An inexpensive real-time microcomputer-based cognitive laboratory system

A computer system, based on the Radio Shack Color Computer, for running experiments in cognitive psychology is described. The system was designed according to the following principles: first, all of the equipment should consist of inexpensive, off-the-shelf components; second, the language used to implement experiments should have real-time commands embedded within the character strings to be displayed, and these real-time commands should be interpreted at run time; third, the system should serve multiple subjects, yet one host should be able to run display terminals for several subjects on independent experiments; and fourth, the system should be able to interface to other display devices and other response-recording devices. Two examples of other devices are discussed: an oscilloscope for rapid visual display and an Apple Macintosh for display of pictures.     

The presentation of visual stimuli: An inexpensive microcomputer-based system

The presentation of visual stimuli and subject response recording are integral to many experimental paradigms. A microcomputer-based video display system is described that is extremely versatile and less expensive than slide projector systems.     

An inexpensive reinforcement dispenser

An inexpensive (less than $35) solid food reinforcement dispenser was developed using commercially available parts for commonly found vending machines. This device proved to be reliable and efficient in repeated use with laboratory primates in a video task testing situation.     

An inexpensive contact-sensing device

A detector is described that utilizes phase-shift techniques for the measurement of contact responses.     

An inexpensive retraction mechanism

An electric retraction mechanism, which is adaptable to a wide range of operant manipulanda, was developed. Miniaturized, inexpensive toy railroad equipment was used to simplify construction. The mechanism, utilized as a retractable rat lever, has operated reliably and uniformly over a range of independent retraction and extension times.     

An inexpensive liquid dispenser

An inexpensive liquid reinforcement dispenser was developed from a commercially available automobile windshield washer fluid pump. When tested on laboratory primates, this device proved to be as efficient and reliable as far more expensive models.     

An inexpensive pure-tone pattern generator

A low-cost sound pattern generator that is remotely programmable has been developed to produce pure-tone auditory patterns. The device, which is compatible with relay programming equipment, can generate either of two auditory patterns in the sequence ABA or BAB. The generator features an independently settable range of ON and OFF durations (0.1 to 1.0 sec) for pure-tone bursts and a selectable range (0.2 to 2.0 sec) of intercycle intervals. The inexpensive construction cost coupled with the flexibility of the timing characteristics of the generator should make it of interest to a wide variety of auditory researchers.