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How did humans evolve to enjoy drinking alcohol?

We’ve had a taste for the stuff since before people were people — according to one scientist.

QUESTION: HOW DID people evolve to drink alcohol?

There are endless arguments for why people drink, the simplest being that alcohol is tasty and it makes us feel good.

But those reasons do not address the ultimate explanation for why our brains evolved to like alcohol in the first place, at least according to Robert Dudley, a professor of biology at the University of California, Berkeley, and author of “The Drunken Monkey.”

Dudley’s drunken monkey hypothesis is the first attempt to place alcoholism in an evolutionary context.

In a 2004 paper, he argued that modern patterns of alcohol consumption and abuse have a biological basis that can be traced to our fruit-eating primate ancestors.

Hard-Wired For Booze

Sugars in fruits, grains, and nectar are naturally turned to ethanol by yeasts during a process known as fermentation.

The earliest archaeological evidence suggests, based on chemical residues from pottery jars, that humans did not start fermenting honey, rice, and fruit to produce alcoholic beverages until 9,000 years ago.

But these fermented beverages were probably not our first exposure to alcohol, according to Dudley. Our pre-existing taste for booze likely developed tens of millions of years ago in our primate ancestors, who survived mostly on fruits.

As fruit ripens, more alcohol is created by the yeasts. When a fruit starts to seriously rot, it can contain up to 8% ethanol, although most ripe fruit contains less than 1%.

Dudley’s theory suggests that the alcohol concentration of ripe fruit would have served a purpose for both the fruit-bearing plant and the primate. In tropical forests, fruit can be hard to track down. However, the scent of alcohol from ripe fruits travels long distances, and may have helped primates to find their next meal.

Being attracted to the scent of ethanol from ripe fruits would have been evolutionarily adaptive, enabling the primates to find fruit easier. It was also helpful to the plants, because the primates helped to disperse the seeds in the fruit.

But the gains of eating these alcoholic fruits doesn’t end there. Once digested, the theory goes, the alcohol would have stimulated feeding, encouraging the primates to “gobble up the food before anyone else got to it.” Humans know this feeling today as the aperitif effect, which you may have experienced if you’ve ever had a cocktail before a meal and found yourself hungry. Or craved cheese fries after a night out.

Modern Problems

Primates probably weren’t getting wasted, because fruits house only tiny concentrations of alcohol compared to today’s drinks. In one study, Dudley found that the pulp of ripe palm fruits contained ethanol concentrations of 0.9% on average. Most beers have an alcohol strength of 4% and wine usually 14%.

This could explain why a little bit of alcohol can be healthy, he said. The problem today is that humans aren’t drinking alcohol in small amounts. Much like the story of sugar — which in ancient times was limited — alcohol is not only plentiful but, thanks to distillation, available in much higher concentrations than found in fruit.

Our bodies have preserved the biological urge to drink from when alcohol sources were few and far between, even though we live in an age where the supply is unlimited.

This post is part of a continuing series that answers all of your “why” questions related to science. Have your own question? Email dspector@buisnessinsider with the subject line “Q&A”; tweet your question to @BI_Science; or post to our Facebook page.

Read: Joan Burton accidentally poses with giant spliff

Read: Dun Laoghaire’s new Wetherspoon’s will be open in time for your 12 pubs

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    Mute mickmc
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    Dec 21st 2016, 7:29 AM

    I love to see the winter solstice arrive. After today the dark days are heading slowly but surely in the right direction.

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    Mute Mick McGuinness
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    Dec 21st 2016, 7:13 AM

    Happy Winter Solstice Ireland

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    Mute Mr Snuffleupagus
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    Dec 21st 2016, 7:16 AM

    @Mick McGuinness: As the shortest day of the year, many, myself included, find this week to be one of the most difficult of the year. On the positive side, from next few weeks onwards, days get longer.

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    Mute Damocles
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    Dec 21st 2016, 9:28 AM

    How does Newgrange compensate for axial tilt changes?

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    Mute Chris Kirk
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    Dec 21st 2016, 9:48 AM

    @Damocles: It probably has built in solar panels supplied by DCC……

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    Mute Gerald Kelleher
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    Dec 21st 2016, 10:44 AM

    @Damocles:

    To answer that question you would need considerable concentration, as much concentration as the original builders of the alignment give in creating a spectacle that is as enjoyable today as it was 5200 years ago when the first people saw it and on the exact same days as today.

    Keep in mind that there is a 1000 year difference between Newgrange and Stonehenge yet both display Solstice alignments which we both enjoy today on the exact same date. This means that nothing has changed in the relationship between the North and South polar points both to the Sun and the circle of illumination as both turn in a small circle annually. Presently it is Polar noon at the South pole where it is position midway to the circle of illumination just as it was 5200 years ago.

