By Reena Clements
“Magic mirror on the wall, who is the fairest one of all” says the evil Queen of Snow White and the Seven Dwarfs. I don’t deny that growing up on Disney gave me a somewhat skewed sense of reality at times. Wouldn’t it be nice to all have our own magic mirrors, constantly reminding us how wonderful and beautiful we are in the midst of the stress that is life?
A recent study by researchers at Cornell University have shown that we may actually have such a magic mirror – Facebook, as fate would have it. There are varying opinions concerning internet use on our personalities, but this study shows that Facebook can have a short term positive effect on self esteem. More
In Disney/Pixar’s “Finding Nemo,” Marlin and Dory are swimming through murky waters en route to Sydney Harbor. Marlin suddenly exclaims, “Wait, I have definitely seen this floating speck before. That means we’ve passed it before and that means we’re going in circles and that means we’re not going straight!” – and he is probably right.
Is it really possible that when we cannot see where we are going, we actually travel in circles? Souman et al. tested this belief through a variety of experiments. They found in all cases that when deprived of a visual stimulus, it is actually impossible to travel in a straight line.
The first set of experiments had participants travel through a wood without visual impediments (such as blindfolds). One set of subjects traveled through the woods when it was cloudy, the second set when it was sunny. All of the cloudy group walked in circles and walked in areas that they had previously been, without noticing they had crossed a previous path. In contrast, all of the subjects who could see the sun were able to maintain a course that was relatively straight and had no circles.
The experiment was also performed on blindfolded subjects in an open field.
The blue paths correspond to the subjects that walked on cloudy days. Their paths are mostly curved with many circles. The small straight areas of walking are most likely caused by the setup of the trial – participants walked for a period of time, then were unblindfolded and allowed to walk to the starting point of the next walking block. Even so, when blindfolded, lack of a visual stimulus when blindfolded always resulted in walking in curved motions or in circles. This contrasts the yellow path; this subject walked on a sunny day, and maintained a straight course for a long distance.
What causes this strange phenomenon? Could it perhaps be subtle differences in leg length that introduce a bias to walk in one direction, thus accounting for the circular motion? Nope – the circle directions were still random. Adding shoe soles to add a more than subtle difference in leg length didn’t make a difference: the participants continued to walk in random circles.
Perhaps the only explanation is that our vision is so necessary for our daily lives that our body randomizes without it. This idea is demonstrated in studies in which subjects are kept in a room with constant lighting: their biological clocks become completely randomized with no night and day inputs. More studies should be performed to truly understand the importance of the visual system. Since we rely so heavily on vision, is it natural for movements to become randomized without it? Do those who are blind from birth experience the same walking in circles phenomenon? For now, the conclusion here is that the sensory systems are complex and there is still much work to be done in understanding this strange phenomenon. So, if you ever find yourself lost in murky Australian waters, you probably should not just keep swimming, but rather, ask a friendly passing whale for directions.
Walking Straight into Circles – Current Biology
What would happen if humans were like turtles – alone at birth with no mom to guide them back home? We probably would not survive very long before getting attacked and/or eaten by something bigger than us. For many animal species, instinct guides survival. But for humans and other mammal species, nurture as an infant is crucial to our development.
Weaver et al investigated the phenomenon of nurture in rats. They noted that some rat moms extensively licked and groomed their pups, while others ignored their pups. Pups that received attention during the first week of life grew up to be happy and calm, while those that were ignored grew up to be anxious, and were more prone to disease. Epigenetics studies the genomic changes that occur in response to the external environment. The differences in behavior are due to a change in a glucocortocoid receptor (GR) gene during development. At birth, the gene is highly methylated and inactive. If a rat mother is attentive towards her pups, the pups’ GR gene gradually demethylates, making the gene more active. These pups will be more relaxed in response to stress. Those that were not given attention, and do not express the GR gene, respond poorly to stress. You can try being a rat mom in an interactive game here .
A related study by McGowan et al studied hippocampal tissue in humans that had committed suicide and been abused as a child, and humans that had committed suicide with no history of child abuse. When compared to controls and subjects that were not abused, the subjects that had been abused had decreased level of a GR protein. This shows that events later in life (such as those leading to a suicide) do not actually alter genetic makeup, rather, it is the early childhood interactions which cause epigenetic changes leading to adult behavior. These data are consistant with those of the rats and show the importance and effect of having proper nurture as a child.
But in reality, how important is it to be calm and controlled in response to stress? Rats are found in urban areas as well as in the wild.
What were to happen if one of the calm happy rats were to stumble upon a mouse (or, in this case, rat) trap? It would be less concerned about danger and be more likely to die, whereas an anxious rat would be guarded and could better survive the harsh environment.
What is the significance of these epigenetic changes for humans? Maybe living in a developed society has prevented us from realizing just how much nurture plays a role in development. Do those born into a war-ridden society have an inactive GR gene and thus a guarded and anxious personality? This is probably advantageous for survival.
In our society, we will of course never be left alone immediately after birth to fend for ourselves. But, what degree of nurture must we receive in order to grow up to be productive members of society? Why are species like turtles able to survive without a mom? Epigenetic studies will be key in future questions concerning nature and nurture.