Loneliness changes the structure and function of the brain

Loneliness increases the risk of poor sleep, higher blood pressure, cognitive and immune decline, depression, and ultimately an earlier death. Why? The traditional explanation is that lonely people lack life’s advisors: people who encourage healthy behaviours and curb unhealthy ones. If so, we should invest in pamphlets, adverts and GP advice: ignorance is the true disease, loneliness just a symptom.

But this can’t be the full story. Introverts with small networks aren’t at especial health risk, and people with an objectively full social life can feel lonely and suffer the consequences. A new review argues that for the 800,000 UK citizens who experience it all or most of the time, loneliness itself is the disease: it directly alters our perception, our thoughts, and the very structure and chemistry of our brains. The authors – loneliness expert John Cacioppo, his wife Stephanie Cacioppo, and their colleague John Capitanio – build their case on psychological and neuroscientific research, together with animal studies that help show loneliness really is the cause, not just the consequence, of various mental and physical effects.

The review suggests lonely people are sensitive to negative social outcomes and accordingly their responses in social settings are dampened. We know the former from reaction time tasks involving negative social words (lonely people respond faster), and tasks involving the detection of concealed pain in faces (lonely people are extra sensitive when the faces are dislikeable). Functional imaging evidence also shows lonely people have a suppressed neural response to rewarding social stimuli, which reduces their excitement about possible social contact; they also have dampened activity in brain areas involved in predicting what others are thinking – possibly a defence mechanism based on the idea that it’s better not to know. All this adds up to what the authors characterise as a social "self-preservation mode."

Meanwhile, animal models are helping us to understand the deeper, biological correlates associated with loneliness. For mice, being raised in isolation depletes key neurosteroids including one involved in aggression; it reduces brain myelination, which is vital to brain plasticity and may account for the social withdrawal and inflexibility seen in isolated animals; and it can influence gene expression linked to anxious behaviours.

What about changes to our neural tissue? Human research is suggestive: in one study, people who self-identified as lonelier were more likely to develop dementia. Here, initial cognitive decline could be causing loneliness, but animal work gives us some plausible mechanisms for loneliness’ impact: animals kept in isolation have suppressed growth of new neurons in areas relating to communication and memory, just as very social periods such as breeding season see a pronounced spike in growth.

Other basic brain processes are also upset by isolation. Isolated mice show reduced delta-wave activity during deep sleep; and their inflammatory responses also change, meaning that in one study, three in five isolated mice died following an induced stroke, whereas every one of their cage-sharing peers survived the same process.

The research is clear that loneliness directly impacts health, so we need to do what we can to help people free themselves from social marginalisation. I’ve seen one approach during my time serving with time banking charities, in which people give their own time in return for someone else’s in a different situation – a process that can build social networks. Also the issue is acquiring momentum through the Campaign to End Loneliness and technology solutions such as the RSA’s Social Mirror project – an app that tells people about local social groups and activities. Mainstream health is also picking this up under the term “social prescription” (physicians advise patients of social groups and activities and “facilitators” help the patients take up the opportunities). But amongst all the institutional activity, we mustn’t forget our individual duties: sometimes all that’s needed is to reach out.

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Cacioppo, S., Capitanio, J., & Cacioppo, J. (2014). Toward a neurology of loneliness. Psychological Bulletin, 140 (6), 1464-1504 DOI: 10.1037/a0037618

Post written by Alex Fradera (@alexfradera) for the BPS Research Digest.

New sleep research

For many years psychologists have divided people into two types based on their sleeping habits. There are Larks who rise early, feel sprightly in the morning, and retire to bed early; and Owls, who do the opposite, preferring to get up late and who come alive in the evening.

Have you ever thought that you don't fit either pattern; that you're neither a morning nor evening person? Even in good health, maybe you feel sluggish most of the time, or conversely, perhaps you feel high energy in the morning and evening. If so, you'll relate to a new study published by Arcady Putilov and his colleagues at the Siberian Branch of the Russian Academy of Sciences.

The researchers invited 130 healthy people (54 men) to a sleep lab and kept them awake for just over 24 hours. The participants were asked to refrain from coffee and alcohol, and several times during their stay they filled out questionnaires about how wakeful or dozy they were feeling. They also answered questions about their sleep patterns and wakeful functioning during the preceding week.

By analysing the participants' energy levels through the 24 period and their reports about their functioning during the previous week, Putilov and his team identified four distinct groups. Consistent with past research, there were Larks (29 of them), who showed higher energy levels on the first and second mornings at 9AM, but lower levels when tested at 9PM and midnight; and there were Owls (44 of them), who showed the opposite pattern. The Larks also reported rising earlier and going to bed earlier through the previous week, whereas the Owls showed the opposite pattern. There was an average two-hour difference between the sleep and wake cycles of these two groups.

