Methods & Figure 1
Why did they use the breathing cues? (Fig. 1)
To ensure that participants were breathing in the olfactory stimuli in a controlled manner.
What were the main findings of Figure 2?
The stress sweat condition activated the left amygdala relative to the exercise group in both the original experiment and in replication.
What were they trying to test?
If those exposed to stress sweat were more sensitive to subtle emotional cues in faces.
What is the definition of apocrine sweat?
It is emotion/stress sweat
Why did they use first-time tandem skydiving and running on a treadmill to obtain the sweat stimuli? (methods)
Skydive was controlled by the tandem-master so it was mainly emotional stress while running on a treadmill is mainly physical stress.
What was the main purpose of the experiments?
To ensure that the amygdala activation differences in response to stress vs. exercise was due to the "engagement of emotional processing" rather than the perception of different odors between samples.
Why did they need to use the GCMS? What were they looking for in their samples?
They used the GCMS because they needed to make sure they had the hydrophobic compounds of sweat that they were trying to test the effects of and make sure that they had actually produced stress sweat compared to exercise sweat.
What is the difference between original and replication groups? What is the purpose of having these two groups? (Fig. 2)
Original group was presented only sweat from male donors while the replication group was presented sweat from 50% male donors and 50% female donors. The purpose was to eliminate the possibility of reproductive chemosignals playing a factor in brain activation.
What did they conclude from the figures?
That there was the presence of hydrophobic molecules and that they contained molecules associated with apocrine sweat.
What is the difference between the findings of Figure 2 and Figure 3? Also, what was their reason for the increased activation in the cerebellum (Table 1)?
Figure 2 found that the stress sweat resulted in left amygdala activation and Figure 3 used full-brain activation maps to confirm that the differences in activation between the two conditions was pronounced in the left amygdala.
They reasoned that the increased activation in the cerebellum was most likely due to the participants focus on the breathing cues which required them to time their inhalation and exhalation to the rings and that stress made the visual cues more salient.
Why did they choose to analyze the breathing condition instead of the sniffing condition in this experiment? (Fig. 1)
Because the brain activation from breathing is more similar in time-course to emotional processing than that of the sniffing group, which is more similar to brain activity seen when processing olfactory stimulant.
What was the 3rd experiment they performed to confirm their findings from Figure 4 (not picture in figure 4)?
They also conducted a double blind forced choice discrimination experiment where 16 participants identified whether 16 test and control pairs were different or identical. Ratings were not significantly different from chance. Suggests that participants were not able to consciously distinguish between test and control odors.
What were the findings of Figure 5?
The slope of the curve became more steep (43%), which indicates that they were able to better discriminate between neutral/angry faces.
But there was no difference between inflection points, meaning that people were not more likely to assign a neutral face as threatening under the stress condition, but rather had increased accuracy in the evaluation of a threat.