Discrete-trial alternation in the rat.
Short gaps between trials speed up alternation learning; long gaps slow it down.
01Research in Context
What this study did
Scientists taught rats a left-right lever game.
Each trial, the rat had to press the opposite lever from the last one.
They tested how fast rats learned when the pause between trials was 0, 5, 10, or 20 seconds.
They also watched what happened when the rule suddenly changed.
What they found
Rats mastered the simple every-other-lever rule fastest with no pause.
Longer pauses slowed learning.
When the rule flipped without warning, the rats made a quick burst of mistakes, then caught on.
How this fits with other research
Porritt et al. (2009) later showed the same pause-hurts-learning rule works with children doing matching tasks.
KIEFFETHOMAS (1965) had already seen rats pause longer before tougher alternation ratios; Sachs et al. (1969) added that extra pause time itself hurts speed.
Raslear et al. (1992) seemed to disagree—longer pauses cut sensitivity in a timing task.
The clash disappears when you see the tasks: alternation needs fast rhythm, timing needs memory, so pauses help one and hurt the other.
Why it matters
Keep drills rapid and tight when you want a learner to chain responses.
Start with a simple back-and-forth pattern, then stretch the pause only after the rule is solid.
If you must change the rule, expect a brief error spike and stay calm—it will pass.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Cut inter-trial pauses to one second when teaching a new left-right sequence.
02At a glance
03Original abstract
The acquisition and maintenance by rats of single alternation, double alternation, and four other repeating patterns of reinforced and non-reinforced trials was studied in a discrete-trial lever-pressing situation. The rats learned all these patterns in a small number of experimental sessions. Single alternation was learned more rapidly than the more complex patterns. Rate of learning single and double alternation decreased moderately as inter-trial interval increased. Abrupt changes in the scheduling of trials, either by doubling the inter-trial interval or by shifting from fixed to variable trial spacing, temporarily disrupted the patterned performance. Two hypotheses concerned with the means by which the rats could have learned to conform to the pattern were examined: (1) "timing" of the interval between successive reinforcements; and (2) control of responding on a trial by the outcome of preceding trials, depending on the consistency with which these outcomes were associated with reinforced or non-reinforced trials in the pattern and on how many trials back these outcomes occurred. The second hypothesis accounted for the relative frequency of errors on trials at various locations in the sequences, and predicted most of the changes in error frequency observed in experiments in which "inter-trial stimuli" were added to the sequences.
Journal of the experimental analysis of behavior, 1969 · doi:10.1901/jeab.1969.12-609