Question

One recent study, conducted in Hungary, trained 13 dogs to lie perfectly still in a functional MRI machine. After being trained for several weeks, the canine participants donned doggy headphones and heard different words pronounced in different tones of voice.

Here's how the CNN journalist described the study: The study involved 13 dogs -- golden retrievers, border collies, a German shepherd and a Chinese crested -- who were trained to lie down and remain still for more than seven minutes while in a brain-scanning MRI machine. The researchers used the machine to record and measure neural activity in the dogs' brains while they listened to a woman trainer, whom they were familiar with, recite various words in various intonations. For instance, positive or meaningful words such as "well done," "good boy" and "clever" were said in both a praising intonation and a neutral intonation. Neutral or meaningless words, such as "even if," "although" and "however," also were said in both intonations.

Only when a praise word was spoken to the dogs in a praising tone of voice did the brain's reward center light up like a Christmas tree in the brain scans. The reward center is the part of the brain that responds to pleasurable stimuli, like food treats or being petted.

Q1: What was the dependent variable, or DV, mentioned in the excerpt above?

Q2: Sketch a graph of the results that the journalist described. (Hint: Put the DV on the y-axis, as usual. Pick one IV for the x-axis, and another IV for different-colored dots or bars.) Inspecting the graph you created, is there an interaction in these data? What about each main effect--would you predict they would be significant?

Answer 1

Answer to question# 1)

(Since there is no numerical data provided for the variables, working on second question is not possible)

The dependent variable is the variable in which the response of the dog's brain is being observed by the brain scanning MRI machine. The response of the reward center to the various words and different intonations is recorded. This response is the dependent variable here.

The aim is to see if the response variable (reward center) gives any response for the the different combinations of different words and different intonations.