by Dean Burnett
This study is known as the ‘door study’, because the door is the most interesting element here, apparently. Scientists are a weird bunch.
The limits of human attention can and do have serious scientific and technological consequences too. For example, heads-up displays, where the instrument display in machines such as aeroplanes and space vehicles is projected onto the screen or canopy rather than read-outs in the cockpit area, seemed like a great idea for pilots. It saves them having to look down to see their instruments, thus taking their eyes off what’s going on outside. Safer all round, right?
No, not really. It turned out when a heads-up display is even slightly too cluttered with information, the pilot’s attention is maxed out.16 They can see right through the display, but they’re not looking through it. Pilots have been known to land their plane on top of another plane as a result of this (in simulations, thankfully). NASA itself has spent a lot of time working out the best ways to make heads-up displays workable, at the expense of hundreds of millions of dollars.
These are just some of the ways the human attention system can be seriously limited. You might like to argue otherwise, but if you do you clearly haven’t been paying attention. Luckily, we’ve now established you can’t really be blamed for that.
Notes
1 R. C. Gerkin and J. B. Castro, ‘The number of olfactory stimuli that humans can discriminate is still unknown’, edited by A. Borst, eLife, 2015, 4 e08127; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4491703/ (accessed September 2015)
2 L. Buck and R. Axel, ‘Odorant receptors and the organization of the olfactory system’, Cell, 1991, 65, pp. 175–87
3 R. T. Hodgson, ‘An analysis of the concordance among 13 US wine competitions’, Journal of Wine Economics, 2009, 4(01), pp. 1–9
4 See Chapter 1, n. 8
5 M. Auvray and C. Spence, ‘The multisensory perception of flavor’, Consciousness and Cognition, 2008, 17(3), pp. 1016–31
6 http://www.planet-science.com/categories/experiments/biology/2011/05/how-sensitive-are-you.aspx (accessed September 2015)
7 http://www.nationalbraille.org/NBAResources/FAQs/ (accessed September 2015)
8 H. Frenzel et al., ‘A genetic basis for mechanosensory traits in humans’, PLOS Biology, 2012, 10(5)
9 D. H. Hubel and T. N. Wiesel, ‘Brain Mechanisms of Vision’, Scientific American, 1979, 241(3), pp. 150–62
10 E. C. Cherry, ‘Some experiments on the recognition of speech, with one and with two ears’, Journal of the Acoustical Society of America, 1953, 25(5), pp. 975–9
11 D. Kahneman, Attention and Effort, Citeseer, 1973
12 B. C. Hamilton, L. S. Arnold and B. C. Tefft, ‘Distracted driving and perceptions of hands-free technologies: Findings from the 2013 Traffic Safety Culture Index’, 2013
13 N. Mesgarani et al., ‘Phonetic feature encoding in human superior temporal gyrus’, Science, 2014, 343(6174), pp. 1006–10
14 See Chapter 3, n. 14
15 D. J. Simons and D. T. Levin, ‘Failure to detect changes to people during a real-world interaction’, Psychonomic Bulletin & Review, 1998, 5(4), pp. 644–9
16 R. S. F. McCann, D. C. Foyle and J. C. Johnston, ‘Attentional Limitations with Heads-Up Displays’, Proceedings of the Seventh International Symposium on Aviation Psychology, 1993, pp. 70–5
* Some scientists have called this finding into question, arguing that this staggering number of smell sensations is more a quirk of questionable maths used in the research than the result of our mighty nostrils.1
† It’s important to clarify the difference between illusions and hallucinations. Illusions are when the senses detect something but interpret it wrongly, so you end up perceiving something other than what the thing actually is. By contrast, if you smell something with no source, this is a hallucination; perceiving something that isn’t actually there, which suggests something isn’t working as it should deep in the sensory-processing areas of the brain. Illusions are a quirk of the brain’s workings; hallucinations are more serious.
