http://psychology.usf.edu/faculty/data/ddiamond_cv.pdf
There are studies related to the whys to find solutions. This is well written.
Btw: Relevant reading begins at page ten.
“...
Universal Observation of a False Memory
An important and universal observation of the reports from these parents and caretakers is based on their activity during the day after the child is left in the car. These parents go about their daily routine, sometimes for an entire day’s work and they even the use the car (with the deceased child in it) during the day, without the parent having any awareness the child is in the car. These people universally report having complete confidence that the child was safe, at the location where the parent had intended on taking the child. Indeed, many parents return to the daycare expecting to retrieve their child, only to be told that the child did not arrive at daycare that day. These individuals are then horrified to learn that their child spent the entire day in their car, with fatal consequences.
It is potentially of scientific value to explore the process by which the brain somehow creates the false memory that the person has fulfilled his/her task of bringing the child to daycare, or that the child was at home. It is notable that everyday routine activities that may involve the child, such as discussing the child with others, or having a picture of the child at the parent’s workplace, do not serve as reminders that the child is in the car since the brain has provided the person with the false memory that the child is safe at home or at daycare.....” pg 14