Man and superman

Doping, genetics, resources, abilities, hard work, diet, training - these are all some of the variables that factor into any great performance - athletic or non-athletic. The stakes however are a lot higher and far more important in the extremely competitive world of sports.

I have previously touched on this subject as part of the Olympics brouhaha but was reminded of the subject again when I came across Malcolm Gladwell's piece in the NewYorker on the same subject.

Gladwell's take is fairly similar to mine except however, in its tone, he almost seems to absolve the athletes of any wrong-doing in an attempt to enhance their performance (including Lance Armstrong). 

After all, genetics gifts a select few, but science can level the playing field for the rest.

Gladwell however fails to touch on the scores of other biases that can factor in and 'un-level' the playing the field. He talks of the Kenyan runners but fails to mention how they get little to no training and how they run bare-feet on a minimalist caloric supply. 

But despite its limitations, I agree with a lot of what Gladwell says - because over the years, the boundaries of right and wrong have indeed been blurred. As science advances, these questions will only become more and more relevant and widespread.

From the use of protein and hormonal supplements in sports to the use of memory and cognitive enhancements in other fields, there is a whole minefield of controversial subjects. People have yet to take seriously the effect of chemical supplements, vitamins, herbal supplements, memory enhancers, nutritional supplements, etc in academic pursuits like a spelling bee or a Maths and Science Olympiad; but the underlying principles are the same between these diverse fields. 

How much can you level the playing field and at what point should you give up? 

These are important questions that need to be thought about - from social, cultural, legal and scientific perspectives. 

A triumph for Whorf - an existential flip for the rest of us!

Imagine a world where the sky was green. Not because you were on a different planet but because you didn’t know the word ‘blue’… 

This may seem like the stuff of science fiction but empirical evidence over the years is now suggesting that our words might indeed be shaping our thoughts and perceptions. 

Benjamin Lee Whorf, a linguist and a fire prevention engineer, was one of the pioneers to put forward this idea of linguistic relativity with Edward Sapir - his mentor at Yale.  Their fundamental idea was that linguistic categories influence perception and cognition or putting it simply - our language and our words influence our thoughts and our perceptions. 

Yes. You read it right. 

Our words influence our thoughts and our perceptions. Not just the other way around.

Sapir and Whorf's idea of linguistic relativity was explicitly drawn on Einstein's principle of general relativity such that the grammatical and semantic categories of a specific language provide a frame of reference through which the observations are made. They were deeply influenced by the ideas of Bertrand Russell and Ludwig Wittgenstein, whose view was that natural language potentially obscures, rather than facilitates, the mind's ability to perceive and describe the world as it really is. In the mid-twentieth century, this argument built the case for the extensive use of formal logic, to question the very fundamentals of logic and mathematics and to arrive at a set of axioms based on rigorous thought and didactic reasoning. Whorf  built on the ideas of Nietzsche and Wittgenstein and developed the theory of linguistic relativity but it was based on little empirical evidence and thus fell out of with the intellectual community within a decade of his death. In one oft quoted passage, Whorf writes: 

"We dissect nature along lines laid down by our native language. The categories and types that we isolate from the world of phenomena we do not find there because they stare every observer in the face; on the contrary, the world is presented in a kaleidoscope flux of impressions which has to be organized by our minds—and this means largely by the linguistic systems of our minds. We cut nature up, organize it into concepts, and ascribe significances as we do, largely because we are parties to an agreement to organize it in this way—an agreement that holds throughout our speech community and is codified in the patterns of our language. The agreement is of course, an implicit and unstated one, but its terms are absolutely obligatory; we cannot talk at all except by subscribing to the organization and classification of data that the agreement decrees. We are thus introduced to a new principle of relativity, which holds that all observers are not led by the same physical evidence to the same picture of the universe, unless their linguistic backgrounds are similar, or can in some way be calibrated."

But can this really be true? Can our language determine our perception of the universe?

Apparently, it can. And, here is some of the evidence for it that has compelled me to make that existential flip in my thinking and perception.

