Brain & Mind

Intelligence is elegant, elastic and elusive; a universal human quality and a much-prized talent. It is intertwined with both thinking and thoughtfulness, the play of abstract ideas and the concern for how choices may play out and their effect on others. Many competing or coalescing theories of intelligence have emerged since the introduction of the IQ test in the early 1900s, but there is still a lack of consensus among psychologists about how it is defined and whether it can be accurately assessed in all its aspects.  The idea that our own human intelligence presents such a challenge to our intelligence makes it seem appropriate that the word also refers to significant information obtained, often deviously, from a secret, underground source.

When performing creative thinking tasks, the brains of highly creative people tend to adopt an atypical approach that makes distant connections quickly, bypassing the usual ‘hubs’ seen in less creative brains. Research with creative people has shown that they tend to ‘stay off the beaten path’, their connections taking new and different routes across the brain. Research studies have shown that exceptional creativity is associated with more random connectivity at the global scale of the brain, while within local brain regions the pattern is more varied. Distant connectivity may often be less efficient than the ‘hub’ route, but it enables brain activity to make distinctive and original new connections. The wealth of research into the sources and the sparking of creativity has led to the development and testing of creativity training techniques. As examples, these have included a narrative or speculative storytelling approach and the use of divergent thinking to brainstorm different responses to a problem or situation.

Sometimes, of course, it is the lack of conscious mental effort that opens us up to the big idea or flight of the imagination. Someone may say that inspiration came to them while they were walking in the woods, or that they do their best thinking when having a shower or going for a run. Studies have shown that exercise improves cognitive function through increasing blood flow around the body and boosting the production of chemicals that control the growth of new blood vessels in the brain. It clears the mind, put things in perspective, releases feel-good dopamine and allows our brains to wander the ‘paths less travelled’. This is caused by the brain’s default mode network (DMN) going into overdrive when we stop focusing on the task in front of us. The DMN assists us to solve problems in more creative ways and seems to do this especially well when we disconnect. A similar effect may be noticed when we momentarily doze off or allow our mind to wander and go off at tangents, which it will tend to do for a large proportion of our waking day. The tangle of thoughts and memories may be associated through specific sensory and emotional details and encounters, although we may not consciously understand what triggered them. Their spontaneous nature can provoke new ideas when we are least expecting them. 

Immersion in a highly rewarding activity, be it playing music, running, writing, dancing, aikido or any other creative, physical or intellectual pursuit, can bring on the state of ‘flow’. It is often described as ‘being in the zone’ and involves intense focus and concentration, to the extent that you lose the sense of time and feel a merging of your actions and awareness. The experience does not feel physically or mentally taxing and you retain a sense of control. Scientists refer to flow as autotelic (intrinsically rewarding). It occurs when the challenge of a task is balanced with one’s skills and experience and they are both at a high level. People can find flow in everyday experiences through practice, attention and honing specific skills. It is also possible to attain the state of flow by using interactive media, like playing a video game. Game developers are familiar with the idea and think a great deal about how to design their games so that the players will enjoy (and return for) this result. Research has also shown that the effects of such activities go beyond a satisfying immediate experience, in that they boost resilience, are good for overall brain health and protect areas of the brain that are vulnerable to ageing.

The influence of the internet – on what we think about, how we learn and which opinions we decide to adopt – seems boundless and incalculable. In theory, the instant access to factual knowledge frees the brain to engage in critical thinking around issues and develop information literacy, in terms of understanding data and dealing with complexity and uncertainty. These skills are part of the scientific approach, which gives us a way to perceive the world beyond our own senses, prejudices and insecurities. The problem is that we are faced with a wealth of high-quality information alongside a torrent of low-quality, distracting and manipulative comment and behaviour. Online search platforms hijack our attention to direct it towards things that arouse emotions, and the sheer volume of material is leading to shorter attention spans and fiercer competition. In this context, the ability to stay focused is particularly important when selecting what we most value and blanking out or avoiding the unwanted noise. Research has shown that simple brain training through daily activities that require quick decision-making or task-switching, such as puzzles and dancing, can speed up mental processing and help to improve cognitive abilities.      

Maintaining attention is not always easy; it is a fickle thing. Past studies have indicated that the brain can shift focus four times a second, as if scanning its surroundings for stimuli it might need to register. Losing focus can expand the scope of attention, allowing us to introduce divergent thinking by integrating and making links between far-flung concepts, while shifting between periods of being focused and less focused. In other contexts, such as formal education, learning is a long term process that also involves repetition, perseverance and a huge degree of commitment. The steady accumulation of knowledge and the growth of opportunities to apply that knowledge in a specialist area are highly valued in our modern complex societies, but it is also vital to foster the sense of accomplishment that comes through gaining mastery in any much desired skill that we have found difficult and daunting.