‡ Not that the eyes aren’t impressive, because they are. The eyes are so complex that they’re often cited (not a pun) by creationists and others opposed to evolution as clear proof that natural selection isn’t real; the eye is so intricate it couldn’t just ‘happen’ and therefore must be the work of a powerful creator. But if you truly look at the workings of the eye, then this creator must have designed the eye on a Friday afternoon, or while hung over on the morning shift, because a lot of it doesn’t make much sense.
§ Modern camera and computing technology means it’s much easier (and considerably less uncomfortable) to track eye movements. Some marketing companies have even used eye scanners mounted on trolleys to observe what customers are looking at in shops. Before this, head-mounted laser trackers were used. Science is so advanced these days that lasers are now old-fashioned. This is a cool thing to realise.
¶ For the record, some people claim that they’ve had eye surgery and their eye was ‘taken out’ and left dangling on their cheek at the end of the optic nerve, like in a Tex Avery cartoon. This is impossible; there is some give in the optic nerve, but certainly not enough to support the eye like a grotesque conker on a string. Eye surgery usually involves pulling the eyelids back, holding the eye in place with clamps, and numbing injections, so it feels weird from the patient’s perspective. But the firmness of the eye socket and fragility of the optic nerve means popping the eye out would effectively destroy it, which isn’t a great move for an ophthalmic surgeon.
|| Exactly how we ‘focus’ aural attention is unclear. We don’t swivel our ears towards interesting sounds. One possibility comes from a study by Edward Chang and Nima Mesgarani of the University of California, San Francisco, who looked at the auditory cortex of three epilepsy patients who had electrodes implanted in the relevant regions (to record and help localise seizure activity, not for fun or anything).13 When asked to focus on a specific audio stream out of two or more heard at once, only the one being paid attention to produced any activity in the auditory cortex. The brain somehow suppresses any competing information, allowing full attention to be paid to the voice being listened to. This suggests your brain really can ‘tune someone out’, like when they won’t stop droning on about their tedious hedgehog-spotting hobby.
6
Personality: a testing concept
The complex and confusing properties of personality
Personality. Everybody has one (except maybe those who enter politics). But what is a personality? Roughly, it’s a combination of an individual’s tendencies, beliefs, ways of thinking and behaving. It’s clearly some ‘higher’ function, a combination of all the sophisticated and advanced mental processes humans seem uniquely capable of thanks to our gargantuan brains. But, surprisingly, many think personality doesn’t come from the brain at all.
Historically, people believed in dualism; the idea that the mind and body are separate. The brain, whatever you think of it, is still part of the body; it’s a physical organ. Dualists would argue that the more intangible, philosophical elements of a person (beliefs, attitudes, loves and hates) are held within the mind, or ‘spirit’, or whatever term is given to the immaterial elements of a person.
Then, on 13 September 1848, as a result of an unplanned explosion, railroad worker Phineas Gage had his brain impaled by a metre-long iron rod. It entered his skull just under his left eye, passed right through his left frontal lobe, and exited via the top of his skull. It landed some 25 metres away. The force propelling the rod was so great that a human head offered as much resistance as a net curtain. To clarify, this was not a paper cut.
You’d be forgiven for assuming this would have been fatal. Even today, ‘huge iron rod right through the head’ sounds like a 100-per-cent-lethal injury. And this happened in the mid-1800s, when stubbing your toe usually meant a grim death from gangrene. But, no, Gage survived, and lived another twelve years.
Part of the explanation for this is that the ir
on pole was very smooth and pointed, and travelling at such a speed that the wound was surprisingly precise and ‘clean’. It destroyed almost all the frontal lobe in the left hemisphere of his brain but the brain has impressive levels of redundancy built into it, so the other hemisphere picked up the slack and provided normal functioning. Gage has become iconic in the fields of psychology and neuroscience, as his injury supposedly resulted in a sudden and drastic change in his personality. From a mild-mannered and hardworking sort, he became irresponsible, ill-tempered, foul-mouthed, and even psychotic. ‘Dualism’ had a fight on its hands as this discovery firmly established the idea that the workings of the brain are responsible for a person’s personality.
