Why is she doing this?

Children need boundaries to feel secure. The behavior you describe is your child requesting them.

  At various points during their development, children will push boundaries to

1. make sure they exist
2. know exactly where they are and
3. find out what will happen if they cross them.

Boundaries are like a psychological safety net for children. They want boundaries and need boundaries to feel secure and grow properly.

As a parent, it is your job to establish these boundaries and enforce them for the benefit of your child.

What else can we try?

I can tell you two very effective techniques I began when my children were slightly older than yours. Both involve turning their behavior self-management into a type of game.

The first thing I did was the behavior meter. Basically, this was my thumb that when pointing straight up meant their behavior was good and pointing straight down meant their behavior was bad. When I first started it, the children could understand by my facial expressions and tone what the calibration was. Whenever their behavior would begin to slip, I would pull out my thumb and point it at whatever angle was corresponding to their behavior. Usually, this would be some angle just slightly off of vertical because I would do it quickly to give their self-management skills time to kick in before they got out of hand. Their goal was to instinctively prevent the thumb from going down and to get it back up to straight up vertical as quickly as possible. This helped give them real time feedback without waiting until the behavior got so bad a punishment was necessary. They could self-regulate more effectively. It worked great.

The second thing I did was to start smart kid points. Every time they did something good or smart I gave them smart kid points. Then when they asked if they could have something for Christmas I would check how many points they had then it would become a reward based system. I actually wrote down the points on a spreadsheet so I could show them how many they had whenever they asked.

TL;DR: Children want boundaries. Help them self-regulate their behavior by making it a fun game involving points or a scoring system.

Why is she doing this?

Children need boundaries to feel secure. 

The behavior you describe is your child requesting that you set her boundaries. At various points during their development, children will request boundaries in order to:

1. know they exist
2. discover exactly where they are and
3. find out what will happen if they cross them.

Boundaries are like a psychological safety net for children. They want boundaries and need boundaries to feel secure and grow properly.

As a parent, it is your job to establish these boundaries and enforce them.

What else can we try?

I can tell you two very effective techniques I began when my children were slightly older than yours. Both involve turning their behavior self-management into a type of game.

Behavior Meter

The first thing I did was the behavior meter. Basically, this was my thumb pointing an angle (up, down or in between). When my thumb pointed straight up, it meant their behavior was perfect. When it pointed straight down it meant their behavior was unacceptable and immediate consequences and corrective measures would always follow. In between was their signal to self-regulate. 

When I first started it, the children could understand by my facial expressions and tone what the calibration was. Whenever their behavior would begin to slip, I would pull out my thumb and point it at whatever angle was corresponding to their behavior. Usually, this would be some angle just slightly off of vertical because I would do it quickly to give their self-management skills time to kick in before they got out of hand. 

Their goal was to instinctively prevent the thumb from going down and to get it back up to straight up vertical as quickly as possible. This helped give them real time feedback without waiting until the behavior got so bad a punishment was necessary. They could self-regulate more effectively. It worked great.

Smart Kid Points

The second thing I did was to start smart kid points. Every time they did something good (or smart) I gave them smart kid points. Because let's face it, everyone enjoys earning points. It's fun! For some reason humans seem universally programmed to want to earn points and no amount of points is ever enough. So I used this fact to my/our advantage.

Then when they asked if they could have something for Christmas I would check how many points they had then it would become a reward based system. I actually wrote down the points on a spreadsheet so I could show them how many they had whenever they asked.

Why is she doing this?

Children need boundaries to feel secure.

At various times during their development, children will push boundaries to a. make sure they exist b. know exactly where they are and c. find out what will happen if they cross them. Boundaries are like a psychological safety net for children. They want boundaries and need boundaries to feel secure and grow properly.

As a parent, it is your job to establish the boundaries and enforce them.

What else can we try?

I can tell you two very effective techniques I began when my children were slightly older than yours. Both involve turning their behavior self-management into a type of game.

The first thing I did was the behavior meter. Basically, this was my thumb that when pointing straight up meant their behavior was good and pointing straight down meant their behavior was bad. When I first started it, the children could understand by my facial expressions and tone what the calibration was. Their goal was to instinctively prevent the thumb from pointing down. This helped give them real time feedback without waiting until the behavior got so bad a punishment was necessary. They could self-regulate more effectively. It worked great.

The second thing I did was to start smart kid points. Every time they did something good or smart I gave them smart kid points. Then when they asked if they could have something for Christmas I would check how many points they had then it would become a reward based system. I actually wrote down the points on a spreadsheet so I could show them how many they had whenever they asked.

Why is she doing this?

Children need boundaries to feel secure. The behavior you describe is your child requesting them.

At various points during their development, children will push boundaries to

1. make sure they exist
2. know exactly where they are and
3. find out what will happen if they cross them.

Boundaries are like a psychological safety net for children. They want boundaries and need boundaries to feel secure and grow properly.

As a parent, it is your job to establish these boundaries and enforce them for the benefit of your child.

What else can we try?

I can tell you two very effective techniques I began when my children were slightly older than yours. Both involve turning their behavior self-management into a type of game.

The first thing I did was the behavior meter. Basically, this was my thumb that when pointing straight up meant their behavior was good and pointing straight down meant their behavior was bad. When I first started it, the children could understand by my facial expressions and tone what the calibration was. Whenever their behavior would begin to slip, I would pull out my thumb and point it at whatever angle was corresponding to their behavior. Usually, this would be some angle just slightly off of vertical because I would do it quickly to give their self-management skills time to kick in before they got out of hand. Their goal was to instinctively prevent the thumb from going down and to get it back up to straight up vertical as quickly as possible. This helped give them real time feedback without waiting until the behavior got so bad a punishment was necessary. They could self-regulate more effectively. It worked great.

The second thing I did was to start smart kid points. Every time they did something good or smart I gave them smart kid points. Then when they asked if they could have something for Christmas I would check how many points they had then it would become a reward based system. I actually wrote down the points on a spreadsheet so I could show them how many they had whenever they asked.