Babies in Hot Cars:
What Three Experts Say

The experts:

John Disterhoft, PhD, director of Northwestern University Institute for Neuroscience, Feinberg School of Medicine. Why ask him? He’s a noted researcher in how the brain’s neural networks affect learning, cognition, attention and awareness. He replied to my interview questions via email.

Charan Ranganath, PhD, professor at the University of California-Davis Center for Neuroscience. Why ask him? He studies the neurocognitive workings of human memory and how different brain regions interact when performing tasks involving short-term and long-term memory. He replied to my questions via email.

Mark McDaniel, PhD, founding co-director of the Center for Integrative Research on Cognition, Learning, and Education at Washington University in St. Louis. Why ask him? He’s an expert on the processes that lead to memory failure. This was a phone interview.

Email interviews, July 2014

RON GERACI: Is the same neurological brain processes at work, metaphorically or literally, when a person accidentally leaves a hot cup of coffee on the roof of a car [after setting it there to open the door] and when a person accidentally leaves a baby in the backseat of a car? 

JOHN DISTERHOFT: I suppose they are [the same]—but it seems that a baby in the backseat of a car should be more prominently in memory than an inanimate cup of coffee on the car roof.  So the issue is, how can a person not attend to a living being, especially your own child, in the back seat?  [Disterhoft didn’t mention his children in his responses, unlike Ranganath and McDaniel, but he’s a parent and grandparent.—RG]

CHARAN RANGANATH: Cognitively, it is one thing to knowingly leave a child in the car and then forget that they are still there later, and another to leave while totally being unaware that the child was in the car to begin with.

There’s a few factors to consider in these types of situations.

First, the brain is designed to tune out things that are stable over time—this is called habituation. Say, you are in a room with a funky smell.  You might immediately say “that smells terrible, I can’t pay attention to anything else.” After about 5 minutes, you habituate and are minimally aware of that smell, unless there is a breeze or something blowing it around. This is a fundamental principle of the brain. If you look at neuronal activity, you see large changes in activity elicited by transient changes, but once something is sitting in the same place for a long time, you get a massive drop in responses to that thing. So, if you are in a car with a baby, and the baby is sleeping quietly for a long time, it could be easy to habituate to the baby’s presence, particularly if you are thinking about something else that is urgent or pressing.

Habits also play a role. In quite a few of the baby-in-car stories, the parent was doing something that was unusual relative to the usual routine. For instance, suppose normally you take the baby to the daycare center in the morning, and sometimes afterward you go grocery shopping. So, on one day, the center is closed and instead you have to bring the baby with you to the supermarket. At this point, your set habits will kick in. That makes it harder for you to remember that you have a baby in the back seat and do things differently on this occasion.

What if the parent is aware of the child’s presence, but plans to come back quickly? This might happen because the parent thinks “there’s no way I could leave my baby for more than a minute or two.” Unfortunately people tend to routinely overestimate their ability to remember both important and unimportant things (the ability to predict what you will remember later is called “metamemory”). What probably happens is that the person imagines the situation, and in their imagined scenario everything goes according to plan and they remember the event successfully. This leads the person to minimize the likelihood that things will not go according to plan, and thereby overestimate their likelihood of remembering.

Once you leave the car, you have to remember to come back. In general, the ability to remember to do something in the future is called “prospective memory”, and in particular, remembering to come back to the car at a particular time would be a form of “time-based prospective memory.” If you are talking about remembering for just a few seconds (such as while you feed the parking meter), this is not so hard, because you can do it by keeping that goal in your mind (or what is called “working memory”. But if you have to remember it for a longer period of time (such as when you jump into the mall to pick up something from a store), it is difficult for anyone to child in mind continuously throughout that period, and nearly impossible if you are being distracted by texts, emails, phone calls, etc. In a nutshell, prospective memory is hard, and most people underestimate how hard it is.

There is surprisingly little neuroscience research on prospective memory, but we are pretty certain that, even more than remembering events from the past, the ability to spontaneously remember to do things in the future depends on the hippocampus and prefrontal cortex. The thing is, there are a lot of factors that can influence functioning of both of these regions. These areas are also critical for overcoming strong habits and using your current goals to guide behavior.  Frontal dysfunction in particular is associated with poor metamemory and poor prospective memory. Chronic stress, sleep deprivation, and aging are all associated with reduced functioning of the hippocampus and especially the prefrontal cortex. Of course, this is exactly the zone where many parents are at (yes, sadly, age-related effects on brain function can be apparent even in one’s 30s).

So, what this all indirectly suggests is that if you are a stressed and sleep deprived parent, and you are taking care of a quiet baby in an unusual situation, there’s good reason to think that you might forget the baby’s presence. Alternatively, if you knowingly leave that baby in the car, you could overestimate your ability to come back on time. In general, the solution is (1) don’t knowingly leave the baby in the car, period, and (2) if you are caring for a baby in an unusual and stressful situation, recognize that you’re likely to be forgetful and take countermeasures to force yourself to pay attention to the child and minimize distractions like email, texts, etc.

