Iversen, I. H. (2002).
Response-initiated imaging of operant behavior using a digital camera.
Journal of the Experimental Analysis of Behavior,
77, 283-300.
A miniature digital camera, QuickCam;rm Pro 3000, intended for
use with video e-mail, was modified so that snapshots were
triggered by operant behavior emitted in a standard experimental
chamber. With only minor modification, the manual shutter button
on the camera was replaced with a simple switch closure via an
I/O interface controlled by a PC computer. When the operant
behavior activated the I/O switch, the camera took a snapshot of
the subject's behavior at that moment. To illustrate the use of
the camera, a simple experiment was designed to examine
stereotypy and variability in topography of operant behavior
under continuous reinforcement and extinction in 6 rats using
food pellets as reinforcement. When a rat operated an
omnidirectional pole suspended from the ceiling, it also took a
picture of the topography of its own behavior at that moment. In
a single session after shaping of pole movement (if necessary),
blocks of continuous reinforcement, in which each response was
reinforced, alternated with blocks of extinction (no
reinforcement), with each block ending when 20 responses had
occurred. The software supplied with the camera automatically
stored each image and named image files successively within a
session. The software that controlled the experiment also stored
quantitative data regarding the operant behavior such as
consecutive order, temporal location within the session, and
response duration. This paper describes how the two data types -
image information and numerical performance characteristics - can
be combined for visual analysis. The experiment illustrates in
images how response topography changes during shaping of pole
movement, how response topography quickly becomes highly
stereotyped during continuous reinforcement, and how response
variability increases during extinction. The method of storing
digital response-initiated snapshots should be useful for a
variety of experimental situations that are intended to examine
behavior change and topography.
Key words: response-initiated image taking, digital camera,
frame-by-frame analysis, response topography, response
variability, extinction, rats