The arrival of AI, now entering its ‘generative’ phase, promises (or threatens) to disrupt and reorient human thinking and learning in many different contexts. As an early example, ChatGPT is a large language model that uses algorithms and predictive text to create new content based on human prompts. It takes in the conversation presented to it, explores a probability for all the words in its vocabulary relevant to that conversation, and responds by choosing the most likely next word. The contrasting media headlines highlight the wide range of reactions: ChatGPT is great – you’re just using it wrong; Access to ChatGPT-style tech is about to change our world; Is ChatGPT too clever for its own good? One early editorial in the Guardian newspaper (Feb 2023) referred to concern about dumbing down effects by comparing humanity to the juvenile sea squirt, which “looks for a suitable rock or hunk of coral … to make its home for life” and on finding the right place, proceeds to eat its brain as it is no longer needed. Other less sceptical or less humorous commentators have viewed it as an exciting, helpful and time-saving aid to human intelligence and inventiveness.

Neuroscience has shown that people have very diverse emotional responses or affect styles, which have both biological and social roots. Those with a happier disposition are naturally more likely to look for positive input, while still being able to recognise the negative stimuli around them. The technique of cognitive reappraisal has been shown to physically alter brain activity through a process of reframing that lessens the weight of negative emotions. This can change our emotional response to a particular stressful situation by altering how we think about it and the meaning we attach to it. Another tool for emotional regulation is known as mindful meditation, which can improve our mood and response to external stimuli through awareness of sensations, thoughts and feelings.

The everyday actions involved in giving thoughtful attention to mental fitness and brain health are now well established, although specific recommendations – on diet, exercise, movement, breathing, meditation, sleep, social connection and creative activities – will vary to some extent. Your editor’s choice is eating a few squares of super-dark chocolate. The benefits of cocoa include improved heart health, enhanced cognitive function and overall mood enhancement, all of which are attributed to its content of powerful antioxidants. It also provides essential minerals like magnesium, copper and iron, and it can help to regulate blood pressure, reduce inflammation and slow the cell damage through ageing. And it tastes divine.

Curiosity is a positive driving force, as well as being associated with risk-taking and potentially dangerous outcomes. It leads to activation of several areas of the brain, including regions linked to learning and systems connected to desire for rewards. We are not all equally curious and we are curious about different things. Epistemic curiosity describes the wish to acquire new information – such as facts and ideas – and bridge gaps in knowledge. Social curiosity centres on fascination with other people and how they think, feel, act and react, while perceptual curiosity takes in and maximises sensory information. 

Epistemic curiosity can be stimulated by a focus on encouraging children – and adults – to ask questions and to understand what makes a good question, rather than to be rewarded for producing the right answer to a set question. We live in a world dominated by the search for answers: answers to everyday questions, which we can immediately find at our fingertips, and answers to our greatest social, political and scientific questions. There is a need to pay more attention to the quality of the questions, because without good questions and a more question-oriented world, we end up with many answers we don’t need or want. 

Social and perceptual curiosity can be linked to the trait of sensitivity, which researchers have described as having two core components: the perception of sensory input from the environment; and the cognitive processing of this information, such as thinking deeply and reflecting on experiences. It is partly genetic, with about 50% of differences in sensitivity being explained by genetic factors and the other 50% by our environment and life experiences. While a number of individual genes have been identified as relevant to sensitivity, it is likely to be associated with thousands of genes, each having a small effect.

Research has shown that people with high sensitivity are particularly receptive to positive experiences and are more likely to struggle in stressful situations, while those who are low in sensitivity tend to be more resilient in adversity but will benefit less from positive experiences. The advantages to higher sensitivity include greater empathy and creativity, due to heightened perception and deeper processing. People who are low in sensitivity and high in personality traits such as psychopathy or narcissism, are likely to be more callous and antagonistic and are considered to have deficits in empathy. However, being at either end of the sensitivity spectrum can lead to psychological problems.

A human emotion is a response to a stimulus that alters our psychological and physiological state of wellbeing. Both positive and negative emotions can cause a variety of physical reactions, including restlessness, shaking, headaches and muscle tension. Emotions are complex and there are many theories about how they are best described and explained, with some experts emphasising our cognitive processes, while others focus on physiological responses, or on social theories that view emotions as the products of particular human environments.

Within the brain, our limbic system has been identified as having the primary responsibility for processing emotional experiences. The brain also has an emotional filter, located in the amygdala, that stores sensory memory from previous experiences and uses this as a gauge to determine how to respond to an event. Based on this interpretation, it sends information to other parts of the brain, resulting in the release of specific neurotransmitters and hormones. If the event is interpreted as exciting or enjoyable, there will be a release of dopamine, oxytocin, serotonin and endorphins that influence how the body reacts. If the message has a warning of something worrying or frightening, it will be epinephrine, cortisol, adrenaline and others that are called to assist with the fight-or-flight response designed to keep us safe. 

