An inexpensive digital millisecond timer and event counter

A simple circuit for a digital millisecond timer and event counter is described. The total cost of the unit including all components, a power supply, and an enclosure is less than $30. Daily use in simple reaction time experiments has demonstrated the reliability of the design.     

A technique for converting from intravenous drug self-administration to liquid reinforcement

A rapid inexpensive technique for changing from intravenous drug self-administration (DSA) to liquid reinforcement is described. Utilizing a standard peristaltic-type infusion pump typically used in DSA experiments and a specially designed drinking cup, the changeover from intravenous DSA to liquid reinforcement can be accomplished in a few minutes at a cost of less than $10.     

TRANSITIONS IN CHILDREN'S ROLES AND CAPABILITIES*

Stage theories and empirical studies have concentrated on a few periods of childhood (e.g., age 5 to 7 years) as important times of transition. On the basis of ethnographic suggestions that the age period 8 to 10 years also involves interesting changes, the authors carried out a search of published empirical studies for findings of transitions in capabilities at 8 to 10 years. An annotated bibliography is provided summarizing the studies found in a 5-year period in three journals. The authors discuss possibilities for characterizing the transition at age 8 to 10, as well as how such a transition meshes with the concept of stage.     

A set-theoretic random utility model of choice behavior

A random utility model of choice was developed by combining the basic ideas of the well-known theories of Thurstone and Restle. The new model has exactly the same number of free parameters as Tversky's Elimination-by-Aspects model. Furthermore, both models were found to fit, with equal accuracy, the data reported by Rumelhart and Greeno, and Tversky. It was concluded that although the two theories are not identical, they may be difficult to discriminate empirically.     

A voice-operated method for administering the MMPI

Paper/pencil psychological tests such as the Minnesota Multiphasic Personality Inventory (MMPI) are difficult to complete independently by patients with limited hand function. This paper describes a voice recognition system developed to allow patients with no hand function to take the MMPI independently. Profiles generated by this system are not statistically different from those generated by standard MMPI booklet format. Limitations and possible extensions of the system as it currently exists are discussed.