Empathy and Isolation: Living Vicariously

     Our class, like many individuals are in the field of animal psychology, was divided as to whether or not the study conducted by Bartel et al. (2011) Actually measured the cognitive process it intended to support: Empathy. One of the most important aspects of an experimental design is validity: that the test conducted actually measures the aspect the researcher(s) are trying to support or reject. However, While Bartel et al. conducted an interesting study, the validity of their design was not nearly as well implemented as the study conducted by Panksepp & Lahvis (2016).

     As  you may recall, Bartel et al. (2011) conducted an experiment in which rats released a fellow cage-mate from a retainer as a test of empathy. While the video made the study appear to support the idea of empathy in rats, the article and further research conducted by Professor Manor painted a different picture in which the rats were more than likely responding to something they were conditioned to do. This significantly lowers the validity of Bartel et al.'s design, and the implications of the study.

     Contrarily, Panksepp & Lahvis (2016) designed an experiment to test the capacity of mice for empathy. This design assessed empathy in the context of how empathy is affected by socialization/isolation, sex of subject, and vicarious/direct conditioning to a stimulus.

     Shortly after weaning, mice were randomly assigned to housing conditions of either isolation, in which either a male or female mouse were housed alone, or social housing, in which two males and two female mice were housed together (Fig. B) (Panksepp & Lahvis, 2016). The mice were then conditioned with two experimental conditions and two control conditions. In the first of the two experimental conditions (vicarious condition), a mouse was placed in chamber through which they could observe two novel mice in separate adjacent chambers separated by an opaque piece of plexiglass. The two novel mice received fear conditioning, during which a tone (CS) was played and a scramble shock (US) was administered. The observer mouse itself never received a shock.

     In the second of the two experimental conditions (direct condition), a mouse was placed into the chamber by itself, and directly received the fear conditioning of both tone (CS) and shock (US). The two control conditions were the same as the experimental conditions, save that no mice ever received the scramble shock (US) only the tone (CS). These four groups were performed on both socially raised mice and isolation mice as either the observer or the direct target of the conditioning. The results included only the experimental conditions accounting for a difference in the sex of the observer/direct target mouse for a total of eight groups (isolate-direct-male; social-direct-male; isolate-direct-female; social-direct-female; isolate-vicarious-male; social-vicarious-male; isolate-vicarious-female; and social-vicarious-female).

     The actual testing began where every mouse regardless of condition, sex, or housing were presented with the tone (CS) fifteen minutes and twenty-four hours after conditioning to assess the effects of the conditioning on short and long term memory respectively. The response to conditioned fear was assessed by the number of freezing behaviors each mouse displayed when the tone was played, with freezing being described as complete absence of movement other than respiratory movements, and was assessed with computer-assisted software.

 

     A significant main effect of housing was found (Panksepp & Lahvis, 2016). Compared with 15-min postconditioning, CS-induced freezing was more sensitive to housing conditions of mice at the 24-hr testing, and socially housed mice expressed higher levels of freezing than isolate mice in all conditions except the male-direct. Female mice were also more likely to display freezing behaviors than the male mice.

     Results of the study supports the idea that mice in the vicarious model of fear conditioning display some basic characteristics of empathy. This is emphasized by the defining of empathy. Where Bartel et al. (2011) defined empathy in the context of prosocial behavior, behaviors meant for the benefit of another organism, Panksepp & Lahvis (2016) define empathy as the expression of an affective response more appropriate to another’s situation than to one’s own. This distinction is vital to the validity of the test because while the former definition does not require the emotions of the prosocial be involved, the latter definition does, which is a vital aspect of empathy. The mice clearly show this in the vicarious condition where while the observer mice were never directly shocked, they still freezes when the tone (CS) is played. This response, being a more appropriate affective response to the situation of the two novel mice who were shocked, displays the fundamental principle of empathy. 

     While the study by Bartel et al. (2011) is controversial and debatable as the the validity to which the experimental design measures empathy, the design by Panksepp & Lahvis (2016) is more valid. From reading the article, the design seems to be a valid way to measure empathy, and is strong support for the assertion that mice do possess basic aspects of empathy.

 

References

Bartel et al. (2011). Empathy and Pro-Social Behavior in Rats. Science, (344). doi:

     10.1126/science.1210789

Panksepp & Lahvis (2016). Differential Influence of Social Versus Isolate Housing on Vicarious Fear

     Learning in Adolescent Mice. Behavioral Neuroscience, (130), pp. 206-211. doi:

     10.1037/bne.0000133