RG: Do our brains seem to have a way of prioritizing the retrieval of info that we’d consider “critically important” (such as an act we must perform, imminently or very soon) over information we may typically consider less important? (Realizing that the urgency we place on information at any given moment can change with context.)

JOHN DISTERHOFT: Yes—things are prioritized by attending to them.  Most people seem to give a lot of attention to children. No doubt this is how these cases gain notoriety.

CHARAN RANGANATH: There are definitely multiple ways that the brain prioritizes learning and retrieval, although we’re just scratching the surface. One is memory for arousing events—the brain is highly efficient at retrieving memories for emotionally arousing events. Another is reward—people are better at remembering events that are intrinsically rewarding, or associated with extrinsic rewards. A third is surprise—people remember events that are surprising or unexpected.

The baby-in-the-backseat scenario doesn’t fit any of these, and to my knowledge, it hasn’t been studied. It’s quite easy for me to believe that there would be something in the brain that would trigger an enhancement in memory for things that involve your children, or other individuals, but I don’t know of anything on the topic. That would certainly explain why people are much more likely to leave something on top of the car (or forget to take something that they need from the car) than they are to leave a baby in the car. But unfortunately, you have all those factors I described above working against you, so even then, sometimes people can forget.

RG: People often purposely create very bold, powerful memory triggers (such as electronic alarms, signs or notes and other strategies) for things we consider “critically important.” Does any research suggest our brains might do this in ways we don’t consciously notice?

JOHN DISTERHOFT: Our brain does this sort of thing quite automatically–again, by directing attention to important stimuli.

CHARAN RANGANATH: People definitely use cues in the environment to remind them of things that they have to do, and these cues serve a critical role in prospective memory. So, for instance, seeing the garbage can by your house can remind you to pay the city services bill. People probably form these associations between cues and the things they have to remember without much thought, but they probably don’t do this often enough (see more below).

RG: Do you feel memory researchers view the reported occurrences of people leaving babies in automobiles due to forgetfulness in a tangibly different way than laypeople do?

JOHN DISTERHOFT: No, except that they would appreciate even more how little regard a parent must have for a child in order to “forget it” in the back seat.

CHARAN RANGANATH: I think the biggest difference is that memory researchers really understand that memory is really fallible, so we can more easily imagine how something like that could happen.

As a parent, it didn’t even occur to me that someone could leave the car without being aware that their baby was inside. But my daughter is now 13 and most of my memories of her first few years were clouded by stress and sleep deprivation. I really had to think back about what it was like, and I got more empathy for the parents. I think that, as people have more and more things they are expected to do, and have more and more devices that keep them focused on those responsibilities, they become much more bound by habits. When I think about it that way, it’s much more understandable to me how a parent could make a mistake like that.

RG: Has brain research suggested any novel, unexpected or little-discussed (among lay people) strategies that may help a person avoid forgetting something they consider to be “critically important”?

JOHN DISTERHOFT: Not that I’m aware of.

CHARAN RANGANATH: Well, not so much brain research as psychology research, [which] has long shown that memory (especially prospective memory) is a lot better when you have a salient cue. Everyone who needs to remember something in the future should think of a cue that will be available at the right time and then imagine using it to do the right thing. So, if you have to pick up your child from daycare at 4, think of where you’ll be at 3:45 and imagine yourself seeing something in that place that will lead you to head to the daycare center. Then, when you are in that place, it will naturally lead you to remember to go to the daycare center.


Phone Interview, July 2014

RON GERACI:  We’re seeing headlines again about babies being left in cars.


RG:  The public seems divided into two camps about it. One camp says, these are not normal people; they’re negligent—no one could ever do this unintentional unless they’re criminally negligent. The other is, these people are normal it’s a cognitive hiccup, we could all do it.

It this error is the same as when you leave a hot cup of coffee on the top of your car after you go to a convenience store or is the brain doing a much different thing when the child’s in the car?

MARK MCDANIEL:  From my perspective and from the research that I’ve done and the literature on a topic called prospected memory, which is the kind of memory we use when we’re trying to execute an intention at some later time. If you have a child in the car seat and your intention is to drop that child off at daycare, we, we call that a prospective memory task. If you set a cup of coffee on top of your car and your intention is to take that couple off before you start driving away, we also call that a prospective memory task.

Given the research thus far, it seems reasonable to believe that both those prospective memory tasks are supported by similar cognitive processes. Do you mind, Ron, if I talk a little bit theoretically about what those processes are?

RG:  No, please go ahead.

