Methodology
Pipeline
- Parse. Read the igraph-exported GraphML into a directed graph (65 nodes, 1139 edges). Parallel edges collapsed; self-loops kept out of degree.
- Measure. Compute degree, density, global and per-node reciprocity, local clustering, PageRank (damping 0.85), Brandes betweenness, eigenvector centrality, all-pairs BFS for path length and diameter, and Tarjan SCCs.
- Partition. Louvain on the undirected projection (reciprocated pairs weighted 2×, one-directional 1×) with a fixed-seed shuffle, so the community assignment is deterministic. Result: 3 communities, modularity 0.295.
- Map. Each personality axis is a documented linear function of one or more metrics, clamped to [0,1]. The exact arithmetic is shown under every trait on the personality page.
The mapping rules
| Personality axis | Driven by | Reading |
|---|---|---|
| Sociability | global reciprocity | mutual edges → reactive, answers what it is asked |
| Associative thinking | mean local clustering | neighbourhoods close on themselves → tangential |
| Impulsiveness | avg shortest path, diameter | ~2-hop reach → few reasoning steps |
| Excitability | density, mean degree | wide fan-out → arousal escalates fast |
| Fixation | out-degree dispersion | hub-dominated traffic → recurring preoccupations |
| Exploration | community count, modularity, SCC size | distinct territories to roam |
| Independence | largest strongly-connected core | self-sustaining internal dynamics |
| Emotional volatility | excitability + low modularity + impulsiveness | uncompartmentalised states propagate |
| Warmth | reciprocity + clustering | mutual, tight wiring → attaching |
How the graph is used at runtime (Phase 2)
The connectome isn’t just a seed — the agent keeps it in memory. An incoming stimulus (a mention, a task, an observation) is mapped onto a few seed nodes; activation spreads along the real directed edges with per-hop decay; whichever community ends up hottest selects the current mood, and the hottest individual nodes bias what the agent attends to. The activationDecay knob on the cognitive-style panel is derived from graph density and fed straight into that simulation.
Determinism
Same file in → identical profile out (the only varying field is a timestamp). Every RNG in the pipeline is seeded from a hash of the node count, edge count, and the dataset DOI. Covered by the test suite in packages/connectome.
Source data
mixed.species_brain_1.graphml — cat cerebral-cortex connectivity from tract-tracing studies, DOI 10.1523/JNEUROSCI.1448-13.2013 (The Journal of Neuroscience 33(32):12929). No region labels are present in the file; nodes are n0–n64.
Retrieved as GraphML from NeuroData’s Open Connectome Project graph database — a public repository of tract-traced and EM-reconstructed connectomes across species, hosted by NeuroData (JHU).