The psychological effects of your morning coffee – BPS

The neither-up-nor-down side

While caffeine improves a range of cognitive abilities, creativity is not one of them. Darya Zabelina at the University of Arkansas and colleagues gave participants either a 200mg caffeine pill (equivalent to one strong cup of coffee) or a placebo, then a battery of tests.

As expected, those with caffeine in their system did better on a problem-solving task, which involved coming up with a fourth word that could link three given words (such as ‘cheese’ for cottage, swiss and cake). The team also assessed participants’ creativity, using a divergent thinking test. The participants had to use simple symbols as the start of a more complex drawing, and come up with as many uses as possible for an everyday object, for example. On these tests, was no difference between the two groups. The researchers speculate that this is because creative thinking is easier when the brain is in a less focused, more relaxed state (which caffeine does not foster).

The social side

If you want someone to feel warmly towards you, hand them a hot cup of coffee. That, at least, is the controversial conclusion of well-publicised research by US psychologists Lawrence Williams and John Bargh. Bargh has run a series of studies that suggest that physical heat or cold affect our perceptions of social warmth. His argument is that from our earliest days, we associate physical warmth with the comforting presence of a caregiver, and that this unconscious association persists into our adult lives. It’s been suggested that when we experience physical warmth as an adult, this encourages not only warm feelings towards whoever we are with, but also generates a kind of partial social satiety.

The original 2008 Williams and Bargh study notoriously failed to replicate, and other findings in this field have been mixed. However, some researchers argue that at least some of these inconsistencies could be down to variations in the ambient temperature on the day, or in the room. When ambient temperature was controlled for in a recent study, the team found support for the idea that temperature warmth may indeed influence our social judgements, reducing a desire for social contact.

The limits

Many of us ‘treat’ a bad night’s sleep with an extra cup or two of coffee the next morning. Past studies have led researchers to suggest that all of the cognitive deficits associated with sleep deprivation (including a slower reaction time and poorer concentration) stem from impaired attention. And as caffeine boosts attention, then coffee should indeed at least help with all the problems caused by a lack of sleep. However, a study published last year reported that there is one category of sleep-deprivation deficits that it does nothing to address: ‘place-keeping’ deficits. These are problems with keeping track of where you are in a relatively complex task, whether that’s working through steps in a hospital setting or a factory, or writing an essay. Place-keeping deficits don’t stem from impaired attention. So this work suggests that a lack of sleep has broader cognitive impacts — and also implies that it’s wrong to assume that coffee will treat all the resulting problems.