The evolution of peace (and war) is driven by an elementary social interaction mechanism.

Here we revise Glowacki's model by proposing a simple and empirically tested mechanism that is applicable to a comprehensive set of social interactions. This parsimonious mechanism accounts for the choice of both cooperative and peaceful alternatives and explains when each choice benefits the interacting parties. It is proposed that this mechanism is key to the evolution of both peace and conflict.

The effect of similarity perceptions on human cooperation and confrontation.

By assuring aversive actions are followed by similarly aversive reactions, legislators of antiquity aimed to reduce belligerence and aggression. In the present study we show how similarity perceptions drive cooperation and confrontation across several strategic decision types. Examining the choices made in three one-shot symmetric conflict games: the prisoner's dilemma, the chicken, and the battle of the sexes, we show how a short encounter with a stranger accounts for the formation of subjective similarity perceptions, which together with the expected payoffs of the game determine the choice of the preferred alternative.

Interacting with others while reacting to the environment.

Here, we revise Pietraszewski's model of groups by assigning participant pairs with two triplets, denoting: (1) the type of game that models the interaction, (2) its critical switching point between alternatives (i.e., the game's similarity threshold), and (3) the perception of strategic similarity with the opponent.

Vaccination-hesitancy and global warming: distinct social challenges with similar behavioural solutions.

Although the COVID-19 vaccine has dramatically changed the fight against the pandemic, many exhibit vaccination-hesitancy. At the same time, continued human-induced emissions of greenhouse gases pose an alarming threat to humanity. Based on the theory of Subjective Expected Relative Similarity (SERS) and a recent international study that drastically modified COVID-19 health-related attitudes, we explain why a similar approach and a corresponding public policy are expected to help resolve both behavioural issues: reduce vaccination hesitancy and motivate climate actions.

The behavioural challenge of the COVID-19 pandemic: indirect measurements and personalized attitude changing treatments (IMPACT).

Following the outbreak of COVID-19 pandemic, governments around the globe coerced their citizens to adhere to preventive health behaviours, aiming to reduce the reproduction numbers of the virus. Driven by game theoretic considerations and inspired by the work of US National Research Council's Committee on Food Habits (1943) during WWII, and the post-WWII Yale Communication Research Program, the present research shows how to achieve enhanced adherence to health regulations without coercion. To this aim, we combine three elements: (i) indirect measurements, (ii) personalized interventions, and (iii) attitude changing treatments (IMPACT).

Extending the two faces of subjective randomness: From the gambler's and hot-hand fallacies toward a hierarchy of binary sequence perception.

In this study, we examined perceptions of binary sequences under uncertainty in an attempt to depict a holistic and unifying framework. The first experiment applied a projection method that motivated participants to observe binary series and provide descriptions of their possible underlying mechanisms or processes. This procedure revealed four distinct perceptual categories: two previously studied categories of chance mechanisms and human performance, associated with the gambler's and hot-hand fallacies, and two newly identified categories-periods and processes and traits and preferences.

Fusing enacted and expected mimicry generates a winning strategy that promotes the evolution of cooperation.

Although cooperation and trust are essential features for the development of prosperous populations, they also put cooperating individuals at risk for exploitation and abuse. Empirical and theoretical evidence suggests that the solution to the problem resides in the practice of mimicry and imitation, the expectation of opponent's mimicry and the reliance on similarity indices. Here we fuse the principles of enacted and expected mimicry and condition their application on two similarity indices to produce a model of mimicry and relative similarity.

Friend or foe: subjective expected relative similarity as a determinant of cooperation.

Subjective expected relative similarity (SERS) is a descriptive theory that explains cooperation levels in single-step prisoner's dilemma (PD) games. SERS predicts that individuals cooperate whenever their subjectively perceived similarity with their opponent exceeds a situational index, namely the game's similarity threshold. A thought experiment and 2 experimental studies illustrate and explore SERS's characteristics, showing that the theory predicts cooperation and competition in single-step PD games under 3 informational structures: (a) clear and transparent similarity cues, (b) experienced similarity, and (c) semantic similarity.

The hot hand fallacy and the gambler's fallacy: two faces of subjective randomness?

The representativeness heuristic has been invoked to explain two opposing expectations--that random sequences will exhibit positive recency (the hot hand fallacy) and that they will exhibit negative recency (the gambler's fallacy). We propose alternative accounts for these two expectations: (1) The hot hand fallacy arises from the experience of characteristic positive recency in serial fluctuations in human performance. (2) The gambler's fallacy results from the experience of characteristic negative recency in sequences of natural events, akin to sampling without replacement.