MAKING DECISIONS ON THE FLY - UNRAVELLING THE COMPUTATIONAL PRINCIPLES GOVERNING CHOICE BEHAVIOR IN THE DROSOPHILA MELANOGASTER BRAIN

Foraging animals adopt decision-making strategies that successfully adapt to the dynamically changing availability of rewards in the environment, as well as account for the complexity of the sensory world around them. Understanding the neural principles that underlie these complex decision strategies has been an area of interest in neuroscience for a long time. While a lot of progress has been made on these fronts, a complete picture of these neural algorithms has eluded us for two reasons. In studies of larger vertebrates that have used tasks that account for richness of the natural world, the lack of manipulability of these complex brains has restricted our ability to map the underlying neural algorithms. On the other hand, studies in more accessible small brains have been limited to simple Pavlovian learning tasks for the most part. In this dissertation, my colleagues and I develop a novel foraging task for Drosophila melanogaster, the details of which are described in chapter 2, and leverage this task to provide insight into the neural algorithms underlying decision-making. In chapter 3, we deal with dynamic probabilistic environments, where several animals are known to distribute their choices in proportion to the rewards received from available options - Herrnstein’s operant matching law. Theoretical work suggests an elegant mechanistic explanation for this ubiquitous behavior, as operant matching follows automatically from simple expectation-based synaptic plasticity rules acting within behaviorally relevant neural circuits. However, no past work has mapped operant matching onto plasticity mechanisms in the brain, leaving the biological relevance of the theory unclear. Here we discovered operant matching in Drosophila and using a combination of behavior, computational modeling and optogenetics showed that it requires reward expectation based synaptic plasticity that acts in the mushroom body. Our results reveal the first synapse-level mechanisms of operant matching in the fly brain. In chapter 4, we provide the first biological test of Marr and Albus’ expansion layer theory about sensory discrimination. In particular, the ratio between sensory channels and expansion layer neurons and the number of sensory inputs that individual expansion layer neurons receive are theorized to be key parameters. Leveraging the development of tools that manipulate these parameters in the context of the fly mushroom body, we show that fly behavior agrees with many theoretical predictions. An increase in expansion layer neuron number improves discrimination of odors while an increase in input connectivity causes worsened discrimination. There are however some key differences, suggesting that theoretical models can learn from the experiments and be modified to better explain sensory discrimination. In chapter 5, we move beyond just sensory discrimination and tackle the question of flexible decision-making that must depend on the available options. We find that Drosopihla melanogaster can successfully learn to both distinguish between very similar stimuli and generalize across cues. Rather than forming memories that strike a balance between specificity and generality, we find that flies flexibly categorize a given stimulus into different groups by performing a side-by-side comparison over time of the available options. Together the work in this thesis combines multiple important avenues of neuroscience, providing insight into the neural principles underlying decision-making in dynamic and sensory rich environments

Alternative mechanisms guiding salespersons’ ambidextrous product selling

Ambidextrous product-selling strategies, in which companies’ salespeople concurrently pursue the sale of existing and new products, are hard to implement. Previous studies have addressed this issue for relatively simple consumer settings with the manager in close proximity to the salespersons and focusing on different levels of control and autonomy to resolve this issue. However, little is known about how field salespeople can be influenced to pursue such dual goals proactively for more complex business-to-business products. In this study, the authors distinguish between salespeople’s proactive selling behaviour for new and existing products, and study the impact of two alternative mechanisms: a situational mechanism (i.e. perceived manager product-selling ambidexterity) and a structural mechanism (i.e. salesperson organizational identification). Using a time-lagged, multisource data set from a large ambidextrous company, the authors demonstrate that both mechanisms contribute to salespeople’s proactive selling of new and existing products, but also act as each other’s substitutes. The results suggest two most likely strategies for salespeople to obtain overall sales targets: focusing on existing product selling; or acting ambidextrously. The latter approach offers the benefits of better achieving ambidextrous company sales goals and of greater performance stability, and is thus preferred

Foreign executive appointments: a multilevel examination

As multinational enterprises (MNE) expand, their attachment to the country of origin is challenged by the need to adapt to an increasingly diverse geographical posture. We examine how these countervailing forces affect top management team (TMT) composition and test a model that associates foreign executive appointments with individual- and firm-level antecedents. Using multilevel data comprising 1,446 TMT appointments at 360 large European firms between 2001 and 2005, we show that individual experiential characteristics, the type of TMT function, prior performance of the MNE, and the MNE’s overall degree of internationalization are associated with foreign TMT appointments. We discuss how our findings contribute to the international business literature and complement recent research on the internationalization of TMTs

Formalization, communication quality, and opportunistic behavior in R&D alliances between competitors

