Budding Bug Blog
Cockroaches as Little People
Cockroaches as Little People

Cockroaches as Little People

A few months ago, I acquired three Madagascar hissing cockroaches, which I can see sleeping in their tank at the foot of my bed right now. Many of my friends and family members were viscerally upset when I told them about my new pets, but they’ve definitely grown on me. When people think of cockroaches, we often think of disgusting vermin that we may find in 1-star restaurants and hotels – could they really have a purpose in this world? Turns out, they’re more similar to people than we may have guessed.

A Madagascar hissing cockroach in terrarium

One of my Madagascar hissing cockroaches, Mona. Somewhat relevant to this article is the psychology textbook in the background.

Parker Smale – Mona’s Tower – Personal Collection

One thing that makes cockroaches extra scary is that they can fly. This may be the reason why Blatta orientalis, a flightless species, has been used for so much research. A field-shaking study from 1969 used these cockroaches to replicate and put context to research done on social facilitation in humans. Prior to the experiments run by Zajonc, Heingartner, and Herman (1969), the effect of being observed on someone’s performance was not clear – some studies showed that people performed better when they were being watched, while other studies found the exact opposite. In order to try to standardize their results as much as possible, Zajonc and his colleagues decided to use insects that they could monitor and raise in a lab environment.

Social Facilitation – A change in performance due to the presence of others

The experiment involved placing a cockroach into a tunnel and timing how long it took for it to reach the exit. There were two tunnel options – no intersection (a straight hallway) and intersection (four tunnels joining at an intersection). Additionally, cockroaches could either be surrounded by other cockroaches, which were held in glass boxes outside of the tunnels, or could be along. Overall, the experiment had four conditions – No intersection/No audience, No Intersection/Audience, Intersection/No Audience, and Intersection/Audience.

Diagram showing the two experimental conditions

Above is the general set-up of the experiment – cockroaches would either be put into a simple hallway or into a more complicated intersection (green), where they may or may not be surrounded by other cockroaches in audience stands (yellow)

Parker Smale – Original illustration based on Zajonc 1969

The results of this experiment shined some light on why scientists had been finding such mixed results when studying social facilitation – it was found that having observers made cockroaches faster at finding the exit only when going through the simpler hallway, not when going through the more difficult maze condition. These results supported the hypothesis that social environments increase our general level of arousal or excitation. It is thought that this increase of arousal is good when we know what we’re doing, but can sort of psych us out when we’re less certain or less practiced, a theory that explains why professionals might perform better than usual at competitions while amateurs might perform worse.

Insects are more like humans than many of us believe, something that is clear by how much research is done on insects such as Drosophila, which can be used as model organisms. If you take a closer look at the bugs in your garden (or in your home), then who knows – you might just see a little bit of yourself.

Resources and further reading:

Social enhancement and impairment of performance in the cockroach (Zajonc, Heingartner, & Herman)
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