I need to be concise. Please help me to decrease to 250 words but the meaning remain the same.
*Please help me to have better expression. And if I have any mistakes, please correct me. Thank you.

In this perspective, researchers believe that our personality is the sum of our experiences. Moreover, personality development is the learning process that takes place in our life.
Firstly, classical conditioning shows us that reactions could be acquired by associating one stimulus with another. First of all, there is a pre-existing reflexive connection between a stimulus (US) and a response(UR). A neutral stimulus (CS) is then paired repeatedly in time and space with the US. After the conditioning, presenting the CS by itself can lead to the CR which is the same or similar to the UR. Thus, Jennie might have been through some conditioning that makes her more introvert. For example, once she talks, her mother will immediately slap her. Consequently, she associated the pain with talking. However, we did not find any clue of conditioning in Jennie’s childhood experience in the interview.
Instrumental conditioning indicates that the frequency of a behavior is decided by what consequences come after the behavior. Reinforcement can increase the frequency of response whereas punishment can decrease the frequency of response. Reinforcement and punishment can be a negative one or a positive one. Positive one refers to that something is added, whereas negative refers to that something removed. Jennie’s lower level of extraversion may due to the consequence that comes after her behaviors. Jennie said her mother would give her praise when she was being quiet. The positive reinforcement that people gave to Jennie made her more withdrawn. Gradually, she seldom expresses herself and becomes more like an introvert.
Observational learning takes place when one person performs an action and another person observes it and thereby acquires the ability to repeat it. Jennie may see how others behave. However, in the interview, although her mother and best friends are talkative and are more like an extrovert, Jennie did not influence them. This may due to the idea that observational learning included many variables that affect the result. For example, the characteristics of the model, the behavior and the observer, etc. As a result, she may not be able to perform the observed behaviors.

Question

I need to be concise. Please help me to decrease to 250 words but the meaning remain the same.
*Please help me to have better expression. And if I have any mistakes, please correct me. Thank you.

In this perspective, researchers believe that our personality is the sum of our experiences. Moreover, personality development is the learning process that takes place in our life. 
Firstly, classical conditioning shows us that reactions could be acquired by associating one stimulus with another. First of all, there is a pre-existing reflexive connection between a stimulus (US) and a response(UR). A neutral stimulus (CS) is then paired repeatedly in time and space with the US. After the conditioning, presenting the CS by itself can lead to the CR which is the same or similar to the UR. Thus, Jennie might have been through some conditioning that makes her more introvert. For example, once she talks, her mother will immediately slap her. Consequently, she associated the pain with talking. However, we did not find any clue of conditioning in Jennie’s childhood experience in the interview. 
Instrumental conditioning indicates that the frequency of a behavior is decided by what consequences come after the behavior. Reinforcement can increase the frequency of response whereas punishment can decrease the frequency of response. Reinforcement and punishment can be a negative one or a positive one. Positive one refers to that something is added, whereas negative refers to that something removed. Jennie’s lower level of extraversion may due to the consequence that comes after her behaviors. Jennie said her mother would give her praise when she was being quiet. The positive reinforcement that people gave to Jennie made her more withdrawn. Gradually, she seldom expresses herself and becomes more like an introvert. 
Observational learning takes place when one person performs an action and another person observes it and thereby acquires the ability to repeat it. Jennie may see how others behave. However, in the interview, although her mother and best friends are talkative and are more like an extrovert, Jennie did not influence them. This may due to the idea that observational learning included many variables that affect the result. For example, the characteristics of the model, the behavior and the observer, etc. As a result, she may not be able to perform the observed behaviors.

Answer

"In this perspective, researchers believe that personality is the sum of our experiences. Moreover, personality development is the process that takes place throughout life.

Firstly, classical conditioning shows us that reactions may be acquired by associating one stimulus with another. First of all, there is a pre-existing reflexive connection between a stimulus (US) and a response(UR). A neutral stimulus (CS) is then paired repeatedly in time and space with the US. After the conditioning, presenting the CS by itself can lead to the CR which is the same or similar to the UR. Thus, Jennie may have been conditioned toward introversion. For example, whenever she speaks, her mother  slaps her. Consequently, she associates pain with speaking.

Instrumental conditioning indicates that frequency of a behavior is influenced by what consequences follow. Reinforcement may increase the frequency of response, whereas punishment may decrease it. Reinforcement and punishment can be positive, meaning something is added, or negative, referring to something being removed.  Jennie’s lowered sociability may be due to actions that proceed her behaviors. Jennie's mother would praise her quietness. This positive reinforcement inclined her to withdraw. Gradually, she expresses herself far less, becoming more introverted.

Observational learning takes place when one person observes the action of another, thereby allowing them to imitate them. Jennie sees how others behave. However, in the interview, her mother and friends are talkative and extroverted, Jennie did not influence them. This may due to the idea that observational learning included many variables that affect the result. For example, the characteristics of the model, the behavior and the observer, etc. As a result, she may not be able to perform the observed behaviors."

Answer

I could only bring it down to 289.

"In this perspective, researchers believe that our personality is the sum of our experiences. Moreover, personality development is the learning process that takes place in our life.

Firstly, classical conditioning shows us that reactions may be acquired by associating one stimulus with another. First of all, there is a pre-existing reflexive connection between a stimulus (US) and a response(UR). A neutral stimulus (CS) is then paired repeatedly in time and space with the US. After the conditioning, presenting the CS by itself can lead to the CR which is the same or similar to the UR. Thus, Jennie may have been conditioned toward introversion. For example, when she speaks, her mother immediately slaps her. Consequently, she associates pain with speaking.

Instrumental conditioning indicates that frequency of a behavior is influenced by what consequences come after. Reinforcement may increase the frequency of response, whereas punishment may decrease the frequency. Reinforcement and punishment can be positive, meaning something is added, or negative, referring to something being taken away.  Jennie’s lowered sociability may be due to actions that proceed her behaviors. Jennie's mother would praise her when she was quiet. This positive reinforcement inclined her to withdraw. Gradually, she expresses herself less and less, becoming more introverted.

Observational learning takes place when one person observes the action of another, thereby acquiring the ability to imitate them. Jennie may see how others behave. However, in the interview, although her mother and friends are talkative and extroverted, Jennie did not influence them. This may due to the idea that observational learning included many variables that affect the result. For example, the characteristics of the model, the behavior and the observer, etc. As a result, she may not be able to perform the observed behaviors."

Answer

I used Allessandra Palma's text and removed another 13 thirteen words by removing phrases and replacing with a word that covered the phrase.

Alessandra is correct about the last paragraph it cuts short: that means there is still more than 30 plus words to remove. or sentences to shorten.

Answer

In the last paragraph, it's unclear whether Jenny is the Influencer or the influenced.

Answer

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