The researchers also identified two further chronotypes. There was a "high energetic" group of 25 people who reported feeling relatively sprightly in both the morning and evening; and a "lethargic" group of 32 others, who described feeling relatively dozy in both the morning and evening. Unlike the Owls and Larks, these two groups didn't show differences in terms of their time to bed and time of waking - their habits tended to lie mid-way between the Larks and Owls.

The researchers said their results support the idea of there being "four diurnal types, and each of these types can ... be differentiated from any of three other types on self-scorings of alertness-sleepiness levels in the course of 24-hours sleep deprivation."

We already have bird names for morning and evening people - Owls and Larks. Part of the title of this new paper is "A search for two further 'bird species'". I was hoping the authors might propose two new bird names for their high energy and lethargic categories, but sadly they don't. What about Swift for the high energy category? I'm not sure about a lethargic bird. It's over to you - any ideas? [Readers on Twitter have so far proposed Dodo and Pelican].

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Putilov, A., Donskaya, O., & Verevkin, E. (2015). How many diurnal types are there? A search for two further “bird species” Personality and Individual Differences, 72, 12-17 DOI: 10.1016/j.paid.2014.08.003

Depression can effect our 'gut instincts'

People who are depressed often complain that they find it difficult to make decisions. A new study provides an explanation. Carina Remmers and her colleagues tested 29 patients diagnosed with major depression and 27 healthy controls and they found that the people with depression had an impaired ability to go with their gut instincts, or what we might call intuition.

Intuition is not an easy skill to measure. The researchers' approach was to present participants with triads of words (e.g. SALT DEEP FOAM) and the task was to decide in less than three and a half seconds whether the three words were linked in meaning by a fourth word (in this case the answer was "yes" and the word was SEA). Some triads were linked, others weren't.

If the participants answered that the words were linked, they were given eight more seconds to provide the linking fourth word. However, it was perfectly acceptable for them to say that they felt the words were linked, but that they didn't know how. Indeed, when this occurred, it was taken by the researchers as an instance of intuition - that is, "knowing without knowing how one knows".

There were no differences between the depressed patients and controls in the number of times they provided the correct fourth, linking word, nor in the number times they provided no response at all. This suggests both groups were equally motivated and attentive to the task. But crucially, the depressed patients scored fewer correct intuitive answers (i.e. those times they stated correctly that the words were linked, but they didn't consciously know how).

Having poorer intuition on the task was associated with scoring higher on a measure of brooding (indicated by agreement with statements like "When I am sad, I think 'Why do I have problems others don't have?'"), and in turn this association appeared to be explained by the fact that the brooding patients felt more miserable.

Remmers and her team said their study makes an important contribution - in fact, it's the first time that intuition has been studied in people with major depression. The results are also consistent with past research involving healthy people that's shown low mood encourages an analytical style of thought and inhibits a creative, more intuitive thinking style.

However, I couldn't help doubting the realism of the measure of intuition used in this study. Is a judgement about word meanings really comparable to the gut decisions people have to make in their lives about jobs and relationships?

Two further questions that also remain outstanding are whether an impairment in intuitive thinking is a symptom or cause of depression; and is this intuition deficit specific to depression or will it be found in patients with other mental health problems?

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Remmers C, Topolinski S, Dietrich DE, & Michalak J (2014). Impaired intuition in patients with major depressive disorder. The British journal of clinical psychology / the British Psychological Society PMID: 25307321

Mate 'poaching'

According to one estimate, 63 per cent of men and 54 per cent of women are in their current long-term relationships because their current partner "poached" them from a previous partner. Now researchers in the US and Australia have conducted the first investigation into the fate of relationships formed this way, as compared with relationships formed by two unattached individuals.

An initial study involved surveying 138 heterosexual participants (average age 20; 71 per cent were women) four times over nine weeks. All were in current romantic relationships that had lasted so far from 0 to 36 months. Men and women who said they'd been poached by their current partner tended to start out the study by reporting less commitment to their existing relationship, feeling less satisfied in it, committing more acts of infidelity and looking out for more alternatives.What's more, over the course of the study, these participants reported progressively lower levels of commitment and satisfaction in their relationships. They also showed continued interest in other potential romantic partners and persistent levels of infidelity. This is in contrast to participants who hadn't been poached by their partners - they showed less interest in romantic alternatives over time.