However, reports of Gage’s changes vary wildly, and towards the end of his life, he was employed long-term as a stagecoach driver, a job with a lot of responsibility and public interaction, so even if he did experience disruptive personality changes he must have got better again. But the extreme claims persist, largely because contemporary psychologists (at the time, a career dominated by self-aggrandising wealthy white men, whereas now it’s … actually, never mind) leapt on Gage’s case as an opportunity to promote their own theories about how the brain worked; and if that meant attributing things that never happened to a lowly railway worker, what of it? This was the nineteenth century, he wasn’t exactly going to find out via Facebook. Most of the extreme claims about his personality changes were seemingly made after his death, so it was practically impossible to refute them.
But even if people were dedicated enough to investigate the actual personality or intellectual changes Gage had experienced, how would they do this? IQ tests were half a century away, and that’s just one possible property that might have been affected. So Gage’s case lead to two persistent realisations about personality: it’s a product of the brain, and it’s a real pain to measure in a valid, objective manner.
E. Jerry Phares and William Chaplin, in their 2009 book Introduction to Personality,1 came up with a definition of personality that most psychologists would be willing to accept: ‘Personality is that pattern of characteristic thoughts, feelings, and behaviours that distinguishes one person from another and that persists over time and situations.’
In the next few sections, we’re going to look at a few fascinating aspects – the approaches used to measure personality, what it is that makes people angry, how they end up compelled to do certain things, and that universal arbiter of a good personality, sense of humour.
Nothing personal
(The questionable use of personality tests)
My sister Katie was born when I was three, when my own puny brain was still relatively fresh. We had the same parents, grew up at the same time, in the same place. It was the 1980s in a small isolated Welsh valley community. Overall, we had very similar environments, and very similar DNA.
You might expect us to have very similar personalities. This is the opposite of what happened. My sister was, to put it mildly, a hyperactive nightmare, whereas I was typically so placid you had to poke me to make sure I was conscious. We’re both adults now, and still largely different. I’m a neuroscientist; she’s an expert cupcake maker. This may seem like I’m being condescending, but I’m really not. Ask anyone what they’d prefer: a discussion on the scientific workings of the brain or a cupcake. See which one is more popular.
The point of this anecdote is to show that two people with very similar origins, environments and genetics can still have vastly different personalities. So what chance does anyone have of predicting and measuring the personalities of two total strangers from the general population?
Take fingerprints. Fingerprints are basically the pattern of ridges in the skin at the end of our digits. Yet, despite this simplicity, almost every human on earth has unique fingerprints. If surface patterns of small patches of skin offer enough variety for everyone to have his or her own exclusive set, how much more variety is possible with something that is the result of countless subtle connections and complex features of the human brain, the most complicated thing in the universe? Even to attempt to determine someone’s personality with a simple tool like a written test should be utterly futile, a task akin to sculpting Mount Rushmore with a plastic fork.
However, current theories argue there are predictable and recognisable components of personalities, labelled ‘traits’, that can be identified via analysis. Just as billions of fingerprints conform to just three types of pattern (loops, whorls and arches) and the vast diversity of human DNA is produced by sequences of just four nucleotides (G, A, T, C), many scientists argue that personalities can be viewed as specific combinations and expressions of certain traits, shared by all people. As J. P. Gillard said in 1959,2 ‘An individual’s personality, then, is his unique pattern of traits.’ Note how it says ‘his’; this was the 1950s, and of course, women were allowed to have personalities only from the mid-1970s.
But what are these traits? How do they combine to form a personality? Arguably the most dominant approach at present is the ‘Big 5’ personality traits, which argues that there are five traits in particular that make up a personality, in the same way that multiple colours can be made by combining red, blue and yellow. These traits are often consistent across situations and result in predictable attitudes and behaviours in an individual.
