(A) Photo-ionizer detector (PID) measurements of the TOMs and their components at several delays. PID location was close to the tube carrying odor A (red) and therefore reports only odor A. Recordings were made using the exact same parameters as in the psychophysical experiment. Red and blue rectangular triggers denote the valve-opening signals of odor A and B, respectively. The top row shows PID response to an AB TOM, whereas the bottom row shows the same for a BA TOM. Black trace and gray shading are the mean PID responses and their standard error (SEM; N = 10). PID responses are normalized to a maximal value of 1 and are denoted in arbitrary units (A.U). Time 0 is the time of first valve opening per TOM. The mean latency between trigger onset and the time at which PID response reaches 10% of the maximal value is marked by a dashed black line. Left, center and right panels depict a time delay (Δt) of 75, 150, and 300 ms between TOM constituents, respectively. Within each panel, two scatter plots are overlaid: latency (red, the time it takes the signal to reach 10% of its maximum) and Δt (purple, the time of the second odor pulse). In each plot, the mean and SEM 95% confidence interval are displayed in black and gray, respectively. Individual data points per trial (N = 10) are also shown. Mean ± SEM values also appear as text below the plots. (B) The same as panel (A), but for PID location within the pipe carrying odor B (cinnamon). (C) The same as panels (A) and (B) but for a PID location 5 cm away from the joint location of the odor ports, to mimic the average location of the participants’ nose. At this location, the PID registers signals of both odors. Note that in order to account for the difference in PID response between odorants, here plotted together, the mean latency between trigger onset and the time of PID response was measured for the time taken to reach the 5% of maximal value.