Distinguishing jokes and lies for most people is a simple task that we can all do.  We know whether someone is lying based on the tone of voice or if we witness them lying.  Jokes work similarly, we can tell by the change or pitch in voice whether something is a joke, or sarcastic comment.  Some people can have more trouble based on how they were raised as a child, or the kind of family background they have.  The pitch in your voice can drastically change how someone interprets what you say.  If you were to say, “I love cats” and don’t emphasize any of the words then someone would assume you like them.  If you were to elongate the “love” then it can give off more of a sarcastic tone, or make it sound like a joke.  We are able to distinguish these from a fairly young age, but it is something that is developed over time.

Children undergo a lot of learning while they grow up.  A major part of that is learning and understanding language.  Around 18 months is when children start to understand the concept of jokes or silly situations (Klaff, 2009).  When they start understanding these, they slowly develop an advanced understanding as the age.  It takes some time for this to fully develop for the child.  It’s one of the more complex parts of our speech.  There isn’t really any other time in speech where we might stress a word, or elongate how we say it.  Back to the “I love cats” example, really the only reason you’d stress the word “love” is if you were making a sarcastic or joking comment.  I could see a situation where you would stress it because you really, really do love cats, but for the most part it would be different and have a slightly different pitch or prosody.  Prosody is changing the pitch or tone of your voice to stress or emphasize a word to get a point across.  It makes sense that this is something that children would develop later.  It requires a more complex level of language and speech, and knowing what it means when it’s spoken to you.

A little later in life children get better at being able to understand the complexities of speech.  They have a more complex understanding and are able to use it in their speech.  Around 2 years old is when they are able to make their own object humor (Jarrett, 2012).  They also are more likely to copy a parent’s joke because they thought the joke was funny.  A little later life, around 3 years old they are able to form their own jokes.  Children at the age of 3 can form their own conceptual jokes, and are more likely to come up with their own jokes, without relying on their parents (Jarrett, 2012).  It takes about 3 full years for a child to develop a mostly functioning joke or lie speech.  Obviously the more they grow up, the more they are around other children and pick up on more words or changes in speech.  Having new environments for the children will make it so they learn more around speech because they are exposed to it every day.  It is interesting how long it takes children to understand jokes and the process it takes for them to be able to form their own jokes.  18 months doesn’t seem that late for a child to understand the difference between a joke or lie, but it takes a lot longer for them to be able to fully form their own jokes.  It’s almost like every year they understand more and more in language, which for the most part is true.  At age 2 they develop an understanding and start to make their own jokes.  At age 3 they are pretty much independent and can make their own jokes.  For most people this is the usual path that a person would take in development in these categories, but for others,  they are born with a disability to understanding this, or they get injured so they have trouble understanding it.

