Model-based analyses of choice and eye movement data

How do humans make simple preferential decisions, like decide what to have for breakfast at a hotel buffet? In contrast to the assumption of normative accounts of decision making, humans' preferences are often not stable but constructed at the time of choice and contingent on the decision makers' interaction with the environment. Recent evidence suggests that the allocation of visual attention during deliberation is closely linked to subsequent choices so that alternatives that are looked at longer are generally more likely to be chosen. Prior work has characterized the processes underlying simple decisions in terms of evidence accumulation over time, where momentary rates of accumulation depend on the decision maker's allocation of gaze, and a decision is made when accumulated evidence reaches a certain threshold. However, the generalisability of gaze-dependent accumulation remains unclear in multiple regards: It is not established how well gaze-dependent evidence accumulation describes individual decision makers' behaviour or to what extent the association between visual attention and choice varies between individuals. In addition, it is unclear to what extent the theory applies to behaviour in contexts where choices deviate from normative predictions more substantially. Finally, it remains debated whether visual attention causally influences or rather reflects the construction of preferences. In this thesis, I address these questions across three empirical studies using computational models of the decision process. In Study 1 (Thomas et al., 2019; Molter et al., 2019), we first developed a novel gaze-dependent evidence accumulation model that allowed investigation of choice processes on the individual level. In addition, we published a corresponding Python toolbox to facilitate its use by others. In Study 2 (Molter et al., 2021), we tested the gaze-dependent evidence accumulation framework in a multi-alternative, multi-attribute task involving choices between three risky gambles. The task was designed to elicit context effects in choice behaviour that challenge normative choice theories. These context effects describe preference changes depending on the set of available alternatives. We found not only choices but also decision makers' gaze allocation to be modulated by context, allowing a gaze-dependent evidence accumulation model derived from prior work to generalise to this more complex scenario. Using this new tool, we demonstrated that gaze-dependent evidence accumulation accurately captures individuals' choice and response time data and associations with gaze allocation across four simple choice data sets. Our analysis revealed, however, that individuals strongly differed in the degree to which choices and gaze allocation were linked and that this variability was associated with individual differences in choice consistency. In our preregistered Study 3 (Molter & Mohr, 2021), we finally addressed the causal direction of the association between visual attention and choice. Participants made repeated choices between two risky gambles whose attributes were presented sequentially. This allowed the experimental control of the stimuli's presentation duration and order. Our results confirmed a causal influence of information search on preference construction. However, we identified presentation order, not duration, as the influencing factor, as alternatives presented last were chosen more frequently. Notably, causal order effects are only predicted by some gaze-dependent evidence accumulation models, highlighting potential for future theory development. The studies generally confirmed positive associations between visual attention and choice and provided support for gaze-dependent evidence accumulation theories on the individual level and in more complex choice scenarios. However, our studies also revealed large individual differences and possible limitations of current computational models of decision making. We showed that accounting for those differences and implementing additional mechanisms like accumulation leak to predict acquisition order effects substantially improve prediction of individual choice behaviour. Finally, I discuss these results on the active role of visual attention in the decision process and the theoretical model of gaze-dependent evidence accumulation in the broader context of constructed preferences and outline potential implications for the model-based analysis of choice and eye movement data.Wie treffen Menschen einfache Entscheidungen, zum Beispiel die Auswahl eines Frühstücks am Hotelbuffet? Anders, als es normative Theorien zur Entscheidungsfindung voraussetzen, sind unsere Präferenzen oft nicht starr, sondern werden erst zum Zeitpunkt der Entscheidung durch die Interaktion des Entscheiders mit seiner Umgebung konstruiert. Empirische Befunde zeigen, dass die Verteilung visueller Aufmerksamkeit während