1) Blue or Green - the brain sees it only when it 'knows' it 

In a classical debate, cognitive scientists have been trying to establish the relation between language and perception. At one end of this debate is the strong -form Whorfian-theory that says that our perception of the world is shaped by the semantic categories of our native language and that these categories vary widely across languages. At the other end of the debate spectrum, is the universalist stance which claims instead that there is a universal repertoire of human thought and perception which leaves its imprint on all the languages of the world. Over the years, evidence has swung back and forth but empirical evidence from the domain of color and color-perception were some of the first and most comprehensive to weigh in on this rather fundamental question.

The effect of language on thought and perception was first tested with color perception in a 2006 study by Gilbert et al. Their study attempted to probe the perceptual discrimination of colors that straddled the boundary of blue and green - a boundary that exists in the English language but is absent in many others. The question was: does having a label for a color made a difference in how we see it?

As part of the experiment, English (American) speaking participants were presented with a central fixation cross with a ring of colored squares tiled around it. All the squares in the ring were of the same color except for the target. The participants were required to identify the differently colored square and indicate its location on the left vs. right side of the ring by pressing a button with the corresponding hand. The test was designed in such a way that the target color had either the same name as the color of the other squares (eg. green against the background of a different green) or a different name (eg. green against a background of blue) i.e. belonged to the same category or to a different category. 

Termed as Categorical perception (CP), this test was designed to see if having a different word/name for a color improved our ability to perceive it especially when the stimuli lie at the edge of a boundary. 

Instead of a simple yes or no answer the experiment yielded a rather interesting pattern: The subjects were better able to identify cross-category targets faster than same-category targets but only when presented in their right visual field, thus suggesting that Whorf's hypothesis might have been right after all; atleast half of it. 

Interestingly our language faculties are localized in our left hemisphere and the brain functions contra-laterally (left side of the brain controlling the right visual field). To test the effect of language, a parallel task requiring the use of verbal resources was added to the test and interestingly the effect on categorical perception by the left hemisphere (in the right visual field/RVF) was lost and in fact, was reversed. They also found that such a reversal was not seen when a non-verbal task of similar difficulty was added, thus suggesting that this lateralization effect was because of our language indeed. 

As one would expect, split brain patients whose left and right hemispheres are unable to talk to each other lost any trace of CP bias in the left visual field/LVF.

Interestingly at the time, a separate study by the same group expanded this paradigm to the use of non-color stimuli, namely silhouettes of dogs and cats thus extending the effect of our words on the way we think and perceive the world.  

But then what happens in children who are as yet uncorrupted by language? Do children who cannot yet talk, see and think differently from children who can? 

This is a rather interesting question and was addressed in a study by Franklin et al in 2008 as they first compared infant and adult performance on a visual search task much like that used earlier by Gilbert's 2006 study. As seen previously, adults showed dominant CP in their right visual field influenced by the language center in the left hemisphere. The pre-linguistic infants however showed no such CP bias in the Right visual field (RVF) and instead exhibited a clear CP in the left visual field (LVF). Thus, it seemed that as the children grew up and acquired language, there was a migration in their perception of categories from the RH/LVF (as infants) to the LH/RVF as adults (with language). 

Instead of comparing two very different groups - the infants and the adults, Franklin et al, next compared toddlers (2-5 yr old) in two groups: the learners and the namers. While the namers already had acquired their color terms, the learners were still finding their way around the color spectrum. Interestingly, the learners patterned colors like the infants while the namers showed CP like the adults. This strongly suggested that learning the color terms causes a shift in our categorization of color perception from the right hemisphere to the left. 

What seemed like green to start with suddenly starts looking different once we learn the word blue.  

When investigated further, these differences in color perception were further mimicked at the deeper level of electrical activity in the brain. Functional MRI studies have found that discriminating colors of different lexical categories (vs. the same category) elicited a faster and stronger response in the language regions of the left hemisphere especially when the colors were presented in the right visual field. Based on these studies over the past decade, it thus seems uncontroversial now, that once language is learned, the language labels replace any existing categories and shape our perceptual discrimination (especially in the left hemisphere/ right visual field).