The act of remembering is essential to our survival, our ability to learn and our sense of self. Explicit memory, which is processed in the hippocampus and medial temporal lobe, includes the conscious recollection of names, dates, events etc. Implicit memory includes unconscious, motor and procedural tasks (things we do routinely, without conscious thought). This involves brain areas such as the cerebellum (regulating muscle activity) and striatum (regulating voluntary movement).

Formation of a memory begins with sensory input, which is analysed in the hippocampus to determine if it is worth keeping in long-term memory and transferring to the neocortex. Another cog is the amygdala, which imbues recollections with emotional significance. This occurs through an interplay of electricity and chemicals, as pulses trigger the exchange of messengers called neurotransmitters across the gap (or synapse) between them. In the case of transient memories, this messaging is fleeting. For long-term memories, the brain rewires itself with each new experience, or repeated experience – an ability called  neuroplasticity – and the bonds between synapses become more powerful as signals multiply through learning and familiarity. 

The science of memory now also includes the science of forgetting, based on the knowledge that our neurons have molecular tools working to clear away what is no longer relevant. Evidence from many studies indicates that this culling is just as essential to cognition and survival as the gathering of useful information. It is possible that disruptions to forgetting could provide insights into psychological conditions such as post-traumatic stress disorder (PTSD). Research has shown that memories are reactivated and reassembled each time we bring them to mind. This may be interrupted in a variety of ways: by drugs that inhibit certain receptors or synthesis of proteins, or that lower the level of stress hormones; by deep brain stimulation; and by behavioural approaches, including neurofeedback or subliminal exposure. Although these therapies alter the emotional magnitude of memories, not their factual content, memory elimination might become possible. It could then be for individuals to decide if they want to erase a memory, rather than retain, forget, rewrite or embellish it as we do now. 

Neuroscientists have also explored the odd sensation of déjà vu, which 60% of people report having experienced in their lives. It occurs when frontal regions of the brain attempt to correct an inaccurate memory and is experienced as a conflict between a feeling of familiarity and a recognition that this familiarity is incorrect. There are various theories to explain how this happens in the brain, most of which agree that déjà vu takes place when areas of the brain, such as the temporal lobe, send signals to the frontal decision-making regions that a past experience is repeating itself. The frontal regions check to see if this is consistent with what is possible, leading to a realisation of déjà vu if this is not so. While it is a healthy fact-checking process, it can become distressing if the mechanism no longer works properly and it can be a sign of worsening dementia. 

A full sleep cycle of around ninety minutes has four stages. Stage one marks the transition from wakefulness to sleep and initiates a slowing and calming of body systems. Stage two is a light sleep, which shortens as the cycles continue through the night. Stage three is deep sleep, where body processes slow right down and restoration (of bones, muscles and the immune system etc) takes place. Stage four (REM) brings eye movements and a spike in brain activity, nearing wakefulness levels. This is when vivid dreams occur, but voluntary muscles are temporarily paralysed so the dreams can’t be acted out. Sleep researchers think that brain by-products and toxins are cleared during this stage. Learning and memory consolidation also takes place and stage four is associated with creativity. A lack of deep, restorative sleep is a health issue, increasing the risk of high blood pressure, heart attack, stroke and depression.

Most of our recalled dreams happen during REM sleep, when the secondary visual cortex, which forms images from memory and imagination, is much more active than when we are awake. The prefrontal cortex, where logic and censorship lie, is significantly damped down, as are the areas of the brain responsible for language. As a result, our thoughts, hopes and fears are expressed by dreams in a visual, story-like way, rather than through logic and verbal reasoning. The brain strings the plot together by going through specific types of memories, creating an experience for us to react to on an emotional level, then use to make sense of the world. A significant minority of people also report the experience of lucid dreaming, where you are aware of it being a dream and are able to direct the storyline. In this state, the fast gamma brain waves increase and the frontotemporal cortex, which controls higher cognitive abilities and is inhibited during normal dreams, shows higher activation. 

For a small proportion of the population, fears and bad memories can emerge as chronic nightmares, which can be treated by therapy that coaches them to rehearse positive versions of the dream story. Exposure to a sound with positive association during REM sleep may also help to reduce nightmares. A separate frightening experience is sleep paralysis, characterised by inability to speak or move and typically accompanied by intense fear, vivid hallucinations and the sensation of being held down by an invisible force. It is caused by disruption to the normal transition between REM sleep and wakefulness and is triggered by stress, trauma, sleeping patterns or medications that affect REM cycles, such as antidepressants.     

Edited November 2025