Is behavioral pro-sociality game-specific? Pro-social preference and expectations of pro-sociality

We observed the behaviors of the same people across five games – two prisoner’s dilemma games, a trust game (in which the subject took on the role of both truster and trustee), a dictator game, and a faith game – any pair of which was separated by an interval of several months to reduce potential carry-over effects, and found strong consistency in behaviors among these games. We also found consistency between the expectations of other players’ behaviors and the player’s own behavior across games. We further found that the consistent behavioral pro-sociality observed across different games was related to the general measures of pro-social value orientation and perceiving the game situations. These findings suggest that individual and cultural differences in game behaviors can reflect both the ways in which people perceive game situations and their general social preferences.     

Behavior-Based Assessment of the Auditory Abilities of Brushtail Possums

Brushtail possums (Trichosurus vulpecula) were trained to press a right lever when a tone was presented (a tone‐on trial) and a left lever when a tone was not presented (a tone‐off trial) to gain access to food. During training the tone was set at 80 dB(A), with a frequency of 0.88 kH for 3 possums and of 4 kH for the other 2. Once accuracy was over 90% correct across five consecutive sessions, a test session was conducted where the intensity of the tone was reduced by 8 dB(A) over blocks of 20 trials until accuracy over a block fell below 60%. After each test session, training sessions were reintroduced and continued until accuracy was again over 90%, when another test session was conducted. This process continued until there were at least five test sessions at that tone frequency. The same procedure was then used with frequencies of 0.20, 0.88, 2, 4, 10, 12.5, 15, 20, 30, and 35 kHz. Percentage correct and d' decreased approximately linearly for all possums as tone intensity reduced. Both sets of lines were shallowest at the higher frequencies and steepest at the lower frequencies. Hit and false alarm rates mirrored each other at high frequencies but were asymmetric at lower frequencies. Equal d' contours showed that sensitivity increased from 2 to 15 kHz and continued to be high over 20 to 35 kHz. The possums remained sensitive to the 20 to 35 kHz tones even at low intensities. The present study is the first to report the abilities of possum to detect tones over this range of frequencies and its results support the findings of a microelectrode mapping survey of possums' auditory cortex.     

Modesty in self‐presentation: A comparison between the USA and Japan

Japanese participants in Study 1 exhibited a self‐effacing tendency when no reason for their self‐evaluation was provided. However, they exhibited a self‐enhancing tendency when they were offered a monetary reward for the correct evaluation. In Study 2, Americans, especially American men, exhibited a self‐enhancing tendency whereas Japanese exhibited a self‐effacing tendency when no reason for making the evaluation was presented. This cultural difference disappeared when participants were provided with a monetary reward for correctly evaluating their performance level. These results support the view that the modesty observed in self‐evaluation among Japanese participants is a ‘default strategy’ to avoid offending others.