2) Mapping our space-time paradigm - one word at a time

For a long time in the past, the impact of language on human thought has remained an intriguing question in the realm of psychology, philosophy and linguistics. Very little was done to empirically test any of these claims. However, over the past decade or so, researchers like Lera Boroditsky - a psychologist and neuroscientist at Stanford, have dared to jump in and get their hands dirty in trying to arrive at more definitive answers. Research in Dr. Borodistky's labs at Stanford and MIT is focused on trying to test the hypothesis that language does shape our thoughts, above and beyond our abilities to see color or shape. They have collected data from around the world: from China, Greece, Chile, Indonesia, Russia and Aboriginal Australia and have found that people who speak different languages do indeed think differently. 

Given some thought, this effect of language is rather evident because, after all, different languages tend to provide different levels of information - gender of the subject/object, tense, verb information etc. While some languages like Russian alter the verb to indicate the tense and the gender, some others like Turkish would also indicate how the information was acquired. Some other Romance languages like Spanish and french, also ascribe gender to common nouns - thus making a table masculine or feminine. In fact, some Australian Aboriginal languages have upto sixteen genders that include classes of hunting weapons, canines, things that are shiny, etc. 

Since languages communicate different information in different forms, it is also conceivable that the speakers might end up attending to, partitioning and remembering their experiences differently by virtue of their different languages? Questions like these have been addressed by the work done by Dr. Lera's group and others and have brought us farther along this line of questioning. 


Consider the following examples.

In northern Australia lies Pormpuraaw - a small aboriginal community on the western edge of Cape York, where the locals - Kuuk Thaayorre, have a rather interesting approach to space. Unlike us, english speakers, who define space relative to an observer by the use of words like right, left, front, back etc, the Kuuk Thayorre, like many other Aboriginal groups use the cardinal direction terms - North, South, East and West - to define space. All the time. All space in this community - from a village to an arm or a leg is specified along cardinal directions. Not only does it save them from that moment of confusion we all have, when someone facing us asks us to look right or left, and we wonder - "my left or your left"; this practice also makes them rather capable navigators. This constant training of their attention to the geographical coordinates forces them to pay exquisite attention to their geographical coordinates - all the time. 

But how does the use of cardinal coordinates really affect thought - not just navigational ability? And this is where Boroditsky and her group design some simple experiments to demonstrate that since space is such a fundamental domain of thought, differences in spatial perception also tend to impinge on our other more complex and abstract representations too. Surprising as it may seem, it appears that our representations of things as time, number, musical pitch, kinship relations, morality, and emotions depend on how we think about space. For instance, if people are given pictures that are snapshots of a temporal progression (eg. a man aging or a fruit being eaten) and asked to arrange them chronologically - one can see some very interesting trends. English speakers arranged the cards such that time proceeds from left to right. Hebrew speakers however arranged the cards from right to left (their script progresses from right to left). The Kuuk Thaayorre on the other hand, lacking such concepts as left and right followed a completely different trend. Their arrangements were not random; instead they arranged time from east to west (sunrise to sunset, perhaps?). So, when facing south, they arranged the cards from left to right; and when facing north, they went from right to left, and so on.  

People's ideas and representations of time also differed in other ways such that, while english speakers tend to talk about time using horizontal spatial metaphors (ahead, behind etc), mandarin speakers use a vertical arrangement for time, in keeping with their script. When subjects were given a spot for today and asked to plot yesterday or tomorrow, english speakers nearly always pointed horizontally while mandarin speakers pointed on the vertical axes. In fact, Chinese calendars move downwards and across (right to left on the page) like the written script itself.

In addition, research also shows a strong effect of language on some of the basic aspects of time perception. For example, since english speakers prefer to talk about time or duration in terms of length (short talk vs. long) their perceptions of time tend to be confused by distance information, such that they estimate a longer line to have remained on the screen for a longer period of time, although the two parameters are completely unrelated. 

