At times, we've all been so engrossed in a task that we've lost awareness of our surroundings. Maybe you didn't hear someone calling your name when you were finishing your paper, or maybe you missed the oven timer when you were reading that mystery book. Now researchers Sophie Forester and Charles Spence have reported that concentration impacts our sense of smell. Here's how the research was described on the APS website:
They set up a room to be distinctively aromatic, hiding three small containers of coffee beans around the room overnight. Over the course of two experiments, they led 40 college students into the room one at a time to perform a tough visual-search task on a computer, finding the letter “X” or “N” in a circle of similar-looking letters (“W,” “M,” “K,” “H,” “Z,” and “V”). 40 other students completed an easier version of the same task; searching for the letter “X” or “N” among a circle of lowercase “o”s. [Students had been randomly assigned to either the difficult or easy task.]
The experimenters then took the students into another room and asked them some follow up questions that grew increasingly leading :
- “Describe the room you just completed the task in. Try to describe it using all of your senses.”
- “Did you notice any odors in the room, if so what?”
- “Could you smell coffee in the room?”
Students assigned to the difficult search task were far less likely to report having picked up the aroma (25% of participants said they noticed a coffee smell) compared to the participants assigned to the easy task (60%-70% percent of participants). When the experimenters led the students back into the test room, all of them said they could smell it. Some of them even commented that the room smelled like a cafe.
- What kind of study was this--experimental or correlational? How do you know?
- What was the independent variable? What was the dependent variable?
- Think about construct validity: What do you think of the way they measured their dependent variable? Is this a good measure?
- Now think about statistical validity: How large does this effect seem to be? Take another look at the results and make a comment on the practical effect size.
- What about external validity? To whom might these results generalize? Do you think the pattern for coffee and letter detection might generalize to other smells? To other tasks?
- Now consider internal validity. The authors claim that it was concentration that caused people to not notice the smell. Can you think of any confounds in this design?