Concurrent counting of two and three events in a serial anticipation paradigm

Abstract

Rats were runway trained with four different series of reward events for the purpose of determining if two different number cues (two and three) could be adequately employed to correctly anticipate a terminal nonreward in the series. In two of the series, two rewarded runs always occurred prior to terminal nonreward; one of these series always began with a nonrewarded run, NRRN, and the other did not, RRN. For two other series, three rewarded runs predicted terminal nonreward, NRRRN and RRRN. Each rat experienced each of the four series once a day for 26 days. The interval between runs within a series was about 20 sec, the interval between series was about 15 min, and the order in which the series were presented was randomized daily. Distinctive floor cues (smooth/black or rough/white, balanced over animals) signaled two-count and three-count series. Our animals correctly anticipated (ran slowly to) the terminal nonreward of all four series. On Day 27, an initial nonrewarded run was added to the two series that had been initiated by nonreward <NNRRN and NNRRRN). This addition produced a disruption in terminalevent anticipation that lasted for only 1 training day. In all, the results imply that the animals were concurrently counting both two and three rewarded events, and it is further suggested that counting plays a prominent role in the rat's serial learning.

"Counting" by pigeons: Discrimination of the number of biologically relevant sequential events

“…For example, Burns and Sanders (1987) asked whether rats can be cued independently to enumerate a different number of reinforcements depending on the context of the series. They trained rats on an alternating series of RRN and NRRN under one level of illumination, and RRRN and NRRRN under a different level of illumination, and they found that in both conditions the subjects learned to run more slowly on the last trial.…”

An Attempt at Blocking of Position Learning by Training with Reward-Memory Associations

“…Possible sources of position cues have been reviewed elsewhere (e.g., Burns et aI.,2(04). Briefly, we might imagine position cues being based on an intE~rnal representation of the series positions (0 ' Amato, 1991), or the animals might somehow count the trials or rewards in a series and use number to tag the ordinal positions (Burns & Sanders, 1987;Capaldi & Miller, 1988). Another interesting possibility is that position-learning effects arise from the development of response patterns (Burns et aI., 2004).…”