go/No-Go training and related to food intake both within and outside the laboratory. Study III used data from a pragmatic open trial in which participants used smartphone-based Go/No-Go training at their own discretion to determine dose-response relationships for intake of different food categories. Study I identified 30 randomized controlled trials with 47 effect sizes, delivering at least one of four computer-based impulsive process interventions, for inclusion in the analyses. The overall effect size for eating behavior was small (g = −0.17, CI95 = [−0.29; −0.05], p = .01) with only the Go/No-Go task showing significant effects (g = −0.39, CI95= [−0.57; −0.22], p < .001). The effects on implicit biases were also significantly different from zero (g = −0.46, CI95= [−0.68; −0.25], p < .001) and the effects on bias change and eating behavior were significantly related (B = .42, CI95= [.02; .81], z = 2.07, p = .04, k = 21). Against preregistered hypotheses, analyses in Study II showed no significant differences between healthy and unhealthy foods in N2 ERP strength (p = .18, ηp2 = 0.04), no effect of Go/No-Go training on immediate food intake (p = .50) or N2 amplitudes (p = .57, ηp2 = 0.0004), and no relationship between N2 and food intake both inside (B = -0.41, p = .82) and outside (B = 166.21, p = .53) the laboratory. In Study 3, analyses revealed significant relationships between the self-administered amount of conducted Go/No-Go training and self-reported food intake, such that conducting more blocks of training led to decreased unhealthy (β = -0.004, CI95 = [-0.006; -0.002]) and increased healthy food intake (b = 0.003, CI95 = [0; 0.005]). Separate analyses for different food types indicated variations between food categories in their dose-response relationship, indicating that completing about 8 to 24 4-minute sessions of Go/No-Go training over the course of one month leads to changes in intake by one point. The scientific contribution of this work is thus threefold. Firstly, it provides an overview of the research field, providing a clear recommendation for the precise task to use for intervention delivery, and indicates future directions for the field (Study I). Secondly, it contributes to the ongoing debate about psychological and neural mechanisms of impulsive process interventions in eating behavior and indicates changes in impulsive processes to be one driver of behavioral effects (Studies I and II). Lastly, it provides estimates for necessary dosage and usage recommendations based on real-world data from smartphone-delivered training (Study III), a promising future avenue for large-scale, self-administered training. Based on this thesis, future research should aim to further clarify psychological training mechanisms, establish ideal training design and training schedules, identify groups for whom training is most beneficial, and seek synergistic effects with other interventions targeting eating behavior.Epäterveelliset ruoat ovat usein houkuttelevia ja siten vaikeita vastustaa huolimatta niiden vahingollisista vaikutuksista terveydelle. Kaksoisprosessointimallit, kuten reflektiivis-impulsiivinen malli kuvaa psykologisia prosesseja, jotka vaikuttavat välittömästi palkitsevien mutta terveyttä vahingoittavien ja vähemmän palkitsevien mutta terveyttä edistävien valintojen takana. Nämä mallit pitävät sisällään kaksi vuorovaikuttavaa prosessia, joista toinen on impulsiivinen, nopea prosessi ja toinen reflektiivinen, hidas ja kognitiivisista resursseista riippuvainen prosessi. Useimmat syömiskäyttäytymiseen kohdistuvat interventiot pyrkivät muovaamaan reflektiivisiä prosesseja ja vaikuttamaan niiden kautta käyttäytymiseen. Uudemmat digitaaliset interventiot pyrkivät kuitenkin muuttamaan suoraan syömisen impulsiivisia aspekteja. Tällaiset interventiot ovat pelinomaisia tietokonetehtäviä, joissa käyttäjille esitetään kuvia epäterveellisistä ruoista (kuten suklaa), joihin ei tehtävän kuluessa saa reagoida tai joihin on reagoitava impulssin vastaisesti. Tehtävän tavoitteena on siten vähentää epäterveellisen ruoan ja siihen reagoivan käyttäytymisen assosiaatiota. Tämän väitöskirjatutkimuksen tarkoituksena oli parantaa ymmärrystä näistä impulsiivisiin prosesseihin kohdistetuista interventioista. Tutkimus koostui kolmesta osatutkimuksesta. Ensimmäinen osatutkimus oli erilaisia digitaalisia ja syömiskäyttäytymisen impulsiivisiin prosesseihin kohdistettuja interventiotutkimuksia koskeva meta-analyysi. Sen tarkoituksena oli selvittää mitkä interventiot ovat vaikuttavimpia, sekä sitä missä olosuhteissa kyseiset interventiot vaikuttavat käyttäytymiseen eniten ja mikä on käyttäytymisen taustalla vaikuttava psykologinen mekanismi. Toisen osatutkimuksen tavoitteena oli tunnistaa syömiskäyttäytymisen impulsiivisiin prosesseihin liittyviä neuraalisen aktivaation piirteitä mittaamalla aivosähkökäyrällä osallistujien N2 herätevasteita syömisimpulsseihin kohdistetun intervention aikana. Kolmannessa osatutkimuksessa käytettiin mobiilisovellusta ja tutkittiin kenttätutkimuksesta saadun tiedon avulla altistus-vaste-suhteita syömisimpulsseihin kohdistetuissa interventioissa. Ensimmäisessä osatutkimuksessa systemaattinen kirjallisuuskatsaus tunnisti 30 artikkelia. Interventioilla oli pieni, mutta merkittävä vaikutus syömiskäyttäytymiseen (g = −0.17, CI95 = [−0.29; −0.05], p = .01). Vain niin sanotun Go/No-Go impulssin kontrollitehtävän havaittiin vaikuttavan syömiskäyttäytymiseen (g = −0.39, CI95= [−0.57; −0.22], p < .001). Myös toisessa osatutkimuksessa impulsiivisen reaktion hillintään liittyvät N2 herätevasteet olivat hypoteesin vastaisesti riippumattomia esitettyjen ruokakuvien kaloripitoisuudesta (p = .18, ηp2 = 0.04) eikä niiden vahvuudessa vastoin odotuksia havaittu muutosta intervention kuluessa (p = .57, ηp2 = 0.0004). Lisäksi herätevasteen voimakkuudella ei havaittu olevan yhteyttä kalorikulutukseen intervention aikana (B = -0.41, p = .82) tai sen jälkeen (B = 166.21, p = .53). Kolmannessa osatutkimuksessa havaittiin, että mitä enemmän osallistuja käytti sovellusta, sitä suurempi oli sen vaikutus käyttäytymiseen; epäterveellisen ruoan syöminen väheni (β = -0.004, CI95 = [-0.006; -0.002]), kun taas terveellisen ruoan syöminen lisääntyi (b = 0.003, CI95 = [0; 0.005]). Väitöskirjatutkimuksen tieteellinen kontribuutio voidaan tiivistää kolmeen päälöydökseen. Ensinnäkin, meta-analyysi tähänastisista tutkimuksista osoitti, että No-Go/Go impulssikontrollitehtävällä oli selkein vaikutus syömiskäyttäytymiseen ja impulssikontrolliin. Tulevissa interventioissa tämä on lupaavin tehtävä. Toiseksi, väitöskirjan aivovasteisiin liittyvällä osatutkimuksella on suuri merkitys impulsiivisiinprosesseihin kohdistuvien interventioiden psykologisten mekanismien ymmärtämiselle. Tulokset kyseenalaistavat aikaisemman käsityksen, että impulssikontrolliresurssien vahvistuminen selittäisi intervention vaikutusta syömiseen. Tämän sijaan tulokset osatutkimuksesta 1 ja 2 tukevat vaihtoehtoista tulkintaa, jonka mukaan muutokset ruokien impulsiivisissa prosesseissa selittävät intervention vaikutuksia syömiskäyttäytymiseen. Kolmantena päälöydöksenä ovat kenttäkokeessa saadut havainnot tarvittavasta annosmäärästä ja käyttötavasta mobiililaitteella toteutetuissa interventioissa, jotka tarjoavat lupaavan pohjan itseohjattuun syömiskäyttäytymisen muutokseen. Tulevan tutkimuksen tulisi selventää interventioiden psykologisia mekanismeja, tuottaa tarkoituksenmukaisia ohjeita sovellusten käyttäjille ja identifioida ryhmiä, jotka hyötyvät interventioista eniten. Tämän ohella tutkimuksen tulisi jatkossa etsiä syömiskäyttäytymiseen kohdistuvien interventioiden synergistisiä vaikutuksia

