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Human sexuality turns out to be quite complex and has a strong biological component to it, as well as cultural.


Much has been learned about human sexuality over the past 50 years. Four components are often identified in determining your sexuality: 1) whether you have male or female genitals; 2) who you are attracted to sexually (i.e. males or females); 3) how you "feel" internally (i.e whether you feel like a male or female), and 4) your outward expression of your sexuality (e.g. how you dress, behave, etc). The last 3 at least can have some culturally derived components too.

In most people, if they are female, for example, they have female genitals, are attracted to males, feel and think female in their brains, and outwardly will dress and behave as females in however their culture defines female dress.

But we now know that there are various combinations of these four that manifest in various kinds of gay and transgender people. For example, a transgender male with male genitals might internally feel like a female, be attracted to males sexually, and outwardly want to dress like a woman or perhaps even a man.

So, the way we think and our sexual drive is partially determined by our biology, but also seems to have a cultural component to it as well.


The action potential (electrical impulse) is pulled along the cell by positive ions entering and attracting it before leaving again.


An action potential is the electrical signal that travels down the neuron cell.

The electrical signal is negatively charged, because it is, obviously, electrical. It is drawn along the neuron by a series of positive ions appearing in front of it and pulling it forward. Imagine if you tied a string to a ten pound note and pulled it along the street with a cartoon character chasing after it - that's how I like to think of it.

The inside of the neuron cell is normally negatively charged relative to the outside. Ion channels open when the electrical signal enters the cell and pump #Na^+# ions inside, which attracts the electrical signal along the cell.

Since the cell is normally negative, or polar, the influx of positive ions is known as a depolarisation, because it turns the cell more positive in that area. However, once the cell has reached a certain level of depolarisation, the #Na^+# supply cuts off and the cell begins pumping #K^+# ions out of the cell instead. This turns the cell back to negative, causing a repolarisation.

While this is happening, some of the #Na^+# spreads out and changes the charge slightly further along the cell, which activates more sodium gates and lets sodium flow in further along, which depolarises that segment of the axon and pulls the electrical signal even further along.

The series of depolarisation and repolarisation along the cell makes the action potential move down the axon.

When an electrical impulse reaches the synapse, it opens calcium channels. The calcium enters and causes vesicles (bubbles) of neurotransmitters to bind to the membrane and release the chemicals. The neurotransmitter molecules drift across the synapse and bond to receptors on the next neuron, which initiates the electrical signal and the process of de- and repolarisations repeats.


In Maslow's hierarchy of human needs, self-actualization was supposed to be the pinnacle of human needs. Current research does not support this hierarchal approach, nor that self-actualization is at the top.


Maslow developed his theory of human needs in the mid-twentyth century as a hierarchal pyramid - 1st and most important stuff at the bottom, working your way up to self-actualization at the top. The model was used extensively, especially in educational learning settings.

However, model social psychology recognizes that some of the elements in his hierarchy are important (like food, shelter, etc.). However, it is no longer thought that that a hierarchal pyramidal type structure is valid. Its now thought to be more of an interconnected network of factors that should be present to satisfy needs. See pic.

The idea of "self actualization" is also not considered to be a "core" need any more, but has been replaced by other factors. image source here


Perceptual set is a tendency to perceive or notice some aspects of the available sensory data and ignore others.


Our bodies are magnificent machines. One of the ways they demonstrate this is by taking repetitive motions and actions and reducing the resources needed to perform them. For instance, when a baby is learning to walk, each step is planned and performed. But after a relatively short period of time, they are running without giving it a thought - they just run (and run and run and run...)

Our brains do the same thing. The world is full of information that continually enters our senses. In order to speed up processing time and reduce the energy needed to perform those functions, it operates largely on what is expected and not necessarily on what is actually there.

And that is what Perception Set Theory gets into - how the brain "perceives" - or as the below link describes it - "Perceptual set theory stresses the idea of perception as an active process involving selection, inference and interpretation."

Perceptual set is a tendency to perceive or notice some aspects of the available sensory data and ignore others. For instance, have you ever seen this:

Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.

The brain doesn't read every word but instead selects out important bits and teases out the rest based on expectation and inference.

Another kind of perceptual set is when we have a fear of snakes, to automatically assume that every suspicious looking thing in the grass is a snake - even though most times we're looking at a garden hose.

There are a number of ways perception sets can change. If we're hungry, the perception set will tend to look for food over other things.

The link has a great article about perception sets.

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