Cognitive psychology is concerned with how the brain interprets the information it receives through the senses. Now, you may think that you have five senses, but that’s not entirely correct. People have around 21 distinct senses that they use to interpret the world! Here you discover ten senses and how they interact with each other (and vision).
Listening in on hearing
When you close your eyes, you can truly appreciate the power of your ears. You’re able to hear so much (the clock ticking in the background, the sound of your partner snoring!).
The size of the ear dictates the sounds that can be detected. A larger ear means that low (but not high) pitched sounds can be heard. This is why smaller animals make higher pitched vocalisations (like squeaks!) than larger animals.
The brain can use the information the two ears supply to localise sounds. By working out the time difference between sounds reaching each ear (the interaural time difference), the brain can establish where a sound is coming from. Additionally, the brain can use the slight volume differences in the sound in each ear (the interaural intensity differences) to identify where something is.
Kicking up a stink: Smelling
The sense of smell works by detecting particular chemicals inside the nose. The sense of smell is one of your most powerful senses. Odours bring memories and emotions to life very easily. They can influence people to buy things: for example, estate agents use the smell of coffee to encourage people to buy houses because coffee brings about the sense of home. Odour (and taste) can be used as a warning – bleach and nail varnish remover have bad smells and tastes added to discourage people from drinking them.
People are remarkably efficient at identifying smells associated with themselves. Mark Russell, a British psychologist, conducted the “dirty shirt study” in 1976. People wore the same shirt for 24 hours after washing and didn’t use any perfume. After the study, the same people were able to accurately identify which shirt was theirs.
Here are a few more smelly facts:
Women are generally much better at identifying smells, with a few exceptions: for example, moth balls, beer and ammonia.
Smelling ability diminishes after the age of about 70 years.
Cigarette smoking makes people worse at smell identification.
Blind adults are better at identifying smells than those who can see.
Chewing over the sense of taste
Tasting is done by taste buds in the tongue and mouth. Taste buds aren’t distributed evenly over the tongue ‒ the middle has no taste buds. The number of taste buds varies with age, and tasting abilities are lost over the age of 40 years.
Taste can be divided into five categories based on the different sources:
Salty.
Sour.
Umami.
Sweet.
Bitter.
The common myth that different parts of the tongue are sensitive to different tastes is entirely false. All tastes can be detected throughout the mouth and tongue. However, some tastes are easier to detect than others: salt is easier to detect than sweet.
Some people are better able to detect bitter tastes than others, which is why some people like coffee and others don’t. Taste preference changes with age, with infants preferring sweeter tastes than adults. This is because sweet foods contain sufficient energy for a growing child and are less likely to be poisonous. Hunger also makes people better able to detect tastes.
Taste interacts with vision and smell ‒ which is why food manufacturers dye foods. Foods that are coloured appropriately taste better than foods that aren’t coloured appropriately: would you eat a blue banana? Margarine is dyed yellow to mimic real butter.
Feeling your way towards touch
The skin ‒ the largest organ in the human body ‒ comprises many sensory cells that detect different types of sensory information. Many of the cells, called mechanoreceptors, respond to pressure applied to the skin.
Touch abilities vary across different parts of the body. Better touch perception exists for the hands, tongue and face compared to the back. Part of the reason is that more brain processing exists for these relative to other parts of the body.
Touch has been found to be distinct from pressure, temperature, pain and itch sensors. Touch perception is faster than pain and temperature perception, and so you can feel that you’ve touched something and then feel pain shortly afterwards.
Scratching around to understand itching
Itching is typically caused by irritations on the skin. Itching can be induced psychologically:
Viewing pictures of fleas, mites, scratch marks, allergic reactions can cause participants to scratch.
Itch can also be induced by the sound of and by watching someone scratching. Try it: surreptitiously scratch your arm noisily and see whether others around you scratch. Itching is a social contagion. One theory is that if people in your social group are scratching, they’ve probably come in contact with something bad that you need to remove from yourself.
Neuroscientists have found that parts of the brain associated with reward (pleasure, addition, and craving) seem to be involved in the pleasure of scratching.