For technology ventures (and also other firms), R&D alliances provide great learning opportunities and access to scarce resources. However, R&D alliances, in particular between competitors, also involve the concomitant threat of opportunistic behavior, which many firms attempt to manage by formalizing the partnership. Yet, prior research provided mixed findings suggesting that formalization alleviates opportunism, fails to do so, or, ironically, even promotes it. The questions of whether and, if so, when formalization can deter opportunism remains topical. This study differentiates two forms of opportunistic behavior, strategic manipulation and knowledge appropriation, and examines how they are affected by formalization per se and in combination with communication quality. Findings from 82 R&D alliances between competitors indicate that extensive formalization promotes opportunistic behavior. In contrast, communication quality mitigates the dysfunctional effect on strategic manipulation and also alleviates both forms of opportunism directly. Most effects vary with the type of opportunistic behavior. Our findings add to the literature by demonstrating a positive formalization–opportunism relationship in the context of R&D alliances and by suggesting that relational governance (communication quality) compensates for the dysfunctional effects of formal governance (formalization), rather than both having complementary relationships. The results also support the call for more research into nuances of opportunism: they show that differentiating forms of opportunism matters for understanding the efficacy of safeguards against opportunism. Managers are warned against over-formalizing alliances, which spurs opportunism. Instead, they should cultivate an atmosphere of open communication while they can still maintain some “healthy distrust.” This attenuates the adverse effects of formalization, which is important since a certain level of formalization is often inevitable in R&D alliances

Why helping coworkers does not always make you poor:the contingent role of common and unique position within the sales team

In recent years, many companies have implemented sales teams as a way of streamlining accountability and promoting the development of sales expertise. The success of such work groups largely depends on experienced members' willingness to help coworkers. Previous studies indicate that group structure and individual position along individual attributes (e.g., experience) are important to understand interactions between coworkers. However, sales research on this topic is lacking. Drawing on a motivation-opportunity-ability framework, this study addresses this void by examining the impact of individual salesperson's job experience position within work groups on the motivation to help coworkers and his or her own sales performance. The findings of a multisource, multilevel empirical study reveal interesting effects. The results highlight the important role of job experience position: if a salesperson's level of job experience is common within the sales team, it activates identification as a driver of helping behaviors, which in turn negatively influences own performance. Conversely, if a salesperson's level of job experience is unique, it does not activate identification as a driver of helping, but does positively influence the effect of helping on own performance. The authors discuss implications for theory and practice

Knowledge Transfer and Accomodation Effects in Multinational Corporations: Evidence from European Subsidiaries

Foreign subsidiaries in multinational corporations (MNCs) possess knowledge that has different sources (e.g., the firm itself or various sources in the environment). How such sources influence knowledge transfer is not well understood. Drawing on the “accommodation effect” from cognitive psychology, the authors argue that accumulation of externally sourced knowledge in a subsidiary may reduce the value of transferring that subsidiary’s knowledge to other parts of the MNC. The authors develop a parsimonious model of intrafirm knowledge transfer and test its predictions against a unique data set on subsidiary knowledge development that includes the sources of subsidiary knowledge and the extent of knowledge transfer to other MNC units. The authors show that a high level of externally sourced knowledge in a subsidiary is associated with a high level of knowledge transfer from that subsidiary only if a certain tipping point of internally sourced knowledge has been surpassed. This suggests that subsidiary knowledge stocks that are balanced in terms of their origins tend to be more valuable, congruous, and fungible, and therefore more likely to be transferred to other MNC units

Attentional Gain and Processing Capacity Limits Predict the Propensity to Neglect Unexpected Visual Stimuli

Exogenous allocation of attentional resources allows the visual system to encode and maintain representations of stimuli in visual working memory (VWM). However, limits in the processing capacity to allocate resources can prevent unexpected visual stimuli from gaining access to VWM and thereby to consciousness. Using a novel approach to create unbiased stimuli of increasing saliency, we investigated visual processing during a visual search task in individuals who show a high or low propensity to neglect unexpected stimuli. When propensity to inattention is high, ERP recording show a diminished amplification concomitantly with an increase in theta band power during the N1 latency, followed by a poor target enhancement during the N2 latencies. Furthermore, a later modulation in the P3 latency was also found in individuals showing propensity to visual neglect, suggesting that more effort is required for conscious maintenance of visual information in VWM. Effects during early stages of processing (N80 and C1) were also observed suggesting that sensitivity to contrasts and medium to high spatial frequencies may be modulated by low-level saliency (albeit no statistical group differences were found). In accordance with the Global Workplace Model (GWM), our data indicate that a lack of visual attention resources in the low-level processors may be responsible for the failure to “ignite” a state of high-level activity spread across several brain areas that is necessary for stimuli to access awareness. These findings may aid in the development of diagnostic tests and intervention to detect/reduce inattention propensity to visual neglect of unexpected stimuli