But these tests are plagued by one critical question - the question of causality. How do we know that these people of different cultures are perceiving things differently only because of their language and not because of anything else. Reason would dictate that if these people learnt a new language, their perception of the world would change accordingly. And so, in one such study, English speakers were taught to use size metaphors like in Greek to describe duration or vertical metaphors like in Mandarin to describe event order. Remarkably, once the english speakers had learnt to talk about time in these new ways, their cognitive performance began to resemble that of native Greeks and Chinese thus establishing a rather conclusive role for language in instructing how we think.  

3) Word games - when the same 'key' can become heavy or tiny! 

The sub-conscious impact of language also extends from the realm of abstract concepts like time and space into the more physical. 


A clear case in point is that of grammatical gender as seen in romance languages like Spanish, German and French where nouns are assigned masculine or feminine genders. Speakers, in turn have to change pronouns, adjectives, verb endings, possessives, numerals and so on, depending on the noun's gender. 


But do these subconscious perceptions subsequently bias our opinions of everyday objects? When tested, it was indeed found to be so. In one study from Boroditsky's group, the experimenters asked German and Spanish speakers to describe objects having opposite gender assignment in the two languages to see how the gender influences perception. When asked to describe a "key" - a word that is masculine in German and feminine in spanish - the German speakers used words like "hard", "heavy", "jagged", "metal", "serrated", "useful" etc while the spanish speakers were more likely to use words like "golden", "intricate", "little", "lovely", "shiny", and "tiny". 


Interestingly, these results emerged even though the testing was done in a third neutral language like english. The same pattern of results also emerged in entirely non-linguistic tasks like when subjects had to put images together. 

Apparently, even small flukes of grammar, like the seemingly arbitrary assignment of gender to a noun, cal dramatically alter our perception of the world. 

4) Honest lies - true testimonies of events that never happened

Honest lies are factually inaccurate information that we have told with all honesty because that's what we remember them to be. We have all told them inadvertently because of when, how and where were asked the question. 


Innocent people have been caught on the wrong side of law while liable culprits and criminals have sometimes been set free because of this strange malleability of the human mind. And no one paid much attention to study this phenomenon because we were all oblivious to how our mind was being tricked and how it was in turn tricking us, until of course, a psychologist from UC Irvine, Elizabeth Loftus dived in and highlighted some of these hard-to-swallow facts. 


Loftus' journey began at a social-psychology class when she saw that people could name a 'yellow bird' faster than a 'bird that's yellow'. Her subsequent search for interesting puzzles, funds and opportunity, brought her to the US department of transportation where Loftus began her research into car accidents and the limitations of eye-witness testimony. She empirically showed that people's eye-witness testimonies and versions of accidents can vary depending on the wording of the questions asked of them. She showed people clips of car accidents and asked them to estimate the speed of cars. People when asked, "How fast were the cars going when they smashed into each other?' gave higher estimates on average than those with whom the verb "hit" was used. Those who heard the verb 'contacted' in the question gave the lowest estimates of the speeds again confirming the idea that words and language can mould and shape our thoughts. 

The effect of words and language on our thinking does not merely extend to how we judge unknowns like the speed in this instance - they can also mislead us into fabricating parts of the story. Those asked about cars smashing into one another were more than twice as likely as others to report seeing broken glass when asked about the accident a week later, even though there was none in the video. This clearly suggested that our words and language can sub-consciously lead us into confabulating 'facts' and contaminating our memory traces. 

After these dramatic beginnings, Loftus went on to publish several other studies that showed how memories can be contorted and eye-witness accounts can be tainted. She has gradually extended her work from the realm of pure academic interest into having social ramifications and is currently pushing for broader legal reforms. While the focus of Loftus' studies is on the unreliability of our memories, her work is also relevant to the effect of language on thinking. As can be seen from her experiments, the exact phrasing of the question had a profound effect on what and how people thought and recalled events. 

5) Gender personification, abstraction and art 

This is a rather interesting idea that explores the effect of native languages on an artists perception of abstract concepts in art such as death, victory, sin, time etc. When representing such emotions in human forms, how does an artist decide the gender? Accordingly to Dr. Boroditsky, it appears that in most such abstract personifications (85% apparently), whether a male or a female figure is chosen is predicted by the grammatical gender of the word in the artist's native language. Not too surprising, perhaps, once we make that Whorfian existential flip. 




