ICE 2: Rat Empathy

ICE 2: Is this rat empathy?

            In this exercise, we were presented with a study that tested rats for their level of empathy.  First, we must agree on a definition of empathy, that is, to overcome personal fears in order to help a fellow species in a dangerous situation recover from or escape from the dangerous situation.  The focal rat was put in a variety of situations in which a decision must be made.  A fellow rat hereafter referred to as Bob, was caught in a trap.  The rats had to adjust to their own fears of entrapment, but after a certain period of time passed, Bob was usually freed.  Bob was then set against several variables, and the outcome was measured. Overall, the study found that rats do show some level of empathy.  (Certain aspects of the study will be addressed throughout the hypothesis and experiment.)

            Hypothesis 1: The rats exhibit clan (kin) selection, which implies the focal rat will help their kin companion in order to increase the fecundity of their clan.  This dictates that group selection is the driving force behind the rats’ behavior and leads to variance in rat empathy levels.

            Hypothesis 2: Rats do show some level of empathy; however, this must be approached from a “rat” definition, and not a “human” definition, of what is empathy.  To understand this dilemma, we analyzed the information we were given.

(1) The focal rat choses to free Bob and to eat chocolate chips equally. (2) The rats always choose to eat chocolate chips or to free Bob over an empty trap. (3) Over time, the focal rat was able to learn, leading to a faster reaction and less fear-showing behaviors when facing trapped Bob.  From this, we can define rat empathy, but first we must test for a variable not addressed in the experiment.  Is Bob a potential mate?  If the focal rat frees Bob of the same sex equally or greater than that of Bob of the opposite sex, then we can assume rats show empathy as defined above.  If the focal rat frees Bob of the same sex less than Bob of the opposite sex, then we can conclude that mate choice is the driving factor in the focal individual’s behavior.

            Experiment regarding Hypothesis 2:  There is a 50% chance that Bob is a potential mate.  The focal individual is either male or female and Bob is either male or female.  Because there is only one focal individual, and we know the sex of that individual, the only variable that matters is Bob’s sex giving us 50% potential for a mate.  For this experiment we will run several variables for the focal individual: Bob of opposite sex, Bob of same sex, pregnant Bob, not pregnant female Bob.  For our control we will also use an empty trap and a toy rat. We will also include the presence of chocolate chips and no chocolate chips in a separate trap from that containing Bob.  Each rat will be tested randomly, but will face all variables.  The rats will be fed prior to each test approximately two hours before each test.  This ensures that the rats are not hungry, but still may choose to eat a chocolate chip.  This set-up can be seen in Figure 1.

Treatment	Sex of Focal Individual	Sex of Bob Trap 1		Control Trap 1	Chocolate Chips Trap 2
1	Male	--------		Empty	Yes
2	Male	--------		Empty	No
3	Male	--------		Toy	Yes
4	Male	--------		Toy	No
5*	Male	Male		--------	Yes
6*	Male	Male		--------	No
7**	Male	Pregnant Female		--------	Yes
		Female	No
8**	Male	Female	No	--------	No
9***	Male	Female	Yes	--------	Yes
10	Male	Female	Yes	--------	No
11	Female	--------		Empty	Yes
12	Female	--------		Empty	No
13	Female	--------		Toy	Yes
14	Female	--------		Toy	No
15**	Female	Male		--------	Yes
16	Female	Male		--------	No
17*	Female	Female		--------	Yes
18*	Female	Female		--------	No
		Figure 1: Experimental design for Hypothesis 2

*If Bob is freed, then the focal individual shows empathy as defined by Hypothesis 2.  However, if the focal individual chooses to eat chocolate chips at a rate of greater than 50%, then no empathy is shown.

**In these treatments, we expect the focal individual to choose a potential mate over chocolate chips.  This would support our hypothesis.

***In these specific treatments, the focal individual faces a trapped pregnant female.  If the rate at which she is freed is much greater than the rate at which the focal individual chooses chocolate chips, then the focal individual shows empathy.  In this specific case, the female is not a potential mate due to her pregnancy.  When rats mate, the male leaves a sperm plug at the opening of the vagina so that no other male can mate with her.  This assures that the female’s offspring are also his offspring. (Learned from working in Dr. Rasco’s lab.)  The focal individual would have no other reason to free Bob, thus showing true empathy.

            From the experimental design we have three expectations: (1) if Bob is the same sex as the focal individual, the focal individual will choose chocolate chips, (2) if Bob is the opposite sex as the focal individual, the focal individual will choose to free Bob on the basis that he/she is a potential mate, and (3) regardless of sex, the focal individual will choose to free Bob in the absence of chocolate chips.  Any unexpected ratios (greater than 50%) from expectation (1), rat empathy is shown.

            We chose to add something that was not addressed in the original experiment, that is, what affect does the sex of Bob have on the focal individual?  We originally hypothesized that the focal individual will free Bob of the opposite sex based on mate potential, but there are other interesting factors to look out for.  These were used in the original experiment.  Does the sex of Bob change the stress levels in the focal individual?  Does the focal individual learn more or less quickly based on the sex of Bob?  Does the reaction time of the focal individual change with the sex of Bob?  In this experiment, these values will be measured and recorded against each other to look for any trends.  I would expect that the focal individual, especially if male, would show greater stress levels in the presence of the opposite sex, but would be able to adapt more quickly and respond appropriately (free Bob!).

            Overall, I think rats do show empathy, but gender must be addressed to get a clearer picture of what drives the choices made by the rat under study.  This was a great exercise in morality of animals, and will most likely be addressed further in my portfolio on our obligation to psychopaths.