arXiv subjects

Bijin Joseph

Publications and source records attributed to Bijin Joseph.

3 recordsLinked to original sources

arXiv2025

When Influence Misleads: Informational and Strategic Limits of Social Learning in Trading Networks

Social learning is a fundamental mechanism shaping decision-making across numerous social networks, including social trading platforms. In those platforms, investors combine traditional investing with copying the behavior of others. However, the underlying factors that drive mirroring decisions and their impact on performance remain poorly understood. Using high-resolution data on trades and social interactions from a large social trading platform, we uncover a fundamental tension between popularity and performance in shaping imitation behavior. Despite having access to performance data, people overwhelmingly choose whom to mirror based on social popularity, a signal poorly correlated with actual performance. This bias, reinforced by cognitive constraints and slow-changing popularity dynamics, results in widespread underperformance. However, traders who frequently revise their mirroring choices (trading explorers) consistently outperform those who maintain more static connections. Building an accurate model of social trading based on our findings, we show that prioritizing performance over popularity in social signals dramatically improves both individual and collective outcomes in trading platforms. These findings expose the hidden inefficiencies of social learning and suggest design principles for building more effective platforms.

physics.soc-ph↗

arXiv2022

Variation of Gini and Kolkata Indices with Saving Propensity in the Kinetic Exchange Model of Wealth Distribution: An Analytical Study

We study analytically the change in the wealth ($x$) distribution $P(x)$ against saving propensity $λ$ in a closed economy, using the Kinetic theory. We estimate the Gini ($g$) and Kolkata ($k)$ indices by deriving (using $P(x)$) the Lorenz function $L(f)$, giving the cumulative fraction $L$ of wealth possessed by fraction $f$ of the people ordered in ascending order of wealth. First, using the exact result for $P(x)$ when $λ= 0$ we derive $L(f)$, and from there the index values $g$ and $k$. We then proceed with an approximate gamma distribution form of $P(x)$ for non-zero values of $λ$. Then we derive the results for $g$ and $k$ at $λ= 0.25$ and as $λ\rightarrow 1$. We note that for $λ\rightarrow 1$ the wealth distribution $P(x)$ becomes a Dirac $δ$-function. Using this and assuming that form for larger values of $λ$ we proceed for an approximate estimate for $P(x)$ centered around the most probable wealth (a function of $λ$). We utilize this approximate form to evaluate $L(f)$, and using this along with the known analytical expression for $g$, we derive an analytical expression for $k(λ)$. These analytical results for $g$ and $k$ at different $λ$ are compared with numerical (Monte Carlo) results from the study of the Chakraborti-Chakrabarti model. Next we derive analytically a relation between $g$ and $k$. From the analytical expressions of $g$ and $k$, we proceed for a thermodynamic mapping to show that the former corresponds to entropy and the latter corresponds to the inverse temperature.

physics.soc-ph↗

arXiv2021

Kinetic Exchange Income Distribution Models with Saving Propensities: Inequality Indices and Self-Organised Poverty Level

We report the numerical results for the steady state income or wealth distribution $P(m)$ and the resulting inequality measures (Gini $g$ and Kolkata $k$ indices) in the kinetic exchange models of market dynamics. We study the variations of $P(m)$ and of the indices $g$ and $k$ with the saving propensity $λ$ of the agents, with two different kinds of trade (kinetic exchange) dynamics. In the first case, the exchange occurs between randomly chosen pairs of agents and in the next, one of the agents in the chosen pair is the poorest of all and the other agent is randomly picked up from the rest of the population (where, in the steady state, a self-organized poverty level or SOPL appears). These studies have also been made for two different kinds of saving behaviors. One, where each agent has the same value of $λ$ (constant over time) and the other where $λ$ for each agent can take two values (0 and 1), changing randomly over a fraction of time $ρ(<1)$ of choosing $λ= 1$. We find that the inequality decreases with increasing savings ($λ$); inequality indices ($g$ and $k$) decrease and SOPL increases with increasing $λ$, indicating possible applications in economic policy making.

physics.soc-ph↗