    I wouldn’t get caught up in the original technical points of Copernicus but he sacrificed his correct view on the annual motion of the polar points in the period when he wrote his short treatise in 1514 and De Revolutionibus in 1542 -

    “The third is the motion in declination. For, the axis of the daily rotation is not parallel to the Grand Orb’s axis, but is inclined [to it at an angle that intercepts] a portion of a circumference, in our time about 23 1/2°. Therefore, while the earth’s center always remains in the plane of the ecliptic, that is, in the circumference of a circle of the Grand Orb, the earth’s poles rotate, both of them describing small circles about centers [lying on a line that moves] parallel to the Grand Orb’s axis. The period of this motion also is a year, but not quite, being nearly equal to the Grand Orb’s [revolution].” Copernicus

    http://copernicus.torun.pl/en/archives/astronomical/1/?view=transkrypcja&

    In trying to account for the Precession of the Equinoxes to account for the small observed discrepancy he shifted the annual circle scribed by the polar points to the Sun and shoved it into a 25,900 year cycle which is now called axial precession -

    https://upload.wikimedia.org/wikipedia/commons/4/43/Earth_precession.svg

    It is unfair on the readers here and on me to explain something which is highly intricate however the fact is that Newgrange and Stonehenge along with all ancient alignments from other cultures still hold to the Solstice and Equinox points. If axial precession were true then Newgrange would have lost its Solstice alignment thousands of years ago but that it hasn’t tells those who are considerate and intelligent something.

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    Mute Meanderingsz
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    Dec 21st 2016, 11:42 AM

    @Gerald Kelleher:

    The Newgrange we see today was largely constructed in the 70s and 80s, including the light well.
    Unfortunatly our need to be recognised and celebrated once again lead us to deception – to construct a false monument. Many archeologists have stated there is absolutely no historical significance in the modern light well or the facade of the building – the deception is compounded by the visitor information and graphics used, though everybody agrees the newgrange building is almost entirely less than 50 years old the literature provided to visitors shows ancient people interacting with it.

    Its pathetic that we need to lie about things isnt it?!

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    Mute Ken Mitchell
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    Dec 21st 2016, 12:43 PM

    It’s true they reconstructed it in the 70s but they were basing this on similar ancient monuments they know about around the country – lough crew in nearby oldcastle springs to mind but there are many others around the country that align of specific days. The light actually enters enters the cahmber approx 2 days either side of the equinox so there is a bit of wiggle room in regard to axial tilt and the passage of time.

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    Mute Gerald Kelleher
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    Dec 21st 2016, 12:53 PM

    @Meanderingsz:

    Pathetic indeed !, attention seekers often gain a reputation and a lifestyle by saying Shakespeare didn’t write his prose, Jesus is an invention of St Paul or some variation on that theme. I trust the readers in this thread to consider the exquisite effort and reasoning that goes into these alignments and if you wish to create academic pretense with professor X or Y about the alignment and its age then be my guest however it means that you actually have to account for things as why the alignment stays fixed to the Solstice points.

    The author of the article got a few technical points wrong which I may gently correct. The neolithic builders were not astrologers as astrology is really only associated with the Greek geocentric framework where the Sun was seen to move through the Zodiac with people’s birthday date coinciding with the Sun among a grouping of stars known as constellations. If a person is born from late July through August the Sun is in the constellation Leo. Johannnes Kepler was both an astrologer and an astronomer and it shows up in the technical details of his work however there is an older system of reckoning before the Greeks which the builders of Newgrange and Egypt would have known. They did not think of the motion of the Sun through the Zodiac but the seasonal appearance of certain stars such as the first appearance of Sirius which allows for our present reckoning of the Solstice within the calendar system and more importantly, the geocentric framework of the Greeks.

    “.. on account of the procession of the rising of Sirius by one day in the course of 4 years,.. therefore it shall be, that the year of 360 days and the 5 days added to their end, so one day shall be from this day after every 4 years added to the 5 epagomenae before the new year” Canopus Decree 238 BC

    The further back in history a person is prepared to go the more they love what humanity has achieved and it is possible to correct mistakes picked up along the way and add nothing to the appreciation of what the builders,artists, quarrymen, sailors, architects and the remainder of a national community who built that monument.

    The Equinox alignment of Knowth or Loughcrew plays wonderfully against the exquisite roofbox of Newgrange as the rapid declination of the Sun around the Equinox (when there is a marked difference in the transition to longer or shorter daylight hours) make such a roofbox impossible. It is an honour to appreciate the technical details between the different monuments which is why the ancient community should be admired and with pride.

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    Mute Coles
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    Dec 21st 2016, 1:39 PM

    @Gerald Kelleher: Great contribution.

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    Mute Gerald Kelleher
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    Dec 21st 2016, 5:28 PM

    @Coles:

    Thank you. It is done to allow archaeologists to do their job free of speculation and within the atmosphere of recorded history and especially the astronomical tradition. Newgrange was lost to history for thousands of years but fortunately people cared enough to restore it to a condition that is their best guess and retains most of the significance of the culture that built it and it belongs to them as it does to us as a nation and the world.

