Subjective patterns of randomness and choice: some consequences of collective responses.

Any individual's response intended to be random should be as probable as any other. However, 3 experiments show that many people's independent responses depart from the expected chance distribution. Participants responding to instructions of chance and related concepts favor the available options unequally in a similar way. Consequently, in hide-and-seek games, hiders converge on certain locations and are thereby detected beyond chance by seekers who share their preferences. People agree on salient and on nonsalient options, both of which are preferred under different instructions and even in the absence of instructions. Group responses strongly correlate under diverse, even opposing (e.g., competitive and cooperative) directions. Apparently, common default tendencies, combining random and aesthetic choices, are only somewhat modified under specific instructions. Maximal agreement with others is obtained through one's own aesthetic choices. Hence, implementing one's personal aesthetic preferences succeeds in matching others' choices even better than deliberate mutual coordination efforts. These results broadly replicate in 1- and 2-dimensional tasks. Implications of the findings, their possible roots, and their connection to constructs from, e.g., game theory and subjective-complexity research, are discussed.

The allure of equality: uniformity in probabilistic and statistical judgment.

Uniformity, that is, equiprobability of all available options is central as a theoretical presupposition and as a computational tool in probability theory. It is justified only when applied to an appropriate sample space. In five studies, we posed diversified problems that called for unequal probabilities or weights to be assigned to the given units. The predominant response was choice of equal probabilities and weights. Many participants failed the task of partitioning the possibilities into elements that justify uniformity. The uniformity fallacy proved compelling and robust across varied content areas, tasks, and cases in which the correct weights should either have been directly or inversely proportional to their respective values. Debiasing measures included presenting individualized and visual data and asking for extreme comparisons. The preference of uniformity obtains across several contexts. It seems to serve as an anchor also in mathematical and social judgments. People's pervasive partiality for uniformity is explained as a quest for fairness and symmetry, and possibly in terms of expediency.