Investigating the Influence of Intergroup Contact in Virtual Reality on Empathy : An Exploratory Study Using AltspaceVR

Virtual Reality (VR) has often been referred to as an “empathy machine.” This is mostly because it can induce empathy through embodiment experiences in outgroup membership. However, the potential of intergroup contact with an outgroup avatar in VR to increase empathy is less studied. Even though intergroup contact literature suggests that less threatening and more prosocial emotions are the key to understanding why intergroup contact is a powerful mean to decrease prejudice, few studies have investigated the effect of intergroup contact on empathy in VR. In this study, we developed a between-participants design to investigate how VR can be used to create a positive intergroup contact with a member of a stigmatized outgroup (ethnic minority) and present the results of the effect of intergroup contact in VR on empathy. Sixty four participants experienced either positive contact (i.e., equal intergroup status, collaborative) with a black (experimenter-controlled) avatar (experimental condition) or no intergroup contact (i.e., ingroup contact with a white avatar; control condition), with situational empathy (personal distress and empathic interest) being measured through a self-report questionnaire up to a week before and right after the VR contact experience. The experiment showed that satisfying degrees of body ownership of participants’ own avatar and co-presence with the contacted avatar can be achieved in simple and universally accessible virtual environments such as AltspaceVR. The results indicated that while VR intergroup contact had no significant direct effect on empathy, exploratory analyses indicated that post-intervention empathic interest increased with stronger feelings of co-presence in the intergroup contact condition.Peer reviewe

