Unfortunately, humour research suffers from lack of funding. However, there is an occasional scholar who helps us better understand what’s happening to our human physiology when we laugh, think positively, or shift perspective from "half empty" to "half full" thinking.

Probably the most controversial "finding" surrounding medical studies involving mirthful laughter is whether or not the stimulation of one of the body’s natural painkillers, known as "endorphins," is actually triggered. Most people don’t really care – as long as they have experienced the phenomenon of pain reduction – what, exactly, has caused the reduction.
However, because of the controversy that exists among scholars, you won’t hear Shirley professing the value of endorphin release during mirthful laughter. You will hear her provide personal testimony, however, with the acknowledgement that "some powerful painkiller is being activated during these experiences, and medical science just hasn’t caught up to the human understanding of what that means."

On a more positive note, there is more-conclusive evidence that mirthful laughter does, in fact, stimulate the immune system. The studies that resulted in this finding were significant because, prior to this, humour scholars had only been able to claim that mirthful laughter reduced the inhibitors to the immune system. In that way, the laughter merely served to put inhibitors at bay so the immune system could do its intended work of fighting infection and disease.
These more recent studies, however, demonstrated not just an inhibitor-suppressant effect, but also demonstrated how, in fact, the immune system was strengthened or made even more effective following a mirthful laughter experience.

Evidence exists that tears of emotions – laughter and sorrow (or grief) – are chemically different than those tears we shed when we get something in our eye, or when we’re peeling onions. Without going through the entire medical explanation (which Shirley understands when it’s described by medical specialists who help explain these phenomena, but which she can’t possible reiterate in these few pages), Shirley summarizes the process by explaining that, the chemical composition of tears of emotions are consistent with the body’s blood chemistry when it (the body) is in a reduced-stress state.
In other words, emotional tears help the body regain a balanced stress level, which in turn allows the systems of the body (cardio-vascular, endocrine, immune, muscular, etc.) to more efficiently be able to perform their respective duties to maintain the body’s state of wellness.

Especially in the case of mirthful laughter, the cardio-vascular and respiratory systems experience very deliberate exercise. For example, the heart rate is increased, and respiration becomes more rapid, causing a profound process of air exchange – exhaling of carbon dioxide, with replacement by oxygenated air which, in turn, feeds the blood throughout the entire capillary system. As a result, body temperature often rises (similar to the effects of exercise) and oxygenated blood feeds the entire body, including the brain (a very good thing for thinking and learning).

Mirthful laughter exercises large and small muscles, including facial, thoracic, abdominal and pelvic, in particular. This activity creates benefits very similar to the alternating contracting and relaxing of muscles during traditional exercise. This action allows fibres and tissues that make up the muscles to efficiently and effectively access the aforementioned oxygenated blood, improving the health of those muscles.
Dr. William Fry, one of the world’s leading medical researchers in humour, has stated that he believes that eventually researchers will have scientific evidence that humour and/or one of its resultant human reactions, mirthful laughter, favourably impact virtually every system in the human body. To date, he says, that remains an exploration into largely uncharted territory, as medical scientists are still discovering new systems not formerly known!

As a layman’s definition that separates emotional benefits from psychological ones, Shirley says she sees emotional as "the way we look inwardly at ourselves." That is, the way we feel about ourselves.
If you’ve ever experienced depression, this should need little explanation. It’s the perspective that causes a person to say, "Poor me," or "I’m not important enough to ask anyone else to care about helping me."
Humour helps a person reconnect with what’s right about oneself in at least two ways: it causes the person to focus outward, for the good of others; and in so doing 2) the person serves as an "energy generator" to others. This often results in an increased feeling of self-worth. If nothing else, it causes an individual to have other healthy relationships available to stimulate positive interaction. This interaction is essential in boosting one’s self image.