des Entscheidungsprozesses eng mit den getroffenen Entscheidungen zusammenhängt, wobei ein längerer Blick auf eine Alternative mit einer höheren Wahrscheinlichkeit verbunden ist, diese auszuwählen. Frühere Arbeiten haben die Prozesse, die solchen einfachen Entscheidungen zugrunde liegen, als Akkumulation von Evidenz über Zeit charakterisiert, wobei die Akkumulationsrate zu jedem Zeitpunkt von der Blickrichtung des Entscheiders abhängt. Danach wird eine Entscheidung getroffen, sobald die Evidenz für eine Alternative einen bestimmten Grenzwert überschreitet. Es ist jedoch in mehrerlei Hinsicht unklar, inwiefern diese Theorie von blickabhängiger Evidenzakkumulation generalisierbar ist. Zum einen ist nicht sichergestellt, dass blickabhängige Evidenzakkumulation das Verhalten \emph{einzelner} Entscheider erfasst, und in welchem Ausmaß der Zusammenhang visueller Aufmerksamkeit und Entscheidung zwischen Personen variiert. Zum anderen ist unklar, ob dieser Erklärungsansatz in Situationen Bestand hat, in denen Entscheidungen deutlich von normativen Vorhersagen abweichen. Zuletzt bleibt umstritten, ob visuelle Aufmerksamkeit kausalen Einfluss auf Entscheidungsprozesse hat oder vielmehr die Konstruktion von Präferenzen nur abbildet. Die vorliegende Dissertation soll diese Fragen in drei empirischen Studien unter Nutzung computerbasierter Modelle des Entscheidungsprozesses beantworten. In Studie 1 (Thomas et al., 2019; Molter et al., 2019) wurde zunächst ein neuartiges blickabhängiges Evidenzakkumulationsmodell entwickelt, das die Untersuchung des Entscheidungsprozesses einzelner Entscheider erlaubt. Hierzu wurde zusätzlich eine Python-Software-Toolbox veröffentlicht, die auch anderen Forschungsgruppen eine Anwendung des Modells ermöglicht. In vier verschiedenen Datensätzen konnten wir mithilfe dieses Werkzeugs zeigen, dass blickabhängige Evidenzakkumulation präzise Vorhersagen über Entscheidungen, Antwortzeiten und deren Zusammenhänge mit visueller Aufmerksamkeit für einzelne Entscheider macht. Unsere Analysen zeigten jedoch auch, dass Individuen große Unterschiede beim Zusammenhang von visueller Aufmerksamkeit und Entscheidung aufwiesen. Diese individuellen Unterschiede gingen zudem mit individuellen Unterschieden in der Konsistenz, mit der Entscheidungen getroffen wurden, einher. In Studie 2 (Molter et al., 2021) wurde das Konzept blickabhängiger Evidenzakkumulation in einer Entscheidungsaufgabe geprüft, in der drei risikobehaftete Lotterien als Alternativen mit mehreren Attributen zur Auswahl standen. Die Aufgabe wurde so entwickelt, dass Kontexteffekte im Entscheidungsverhalten auftreten sollten. Kontexteffekte beschreiben Präferenzänderungen in Abhängigkeit der verfügbaren Alternativen und stellen starke Abweichungen von normativen Vorhersagen dar. Die Ergebnisse zeigten, dass nicht nur das Entscheidungsverhalten, sondern auch die Verteilung visueller Aufmerksamkeit vom Kontext der verfügbaren Alternativen moduliert wurde. Dies ermöglichte es einem aus Vorarbeiten abgeleiteten blickabhängigen Evidenzakkumulationsmodell, Entscheidungsverhalten in diesem komplexen Szenario zu erfassen. Zuletzt wurde in einer prä-registrierten dritten Studie (Molter & Mohr, 2021) die Richtung des Kausalitätszusammenhangs zwischen visueller Aufmerksamkeit und Entscheidung beleuchtet. In unserem Experiment trafen Teilnehmer wiederholte Entscheidungen zwischen zwei Lotterien, deren Attribute sequenziell präsentiert wurden. Dies ermöglichte die experimentelle Kontrolle von Präsentationsdauer und Reihenfolge der Stimulusinformation. Die Ergebnisse bestätigten einen kausalen Einfluss der Informationssuche auf die Präferenzkonstruktion. Jedoch wurde hier die Präsentationsreihenfolge, nicht die Präsentationsdauer als Einflussfaktor identifiziert. Bemerkenswert ist hierbei, dass nur manche blickabhängigen Evidenzakkumulationsmodelle solche kausalen Einflüsse der Reihenfolge vorhersagen. Unsere Ergebnisse zeigen dementsprechend ein mögliches Potenzial für zukünftige Theorieentwicklung auf. Unsere Studien bestätigten grundsätzlich den positiven Zusammenhang zwischen visueller Aufmerksamkeit und Entscheidungen. Zudem unterstützen sie Theorien blickabhängiger Evidenzakkumulation im Rahmen individueller und komplexer Entscheidungen. Die Analysen haben allerdings auch bedeutende individuelle Unterschiede und mögliche Grenzen aktueller Modelle sichtbar gemacht. Hier konnten wir jedoch zeigen, dass die Berücksichtigung solcher Unterschiede und die Hinzunahme zusätzlicher Mechanismen wie imperfekter Akkumulation die Vorhersage individuellen Verhaltens erheblich verbessert. Zum Abschluss der Arbeit werden diese Ergebnisse einer aktiven Rolle visueller Aufmerksamkeit im Entscheidungsprozess sowie das theoretische Modell blickabhängiger Evidenzakkumulation im weiteren Kontext konstruierter Präferenzen diskutiert und mögliche Implikationen für die computermodellbasierte Analyse von Entscheidungs- und Blickbewegungsdaten aufgezeigt

