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Post No.: 0401multitasking


Furrywisepuppy says:


We are generally overconfident in our ability to do multitasking. Doing a lot of media multitasking is actually related to lower performances in formal tests of concentration and task-switching.


There are auditory-verbal, visual-spatial and motor-based tasks, and we may be able to perform two tasks in parallel if they involve distinctly different modalities. So we may be able to comfortably listen to music and paint a picture at the same time, for they involve different modalities (auditory and visual), but we cannot easily listen to music with lyrics and write a dissertation at the same time (for they’re both verbal tasks).


It therefore seems fine to talk (hands-free if on a phone) and drive at the same time (an auditory-verbal task and a visual-spatial and motor task) – but do note that we sometimes create mental images during conversations and these will interfere with our attention on the road, thus it’s not that simple. This means that even using a hands-free phone setup when driving can potentially cause a distraction.


When two tasks utilise overlapping modalities, we have to constantly mentally switch between attending to one task or the other. Our eyes can only be looking at one thing at a time, our ears can only focus on one voice at a time, we can only ask our memories to answer one query at a time, we can only use our dominant paw to do one thing at a time, and so on. We can at best very rapidly flit back-and-forth between paying attention on one separate task then another but not perform them strictly simultaneously. And split/divided attention activities reveal that we’re not very good at switching between tasks that require focused attention.


All this mental switching, even if rapid, will mean that we’ll miss information or make errors due to paying insufficient attention. Multitasking can mean a superficial skimming of incoming information, which can result in a high rate of fuzzy inaccuracies (the same problem is true with practices like ‘speed reading’). Paying only partial attention can therefore make us think we understand something fully but we’ll miss the depth, perhaps without realising it – precisely because of our partial attention. We might never be aware of what we’ve missed because we’ve logically missed it.


Every time we switch our attention back onto a task, our brain must essentially re-orientate in order to re-focus on that task. The brain basically has to ask ‘now where was I during this task?’ every single time one’s attention is diverted back onto it from another task. Even if this might only take milliseconds to answer each time, this multitasking is highly inefficient and a waste of time compared to switching attention only once i.e. attending to one task until it’s completed then attending to the next; unless the tasks don’t require or benefit from applying continuous concentration (e.g. cooking something on the stove and cooking something in the oven at the same time doesn’t normally require us to watch each task literally constantly without interruption). Multitasking can therefore result in taking a much longer time to complete all tasks compared to doing them each sequentially, and result in a much greater error rate too, which might be materially costly.


Playing a game on one’s phone whilst watching a movie, for instance, means that we won’t get the best from either activity, which might be personally acceptable if one doesn’t really care that much about one activity or the other (e.g. the game is important but following the movie isn’t) – but if that’s the case then why not ditch that task altogether? This modern age of multiple media sources at our fingertips can give us the impression of doing much more than people from previous generations, but these extra features in our environment are more often adding distractions rather than increasing productivity if we think that we can consume them all simultaneously. The environment may have evolved greatly over the past few decades but it doesn’t mean that we have too.


Even when multitasking with tasks that employ completely non-overlapping modalities, this is only possible up to a certain level of intensity with any single task i.e. if any single task is mentally intensive then we must solely concentrate on that, even if it’s in a different modal category to another task we wish to perform simultaneously (e.g. we’ll tend to stop talking or listening when we’re reverse parking into a very tight spot, even though one task is auditory-verbal and the other is visual-spatial and motor).


Some people may appear to be naturally better at multitasking than others, but there is no clear evidence that women are better at multitasking than men, or vice-versa, hence such differences won’t be down to one’s gender. Nonetheless, even the best do worse when multitasking compared to doing each task separately.


Regarding the field of cognitive ergonomics and human-centred design – our ‘situational awareness’ depends on receiving prompt, clear, accurate and consistent feedback, and depends on our limited attentional resources. Research and design in this area again shows that, apart from when we are at our limit (when we’ll need to focus strictly entirely on one task at a time), we can sing and perform a motor task such as dance at the same time, or listen to instructions and process a spatial task at the same time, for example, but we cannot perform two separate and distinct verbal and auditory tasks well at the same time, or complete two separate and distinct motor tasks or spatial tasks simultaneously, for example. Good ergonomic user-interface and product design therefore doesn’t overload people’s attentional resources or mental capacities. We need the relevant information at, and only at, the right times rather than bombarding people with as much information as possible.


