Rabbit in the headlights
There’s a fresh nip in the air at dawn and the evenings are noticeably shorter.
Before long, my mum and her friends – and lots of mine – will start to have second thoughts about driving to an event in the evening, knowing they’ll have to drive home after dark.
Most do their level best to avoid it – that’s pretty sensible given that they’re 23% more likely to get injured in a collision after nightfall – Exploring the Causal Impact of Age and Nighttime Driving on Road Traffic Injuries among Elderly Drivers: A Bayesian LASSO Approach.
This study suggests that some might even welcome a ban on night-time driving if it meant they could keep their licence to drive during the day – Adapting to vision changes: nighttime driving experiences of older adults.
Although those older adults behind the wheel at night are an obvious source of concern, thousands of care workers are on the road in the twilight hours or before the sun rises at dawn. Night-shift workers are at much higher risk of road traffic accidents even on a short 30-minute commute – Sleepiness and driving events in shift workers: the impact of circadian and homeostatic factors.
So what’s that got to do with the lights – and is there anything practical we can do to keep ourselves safe on the road as we age?
1/ Time of day effects – we’re all slower when we’re tired, so spending half an hour in bright lighting – and ideally cooling down – before you take the wheel could trick your brain into thinking it’s not late after all and improve reaction times. Studies with truck drivers in the Arctic Circle found that adding a panel of bright light to the cabins improved performance and safety before, during and after driving without negative side-effects for the following night’s sleep. I’m not suggesting my mum adds that to her little ‘red bullet’ – but for care workers, having the option of a ‘light shower’ before they head home might help – Multimodal in-vehicle lighting system increases daytime light exposure and alertness in truck drivers under Arctic winter conditions.
2/ Twilight zone – your retina has to work harder in low light levels – known as ‘mesopic’ vision, it’s much harder to see fine details, contrast and colours. To compound the problem, making sense of signals that have filtered through a grubby windscreen, greasy glasses and natural clouding of the lens, cornea and vitreous humour. the clear gel inside the eye is a lot to ask. Making sure the windscreen is clean all the way to the edges, adding anti-glare filters to glasses and getting eyes checked for early stage cataracts could all give your eyes a fighting chance of keeping you safe,
3/ Glare from headlamps – it’s frightening to be rolling along at 30 miles an hour (or more) with blinding headlamps in the centre of your visual field. In towns and cities, the sheer density of information on reflective signs can add to that sense of overwhelm and confusion – Information density threshold of urban road traffic signs based on visual comfort. The obvious solution is to tackle the root of the problem – the light sources themselves. But in the meantime. directing your gaze slightly off centre and towards the edge of the road will give your pupil a break and help you to cope with that ‘rabbit in the headlamps’ fight or flight response. Eye Movement and Pupil Size Constriction Under Discomfort Glare.
But it’s worth remembering that one in five accidents are ‘rear-end’ collisions – Rear-end collisions account for 22.5% of all accidents, AX finds. Frustrating as it may be to sit behind a slow driver when you’re late, as my recent speed awareness course reminded me, choosing a safe speed and keeping your distance is the best protection you can get.
Seeing eye to eye with a wasp
A familiar sight at a summer picnic here in the UK most of us bat them away – or reach for a can of spray.
We’re coming into peak wasp sting season, and given how serious that can be, especially for older adults, I can understand the reaction – Clinical characteristics of older people and risk factors for developing multiple organ dysfunction following wasp stings.
But, watching a team of wasps carve busily away at my bacon and eggs one morning got me wondering what it could see. Having read a bit more how their visual system works, I just hope it remembers my smile!
Wasps are social and territorial creatures with a complex hierarchy enforced by aggression – Paper wasps: A model clade for social cognition.
So working out who is who matters a lot. But analysing every feature – eye, nose, jawline – takes time and processing power. So it turns out that just like us, they take a wholistic view, with specialist ‘face cells’ (scientists have coined the term ‘wasp cells’) encoding patterns that correspond to a specific individual – Neural correlates of individual facial recognition in a social wasp. They can remember social interactions for over a week, learn who is a ‘baddy’ – Like humans, wasps seem to recognize faces as more than the sum of their parts, and even practice ‘social eavesdropping’ – deciding whether to pick a fight with a rival based on how well they saw their potential opponent perform with another – Wasps Use Social Eavesdropping to Learn about Individual Rivals.
Perhaps unsurprisingly, wasps have excellent colour vision – like us they’re better at identifying colour faces than black and white ones – and are attracted to vibrant colours associated with sources of food. One study that looked at the optimal colour for non-toxic traps found that yellow, pink and white caught the most – Color preference of social wasps to non-toxic traps.
So if you want to enjoy your breakfast without waspish company, wear dull colours and steer clear of scrambled eggs!