Neuronal and behavioral correlates of the influence of contextual cues on value-based decision making = Die neuronalen und behavioralen Korrelate des Einflusses von kontextuellen Reizen auf das wertebasierte Entscheidungsverhalten : Kumulative Arbeit

Value-based decisions are almost omnipresent in life. However, they are not very well understood. Previous research has shown that the decision-making process is dynamic, and can be influenced, for instance, by increasing the saliency of a certain attribute. Therefore, one could hypothesize that it is possible to make decision-makers aware of certain long-term attributes in order to improve decisions. In four main studies published during my doctoral work, I investigated the role of contextual attributes on value-based decision making and how they influence dietary choices. The text presented here puts the published studies into a broader context and reviews various topics, such as the influence of attention on decision making, neuroscientific evidence as well as computational models in decision-making research

What I see is what I want: top-down attention biasing choice behavior

Health and self-regulatio

Prosocial preferences condition decision effort and ingroup biased generosity in intergroup decision-making

Ingroup favoritism and discrimination against outgroups are pervasive in social interactions. To uncover the cognitive processes underlying generosity towards in- and outgroup members, we employ eye-tracking in two pre registered studies. We replicate the well-established ingroup favoritism effect and uncover that ingroup compared to outgroup decision settings are characterized by systematic differences in information search effort (i.e., increased response times and number of fixations, more inspected information) and attention distribution. Surprisingly, these results showed a stronger dependency on the in- vs. out-group setting for more individualistic compared to prosocial participants: Whereas individualistic decision makers invested relatively less effort into information search when decisions involved out-group members, prosocial decision makers’ effort differed less between in- and outgroup decisions. Therein, choice and processing findings showed differences, indicating that inferences about the decision process from choices alone can be misleading. Implications for intergroup research and the regulation of intergroup conflict are discussed.Social decision makin

Uncovering the computational mechanisms underlying many-alternative choice

How do we choose when confronted with many alternatives? There is surprisingly little decision modelling work with large choice sets, despite their prevalence in everyday life. Even further, there is an apparent disconnect between research in small choice sets, supporting a process of gaze-driven evidence accumulation, and research in larger choice sets, arguing for models of optimal choice, satisficing, and hybrids of the two. Here, we bridge this divide by developing and comparing different versions of these models in a many-alternative value-based choice experiment with 9, 16, 25, or 36 alternatives. We find that human choices are best explained by models incorporating an active effect of gaze on subjective value. A gaze-driven, probabilistic version of satisficing generally provides slightly better fits to choices and response times, while the gaze-driven evidence accumulation and comparison model provides the best overall account of the data when also considering the empirical relation between gaze allocation and choice

Cognitive control of saccadic selection and inhibition from within the core cortical saccadic network

The ability to select the task-relevant stimulus for a saccadic eye movement, while inhibiting saccades to task-irrelevant stimuli, is crucial for active vision. Here, we present a novel saccade-contingent behavioural paradigm and investigate the neural basis of the central cognitive functions underpinning such behaviour - saccade selection, saccade inhibition and saccadic choice – in female and male human participants. The paradigm allows for exceptionally well-matched contrasts, with task demands formalized with stochastic accumulation-to-threshold models. Using functional magnetic resonance imaging, we replicated the core cortical eye-movement network for saccade generation (frontal eye fields, posterior parietal cortex and higher-level visual areas). However, in contrast to previously published tasks, saccadic selection and inhibition recruited only this core network. Brain12 behaviour analyses further showed that inhibition efficiency may be underpinned by white matter integrity of tracts between key saccade generating regions, and that inhibition efficiency is associated with right inferior frontal gyrus engagement, potentially implementing general-purpose inhibition. The core network, however, was insufficient for saccadic choice which recruited anterior regions commonly attributed to saccadic action selection, including dorsolateral prefrontal cortex and anterior cingulate cortex. Jointly, the results indicate that extra-saccadic activity observed for free choice, and in previously published tasks probing saccadic control, is likely due to increased load on higher-level cognitive processes, and not saccadic selection per se, which is achieved within the canonical cortical eye movement network

