Influence of biases in numerical magnitude allocation on human prosocial decision making

Over the past decade neuroscientific research has attempted to probe the neurobiological underpinnings of human prosocial decision making. Such research has almost ubiquitously employed tasks such as the dictator game or similar variations (i.e., ultimatum game). Considering the explicit numerical nature of such tasks, it is surprising that the influence of numerical cognition on decision making during task performance remains unknown. While performing these tasks, participants typically tend to anchor on a 50:50 split that necessitates an explicit numerical judgement (i.e., number-pair bisection). Accordingly, we hypothesize that the decision-making process during the dictator game recruits overlapping cognitive processes to those known to be engaged during number-pair bisection. We observed that biases in numerical magnitude allocation correlated with the formulation of decisions during the dictator game. That is, intrinsic biases toward smaller numerical magnitudes were associated with the formulation of less favorable decisions, whereas biases toward larger magnitudes were associated with more favorable choices. We proceeded to corroborate this relationship by subliminally and systematically inducing biases in numerical magnitude toward either higher or lower numbers using a visuo-vestibular stimulation paradigm. Such subliminal alterations in numerical magnitude allocation led to proportional and corresponding changes to an individual’s decision making during the dictator game. Critically, no relationship was observed between neither intrinsic nor induced biases in numerical magnitude on decision making when assessed using a nonnumerical-based prosocial questionnaire. Our findings demonstrate numerical influences on decisions formulated during the dictator game and highlight the necessity to control for confounds associated with numerical cognition in human decision-making paradigms. NEW & NOTEWORTHY We demonstrate that intrinsic biases in numerical magnitude can directly predict the amount of money donated by an individual to an anonymous stranger during the dictator game. Furthermore, subliminally inducing perceptual biases in numerical-magnitude allocation can actively drive prosocial choices in the corresponding direction. Our findings provide evidence for numerical influences on decision making during performance of the dictator game. Accordingly, without the implementation of an adequate control for numerical influences, the dictator game and other tasks with an inherent numerical component (i.e., ultimatum game) should be employed with caution in the assessment of human behavior.

Pair-splitting, pair-reaping and cardinal invariants of Fσ-ideals

We investigate the pair-splitting number which is a variation of splitting number, pair-reaping number which is a variation of reaping number and cardinal invariants of ideals on ω. We also study cardinal invariants of Fσ ideals and their upper bounds and lower bounds. As an application, we answer a question of S. Solecki by showing that the ideal of finitely chromatic graphs is not locally Katětov-minimal among ideals not satisfying Fatou's lemma.

Personality Differences in Serial Learning under Distraction

Previous work by Shanmugan had indicated that extraverts were able to perform better than introverts while under distraction. This experiment used serial learning of number groups, with a previously learned list of number pairs as a distractor in the final part of the experiment. It was found that greater percentage savings were obtained by extraverts under these conditions. In a third group of Ss initial distraction was arranged by placing a number pair in a group of four numbers. Extraverts also learned faster under these conditions. Several explanations of the present data are possible: (1) Jensen proposed that extraverts are more resistent to response competition, (2) Eysenck suggested that arousal, and hence, consolidation processes are less marked and intertere less in short-term memory in extraverts, (3) differences in strength of initial registration in very short-term memory may underlie the effect.

Verbal problem solving

A problematic situation occurs whenever a habitual response cannot be given to the problem encountered. In the field of arithmetic, the pupil may not know the answer to a basic number pair, such as 12÷3. A situation of this kind constitutes a problem for that pupil. Most teachers of arithmetic infer that problem solving refers to verbal problems. To limit the topic of this article, work dealing with problem solving will be confined to verbal problems.