Hey! Watch those hands! Proprioception
Touch is an active process and so the brain has to know where the hands are (called proprioception). Whenever you have to touch your body (such as when putting on a shoe, or touching your nose) without looking at yourself, you’re using this sense. This sense is affected when intoxicated.
Proprioception can cause illusions, for instance phantom limb syndrome, where people who’ve had a limb amputated still feel something on that limb (typically pain).
Another illusion to do with proprioception is the Rubber Hand Illusion, a fairly unbelievable illusion that you can easily try out (it works in 80 percent of people).
This illusion demonstrates proprioception drift: where the sense of proprioception moves from the body to something else that the eye can see. Vision dominates the sense of proprioception.
Combining touch information with proprioception helps the brain identify what objects are being touched, a process known as haptics.
Knowing where you are: Magnetoreception
Many animals, especially birds, can navigate based on the Earth’s magnetic fields. Surprisingly, humans have this ability but it is far weaker than that of birds. The theory is that magnetoreception in humans is to do with iron in their noses.
One study involved putting participants near a strong magnetic field and then disorienting them (by spinning them around). Participants placed next to the strong magnetic field performed much worse at identifying north, south, east and west than those participants who weren’t.
“Time flies when you’re having fun”: Judging the passing of time
Humans are surprisingly good at perceiving time, without counting or even thinking about it. But are less good if their attention is divided. Because the cognitive processing of a familiar (or typical, uninteresting) objects is easier time perception is tricked into thinking the familiar object is present for longer.
Arousal also affects time perception. When things are highly negative they’re perceived (such as spiders for spider phobics and critical or angry faces) to last longer than highly positive things, although, interestingly, when things are slightly negative they’re perceived to last a shorter amount of time than slightly positive things.
Consumer psychologists use this knowledge to develop techniques to improve customer satisfaction when waiting. Therefore mildly irritating music is played in lifts and during telephone queues!
Age also affects time perception:
Children under the age of 8 years judge things as lasting longer than they do.
Young adults are most accurate at time perception.
As people get older, they experience things as taking longer than they do.
Disorders such as Parkinson’s disease and ADHD cause impaired time perception. Typically, sufferers perceive durations to be much longer than they are.
‘I’m gasping!’: Thirst and hunger
These two separate senses allow your body to identify when you need to drink and eat.
Food and drink are the easiest stimuli to use as rewards in behaviourist experiments because of their importance in survival: when training people, giving a reward of food to a hungry person is the most effective technique.
Hunger and thirst, create an internal representation of the stimuli that alleviate them: when you feel thirsty, you immediately think of water (or a nice cool beer, hmmm . . . beer). Cognitive psychologists presented hungry participants (who hadn’t eaten for 16 hours) with an image containing many objects. Hungry participants were more likely to report seeing items that were related to food (such as a plate).
Psychologists modified the Stroop task using food or non-food related words in coloured ink to hungry and not hungry participants. Hungry participants took longer to name the colour that the food-related words were written in than the non-food related words. Similar results are obtained in participants with anorexia nervosa and bulimia nervosa (psychological disorders regarding the perception of your own body, where sufferers believe they’re overweight when they’re in fact underweight). Food related words have preferential access to memory, and therefore interfere with processing more when hungry than when sated.
Feeling the pain: Nociception
Nociception (pain perception) is not directly related to the extent of tissue damage: many psychological factors affect the feelings of pain. Neuroscientists have found evidence to suggest that a vast cortical network is associated with pain perception.
Being able to feel pain prolongs life, because knowing that damage exists helps people to deal with it. People who can’t feel pain (due to damage to their pain receptors) don’t live as long as other people, because they’re unaware of physical damage that happens to them.
Pain perception is much reduced if attention is paid to another task: if you can distract yourself from the pain, it is reduced. Similarly, the perception of pain affects performance in attention tasks, suggesting that pain uses cognitive resources.
Anticipation of and anxiety over pain occurring activates the pain system in the brain, enhancing the feeling of pain rather than reducing it. Pain can be reduced when viewing happy but not angry faces.
Pain perception can be reduced by taking placebos (drugs that contain no active ingredients), suggesting that if you believe your pain will be reduced, it will be.