There are a couple of disorders that can effect an individuals understanding of a joke or a lie in speech.  Right Hemisphere Brain-Damaged, or RHD people have a slightly challenging time understanding a joke or lie in a story or speech.  A study by Ellen Winner Et Al. went in to the topic of Theory of Mind or ToM.  ToM is where you understand what someone else sees and what they understand.  Sort of like putting yourself in their shoes.  One of the examples used in the Winner study was where a man called out of work sick to go to hockey game.  While at the hockey game the boss noticed he was at the game, but the man who called out did not see him.  When the man’s friend asked if his boss knew he was at the game he would reply no, because he doesn’t know that his boss is actually at the game.  When the boss asks the man whether the sleep helped him get better the man would reply in a lie because he didn’t know he was seen at the same.  This would be an example of second-order beliefs.  First-order is where the man knows that his boss doesn’t know he’s at the game.  Second-order is the boss.  The reason the boss is second-order is because the man doesn’t know what his boss has seen, so he doesn’t know that he has been caught by the boss.  The study had 13 RHD patients answer questions throughout the story based on first-order and second-order beliefs.  What was found was that RHD people have a slightly harder time understanding the concept of what someone else sees.  All of the people in the study were stroke patients with varying degrees of damage to the brain.  When it came to the joke stories the RHD people had a slightly less hard time compared to the control.  Over all the study found that RHD people are more inclined to make mistakes regarding these types of social interactions, but they are able to get through them.  The reason for these issues might be due to the fact that the right side of the brain controls reasoning, memory, social communication and problem solving (Right Hemisphere Brain Damage (RHD), 2017).  There are other impairments, but these seem to be the biggest issue for the study.  The combination of these could hinder someone’s ability to see things from someone else’s eyes.  Not being able to understand social situations means they might not be able to understand why the individual would be in trouble in the first place.  They might not see an issue with what happened.  Memory would be a big one because they just might not remember the situation that occurred so they wouldn’t be able to say what happened.  Really what it comes down to is that they have trouble understanding what happens when someone else sees something.  One thing the study mentioned was that they didn’t have a Left-Hemisphere brain-Damaged control to test against either.  LHD people tend to have an aphasia of some sort which means they can think of the words they want to say, but they might not be able to say them or they have trouble learning new things at all.  It would be very hard to test them in this study because they would have trouble replying to the questions.  In the study they mention that the frontal lobe of the brain might be more involved with ToM than the right hemisphere.

The frontal lobe is associated with many different things, but one possible run-in with ToM is divergent thinking (Frontal Lobes, 2017).  Divergent thinking is the ability to come up with creative responses to things.  Why I think this might be related is they might only be able to think for themselves.  They might not be able to see something through someone else’s eyes.  Generally I think of ToM as a pretty creative thing that we can do.  Trying to figure out what someone else can see is definitely not a lower function of our brain.  A lot of the issues with ToM in the frontal lobes are similar to RHD like problem solving.  Divergent thinking combined with problem solving might be a major reason they are not able to distinguish first and second-order beliefs.  Primarily second-order beliefs.  Damage to either of these parts of the brain can have an impact on the individuals ToM.  RHD results were higher than the control in the Winner study (Ellen Winner, 1998), but it wasn’t a huge amount.  Depending on the amount of damage to the brain, it will clearly show the effect the ability more and more, which might have been a downfall of the study.  There were different amounts of damage so the results were more of a mean of the group, and the group wasn’t very big.  It would be very hard to get a large group all with the same amount, or close, of brain damage to the right-hemisphere.  Like mentioned before, aphasia can be very hard to test due to the limitations of the individual.

There are a few different types of aphasia.  The 2 big forms of them are Broca’s and Wernicke’s.  The reason these individuals would be so hard to test are due to their verbal complications.  Broca’s aphasia have a complication with forming full coherent sentences or leave out words like “the” (Types of Aphasia, 2013).  These reasons alone would make it hard to test someone’s ToM because they can’t speak in complete sentences for the most part.  Along with this they can simply say sentences that don’t make sense.  Both of these aphasia’s are located in the left hemisphere so they are closely related.  Wernicke’s aphasia seems like it the worse of the two.  For the most part it revolves around producing words that don’t make sense, or again making sentences that don’t make sense.  One of the main reasons for this is where we store words is located in the left-hemisphere near the Wernicke’s area of the brain (Types of Aphasia, 2013).  A complication in this spot would reduce or jumble up the words that are stored in that area of the brain.  This is the reason an individual with Wernicke’s aphasia has trouble getting words out, or have them make sense.  Broca’s aphasia can have more of a tip-of-the-tongue phenomena.  We’ve all had that moment where we can’t get a word out but we could describe it, or know what it looks like but can’t get it out.  It can be aggravating sometimes because it could happen on the simplest of words.  When we get older it is likely that these happen more often.  For someone with Broca’s aphasia this could happen multiple times in a sentence.  This part of the brain is used for speech mostly, so it would make sense that the person suffering from this aphasia has trouble getting words out.

