Original text
(1) Research on other mammals can give some clues about the origins of human laughter. (2) Rats, chimpanzees, dogs and so on laugh. (3) Rats laugh when they're playing, in the same way that humans do, to show happiness and encourage bonding. (4) And the ones that laugh more prefer to be with other rats that laugh. (5) This is evidence that laughter has evolved from play vocalisation, a thing seen in many other mammals. (6) In humans, they think that laughter has developed into an important form of emotional expression. (7) We use laughter in many channels of communication. (8) E.g. laughter is frequently conveyed in text based media using emoticons. (9) Laughter occurs most frequently when hanging out with friends. (10) In fact, you are 30 times more likely to laugh at something when with other people. (11) Researchers have come up with a theory that laughter is less connected to jokes than to social behaviour. (12) Laughing together shows that the members of a social group understand and are keen on each other.
(13) Brain imaging studies show that humans can differentiate between phony and authentic laughter. (14) Listening to fake laughter produces lots more activity in an area of the brain called the anterior medial prefrontal cortex, which is known to be involved in understanding other people's emotions. (15) This shows that folks automatically try to comprehend someone's deliberate laughs, even when they are not instructed to do so. (16) Brain scans also reveal that laughter is kind of contagious. (17) Funnily enough, the brain responds to laughter by preparing facial muscles to join in. (18) Moreover, the more that someone shows a contagious response to laughter, the better he or she is at telling whether a laugh is real or forced. (19) It seems like participating in laughter is a way of understanding what that laughter means.
Corrected Text
(1) Research on other mammals can provide evidence about the origins of human laughter. (2) Rats, chimpanzees, dogs and other mammals laugh. (3) Rats laugh when they are playing, in the same way that humans do, to show happiness and encourage bonding. (4) Moreover, the ones that laugh more prefer to be with other rats that laugh. (5) This is evidence that laughter has evolved from play vocalisation, a phenomenon seen in many other mammals. (6) In humans, it is thought that laughter has developed into an important form of emotional expression. (7) Laughter is used in many channels of communication. (8) For instance, laughter is frequently conveyed in text based media using emoticons. (9) Laughter occurs most frequently when spending time with friends. (10) In fact, it is 30 times more likely to laugh at something when with other people. (11) Researchers have discovered a theory that laughter is less connected to jokes than to social behaviour. (12) Laughing together shows that the members of a social group understand and appreciate on each other.

(13) Brain imaging studies demonstrate that humans can differentiate between fake and authentic laughter. (14) Listening to fake laughter produces a larger amount of activity in an area of the brain called the anterior medial prefrontal cortex, which is known to be involved in understanding other people's emotions. (15) This shows that people automatically try to comprehend someone's deliberate laughs, even when they are not instructed to do so. (16) Brain scans also reveal that laughter is somewhat contagious. (17) Funnily enough, the brain responds to laughter by preparing facial muscles to participate. (18) Moreover, the more that someone shows a contagious response to laughter, the better that person is at telling whether a laugh is real or forced. (19) It seems like participating in laughter is a method of understanding what that laughter means.