6) To see or not to see - It's all in the dictionary! 

The many examples so far establish a critical effect of words on our thinking, on our ability to categorize and discriminate. But, the effect of language on perception itself remains. To what extent is the awareness of an object affected by factors outside of our vision? The traditional view is that although a number of non-visual factors can affect where and what one attends to, the very content of what we see is not susceptible to outside influences - but is determined by physical factors. 

However, a recent study published in the Proceedings of the National Academy of Sciences, does a lot to overthrow this paradigm. Through empirical evidence, the authors demonstrate a strong effect of language on perception itself; an effect divorced from any higher level cognitive processing that one might suspect. They show that auditory linguistic labels can not just affect what one sees but whether one sees something at all. Their studies show that an otherwise invisible kangaroo can be boosted into awareness by language, by using the word for a kangaroo while seeing the stimulus. 


This idea that a "higher-level" process like word recognition or language can influence a "lower-level" process such as visual perception presents a challenge to our normal feed-forward modeling of cognition and perception; where it is assumed that the world is seen for what it is but then our brains filter out and attend to specific stimuli. 

Although many studies have demonstrated a clear effect of language on post-perception decision making, an outstanding question in the field is to discriminate the effect of language on perception vs. perceptual identification. One way to do this is to keep visual stimulus (object) unchanging while manipulating the top-down influences that change our perception of the object.  This way, any differences in perception by stimulus-driven processes can be ruled out. 

In this study, the authors investigated whether hearing a language label can affect our ability to simply detect the presence of an object. In order to suppress conscious visual awareness along with semantic processing, the authors use a process called as interocular rivalry i.e. they present different stimuli to the two eyes, such that the stimuli compete and the same retinal input can give rise to different conscious percepts. Which of the two stimuli gain our attention is determined by visual aspects of the stimulus - contrast, luminosity, size, eccentricity, contour density etc.

Continuous flash suppression (CFS), a variant of interocular rivalry, is particularly useful to testing visual awareness and forms the basis of these experiments. In continuous flash suppression, an object is placed in interocular competition with high-contrast noise patterns (alternating really fast at 10 Hz) thus suppressing the real stimulus from awareness for extended periods of time. 




The authors began by testing if hearing a verbal cue or language label can make an otherwise invisible object (invisible by CFS) to pop-up and become visible? They reasoned that if words can change our perception of things, then hearing a label before seeing a picture (that is normally invisible due to CFS), should increase the likelihood of seeing the picture. And indeed, hearing a word label (like a kangaroo) before the simple detection task increased performance or increased the ability to detect the "kangaroo". Further, valid labels improved the detection while invalid labels actually decreased performance. As can be seen in the graphs below, these word labels affected both the sensitivity and the speed of the detection. Also, interestingly the study showed that the effectiveness of a particular label varied predictably as a function of the match between the shape of the stimulus and the shape denoted by the label. 

Unlike the previous studies, this report clearly shows that language affects the very visibility of objects. The labels provided by language affect performance not just on tasks requiring processing (explicit identification, categorization or discrimination) of what we see but can actually make us see something that did not exist before.

While one interpretation would categorize such a perceptual bias as entirely maladaptive from an evolutionary standpoint, the alternate possibility suggests that such top-down fine-tuning of perception can make it more sensitive to stimuli that are relevant to what is needed. Such a permeable perceptual system would allow for influences outside of vision (such as language) to exert an influence and to modify both perception and behavior; such as looking for a lion, when someone screams lion behind you.    

This study clearly demonstrates that as was suspected by Whorf, our languages keenly influence not just what we think but also what we see. 

Linguistic relativity - started off as an obscure theory, unsupported by facts and was soon a relic in the textbooks. But empirical evidence from half a century later has not just resuscitated the theory but has re-established it as a cornerstone in the field. 

It seems now that Wittgenstein was well ahead of the rest of us when he said, "Philosophy, is a battle against the bewitchment of our intelligence by means of language." In time however, we should learn enough about these spells to free our minds and our thoughts. 