Attention is about focusing on some things at the expense of other things. Attention has a bottleneck because it’s limited – we can only focus on so much at a time thus some things have to give way. There are also limited physiological resources (e.g. blood flow to the brain for optimal cognition versus blood flow to the gut for optimal digestion) and of course a limited number of physical limbs to do things simultaneously. Basically, there are limited resources at every level for doing anything and these will have to be divided between everything we wish to simultaneously do.


There are innate instincts (no need to teach or learn these), cognitively-involving performances such as learning as a novice in a particular task (these require a lot of mental resources to perform e.g. manually changing gears in a car as a novice), and second-nature performances after one has learnt a task so well that one is an expert in that particular task (these can become as good as instinctive over time e.g. manually changing gears in a car as an experienced driver of cars with manual gearboxes). In Post No.: 0373, Fluffystealthkitten looked at innate versus skilled intuitions.


The more trained someone is at a particular task, the less cognitive load they’ll experience when performing that specific task they’re trained at doing compared to someone who isn’t as trained, so this is a factor too – so if one becomes proficient at performing two tasks then it’s possible to rapidly shift attention between them and perform them both to a satisfactory (though not optimal) level; but only those specific tasks in those specific conditions one has trained oneself to be proficient.


In fact, it becomes less efficient to over-think during tasks we otherwise now have down as second nature. However, if we’ve not personally practised a task for long enough until consistent successful results are second nature to us yet, or we’re a bit rusty, or something’s different this time, then we must beware not to under-think things. For instance, we shouldn’t tell someone who’s never driven before to not consciously step-by-step think carefully about everything they’re doing – that’s obviously why instructors teach one step at a time and make you first consciously aware of each single step that must be taken to safely and smoothly drive. Or if something is even slightly different than usual, such as going from a right-hand-drive to left-hand-drive vehicle or vice-versa, if you don’t think enough then you’re going to be whacking your hand on the door reaching for the gear stick! (Re)learning needs thinking, but thinking needs attention, and attention is limited. Woof!


Errors can be broken down into mistakes (failures in planning – there are rule-based mistakes and knowledge-based mistakes), and slips and lapses (failures in execution – more specifically, slips are attention failures and lapses are memory failures).


Errors often materialise as a result of an error trajectory i.e. a sequence of events that occur that lead towards an error, for which if just one link in that chain were broken then that error would’ve been prevented. This is why multiple ‘redundancies’ are built into important systems – if one thing goes wrong then it shouldn’t cause a catastrophe because something else should catch that problem or make up for it, just like using a safety rope plus a safety net, or wearing a belt plus braces.


In reality, literally everything that ever happens requires a sequence of events to make them happen, where if one vital thing was missing or different then it wouldn’t have happened, whether we talk about fortunate or unfortunate events (or even how planet Earth came to be). But highlighting it here in the context of errors shows us how we can learn from tragic events to put in place systems that can reduce the chances of them happening again in the future.


In any field of design, good designers need to think of things like people making errors, accidents, intentional misuse or product abuse (including the environmental effects of accidents or how a product could facilitate new or greater forms of fraud or terrorism). There are many ways that things can fail, go wrong or be abused and we need to anticipate them and minimise their opportunities and/or consequences (e.g. via a failure mode and effects analysis).


Goalkeepers who haven’t been involved in a game for 80 minutes and then are suddenly called upon are more likely to make errors than goalkeepers who’ve been involved throughout the game – one has got to be mentally ready. (Bear in mind that being mentally ready should be expected in a game that lasts only ~90-120 minutes long but to keep hyper-vigilant for anything 24/7 would otherwise be unhealthy.) This is a more dangerous problem with autonomous vehicles where if the standby human driver isn’t involved enough in the driving then he/she will likely not respond or even recognise an impending collision in time in order to avoid it. There’s therefore actually an optimal level of mental workload or engagement to perform optimally – neither being overloaded nor underloaded is best.


Back to multitasking – the problem of inattentional blindness/deafness is clear evidence that we have limited attentional resources. We cannot pay attention to everything in the environment hence we end up missing lots of things – things we won’t realise we’ve missed because, well, we totally missed them! When we lose one sense, our other senses ‘enhance’, but this is not because those remaining senses become stronger per se – it’s just that we can now allocate more of our limited attentional resources to those remaining senses, which means that we should pick up more information via those senses. We don’t, for instance, hear more if we lose our sight, so much as miss less auditory information if we lose our sight. The fact that this happens once again reveals how much sensory information we normally miss in our daily lives.


Woof. Overall – unless you count breathing while walking as successful multitasking(!) – multitasking increases the rate of errors and/or decreases productivity. So if a set of jobs are worth doing your best at – do them one at a time.


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