The use of virtual reality in studying prejudice and its reduction : A systematic review

Peer reviewe

How bodily expressions of emotion after norm violation influence perceivers’ moral judgments and prevent social exclusion : A socio-functional approach to nonverbal shame display

According to a socio-functional perspective on emotions, displaying shame with averted gaze and a slumped posture following a norm violation signals that the person is ready to conform to the group’s moral standards, which in turn protects the person from social isolation and punishment. Although the assumption is intuitive, direct empirical evidence for it remains surprisingly limited and the mediating social-psychological mechanisms are poorly understood. Therefore, three experimental studies were conducted to investigate the social function of nonverbal displays of shame in the context of everyday norm violations. In Study 1, participants evaluated ten different expressions of emotion in regard to their affective valence, arousal, dominance, as well as social meaning in the context of norm violations. Displays of shame and sadness were seen as the most similar expressions with respect to the three affective dimensions and were perceived to communicate the perpetrator’s understanding of the group’s moral standards most effectively. In Study 2, participants read vignettes concerning norm violations and afterward saw a photograph of the perpetrator displaying nonverbal shame, sadness or a neutral expression. Perpetrators’ displays of shame and sadness increased perceived moral sense and amplified the observers’ willingness to cooperate with the perpetrators. However, neither display weakened the observer’s willingness to punish the perpetrator. In Study 3, the perpetrator was shown to display shame, sadness, anger or a neutral expression after getting caught at mild or severe norm violation. The results replicated previous findings but revealed also that the social effects of shame and sadness displays on punitive and cooperative intentions were mediated by different social appraisals. For example, display of shame uniquely reduced punitive intentions by increasing the perpetrator’s perceived moral sense, whereas expressions of both shame and sadness evoked empathy in the observers, which in turn reduced the punitive intentions. These results give support to the assumption that nonverbal shame displays serve a unique social function in preventing moral punishment and social exclusion. However, this support is only partial as the social functions of displaying shame are largely parallel to those of expressing sadness in the situation.Peer reviewe

Implicit process interventions in eating behaviour : a meta-analysis examining mediators and moderators

Dual-process models integrate deliberative and impulsive mental systems and predict dietary behaviours better than deliberative processes alone. Computerised tasks such as the Go/No-Go, Stop-Signal, Approach-Avoidance, and Evaluative Conditioning have been used as interventions to directly alter implicit biases. This meta-analysis examines the effects of these tasks on dietary behaviours, explores potential moderators of effectiveness, and examines implicit bias change as a proposed mechanism. Thirty randomised controlled trials testing implicit bias interventions (47 comparisons) were included in a random-effects meta-analysis, which indicated small cumulative effects on eating-related behavioural outcomes (g = -0.17, CI95 = [-0.29; -0.05], p = .01) and implicit biases (g = -0.18, CI95 = [-0.34; -0.02], p = .02). Task type moderated these effects, with Go/No-Go tasks producing larger effects than other tasks. Effects of interventions on implicit biases were positively related to effects on eating behaviour (B = 0.42, CI95 = [0.02; 0.81], p = .03). Go/No-Go tasks seem to have most potential for altering dietary behaviours through implicit processes. While changes in implicit biases seem related to the effects of these interventions on dietary outcomes, more research should explore whether repeated exposure to implicit bias interventions may have any practical intervention value in real world settings.Peer reviewe

Bump it up or Ease it off: Positive Associations between day-level Physical Activity and Healthy Eating in Participants of a Health Promotion Course

Unhealthy diets and a lack of physical activity (PA) concur in the same individuals and jointly contribute to overweight and related diseases. Limited self-regulation abilities commonly result in a gap between intentions to eat better and move more and behavior enactment (‘intention-behavior gap’). What is less clear is whether the two health behavioral domains eating and physical activity facilitate or inhibit each other. While cybernetic and resource depletion models would predict that engaging in one behavior leads to reduced effort in the other behavior (compensation), motivational accounts predict the opposite: more PA should increase healthy eating and vice versa (transfer). Elucidating such relationships across time requires multiple assessments from the same individuals and sufficient incidences of both behaviors, and hence, relatively long assessment periods. This study uses data obtained through ecological momentary assessment (EMA) to examine the day-level association between PA and healthy eating. 25 participants (20 women, 5 men, mean age = 56) of a health-insurance organized health promotion course provided daily data on intentions, self-efficacy, and behavior enactment for PA and healthy eating for seven weeks with the average participant submitting data on 42 days. We found that cross-behavior associations on all assessed variables and intention behavior gaps as a marker of self-regulatory success were positive. This positive relation between IBGs was independent of day-level variables typically implicated in self-regulation (stress, mood, tiredness, and hours of sleep during the preceding night). Results contradict cybernetic and resource depletion models of self-regulation and speak more to effects of positive transfer between behaviors. Providing feedback on such positive associations might be a beneficial intervention component to encourage parallel engagement in PA and healthy eating. Future research should aim to further identify other within- and between-person factors (e.g., willpower beliefs) contributing to the PA-healthy eating association