Where do emotions come from, and why do we have them?

How do you know when you're in a particular mood or emotional state? Do you look to your thoughts and reasons, or to your physiology?

For hundreds of years, people have known that physiology affects how we feel. In medieval times, people had a theory of the "Four Humours". Depending on how much of certain fluids you had in your body, people thought you could predict or explain certain moods. Blood was thought to cause changeable moods, black bile was thought to be responsible for melancholia, phlegm for sluggishness, and yellow bile was present in those with anxiety.

Whilst medieval theory didn't hold true, another biological theory emerged a few hundred years later - the idea of embodied emotion.

Charles Darwin, in his study of different species, noted that despite many animals lacking the high cognitive capacities of humans, animals experience the same six basic emotions as we do: happiness, sadness, fear, anger, surprise, and disgust. He argued that emotions are innate and distinct from cognition, and that they emerged due to their fitness value, because they enabled quick communication and sent clear messages to others without the need for explanation.

The first theory surrounding embodied emotion was the James-Lange theory, and to a certain extent it seems to have dominated thoughts on what emotions really are. The theory states, simply, that emotions are the result of physiological changes in the body, and that different emotions are the result of different changes. So, when you feel angry, there may be cognitive reasons behind it, but the actual emotion is derived from a quickened heart rate, a furrowed brow, and tight lips.

But, this theory hasn't gone undisputed. Cannon and Bard didn't agree with the reductionist view of excluding the brain's role in emotions, and argued that the James-Lange theory was flawed. But, it was their logic that was more flawed. They argued that the brain must be involved, because separating the brain and viscera didn't stop self-reported emotions. But, it did reduce them. Their second criticism was that bodily changes are slow, but emotions are quick. Neurons send messages in milliseconds, and some hormones act in seconds or minutes. Not their best avenue for criticism, but to be fair, it was before we knew much about neuronal firing and endocrinology. They then argued that bodily changes aren't emotion-specific. Whilst this is probably their strongest argument, emotions are pretty specific. We know when we're feeling angry compared to sad or fearful or happy. Our bodies do very different things, even if some things overlap, like heart rate quickening.

Though, Cannon and Bard did have a point. There does appear to be some role of cognition in emotions, and they are consistently linked in many ways.

Russell (1980) argued that emotions can be whittled down to two dimensions: valence, and arousal. Whilst physiological changes are necessary for the arousal bit, it's the context, our thoughts and experiences, which decide if something is negative or positive. Without context, it's pretty difficult to argue that the symptoms of an emotion itself are enough to call it an emotion; they are partially evaluative, after all. What one person finds exciting, one person might find it terrifying - just like a good old horror film.

So, where does that leave us? Next time someone asks how you're feeling, do you check in with your body, or your mind?

My advice? Both. The middle ground is definitely the better option.

Neuropsychology, Part I: Broca's aphasia

Neuropsychology is the study of the structure and functioning of brains, and makes use of both cognitive psychology and neuroscience, as well as brain lesion studies. This post is the first in a series looking at some of the most interesting neurological disorders.

Paul Broca was a French physician, who happened to come across a very unusual patient: despite being able to comprehend language, all he could say in response was the single syllable "tan".

Patient Tan, as he was later known as, was admitted to the hospital at the age of 21, able-bodied and intelligent, but only replying to questions "tan, tan", accompanied by a series of gestures. However, his condition began to deteriorate, and after about 10 years, he began to lose the movement of his right arm. The paralysis spread to his right leg, rendering him bedridden for the next few years. It was also thought that his sight worsened, and his intelligence was markedly decreasing.

In 1861, Tan underwent surgery for gangrene on his paralysed right leg, and it was during this time that he met Paul Broca. Broca observed the man, unsurprisingly, with a great deal of interest. How could it be that he deteriorated in this way, with his intelligence, motor skills, and language so severely affected? That he could comprehend language, use his fingers to indicate what time it was without error, and certainly wanted to communicate, but could only utter one syllable?

Unfortunately, Tan died April 17, 1861, with very little known about the causes of his condition. However, the autopsy revealed the cause: the frontal lobe of the left hemisphere was strangely soft, and whilst the orbital region although atrophied had maintained its shape, many of the other frontal structures, were entirely destroyed. The result of this destruction of the cerebral substance was a large cavity filled with fluid.

The middle frontal lobe of the left hemisphere was the most extensive lesion, and the damage to the inferior frontal gyrus in an area now known as Broca's area, was concluded to be the cause of Tan's loss of speech. His condition is now known as Broca's aphasia, the inability to produce speech.

Not only was Tan a remarkable case study for Broca, but the case study was one of the earliest to suggest that language processing occurred in different parts of the brain, and that damage to one area did not mean that all language abilities would be impaired. Thus, it's opened up a field of research into the areas that appear to be involved in language production, a field which is still developing today.

Why one of the most famous psychology studies is pretty much a sham

Pretty much every psychology course in the world covers Watson and Rayner's (1920) "Little Albert" study, where a small child was classically conditioned into producing a fear response to something he'd never feared.

Aside from no regard to ethical standards (proceeding to distress a small child with a loud noise until he cried and crawled away at the sight of something present at the time of the noise), this study pretty much blows. And I'll tell you why.

Watson claims that the child was a healthy young boy, and thus representative of any child. Wrong. Not only are case studies not the most reliable or generalizable of studies, but the little boy wasn't your typical child anyway. He'd had a list of health problems that Watson is thought to have known about, but tried to hide, including hydrocephalus, and meningitis, both of which influence emotional and cognitive development. If you're trying to show that you can condition emotional responses, there would have been thousands of better participants out there.

Next, imagine this. You're Little Albert. You're taken to a room with strange people in who keep coming at you with various things, such as dogs being thrust towards you, and really creepy masks. Then, a strange man gives you a rat. Cool, you can play with it. Then, he starts whacking a metal bar behind your head. It's scary, and loud. He keeps doing it, and you notice the rat is appearing at the same time. Next time the rat comes, you cry. Watson argues that it's because of a conditioned fear of the rat. A much more logical explanation is that yes, you've associated the two, but you're only crying because you're scared the strange man will start making that horrid noise again. Funny thing, interpretation. Oh, and when he starts getting up real close to your face with a super creepy mask on, or throwing that dog at you, he claims that it's because you're really afraid of everything hairy now. Or, John, maybe you just upset the kid?

What's more, is that this was such an unscientific study. No control group, no other participants, no stats, no objectivity, and it's difficult to falsify his theory. He worked with a graduate assistant he was having an affair with too, both of them supporters of behaviourism. There were no observers or independent raters of fear response. It was totally subjective.

So, my verdict. Classic study? Of course. But a good study? Only for an example of how not to conduct yourself in a psychology experiment.