MARK MCDANIEL: The framework that we’ve developed and that has received a lot of support in the experiments that have been done is that prospective memory can be supported basically by two routes or by two processes in the brain.

One process would be what we would call a monitoring process whereby your intentional resources are devoted to keeping that intention in mind, or to periodically revisit that intention to call it up from long-term memory. That is a very cognitively demanding process. It’s one that’s prone to failure when we have to maintain that attention toward the prospective memory intention for long periods of time because any kind of distraction, any kind of thoughts that you get oriented toward can easily preempt your thoughts about the prospective memory intention. Once those thoughts are preempted then you have to, there has to be a route by which you can bring that back into mind.

RG:  Is there some task that would unconsciously spur you to do that?

MARK MCDANIEL: Can I answer that question in a moment?

RG: Certainly.

MARK MCDANIEL:  Because I want to then follow up with the different route or the different process supporting prospective memory and that process is one that’s not very attentionally demanding. That’s a process that relies on a reflective retrieval of the intention from long-term memory when an appropriate cue is in your sphere of attention.

For example, let’s say that I have to remember to give a colleague a message at work and I see that colleague at work. There’s a good chance that seeing the colleague is going to stimulate reflectively or automatically retrieval that I have to give him the message. If I set a cup of coffee on the car, if that cup of coffee is right by the door so that when I open the door I glance that’s the perfect cue to remind me I’ve got to take it off the top of the car.

Let’s now examine, though both of these routes are possible the one is more reflective and depends on external or internal cues. The other is more attentionally demanding and depends on we would call an executive system to maintain concentration on that intention.

Now, let’s think about the car and the baby. I want to put this correctly. It’s not the case that the importance of that intention, per se, is going to change either of the two processes that I mentioned, but it could be the case that the importance has some impact on how you approach those processes. For example, if you’re aware that you lose attentional focus you might say to yourself, I better make sure there’s an external cue that I’m going to look at when I get near that daycare center so that I can have a reminder to retrieve the fact the baby’s in the back.

That’s the simple idea that is behind all of these devices that people are inventing, and behind suggestions [such as putting] the baby rattle in the front seat. Better yet, put it on top of your briefcase. Put the diaper bag on top of your briefcase.  Give yourself any kind of cue. I mean, you could even put something unusual on your briefcase just to signal you when you get out of the car. Something that tells you, wait a minute, there’s something I have to remember to do.

Does the importance of the task could prompt you to do that rather than if you had a cup of coffee on top of the car or you might think it’s trivial an enough that you don’t care if you drive often spill it, so what? You do care, but it’s not enough to make you engineer a cue in the environment.

RG:  Right, so these are not happening in the brain. The brain isn’t treating them any differently, but the importance might prompt you to unconsciously create some external physical cue.

MARK MCDANIEL: That’s right. The other thing is that if you understand that monitoring processes are going to be difficult to maintain, you may somehow reinforce the idea that you don’t want to get distracted, that you’re going to keep reminding yourself. You might develop a better plan for maintaining that monitoring. I have to say those plans can also be fallible.

An example from my personal life—I study this stuff, but even so I’m fallible. I had to pick up my kids from tennis one time, some years ago, and I, throughout the day, kept reminding myself you’ve got a go pick up the kids from tennis because I didn’t usually do it. I got involved in working on a manuscript and as soon as I did my efforts of monitoring were completely preempted. I got a call two hours later from my kid saying where are you? We’re stuck here at tennis.

This is an important intention for me. I had a great motivation to remember it and I tried to implement a monitoring strategy to get it done and I failed. I think that this could characterize what happens with parents. It is important to them. They may try to implement the monitoring strategy and not realize that it can be easily derailed if they encounter some challenge in driving there or if they have a concern about their work that day or any kind of thought that start to push out of this consciousness, push out the intention.

RG: Right.

MARK MCDANIEL:  Here’s another thought. Now, this is very speculative, we haven’t done the research and nobody has, but I’m hoping somebody will. It could be that people have this naïve view that because the intention is so important to take the baby out of the car and drop it off at daycare. It’s so important that the brain will treat it with high priority and you don’t have to worry about it so much.

RG:  Yes, that’s one of my questions.

MARK MCDANIEL:  That’s probably completely wrongheaded. It may be that people in fact, they engineer things better say they remember to take their lunch in to work that day. They leave their lunch bag at the door or to remember to take the library book back; they may leave the library book in the front seat. They may understand that there are likely to forget those things and engineers situation to prevent the forgetting whereas they inappropriately believe that the importance of the kid in the car seat is going to circumvent these usual failures and it doesn’t. It’s probably the same processes.

RG: Your brain makes the same size and color Post-It for the baby and the vegetables in the back seat. It only has that one Post-It pad to use. They’re both the same Post-Its; it’s just that you have to externally do something to make sure you look at one of them. Your brain doesn’t treat those two things differently; it doesn’t internally put the other one in a different category or do something different with it.