Another disorder that is related to these two is Pragmatic Language Impairment or PLI.  PLI is similar to some forms of Autism, but not fully related.  Someone with PLI has a lot of difficulty understanding multiple different types of sentence structures.  There is a whole list of things, but I won’t get into all of them.  A few of the major ones that stuck out were understanding jokes, words or phrases and understanding questions (Pragmatic language impairment, 2017).  These can be compared to Broca’s or Wernicke’s aphasia.  Like Broca’s aphasia, these people can be expressive but not able to get the words out that they want (Pragmatic language impairment, 2017).  Having someone with PLI perform the tests in Winner Et Al’s. test would likely produce similar results that an aphasic individual would.  I don’t think it would be as dramatic, but they would fail in similar areas.  Not being able to understand a joke or lie would hinder their ability to understand the first story about the man going to a hockey game while his boss thinks he is sick.  They likely wouldn’t be able to pick the second-order beliefs that the boss would have.  People with PLI seem to have a lot of trouble understanding a sentence, but can think fairly clearly, they just have trouble getting it out.  It is similar to Autism because it has a lot in common, it just isn’t as severe.  An Autistic individual has issues with communication and social skills.  PLI is generally the diagnosis someone would get if Autism is ruled out for the individual.

There are many different forms of disorders that can affect the understanding or production of speech.  When it comes to understanding ToM there are a few that impair it more than others.  The ones talked about in this were just a few of the complications someone might have with understanding second-order beliefs.  Some of them are related to stroke or lesions to specific areas of the brain.  RHD is commonly caused by stroke, but the aphasia’s talked about can also be caused by a stroke to the left-hemisphere.  Understanding when someone is being sarcastic or joking is something that we do every day.  It’s not something that we need to activate to be able to pick up on the speech changes or seeing things from someone else’s eyes.  It would be hard to imagine not being able to pick up on second-order beliefs because it seems moderately simple.  We might make a mistake every now and then, but the RHD individuals were proportionally worse than the control.  They were around .3 compared to the .1 of the control (Ellen Winner, 1998).  There is an issue for these people understanding ToM, but they are about to function in day to day living.  They just tend to have a slower time understanding certain social interactions.

References

Ellen Winner, H. B. (1998). Distinguishing Lies from Jokes: Theory of Mind Deficits and Discourse Interpretation in Right Hemisphere Brain-Damaged Patients. Brain and Language, 89-106.

Frontal Lobes. (2017). Retrieved from Centre for Neuro Skills: https://www.neuroskills.com/brain-injury/frontal-lobes.php

Jarrett, C. (2012, 11 15). The Jokes That Toddlers Make. Retrieved from Readers Digest: https://digest.bps.org.uk/2012/11/15/the-jokes-that-toddlers-make/

Klaff, L. G. (2009). When Will My Child Be Able to Understand Jokes? Retrieved from Parents: http://www.parents.com/advice/toddlers-preschoolers/development/when-will-my-child-be-able-to-understand-jokes/

Ninh, A. (2011, 4 15). Failure to Detect Sarcasm or Lies: A Sign of a Rare Dementia. Retrieved from Time: http://healthland.time.com/2011/04/15/failure-to-detect-sarcasm-or-lies-a-sign-of-a-rare-dementia/

Pragmatic language impairment. (2017, 11 20). Retrieved from Wikipedia: https://en.wikipedia.org/wiki/Pragmatic_language_impairment

Right Hemisphere Brain Damage (RHD). (2017, 12 4). Retrieved from The American Speech-Language-Hearing Association: https://www.asha.org/public/speech/disorders/RightBrainDamage/

Types of Aphasia. (2013, 3 18). Retrieved from American Heart Association: http://www.strokeassociation.org/STROKEORG/LifeAfterStroke/ RegainingIndependence/CommunicationChallenges/Types-of-Aphasia_UCM_310096_Article.jsp#