Everyone supposedly falls between two extremes of the Big 5 traits:
Openness reflects how open to new experiences you are. If invited to see a new exhibition of sculptures made out of rotten pork, people at the extremes of openness may say, ‘Yes, definitely! I’ve never witnessed art made of rancid meat, so this will be brilliant!’ Or, ‘No, it’s in a different part of town to where I usually am so I won’t enjoy it.’
Conscientiousness reflects the extent to which someone is prone to planning, organising, self-discipline. A very conscientious type might agree to attend the rotten-pork exhibition, after working out which would be the best bus route with alternatives in case of traffic disruptions, and also getting a tetanus booster. A non-conscientious type would just agree to meet there in ten minutes, not ask permission to leave work early and opt to follow their nose to find the location.
Extroverts are outgoing, engaging, attention-seeking, while introverts are quiet, private and more solitary. If invited to the rotten-pork exhibition, an extreme extrovert will attend and bring their own hastily made sculpture to show off, and end up posing alongside all the exhibits for their Instagram account. An extreme introvert wouldn’t talk to someone long enough to be invited.
Agreeableness reflects the extent to which your behaviour and thinking is affected by a desire for social harmony. A very agreeable person would surely agree to attend the rotten-pork sculpture exhibition, but only as long as the person inviting didn’t mind (they don’t want to be a bother). Someone totally lacking in agreeableness probably wouldn’t be invited anywhere by anyone in the first place.
A neurotic person is invited to a rotten-pork sculpture exhibit and they decline and explain why in exquisite detail. See: Woody Allen.
Unlikely art exhibitions aside, these are the traits that make up the Big 5. There’s a lot of evidence to suggest they’re quite consistent: a person who scores high on agreeableness will show the same tendencies in a wide variety of situations. There is also some data linking certain personality traits with specific brain activity and regions. Hans J. Eysenck, one of the big names in personality studies, claimed that introverts have higher levels of cortical arousal (stimulation and activity in the cortex) than extroverts.3 One interpretation of this is that introverts don’t require much stimulation. Extroverts, by contrast, want to be excited more often, and develop personalities around this.
Recent scanning studies, like those by Yasuyuki Taki and others,4 suggest that individuals demonstrating neuroticism show smaller-than-average areas such as the dorsomedial prefrontal cortex and the left medial temporal lobe including the posterior hippocampus, with a bigger mid-cingulate gyrus. These regions
are implicated in decision-making, learning and memory, suggesting a neurotic person is less able to control or suppress paranoid predictions and learn that these predictions are unreliable. Extroversion showed increased activity in the orbitofrontal cortex, which is linked to decision-making, so perhaps because of this raised activity in the decision-making regions, extroverts are compelled to be active and make decisions more often, leading to more outgoing behaviour as a result?
There is also evidence to suggest there are genetic factors underlying personality. A 1996 study by Jang, Livesley and Vernon using nearly 300 pairs of twins (identical and non-identical) suggested that the heritability of the Big 5 personality traits ranged from between 40 per cent to 60 per cent.5
What the preceding paragraphs boil down to is that there are some personality traits, specifically five, that have a large body of evidence behind them and appear to be associated with brain regions and genes. So what’s the issue?
Firstly, many argue that the Big 5 personality traits don’t provide a thorough description of the true complexity of personality. It’s a good overall range, but what about humour? Or tendency to religion or superstition? Or temper? Critics suggest the Big 5 are more indicative of ‘outward’ personality; all those traits can be observed by another person, whereas much of personality is internal (humour, beliefs, prejudices and so on), taking place largely inside your head and not necessarily being reflected in behaviour.
We’ve seen evidence that personality types are reflected in the configuration of the brain, suggesting they have biological origins. But the brain is flexible and changes in response to what it experiences, so the brain configurations we see could be a consequence of the personality types, not a cause. Being very neurotic or extroverted means you end up with distinct experiences, which could be what the arrangement of your brain bits is reflecting. This is assuming the data itself is 100 per cent confirmed, which it isn’t.