The researchers led by Joshua Foster attempted to replicate these results with a second sample of 140 heterosexual participants who were surveyed six times over ten weeks. Again the participants who said they'd been poached by their partners tended to report less commitment and satisfaction in their current relationships, and more interest in romantic alternatives. However, unlike the first sample, this group did not show deterioration in their relationship over the course of the study. The researchers speculated this may be because the study was too short-lived or because deterioration in these relationships had already bottomed out.

It makes intuitive sense that people who were poached by their partners showed less commitment and satisfaction in their existing relationship. After all, if they were willing to abandon a partner in the past, why should they not be willing or even keen to do so again? This logic was borne out by a final study of 219 more heterosexual participants who answered questions not just about the way their current relationship had been formed, but also about their personalities and attitudes.

Foster and his team summarised the findings: "individuals who were successfully mate poached by their current partners tend[ed] to be socially passive, not particularly nice to others, careless and irresponsible, and narcissistic. They also tend[ed] to desire and engage in sexual behaviour outside of the confines of committed relationships." The last factor in particular (measured formally with the "Socio-sexual Orientation Inventory-revised") appeared to explain a large part of the link between having been poached by one's partner and having weak commitment to the new relationship.

Across the three studies, between 10 and 30 per cent of participants said they'd been poached by their current partners. This shows again that a significant proportion of relationships are formed this way, the researchers said, and that more research is needed to better understand how these relationships function. "We present the first known evidence [showing] specific long-term disadvantages for individuals involved in relations that formed via mate poaching," they concluded.

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Foster, J., Jonason, P., Shrira, I., Keith Campbell, W., Shiverdecker, L., & Varner, S. (2014). What do you get when you make somebody else’s partner your own? An analysis of relationships formed via mate poaching Journal of Research in Personality, 52, 78-90 DOI: 10.1016/j.jrp.2014.07.008

Happy walking helps keep people more positive.

Walking in a more happy style could help counter the negative mental processes associated with depression. That's according to psychologists in Germany and Canada who used biofeedback to influence the walking style of 47 university students on a treadmill.

The students, who were kept in the dark about the true aims of the study, had their gait monitored with motion capture technology. For half of them, the more happily they walked (characterised by larger arm and body swings, and a more upright posture), the further a gauge on a video monitor shifted to the right; the sadder their gait, the more it shifted leftwards. The students weren't told what the gauge measured, but they were instructed to experiment with different walking styles to try to shift the bar rightwards. This feedback had the effect of encouraging them to walk with a gait characteristic of people who are happy.

For the other half of the students, the gauge direction was reversed, and the sadder their gait, the further the gauge shifted to the right. Again, these students weren't told what the gauge measured, but they were instructed to experiment with their walking style and to try to shift the gauge rightwards as far as possible. In other words, the feedback encouraged them to adopt a style of walking characteristic of people who are feeling low.

After four minutes of gait feedback on the treadmill, both groups of students were asked how much forty different positive and negative emotional words were a good description of their own personality. This quiz took about two minutes, after which the students continued for another eight minutes trying to keep the gait feedback gauge deflected to the right. The students' final and crucial task on the treadmill was to recall as many of the earlier descriptive words as possible.

The striking finding is that the students who were unknowingly guided by feedback to walk with a happier gait tended to remember more positive than negative self-referential words, as compared with the students who were guided to walk with a more negative style. That is, the happy walkers recalled an average of 6 positive words and 3.8 negative words, compared with the sad walkers who recalled an average of 5.47 positive words and 5.63 negative words. Focusing on the students who achieved the happiest style of gait, they recalled three times as many positive words as the students who achieved the saddest style of gait.

"Our results show that biased memory towards self-referent negative material [a feature of depression] can be changed by manipulating the style of walking," said the research team led by Johannes Michalak. The observed effects of gait on memory were not accompanied by any group differences in the students' self-reported mood at the end of the study, suggesting a direct effect of walking style on emotional memory processes.

The results build on past research that suggests pulling a happy facial expression can lift people's mood. There could be exciting practical implications for helping people with depression, but the researchers acknowledged some issues need to be addressed. For example, the current study involved a small non-clinical sample, and the researcher who delivered the forty emotional words to the walking students was not blind to the gait condition they were in, raising the possibility that he or she inadvertently influenced the results in some way. It's also notable that there wasn't data from a baseline control group whose gait was not influenced; it would have been useful to see how they performed on the memory test.
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  Michalak, J., Rohde, K., & Troje, N. (2015). How we walk affects what we remember: Gait modifications through biofeedback change negative affective memory bias Journal of Behavior Therapy and Experimental Psychiatry, 46, 121-125 DOI: 10.1016/j.jbtep.2014.09.004