Her abstract works of sculpture heavily featured the dynamics of war, peace, and human relationships.
[1][2] Her family was involved with the Dutch communist community, and as such fled the country when the Netherlands was invaded and occupied by Nazi Germany in 1940.
Interested in sculpture from a young age, Dekker was educated at the Dutch Academy of Fine Arts, where she studied in the 1950s.
[3] She then moved to Paris to further her art career; while in France, she worked in the studio of prominent sculptor Ossip Zadkine.
While living in the United Kingdom, Dekker joined the socialist-feminist Hackney Flashers and became a part of the burgeoning Women's liberation movement.