Thomas and Chess: Temperament type longitudinal study and findings

Medically reviewed by Melissa Guarnaccia
Updated January 3, 2024by BetterHelp Editorial Team

Temperament can shape how we behave, learn, and interact with other people.

In the late 1950s, psychologists Alexander Thomas and Stella Chess, working with Richard and Jacqueline Lerner, launched a 30-year longitudinal study that tried to identify different types of temperament in children. Through this study, they sought to explain some of the differences in children’s behavior, which were often attribute to poor parenting at the time.

Below, we’ll look at the nine temperament traits that resulted from the New York Longitudinal Study:

Parenting can come with a range of challenges

The New York Longitudinal Study (NYLS)

The New York Longitudinal Study found that nine traits influenced temperament. Each trait had a range of intensity, and the strength of the traits combined to create the child’s unique temperament. By knowing the child’s temperament, it was thought that parents and caregivers could gauge how the child would react in certain situations and plan for purposeful activities to create a constructive environment for the child. 

Each of these nine traits was measurable, and extremes at either end of the spectrum were thought to be rare. The following are the nine temperament traits used in the New York Longitudinal Study:

1. Activity (energetic vs. sedentary)

This trait measured how much natural energy a child has. Too little energy may make it harder for a child to complete tasks. However, too much energy can make the child harder to control, and the child may be unable to sit still for too long.

2. Regularity (predictable vs. variable)

In the context of this study, routine refers to a child’s natural patterns and schedules for biological functions, such as eating, sleeping, and using the bathroom.

3. Initial reaction (open vs. hesitant)

When a child faces a new experience, such as a new person, environment, or toy, they may accept it quickly, but other children may withdraw.

4. Adaptability (accommodating vs. resistant)

When something in the environment changes, some children adapt quickly, while others may have more difficulty adapting. New rules, a new school, or a new house can make a child more reserved or shy, but the environment may too easily influence a child who is too adaptable.

5. Intensity (exuberant vs. lethargic)

An exuberant child tends to respond emotionally to stimuli. If a sad event happens, they may cry quite a bit, and if something funny happens, they tend to laugh a lot. However, having too big of a response can make it difficult for others to handle those responses. On the other hand, a child with fewer or muted responses may be more challenging for others to read.

6. Mood (positive vs. negative)

Some children tend to naturally be more upbeat, but too much positivity may make it difficult for others to know when they are in distress. However, even on the other end of the spectrum, a child with a tendency toward negativity may also be hard to read.

7. Distractibility (attentive vs. sidetracked)

Children who are distracted typically observe the world around them but may have difficulty focusing on specific tasks. Children who aren't easily distracted can often get their tasks done faster but may not notice things around them that can affect them if they don't react in time.

8. Persistence/attention span (immersed vs. disinterested)

Persistent children may be able to finish a task even if frustrated. If they do homework and encounter a challenging problem, they may be less likely to become annoyed and quit. On the other end of the spectrum, if a child is disinterested, they may quit at the first sign of trouble. However, too much persistence can be a problem, too, if a child doesn't realize when they are in over their head.

9. Sensory threshold (unaffected vs. irritated)

This trait relates to sensory stimuli, or how the child responds to touch, brightness, texture, aroma, taste, etc. Children with a high threshold may appear unaffected and be more comfortable with increased stimuli. Those with a low threshold may become bothered or agitated.

Parenting can come with a range of challenges

Why does temperament matter?

Knowing a child's temperament may give you a better understanding of that child and their likelihood to react in certain ways in a given context. Temperament can vary considerably, and it's possible to observe very different temperaments even in children in the same family. Researchers believe that between , but it can be shaped by environment and nurturing.

If you find that some of your own traits with present challenges in certain life situations, or if you’re raising a child who may have difficulty related to temperament, it may help to speak with a licensed mental health professional. According to the Centers for Disease Control and Prevention, there is a strong connection between the mental health of children and their parents, and taking care of your mental and emotional well-being may help both you and your child.

If you don’t have time for traditional in-person therapy, you may benefit from online therapy. Working with an online therapist lets you get the help you need from the comfort of home, as sessions take place via audio, video, or live chat. With an online therapy service like BetterHelp, you can also contact your therapist anytime through in-app messaging, and they’ll respond as soon as they can. This may prove helpful if you have questions or concerns in between sessions, as you can write them down in the moment rather than waiting until the next therapy session to communicate them. 

Studies show that online cognitive behavioral therapy is effective for treating various conditions, including anxiety, depression, panic disorders, and obsessive-compulsive disorder (OCD). If you’re experiencing  stress or anxiety related to raising a child with behavioral concerns, or if you find that some of your own temperament traits are causing you anxiety, you may benefit from speaking to a therapist online. 


The results of the New York Longitudinal Study by Alexander Thomas and Stella Chess led to the development of nine temperament dimensions, which are believed to exist on a spectrum. Temperament may influence the way a person is prone to react in certain contexts in life. If you have a child who is experiencing challenges related to temperament or behavior, this may take an emotional toll on you and your family. If you find yourself in this situation, it may help to speak with a licensed therapist, whether through traditional in-office therapy or through online therapy.

With BetterHelp, you can be matched with a licensed online therapist who has experience helping parents who are facing challenges with parenting, or whatever other specific concerns you may be facing. Take the first step toward getting support and reach out to BetterHelp today.

Grow your understanding of your temperament

The information on this page is not intended to be a substitution for diagnosis, treatment, or informed professional advice. You should not take any action or avoid taking any action without consulting with a qualified mental health professional. For more information, please read our terms of use.
Get the support you need from one of our therapistsGet Started