Essays on context effects in behavioural economics

This thesis presents four research projects in the broader field of behavioural economics. In doing so, it aims to demonstrate the wide scope of behavioural economics as a scientific discipline, and illustrate its diverse methodological toolkit. Chapter 1 provides a broad overview of the birth of behavioural economics through the history of psychology and economics. Chapters 2–4 investigate context effects in decision making, while Chapter 5 describes an example of the profound effect visceral factors can exert on human behaviour. More specifically, in Chapter 2, we investigate context-dependent choice behaviour within the framework of a popular cognitive model of decision making. Based on results from three tests using data from a value-based and perceptual choice experiment, we find that a mixture of absolute and relative valuation rules describes subjective valuation most accurately across two vastly different choice domains. In Chapter 3, we test whether the attraction effect, a well-known cognitive bias is present in choices involving naturalistic, complex stimuli. The results from two experiments suggest that the attraction effect does not extend to real-world choices. This finding serves as the basis for the research question we investigate in Chapter 4, where our aim is to explore the extent to which the strength of the attraction effect depends on the separability of the attribute dimensions. Potentially owing to the design of the experiment, the results of this investigation are mixed and inconclusive, which prevents us from providing a clear answer to our research question. In contrast to the previous, laboratory-based experimental chapters, in Chapter 5, we use a large observational dataset to investigate the link between England’s participation in national football tournaments and the number of reported domestic abuse cases recorded by the West Midlands Police. Using a regression approach, we find that alcohol-related domestic abuse increases by 61% following and England victory. As well as exploring the characteristics of this increase, we also re-analyse data from a previous study to reconcile our results with earlier findings from the literature, and demonstrate the robustness of the win effect. Our study is the first to highlight the instrumental role alcohol plays in the relationship between football and domestic abuse. Finally, Chapter 6 summarizes the findings, and discusses the limitations and possible directions for future research

Change blindness: eradication of gestalt strategies

Arrays of eight, texture-defined rectangles were used as stimuli in a one-shot change blindness (CB) task where there was a 50% chance that one rectangle would change orientation between two successive presentations separated by an interval. CB was eliminated by cueing the target rectangle in the first stimulus, reduced by cueing in the interval and unaffected by cueing in the second presentation. This supports the idea that a representation was formed that persisted through the interval before being 'overwritten' by the second presentation (Landman et al, 2003 Vision Research 43149–164]. Another possibility is that participants used some kind of grouping or Gestalt strategy. To test this we changed the spatial position of the rectangles in the second presentation by shifting them along imaginary spokes (by ±1 degree) emanating from the central fixation point. There was no significant difference seen in performance between this and the standard task [F(1,4)=2.565, p=0.185]. This may suggest two things: (i) Gestalt grouping is not used as a strategy in these tasks, and (ii) it gives further weight to the argument that objects may be stored and retrieved from a pre-attentional store during this task

Neural and Cognitive Basis of Third-Party Altruistic Decision-Making and Its Modulators

Human beings live in a world full of social connections. Favoring by the evolution, humans could survive the challenges of nature by not only maximizing their own interests (i.e., selfish motives) but also by considering the well fare of others even at a cost to their own resources (i.e., altruistic motives). Beyond the kindness between relatives and direct reciprocity between friends, humans, as third-party bystanders, will sometimes engage in a costly situation where social norms are vio-lated, to achieve justice via either punishing the unknown offender or compensating the anony-mous victim, even when such a violation does not directly affect their own interests and the costs incurred by them will not be paid back. Why do unaffected third parties intervene at a personal cost and what might be the underlying neural as well as cognitive mechanism? What factors might influence their decisions in such situations? To address these questions, the present dissertation used four studies by adopting a modified third-party economic paradigm to capture the third-party altruistic behaviors (i.e., third-party help and punishment) in response to an unfair situation, with the help of the technique of functional magnetic resonance imaging (fMRI; Studies 1-3) and eye-tracking (Study 4). By mainly investigating neural correlates during altruistic decision-making of third parties, Study 1 showed that signals in the bilateral striatum (esp. the ventral part) were stronger when third-party deciders chose to either help the victim or punish the selfish offender. Further analyses revealed an association between either choice of altruistic behavior, or its neural activation, and the empathic concern level, a personality trait closely related with altruism (esp. helping behavior). Studies 2-4 further tested whether, and how, other factors modulate third-party decision-making and the underlying neural or cognitive processes. In particular, Studies 2A and 2B focused on oxytocin, a so-called ―pro-social‖ hormone, and tested whether its effect on other altru-istic behaviors extended to the third-party context. As revealed by Study 2A, and replicated by Study 2B, we observed that intranasal oxytocin affects neither type of third-party altruistic deci-sions; rather, it modulated neural processing, especially via enhancing activity in the temporo-parietal junction (TPJ), a region shown to support mentalizing ability, during the perception of helping decision made by a computer (Study 2A). Study 3 manipulated the attention focus on different aspects of the norm violation (i.e., asking participants to consider either the unfairness of the offender or the feelings of the victim), and showed not only an effect on third-party altruistic choice behavior, but also confirmed the role of TPJ and control-related regions in such modula-tion. Replicating the effects of empathic concern (Study 1) and attention focus on choice behavior (Study 3), Study 4 provided the first empirical evidence that eye-movement pattern during third-party altruistic decision-making could also be biased by both factors and their interaction, shed-ding light on the cognitive mechanism underlying attention and information searching. Limitations of the studies and future research directions were also discussed