Learning how to "make a deal": human (Homo sapiens) and monkey (Macaca mulatta) performance when repeatedly faced with the Monty Hall Dilemma.

The Monty Hall Dilemma (MHD) is a well-known probability puzzle in which players try to guess which of three doors conceals a prize. After selecting a door, players are shown that there is no prize behind one of the remaining doors. Players then are given a choice to stay with their door or switch to the other unopened door.

Monkeys (macaca mulatta and cebus apella) and human adults and children (homo sapiens) compare subsets of moving stimuli based on numerosity.

Two monkey species (Macaca mulatta and Cebus apella) and human children and adults judged the numerousness of two subsets of moving stimuli on a computer screen. Two sets of colored dots that varied in number and size were intermixed in an array in which all dots moved in random directions and speeds. Participants had to indicate which dot color was more numerous within the array.

A transcranial Doppler sonography study of shoot/don't-shoot responding.

The purpose of this study was to examine the relationship between changes in cerebral blood-flow velocity and performance on a speeded shoot/don't-shoot task. Brain activity as indicated by cerebral blood-flow velocity (hemovelocity) was recorded using the transcranial Doppler ultrasonography. A shoot/don't-shoot decision-making task presented participants with threat/nonthreat stimuli in the form of bull's-eye images of various colors.