    It does happen that astronomical insights become neglected until some event draws attention to their presence. The great modern advancement was accounting for why the planets were seen to move as they did until Copernicus came along and worked out that the slower moving planets fall temporarily behind in view if the Earth is given a faster orbital motion much like a faster car in an inner lane on a traffic roundabout overtakes slower moving cars in outer lanes where they fall behind in view -

    https://apod.nasa.gov/apod/ap011220.html

    Sadly this perspective was lost to history for a few hundred years but it is back , made possible and easy enough to understand using contemporary time lapse footage. Unless nuisances come in and try to fabricate or distort the history of human achievement then places like Newgrange and astronomical insights are safe but it does take effort to chase away those who would make little of a recent or ancient astronomical heritage.

    Time to move on.

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    Mute Mr Snuffleupagus
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    Dec 21st 2016, 7:14 AM

    interesting claims made by an archaeologist in an IT report today that the suntrap is only 50 years old and was constructed by the late Professor Michael O’ Kelly. http://www.irishtimes.com/news/ireland/irish-news/newgrange-sun-trap-may-be-only-50-years-old-says-archaeologist-1.2913483

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    Mute Austin Rock
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    Dec 21st 2016, 7:29 AM

    @Mr Snuffleupagus: yeah it was the Romans!!!!

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    Mute Gerald Kelleher
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    Dec 21st 2016, 8:03 AM

    @Mr Snuffleupagus:

    There are always academic attention seekers and the nuisance claim is the archaeological equivalent of driving a truck through a crowd enjoying a seasonal spectacle, if people want to give these notions some currency then they miss the point of what a true community achievement is, in this case a society lived on this island who put its talents together to create a giant monument with astronomical significance.

    http://i.imgur.com/5PVx7Mr.jpg

    I took that image in the central chamber yesterday just as the Sun shone out from behind heavy fog which spoiled the spectacle for those who came earlier and had won the right to be in the chamber via a lottery. It is a privilege as an Irish person to see so many talents to combine and have the real pleasure of standing in a place where people once stood 5200 years ago and witnessed that spectacle for the first time. As an astronomer from their tradition there is no greater gift and one I thought I would never experience.

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    Mute Mr Snuffleupagus
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    Dec 21st 2016, 8:19 AM

    @Gerald Kelleher: The automatic assumption that one is an attention seeker or nuisance for presenting alternative views and interpretations, and not without evidence, is a constant. Often, they turn out to be correct. There’s a hell of a lot of supposition applied retrospectively to anything of considerable age. Theories and hypotheses abound. I’ve been there a few times myself and the state run guided tours had no shortage of unsupported supposition too. This is just another one added to the mix but at least he tries to support some of his claims> O’ Kelly’s work was not without criticism from contemporary peers either.

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    Mute Gerald Kelleher
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    Dec 21st 2016, 9:28 AM

    @Mr Snuffleupagus:

    It is all academic pretense and an attempt to start a bun fight when these nuisances have nothing to say, for everyone else the monument itself is one entire structure that contains so many facets of a community from its artistic skills to its seafaring prowess, from its astronomical knowledge to architecture, from surveying to community spirit from across the nation and some of those things which only surface now and again in contemporary life . I would like to think that it has always been a part of this island’s heritage for the many people who now give their time to the GAA or some other organization that offers a spectacle to the wider community.

    The guides and Prof O’Kelly accomplish a remarkable feat in threading the middle ground between wild speculation and academic pretense thereby projecting much of the original value of the monument. As an astronomer I work in the background as, unless you haven’t noticed, Newgrange is a working astronomical monument and has informed me more than once about holes in modern thinking. I knew yesterday that as I stood in the chamber that people 5200 years ago were standing in the exact same spot at the exact same time so that there is a problem with the contemporary explanation for the Precession of the Equinoxes where axial precession is falsely assigned as a cause.

    I have my own private Equinox alignment spectacle about 19 miles to the North of Newgrange where the passageway stones were excavated by the ancient people. The wall of that cave are made of greywacke ,the same material that lines Newgrange and Knowth passageways and a lovely trip for anyone who is down in Clogherhead at 9 AM around the March or September Equinox.

    http://i.imgur.com/8wx48U4.jpg?1

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    Mute Chris Kirk
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    Dec 21st 2016, 9:46 AM

    @Gerald Kelleher: You were indeed very fortunate as the sunlight was perfect yesterday morning, not so sure about this morning though..

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    Mute Gerald Kelleher
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    Dec 21st 2016, 10:01 AM

    @Chris Kirk:

    To be fair Chris, the morning was anything but ideal for those who had been accorded the right to be in the chamber as the Sun comes into view from behind a distant hill .

    http://i.imgur.com/rw77bcq.jpg

    I was one of the stragglers that stayed behind and just as I entered the chamber the Sun came out when its height was above the low lying fog so by the grace of God I got to witness something special.

    http://i.imgur.com/lvcO9BL.jpg

    I suppose it not just one thing but the whole structure and experience that makes the visit special and even standing outside can be just as satisfying as being inside. In a few days the arc of the Sun will begin to expand and the exquisitely positioned roofbox pointing at a position on a distant hill will be too low to deliver direct sunlight to the chamber. For those who are outside on the Solstice they have time to consider what happens at this time of the year and no other.

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    Mute longhandle
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    Dec 21st 2016, 2:36 PM

    A fantastic spot. I’m not spiritual at all but, there is something very calming about Newgrange.

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