We designed a study to test whether or not a rat will work for exposure to another rat at the same degree to which the rat worked while receiving food reinforcement. We labeled this exposure as social reinforcement.
After conditioning the rat to run through a tunnel, we measured the average response time per trial while the rat received food reinforcement. We discovered that the conditioned rat completed the trick with an average response time of 5.2 seconds per trial over four days of baseline measurements.
Then, we phased out food reinforcement and gradually introduced 15 seconds of exposure to another rat. We phased out the food in intervals of seven. For example, the conditioned rat received food six times and was exposed to the reinforcer rat once. This interval was repeated three times. Next, the conditioned rat received food five times and was exposed to the reinforcer rat twice. This interval was also repeated three times, until the conditioned rat was receiving no food reinforcement, only exposure to the reinforcer rat.
We found this study particularly interesting because of the various types of social reinforcement offered. The experimenters allowed rats visual contact, partial physical contact, or full physical contact when being conditioned. Interesting, the researchers found that while all the rats who had been reared together learned the trick, the rats who had been reared alone learned better based on the amount of contact they were allowed with the reinforcer rat. Also, the rats exhibited more response behavior the more physical contact they were allowed with the reinforcer rat.
This article describes a study in which rats were operantly conditioned using social interaction with a human being as reward. The conditioning was successful for half of the rats, specifically it was successful for the rats who had experienced social interaction prior to the study. The authors suggest that social interaction could be a useful addition to behavioral training, and a possible confound to be aware of if experimenters do not control for it.
Evans, M. J., Duvel, A., & Funk, M.L. (1994). Social reinforcement of operant behavior in rats: A methodological note. Journal of the Experimental Analysis of Behavior, 62, 149-156.
Although this was an article we had discovered previously, we found an interesting portion of the Discussion section worth re-visiting. As we discussed in class, we were curious as to the possible confounds of us, as experimenters, handling the rats. This is a social interaction all its own, and could serve as reinforcement. The authors of this article stated similar potential problems. They discussed the fact that disadvantages to their design could include that the experimenters’ handling of the rats could have been a distraction, a cause for emotional distress in the rats, or could have provided unintentional reinforcement.
Thierse, H.R. & Angermeier, W.F. (1982). Variables of social deprivation in albino rats. Zeitschrift für Tierpsychologie, 59, 211-228.
In this study, adult male rats were operantly conditioned to press a bar. As reinforcement, they were allowed to view another rat. Before the study took place, various groups of rats were kept socially isolated for periods of 0, 10, and 30 days. The experimenters discovered that rats exhibited the highest rates of response the younger the exposure rat, when the conditioned rat had been socially deprived, and when the conditioned rat lived in a single cage (versus living with the exposure rat).
Vallortigara, G., Cailotto, M., & Zanforlin, M. (1990, December). Sex differences in social reinstatement motivation of the domestic chick (Gallus gallus) revealed by runway tests with social and nonsocial reinforcement. Journal of Comparative Psychology, 104(4), 361-367.
This article experimenters trained male and female chicks to run down a hall to reach a box that contained either another chick (social reinforcement) or food (nonsocial reinforcement). Results revealed that female chicks ran faster to the social reinforces than the male chicks. The experimenters hypothesized that the reason for the difference among the sexes is perhaps the idea that social reinstatement tendencies are stronger in females than in males.
New Refrence! November 20, 2007
SALAZAR, J. (1968). GREGARIOUSNESS IN YOUNG RATS. Psychonomic Science, 10(11), 391-392.
Th above reference appears that it may be very helpful for our experiment. It is a new reference that we have not previously posted, which is very exciting to be able to find more information on our experiment! The article describes how young rats (11 weeks and younger) do better in a task when reinforcement is social, which is exactly what we are trying to test! However, the experimenters used younger rats and we do not know the sex of the rats used. Another difference is the rats used in the experiment were occasionally kept in isolation as well, in-which our rats are not kept in total isolation but are not able to have any contact with one another. The article appears to be helpful despite the small differences.
Baseline, Day One. November 15, 2007
Today Penguin ran through her tunnel 80 times in 25 minutes! After she ran through, we removed the tunnel for 15 seconds to simulate the amount of time we will remove the tunnel when Stella is introduced as reinforcement. Penguin was allowed 30 seconds to run through the tunnel; if she hadn’t gone through after 30 seconds, the tunnel would be removed. Luckily, Penguin is so quick that we didn’t have to do this a single time!