References: 

Corrupted memory, Nature, 14 August 2013, A feature on Elizabeth Loftus by Moheb Costandi

 Regier, T., & Kay, P. (2009). Language, thought, and color: Whorf was half right; Trends in Cognitive Sciences, 13 (10), 439-446

Gilbert AL, Regier T, Kay P, & Ivry RB (2006). Whorf hypothesis is supported in the right visual field but not the left. Proceedings of the National Academy of Sciences of the United States of America, 103 (2), 489-94

Franklin A, Drivonikou GV, Clifford A, Kay P, Regier T, & Davies IR (2008). Lateralization of categorical perception of color changes with color term acquisition. Proceedings of the National Academy of Sciences of the United States of America, 105 (47), 18221-5

Radiolab, a public radio program from the WNYC did a wonderful one hour pod-cast on color perception that you might want to listen to

How does language shape the way we think? By Lera Boroditsky

Wikipedia entry on Whorf.

Language can boost otherwise unseen objects into visual awareness, Gary Lupyan and Emily J Ward, Proceedings of the National Academy of Sciences, June 25, 2013 

Diamond, J (2010). Science, 330 (332) The benefits of multilingualism

      A more abridged version of this post was published in Nature India and here is the link for it. 

      Although, I like the crisper version too and appreciate the edits, I like the depth and flow of this one. 

House-hunting the democratic way - learning from the bees...

When I walked into the lecture hall last week, this image looked like a swarm of bees to me. By the time, I walked out one hour later, this is what I saw.

No, this was not the effect of a dream state or a hallucinogen but rather the effect of Dr. Thomas Seeley’s work.

Tim Seeley, as he is known, is an ethologist and an entomologist from Cornell and probably one of the world’s leading expert in the phenomena of swarm intelligence. He has been studying the behaviors and social structures of bees for many decades now. As far as scientific genealogy goes, Tim has great Pedigree. He began his work on bees, as part of his doctoral dissertation with Lindauer who was a student with Karl Von Frisch, the Nobel laureate who pioneered the field itself. It was Von Frisch’s discovery of the now famous waggle dance in bees, as a tool for communication that gave us our first insights into the social structures of the insect world. Von Frisch found that scout bees would return from a food source and would then dance around the hive; soon after which, the rest of the forager bees would go hunting and collecting.

By careful observation over years, Von Frisch found that the duration, direction and quality of the dance would communicate to the rest of the hive, details about the quality, location and distance of the food source. This opened up a whole new field in biology as animals were long considered to be incapable of communication, coordination, culture and altruism. Instead, Von Frisch’s findings attacked the very foundations of human uniqueness and demonstrated these tiny insects to be capable of all this and much more.

Lindauer, Von Frisch’s student and later colleague, followed up on this work and found that a young bee swarm would also choose its future nest site by a decision making process that was based on reports of the dancing scouts. Seeley was intrigued by the idea of swarm intelligence, by the ability of a swarm as a whole to arrive at a decision that could potentially make or break the future of the colony.

His first forays into this question began with determining what the bees were looking for, when they were scouting the real estate market. Honeybee colonies reproduce by budding, whereby the queen and some workers (a few thousand) leave the nest and bivouac on a branch for a few days depending on their resources. At this point, the swarm needs to locate a new home for themselves that will ensure their survival. By chasing bee swarms and by building potential hive sites of many different shapes and sizes as part of his doctoral work, Tim found that the young swarm was looking for a nesting site that was high, well insulated and yet roomy. It had to be high enough to escape predators (at least 15 ft), big enough (atleast 10 gallons) to rear a new brood and to stock supplies to last through the winter. For a honeybee swarm, choosing a potential home is a momentous decision that might compromise their survival itself. The task of hunting is thus delegated to the most experienced workers who scout nearby locations and report to the swarm. 

Lindauer had already shown that the scouts used the waggle dance to “tell” the rest of the swarm about the new site and that the decision was somehow arrived at by a collective process. Trying to understand the dynamics of the swarm was a challenging and almost impossible task at the time, even for someone like Seeley. In the early decades of the field, ecologists were limited to the use of a simple tool set of notebooks, pens, stopwatches, paint sets, wristwatches and little else. Tracking hundreds of individual scouts, their movements, dances and patterns at the level of multiple swarms was impossibility. Even someone as creative and ingenious as Seeley was forced to wait for technology to catch up with his ideas.

