A father forgets to drop his young son off at childcare and instead leaves him locked inside a car, where the boy is discovered dead at home time.

The scenario may seem implausible, but it happened in Perth this week.

And experts say such memory lapses can happen more easily than people would think.

Earlier this week, the body of an 11-month-old boy was found inside the back of his father's car outside the Ladybugs Early Learning and Care Centre in Perth's Helena Valley.

His father arrived at the centre to pick up his son, but was told by staff he had not dropped him off that morning.

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The boy's body was found still strapped into the child capsule inside the car.

Researchers into similar incidents overseas say many parents are vulnerable to lapses of memory, and sometimes with the same devastating results.

Texan couple recall how daughter died outside day care

In the United States as many as 50 children die each year as a result of being left inside cars.

In 40 per cent of cases, the parent or carer forgot to drop the child at their day care or babysitter.

Such was the case for Kristie Cavaleiro and her husband Brett, of Austin, Texas, who lost their daughter Sophia two-and-a-half years ago.

When the couple met for lunch that day, Mr Cavaleiro realised he had forgotten to drop their one-year-old at day care.

"He couldn't remember dropping her off at day care," Ms Cavaleiro explains. "I instructed him to call his office, and at the same time I called the day care.

"His office manager checked his truck and around the same time the day care teacher confirmed that she was not there and so I hung up and immediately called 911.

"Despite us performing early CPR and myself included trying to assist with resuscitation, despite everything, we lost her.

"An hour and 19 minutes after the first 911 call she was declared dead."

Mrs Cavaleiro says that the morning of her daughter's death, her husband had been forced to take a different route to work because of road works at the end of their street.

"Instead of taking the left turn at the traffic light that he would normally take to drop her off at day care, he turned right," she continues.

"She was sleeping in the back and quiet and in a rear-facing car seat and so he just proceeded on his way to his office and in his mind he thought that he had already dropped the child off at day care."

Smallest change to routine can cause memory lapses

Dr Matthew Mundy, a memory expert at the School of Psychology and Psychiatry at Monash University, says every parent is capable of making a similarly fatal mistake.

"For our drive to work, we've formed an autopilot to how to get there and a part of the brain that takes over when those sorts of things happen is called the basal ganglia," Dr Mundy explains.

"This part of the brain is relatively primitive and it sort of monitors our routine motor skills for us. And so while we're driving to work or whilst we're making a cup of tea, we might not be aware of exactly all the decisions that we're making.

"They're actually not conscious to us. And because of that, because we're not consciously making those decisions to turn left and turn right or put the sugar in at the right time, if something distracts us, if maybe a car cuts us off or if the telephone rings, we might miss a step."

Awareness campaigns gather momentum

In a bid to raise awareness, Janette Fennell, president and founder of kidsandcars.org, has been campaigning for many years to persuade car manufacturers to fit devices to stop parents leaving children in vehicles.

She says there are also things that parents can do to remind themselves a child is there.

"[We have] a 'look before your lock' program. What we make are several suggestions," she explains.

"The first one is to take your handbag or your employee badge or your briefcase or your cell phone, put that on the floor in front of where the child's car seat is.

"The second idea we have is to put a stuffed animal in the child's car seat and always have it in there, but right before you are going to place the child in the car, take the stuffed animal and set it up front on the passenger seat, because then you've got this visual reminder."

Since Sophia's death, Mrs Cavaleiro has embarked on an awareness campaign of her own, urging carers to call parents if their children are not dropped off by a certain time.

She says her heart goes out to the father in Perth, with whom she now shares the most tragic of bonds.

"He will have to forever live with the fact that he made, he made a mistake. A human error, he made a single mistake that resulted in the loss of probably his most precious possession."