Posts from the ‘psychology’ Category


All vertebrates’ eyes emerge from a single group of cells, called the eye field, located in the middle of the brain. The eye field cells evaginate to form two optic vesicles, which eventually give rise to two retinas, one on either side of the brain.

Eyes Emerge

Top image: In a ~5 somites embryo, eye field cells are stained red, and forebrain cells are outlined in green (upper left). A few hours later, in a ~10 somites embryo, the eye field (green) separates into two optic vesicles. At the same embryonic stage, the dorsal telencephalon, which sits atop the evaginating eyes, is labeled blue (bottom left). In both of these images, a midline positioned cross outlines the apical surface of the optic vesicles and the ventricular space. The animation follows the development of this same surface as the eyes emerge from the brain.

Sunrise in the Eye

Bottom image: Once the basic shape of the eye is specified, cells within the optic cup differentiate, populating the retina with neurons that sense light and refine the visual information before it is transmitted to the brain. In fish and amphibia, retinal stem cells are maintained throughout the animal’s lifetime in a stem cell niche located adjacent to the lens (yellow). Here in situ hybridization of a zebrafish eye (from a ~ 3-day-old larva) reveals gene expression patterns that distinguish retinal stem cells (red) from the cells that are becoming neurons (purple). By comparing gene expression patterns within the retinal stem cell niche in normal and mutant eyes, we gain insight into how stem cells turn into neurons.

Eyes are not only amazingly complex, but are reducibly so!

Life for the winner is more glorious. It enters the next round of competition with already elevated testosterone levels, and this androgenic priming gives it an edge that increases its chances of winning yet again. Though this process an animal can be drawn into a positive-feedback loop, in which victory leads to raised testosterone levels which in turn leads to further victory.

The science of “the winner effect” and why success breeds more success. (via explore-blog)


Neuroscientist David Eagleman, author of the excellent Incognito: The Secret Lives of the Brain, explains the curious neurological wire-crossing of synesthesia. Complement with a synesthetic person’s first-hand account of the experience.

It seems today’s Tumblr theme is synesthesia. No complaints!


A neuronal kiss

A basket cell kissing a pyramidal cell
from the Blue Brain Project
-by Henry Markram

Researchers at UCLA have been studying the effect of music on human emotions. Specifically, what emotions dissonant (harsh, jarring, inharmonious) music invokes in us. They found that distortion and sharp changes in frequency generally made us feel more excited and carried negative emotions. It’s why rock music makes us so excited and the sound from the shower scene in Psycho is so scary. 

“This study helps explain why the distortion of rock ‘n’ roll gets people excited: It brings out the animal in us,” said Bryant.

As an explanation, the group believes that distorted music brings up the long-engraved fear and excitement rush of hearing an animal in distress. Most distress calls involve a sudden, unnatural expulsion of air through the voice box. The result is a distorted version of their normal sounds.

Jonah Lehrer has a post about how our mental shortcuts and unconscious bias can fool our conscious decision-making process. Here he reports on some new research that suggests more intelligent people could be extra prone to these blind biases:
Perhaps our most dangerous bias is that we naturally assume that everyone else is more susceptible to thinking errors, a tendency known as the “bias blind spot.” This “meta-bias” is rooted in our ability to spot systematic mistakes in the decisions of others—we excel at noticing the flaws of friends—and inability to spot those same mistakes in ourselves.
Logical thinking would lead you to believe that intelligence would make you less susceptible to errors of thought. But, either through conscious or unconscious means, the higher our level of intelligence the less we are able to identify errors in our own thought process. More at The New Yorker. By the way, this dovetails nicely with recent research on why we deny science. While the knee-jerk reaction would be to assume that less education leads less belief in science (evolution, climate change, etc.), it is becoming clear that more education and possessing tightly-held moral values can actually reinforce incorrect ideas, a bias of confirmation. 
Humans are constantly attempt to go past our boundaries, and it seems that the more we do so the less we double-check ourselves. This should serve as a lesson to be careful all the time, no matter how smart you are, and not to dissuade you from pushing yourself to achieve new things!

Why Smart People Are Stupid