Maybe I can elaborate on this a little. I agree, it is certainly perception rather than social psych', but boils down to how social living has affected our perceptual processes. Being social is extremely important to humans, and knowing who is looking at whom gives a lot of very useful information (you can reliably determine who is the leader of any group by measuring how often each person is looked at, and predicting that it is the one who is looked at most often). Knowing who is looking at oneself is even more important.
Therefore, we have a predisposition to pick faces out of even the most complex visual environments, and in particularly to infer where the eyes are looking. Our ability to do this is way beyond our ability to notice other visual cues that are objectively equally minor.
However, you may be talking about the experience of having a feeling that someone is looking at you even though they are behind you and you cannot see them. I doubt that there is much solid research on this, but I would conjecture that if you can do this at a greater-than-chance accuracy that you may be picking up on cues that are in your visual field, like the gaze of other people that you can see being directed towards the person who you cannot see, so that you may still be aware of where they are.
A couple of pieces of research to do with the innate predisposition to look for faces. (1) If a picture of a face is shown to even extremely young babies, they will look at it for much longer than they will for a similarly complex picture that is not of a face. (2) Research has been done to show that we can pick a smiling face out of a crowd of frowning faces almost "preattentively" - that is, without having to focus our attention on each face, the smiling face just "pops out" of the crowd. There was even evidence that it is even easier to pick out a frowning face from a group of smiling faces faster than a smiling face from a group of frowning faces, and the authors offered an evolutionary argument for this saying that we look out for more threatening expressions, and smiling faces are not as threatening as frowning ones. The stimuli they used were very simplistic 'smilies', so I'll try to recreate it here, although I can't use completely comparable faces, and you really need many trials and millisecond timing to study the effect. Anyway, just for illustrative purposes:
This is what is called in Biology sexual dimorphism . It is defined as the existence of physical differences between the sexes, other than differences in the sex organs. It is an evolutionary trait, thas is a result of sexual selection.
As described by Darwin, species in which males and females are more similar are more often monogamous. Species with brightly colored, large, or dangerously armed males are more often fall into polygyny. I.e. several females mate with one male, and other males do not breed at all. The selective pressure on adaptations that enable males to gain access* to females is proportionally stronger. So bigger, or more coloured, or more armed gives the male a competive advantage.
In general, in a given species, the stronger dimorphism, the higher the chance of polygamy, and the less the caring for offspring is shared among the sexes.
Treating the sexual dimorphism as a consequence of sexual selection has been a matter of controversy and has left many loose ends. For example, certain sexual dimorphisms have obvious utility beyond mate attraction and there are characters that cannot be related to sexual selection. The same phenomena can have different physiological meanings. There is simply no general reason for it. Each species is a world of its own....
Because the gravitational pull of the moon on the earth is so weak. Effects on the smaller scale are inconsequential, but there's a whole lot of water in them thar oceans.
mmm, that's a good one (and not a topic i know much about)
tides are caused by gravity. Gravity is a force which has a very small observable effect (compared with electric or magnetic fields) however on a large scale, when we consider the mass of say, the moon, it is quite noticeable. not sure whether that helps or not, but i'll think more on this today.
OK here is another one. I am not sure a scientist is the best person to ask, but give it your best shot (sic) : why does much (post cool) jazz sound like self indulgent musical masturbation ?
By contrast I currently listening to 1940s Reinhart/Grapelli, and I can almost hum along with it. Nice.
OK, it's from leftfield for me, i do play guitar, kinda OK, but never got into new-jazz (can i call it that). most of it is indigestible. Modally speaking, i think the peeps into this stuff are on a mission to bring the abstract to the world; not something i'm all that interested in.
Learn all the rules: modes, chord following, leading, transposition, harmony then the best you can come up with is: a series of random notes that take the music nowhere, but because it labels itself "jazz" hails claim to some intellectual underpinning so people that substitute analysis for passion can try and talk authoritatively about the meaning behind it. Incidentally thats also my pet theory of why modern jazz is so popular in Switzerland....
it's kinda off topic, but perhaps these people have little passion and appearing intellectual would be more to their liking then playing some dirty blues which weeps emotion? anyway, Dave, you sound more then qualified to answer your own questions from now on..........
Can we try to keep this thread on topic somewhat? I intended this thread to be for people to ask questions about biology, chemistry, physics, engineering etc.