A useful layman’s definition separates psychological from emotional by describing this as a person’s outward perspective, or world view. That is, how the person feels about life, its inherent goodness, and its ability to provide satisfaction, joy and goodness.
The ability to see, access and share humour involves an ability and willingness to see things from a different perspective. This helps a person keep problems in perspective with the positive things that also are inevitably a part of that person’s life.
Mosak (1987) cites fine specific uses of humour in psychotherapy:

1.      In establishing a relationship, humour helps patients open up and interact with their therapist.

2.      In diagnosis, a patient’s relationship to his or her humour can reveal much about his or her general use of emotions. Also, the kinds of things a patient laughs at can be revealing.

3.      To assist in interpretation, humour can provide a buffer that facilitates acceptance. Using humour, patients can begin to realize their suffering is not unique, they are not alone and that they have not been singled out to endure the current difficulty.

4.      Often humour is an effective turning point in the therapy. Through paradox or exaggeration patients often reach a discovery regarding their irrational fear or assessment of their situation.

5.      As a criterion for termination of services. Mosak and Maniacci explain that "patients who place their problems into perspective and acknowledge their role in creating and maintaining those problems often rediscover their sense of humour. Their private intelligence is realigned with common sense, and each frame of reference becomes balanced." (Mosak & Maniacci, 1993).

Simply put, people like being around others who make them laugh. When humour is used in a spirit of goodness, it can bring people together which, Shirley helps point out, creates an external support system. As she reminds audiences, the beauty of that laughing support system is truly demonstrated when things aren’t so laughable. As she puts it, "We laugh together so we never have to cry alone."
One interesting observation Shirley has noted regarding the social benefits lies within the reality of family bonding over a period of time. She likens this benefit to the process of brain development.
(Anyone familiar with brain research understands the process of myelination, which protects the brain connections that have been made fairly secure. That is, those connections are protected with a myelin sheath, which protects the dendrite connections from a systematic "housecleaning" by a natural chemical bath. This housecleaning allows dendrites not being stimulated to be absorbed and disintegrated to allow room for the connections that are relevant to the individual’s experiences. (One of the most pronounced examples of this is in language development. While the child is born with the capability of learning ALL languages, by having certain phonemes of the native language being repeated over and over again, the child’s brain learns to identify those phonemes, while losing its ability to recognize those of non-native languages. The stimulated connections are then protected from housecleaning by the myelin sheath at a certain time in early childhood, thus allowing for further, age appropriate development to take place while building upon the child’s reinforced knowledge.)
In studying humour in the course of laughing at – or near – trauma, stressful situations, embarrassment, etc., the laughter is, in effect, creating an "emotional myelin sheath" around that event or situation. In so doing, the pain of the experience is softened as the memory of the experience is packaged in something pleasant (laughter), rather than pain, fear or humiliation.
With these life experiences so protected, the individual remains willing to look back at them (often in conjunction with a return to the laughter that was found near the time of the event). In that way, the experience can remain positioned as one of that individual’s (or group’s) personal stories. These stories, over the course of one’s lifetime, can be important teachers as they teach valuable life lessons, connect people across generations, and help individuals and groups put current or existing "problems" in perspective.
Shirley believes that humour’s most important contribution to the human experience may be this perspective-building outcome. With perspective, a person, group, and society can learn from today’s experiences and take appropriate actions to create an improved tomorrow.

One theory of why people laugh is called the Incongruity Theory of Humour. This theory states that a person laughs when two equal but incongruent thoughts, sights or ideas are present at the same time. In that instant, the mind bounces from one legitimate reality to the other, and in its inability to resolve the incongruity, the observer laughs as an automatic response.
In this way, the mind is actually stimulated to grasp two concepts simultaneously, thus expanding the "wiring" of the brain in additional, multi-levelled ways. By "practicing" the humorous perspective, Shirley argues that the individual is actually stimulating intelligence. Future development of this page will build her defence for this position.
Research has demonstrated that humour is an integral part of creative thinking and problem-solving. In practice, this concept is easy to examine as higher humour individuals demonstrate lower reaction to stressful events, even to the point at which they experience fewer stressful life events than low-humour people.