Thomas And Chess: Temperament Type Longitudinal Study And Findings

By BetterHelp Editorial Team|Updated May 6, 2022
CheckedMedically Reviewed By Whitney White, MS. CMHC, NCC., LPC

One's temperament can shape up how they behave, how they learn, and how they handle people. Alexander Thomas and Stella Chess, two psychologists, tried to figure out a child's temperament, and their study has some interesting findings.

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The New York Longitudinal Study (NYLS)

The NYLS was a study in 1956 that lasted for decades. Its goal was to study temperament in children and to identify traits of temperament. In the end, the study was able to list nine traits that can make up one's temperament.

These traits could be measured, and extremes were rare. However, most children have lower or higher levels of these traits, which were:

  • Energy levels. As you may have guessed, this measured how much energy a child has naturally. Having little energy is a problem, as it makes it harder for a child to complete tasks. Too much energy can make the child harder to control, and they may be unable to handle sitting still for too long. At school, they may squirm or want to get out of their seat.
  • How well a child handles a routine. In life, routines are important. We have time to get up, eat food, go to school, go home, unwind, and so on. Some children adopt a routine very easily. If a child does not have a routine, they can be inconsistent and can miss activities. Having too strict of a routine can make the child upset if something happens to throw everything off.
  • Whether or not a child will accept or withdraw from a new experience. When a child faces a choice for a new experience, some will accept quickly. This can make them open to any new experience under the sun, but they may go in without preparation, and this can be problematic. A child who withdraws may be more prepared, but the problem comes when they are unable to face new experiences altogether.
  • How adaptable they are to environmental changes. When something in their environment changes, they may be able to adapt to it quite easily. New rules, or a new school, or moving can make a child more reserved or shy. A child who is too adaptable may face the challenges of being too easily influenced by their environment.

  • How sensitive they are to certain stimuli. Some children will respond to new stimuli quite well, while others will not be able to handle it. An intense response can cause distraction while a less intense or no response can have its own challenges.
  • How intense they respond to stimuli. A child who responds extremely to stimuli can show their emotion more. If a sad event happens, they will cry quite a bit. If something funny happens, they will laugh a lot. With that said, having too big of response can make it difficult for others to handle when those responses occur. A child with fewer responses or muted ones may be harder for others to read.
  • The child's mood. Are they prone to being positive or negative? Some children are naturally more positive. Too much positivity can make it difficult for others to know when the child is in distress. A child with a tendency toward negativity can also be hard to read.
  • How easily distracted a child is when it comes to certain events. Children who are distracted easily can be able to observe the world around them, but they have a hard time focusing on specific tasks. Children who aren't easily distracted can get their task done faster but may not notice a change occurring that can affect them if they don't react to it in time.
  • How the child can pursue tasks despite pressure. Persistent children can be able to finish a task even if they get frustrated. If they are doing homework and are faced with a tough problem, they are less likely to become annoyed and quit. If a child has less persistence, they may quit at the first sign of trouble. With that said, too much persistence can be a problem if a child doesn't realize they are in above their head in some situations. Sometimes, it's okay to ask for help or quit something if it's not going well.

These traits would be measured, and a profile of the child will be created. This profile can work for young children, even children who are only a few months old. The study controlled markers for race, gender, income, mental disorders, and any other factors that may affect someone as well. These traits can make up different personality types, even though not every child would fit into the types listed.

The Personality Types


40 percent of the children who were studied were "easy". An easy child is one who is positive, regulated, does not react intensely, and is adaptable to any new situations they may face. A child who is easy can establish their routines and have different times where they eat or sleep. They are positive and cheerful and can adapt to rules as they learn them. Easy children were referred to as such because it's easy to raise them and there are usually fewer problems that they may face.

Difficult Children

Difficult children are the exact opposite. They have an irregular functioning, react intensely to a stimulus, withdraw from new situations, are unable to adapt, and are negative. Because of these problems, they were referred to as difficult due to the idea that they are harder to raise. They will have inconsistent eating and sleeping times, have a hard time adjusting to new routines, and they required much patience for their parents to raise. These were about 10 percent of children in the study. A difficult child is not necessarily a badly behaved one, but just someone who has a hard time handling change or other problems they may face.

Slow Warmers

These are children who are slow to warm up, and 15 percent of children in the study were this personality trait. They had low energy, withdrew from activities that were unfamiliar to them, and have a hard time being able to maintain positivity at times. However, they would warm up to changes eventually.

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If you do the math, you may have realized that this only accounts for 65 percent of the children in the study. So, what about the other 35? The other 35 had a combination of traits that didn't quite fit into the three personality types. They may be easy sometimes, but difficult at other times. As it turns out, children can be quite different from each other. This is just how they were born.

Why Does This Matter?

Knowing a child's temperament can give you a better understanding of your child, and even of yourself. It's possible to observer very different temperaments even in children in the same family.

A child's temperament is considered "inborn", but it can be shaped by environment and nurturing. Personality is shaped by experiences and genetics, and temperament plays a role in the development of personality.

If you're wanting to understand your child's temperament and personality or even your own counseling can help.

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