Finally, in the last decade of the twentieth century, as the camera and video recording techniques came of age, Seeley decided that the time was ripe for delving into those forbidden questions. And the answer lay in careful and meticulous observation. Seeley and his students would manually label and mark the thousands of bees in a swarm, but this was only the easy part of the job. They would then video record the entire house-hunting process for a period of 2-3 days and at the end of it, they faced the enormous task of decoding the videos to identify the underlying patterns. The watched the scouts hunt at different locations, coming back to report and then the entire decision making process. Each 16 hour film of the bees’ decision making process would take atleast a month of eye-stinging labour to decipher. What they found was fascinating indeed.

The experienced scout bees would head out and survey the available real estate. They would the, come back and advertise the potential locations and their qualities to their nest mates by performing the waggle dance. The angle of the bees with respect to the sun would indicate the direction of the site, while the duration of the dance would indicate the distance. The quality of the site was indicated by the simple metric of the number of dance repeats that the bee did. The more a scout bee advertised, its location, the stronger the lobby it built. These waggle dances would then recruit additional scouts to the site until a decision was made. Interestingly, each scout bee would only visit one site on most occasions and would only lobby or rather “dance” for it. Each time she returned from the site, the number of dance circuits would progressively decline but each routine would recruit a new wave of scouts, creating multiple, independent reports. 

Seeley and his students began their studies suspecting a consensus building mechanism to be involved – a democracy of sorts. What they instead found was that the scouts themselves don’t pay any attention to the consensus. They decision is made by a quorum, a critical number (20-30) of bees being simultaneously present in the nest site – representing successful reports from many independent scouts. Trying to understand the significance of the number, Seeley and Dr. Kevin Passino, a professor of computer engineering at the Ohio state university, came together and modeled this decision making process. They fund that in a simulation, adjusting the quorum to only 15 bees would result in quick but error prone decisions. Increasing the number to above 20 on the other hand produced slower but only slightly more accurate decisions. It thus seemed that the bees had found the optimum number to balance the cost of resource starvation with expected gain in accuracy. But the precise mechanism underlying this “plebiscite” remained unclear, until of course, Dr. Seeley and his students heard the head butts.

They found that in deciding which site to choose, the scouts would also employ another tactic in addition to the positive-reinforcements achieved by dancing. They also had a stop signal – a booming head butt. When choosing between two nest sites, the scout bees committed to each nest site would direct these head butts to the scouts promoting the other box; thus setting up a cross inhibition between the two populations of scout bees.

The honeybee stop signal is a vibrational signal signal that lasts about 150 ms and has a fundamental frequency around 350 Hz. It is typically delivered, by the sender butting her head against the dancer. Although the dancer may not show an immediate response to the signal, the accumulation of such stop signals is seen to increase the probability that the bee will cease dancing. [Commonly used during foraging, the stop signal is given when a forager bee is attacked in a food source and this reduces the recruitment of colony resources to perilous food sources.]

To further understand the implications of such a cross-inhibitory selection mechanism, Dr. Seeley and his colleagues further modeled the decision making process. Testing individual models of no or indiscriminate stop signals suggested the overwhelming possibility of reaching at an impasse – an impossible deadlock. Such a stable deadlock would result in the swarm never reaching a decision and thus starving to death. Simulations showed that the deadlock persists even when the stop signaling is applied with discretion but below a critical threshold.

When the stop signals are applied above a critical threshold, the swarm is either able to randomly arrive at a consensus for one the two equal alternatives or if the difference in the quality of the two sites is significantly different, then the stop signals ensured a consensus for the superior alternative. The existence of the stop signal and a high enough quorum thus ensure that the bees arrive at an optimal decision most of the times.

