Individual and collective appetite – how is eating shaped by social influence?

2 Ph.D/Postdoctoral Positions

Research objectives: The aim of this project is to determine the influence of social context on eating/feeding behaviour in human and animal collectives. We will examine 1) how the internal states and preferences of individuals within collectives influence the food preferences of others, 2) whether there are fine-scale processes of synchronisation/anti-synchronisation within groups when eating together, such as of chewing/pecking as well as body posture/head/eye movements, and how this impacts food choice and ingestion rate, 3) how social structure (such as perceived social status, social network position and/or dominance rank (depending on species)) relates to social influence during group eating, with respect to what food items are chosen, and how feeding decisions may transmit through groups. To collect these data, we will employ advanced imaging technology to capture the 3D body posture, including the head direction (and where possible, also eye movements), and verbal communication/vocalising, allowing us to infer the fine-scale dynamics of attention: who is looking at whom, when and for how long – and how does this impact the social transmission of eating behaviours?

The Department of Psychology is seeking a Ph.D student or Postdoctoral Researcher to study collective effects during eating in humans. We will collect baseline data by assessing behavioural signatures of individuals when alone and when in a group setting using a standard lunch buffet. Using automated body posture estimation and eye tracking, we will obtain information regarding the complex, time-varying distribution of gaze, both towards the food items and towards other individuals. Recordings of meal conversations will add information about the impact of organisation and content of verbal communications (e.g. turn taking, food talk). How are feeding decisions manifested in groups, and how do physical properties, such as the spatial proximity to food items, the feeding decisions of others, and meal conversations (possible social influence) impact the type of foods people eat, and when they eat them? Is there evidence of fine scale social coupling between individuals, such as synchronisation of sampling of specific food items and/or of chewing and ingestion? By introducing food items varying in novelty and valence (positive, negative, neutral), as well as the informational status of individuals and their apparent (or real) social status within the group, we will ask how sampling of unfamiliar/unusual food items by individuals may be socially facilitated within groups, and how this depends on the social structure, patterns of directed attention, and so on. Because social effects may be more or less pronounced as a function of satiation, we will also manipulate the hunger status of individuals. By employing all of these strategies, we will obtain a detailed understanding of social influence during eating under naturalistic conditions (Adviser: Britta Renner)

The Department of Biology and Max Planck Institute for Ornithology is seeking one PhD student or Postdoctoral Researcher to investigate collective foraging in birds. As with our human studies, we will explore how properties such as social structure (the position of individuals in social networks, informational status, and satiety influence feeding decisions in collective contexts. Many birds (including starlings and zebra finches) feed on the ground, often in moving flocks. We will vary the spatial distribution and quality of resources, as well as their crypticity, allowing us to vary the composition and predictability of food within the environment. In addition to analysing the motion and feeding decisions of the birds, we will also reconstruct the time-varying networks of attention within foraging groups, employing body posture analysis and 3D visual field reconstruction to determine who is looking at whom, and whether properties like social status and informedness impact the social influence of individuals on others’ feeding decisions, and if so, how. This will involve real-time tracking and posture estimation methods that will be developed as part of the Cluster with our colleagues in computer science. We will combine tracking with automated call localisation (via a microphone array) to assess associations and interactions (e.g. aggressive), which will allow us to determine how these features affect collective feeding, and over what timescales. This project is funded by the Max Planck Institute as a contribution to the Excellence Cluster. (Adviser: Iain Couzin)