Once the search committee has made up its mind and the critical quorum of bees is established at the nest site, the scouts lobbying for the site begin their final “move”. They begin with an auditory signal, called as worker piping, that can actually be heard by us. Coincident with this signal, the other bees in the swarm begin to prepare for flight. Bees fly with wings moving at some 250 times per second and this requires their wing muscles to be warm (35 deg C) and metabolically active. To do this, upon receiving the piping signal, the bees warm up their flight muscles by disengaging their chest muscles from their wings and vibrating them. The temperature of the whole swarm rises up rather steeply in less than half an hour.

 

Worker piping and the pitch of the sound perfectly match the beat frequency of a flying bee and some early experiments suggest a critical link between the two. In the final few minutes before the take off, the workers exhibit another rather strange phenomenon - a so called ritualistic buzz run. Here, the bees run across the entire swarm with outspread wings and a buzzing sound, almost invoking everyone into action.  As the swarm is warm and ready, the buzz run begins and finally the swarm lifts-off. It slowly hovers over its temporary home for a minute or two and then starts proceeding towards the nest at speeds ranging from 0.5 – 5 miles per hour. They finally stop near the goalm their future home scented with the Nasonov pheromones from the scouts. In the absence of these scent markers, the swarm finds its more difficult, not impossible, to locate the entrance to the hive site. At this point, they are then guided by these streaker bees, who repeatedly shoot towards the goal and guides the others. The bees thus finally make it to their new home – and a young hive begins to grow.

Although elegant and simple, this mechanism needs further careful study to account for the individuality and subjectivity of the bees.  If in the early phase of the scouting, a single bee dances more enthusiastically for a bad site or less enthusiastically for a good site, then the balance of signals could tilt very rapidly introducing a lot od stochasticity. In fact, as they individually tracked these bees, Dr. Seeley and his group also noticed many differences between them. They are all not the same like a cookie cutter and are rather quirky. Some are really good dancers, some are not; some are really peppy and get going early in the morning while some others have to be woken up. They have a lot of personality and with the cumulative mechanism of this process, small vulnerabilities at the start could easily run amock and alter the fate of the hive.

It would also be interesting to know if the hive changes its criteria and its choices if they are running out of reserves and how the choices are made? The rate of information arriving to the hive could also bias the processing of the input and the cascade to the decision – say a scout flies closer to the swarm and reports back sooner and builds up a bigger lobby. The reliability of the responses of the individual bees to multiple optimal or suboptimal sites is another interesting question that may be rather revealing. All in all, like all great studies in science, Dr. Seeley’s raises many more interesting questions, even as he finds the answers to them.

Interestingly, as Dr. Seeley and his students were uncovering these details of the house-hunting process of the swarm, there emerged a few parallels that are imperceptible to an otherwise untrained mind. What Seeley saw was an emerging parallel between the bee swarm and the human brain. In a swarm, each scout reported on a single find, much like a neuron responding to a particular stimulus. “Both are cognitive entities shaped by natural selection to be skilled at acquiring and processing information to make decisions,” he says. In both these systems, decision-making is a competition between mutually interacting populations of excitable units – neurons or individuals – that accumulate noisy evidence for alternatives and, when population exceeds a threshold, the corresponding choice is made. A common underlying feature for both bees and neural decision-making is the existence of cross-inhibition. A population that inhibits others proportional to its own activation, thus ensuring that only one of the alternatives is chosen.

And so, as I stepped out of that lecture hall at the end of that hour, my rewired brain could see more to the statement “buzz in the brain” than was ever obvious to me. 

The question is what do you see?

References:

1)   Stop signals provide cross inhibition in collective decision making by honeybee swarms, Seeley et al, Science, January 2012

2)   Swarm intelligence in honeybees: Talk by Dr. Tim Seeley at the University of California, San Diego.

3)   Decoding the language of the bee: Nobel lecture, Dec 12, 1973, Karl Von Frisch.

4)   Swarm Intelligence: How Tom Seeley discovered ways that bee colonies make decisions, Part II, MEA McNeil

5)   How honeybees break a decision-making deadlock, Science, 6 January 2012, By Jeremy E Niven

6)   You tube Lecture by Dr. Tim Seeley