MARK MCDANIEL:  As far as we know, what you said is correct.

RG: Okay.

MARK MCDANIEL:  Now further research may show that to be different, but we don’t have any evidence that they would be treated differently in the brain. We think it would be treated the same from a brain standpoint. The only difference would be that you might change your orientation to do more to remember to take the child out of the baby seat, but the same processes are going to be involved. You either have to monitor or cues have to be present to stimulate retrieval.

RG:  That’s great, okay. That’s fascinating. One question is, it possible that this may not even be a memory task? Is it something that was never actually encoded into memory because you just unconsciously assume that this will be triggered by some sort of external event? The same way when you walk into the convenience store you don’t mutter to yourself “I must remember to pay for the coffee instead of walking out with it.”

MARK MCDANIEL:  It’s a good question. The question is, is it something so important—let’s say taking the baby out or something like paying—it does not require an explicit encoding?

I think that in fact it does and I think that in fact prospective memory is likely almost certainly to depend on the degree to which you prepare the good encoding. I think you’re more likely to forget something if you have a fleeting thought I’ve got to remember to send an email when I get to the office.

If it’s just a fleeting thought and it’s not well formed and you don’t give it enough intention to get a good encoding, I think those things, that’s often I think the root of prospective memory failure. You never really encode it well enough to get a retrieval.

RG Right.

MARK MCDANIEL: Again, it could be that your spouse says you’ve got to drop the baby off at daycare. Yeah, fine, thinking that of course I will. If you don’t stop and encode that intention in a good way, even without external cues, is to form a strong link between that intention and things you anticipate occurring on the way to daycare.

For example, if there’s a particular turn off you have to make instead of saying, yeah, okay, you say fine. Then you stop and you imagine yourself approaching the intersection and turn into daycare. That kind of elaborate encoding we know from research is going to produce better prospective remembering. We know that.

I think that’s where people fail here is that they think it’s so important that they don’t have to worry about that and they probably don’t even know these strategies. For almost anything you’re going to have to remember later, a good, strong link between the intention and the anticipated context is going to produce fairly good performance. People just don’t realize that they need to take the time to do that.

RG: People may think once I physically strap the child in the car I don’t need to consciously remind myself to conduct the task. I guess they don’t realize if they don’t have a trigger they could be distracted. I guess a break in routine seems to be the common denominator in all of these?

MARK MCDANIEL:  Exactly. I think that’s exactly right. If the person was routinely dropping the baby off then all these things become more automatized. This is habit and then it’s true that there is a more automatic process by which you just your system just follows that habit. That’s true for paying for something. That’s our habit, when we go in the store we’ve always paid for something, so you don’t really have to think about it. It’s your normal habitual response.

Even so, I would contend that sometimes we could be so distracted when we’re shopping that we could have something in our hand and walk out without paying because we’re so distracted by something else that it circumvents that more automatic paying.

RG: Yes, that happened to me today. I bought three newspapers instead of one, as usual, and I had the extra two tucked under my arm. I was shoplifting two newspapers and I didn’t know it.

MARK MCDANIEL: Exactly and that wasn’t something because you’re a criminal or a deviant personality. It’s because that’s the way the cognitive system works. If your focus is on another item, another kind of task, then we need strong cues to get us back to perform the activity that we need to perform right then.

RG: It seems as though to physically remove the baby from the car is not the thing that they forget. That is preemptively forgotten with the preceding task that they didn’t do, like driving to the day care center. They’re not doing something routine and they’ve forgotten something larger first.

MARK MCDANIEL: That’s right, because if they had driven to the daycare center they would not have forgotten to remove the baby. That’s right. The bigger thing is to get to the daycare center. If they’re not at the daycare center then their whole goal structure is around work and that goal structure is going to exclude, because it’s so ingrained, anything to do with the baby.

Unless there’s a cue there or unless they’ve made a strong trigger. This would be interesting. This would be a cool experiment and you wouldn’t do it with a kid in a car seat, but we’d set up a laboratory where you have somebody form a strong encoding between taking a turn and fulfilling the attention and somehow distract someone so they don’t take the turn. Then, ask what happens if they get to the end could they still remember the baby because they’ve had a strong encoding or would it be completely contingent on that initial turn. That’s a really good question. I don’t know the answer to that.

RG: That’s very interesting. Yeah, the thing that’s just one step down the daisy chain if is cut off as a matter of course.

MARK MCDANIEL: Right, yes. It’s interesting. You mentioned the daisy chain and that reminded me that we’ve done some work with the human factors head at NASA, the National Aeronautics Space Association, he’s no longer there, he’s retired.

He was interested in pilot errors, and these would be prospective memory errors. For example, they’ve got to remember to set the flap a certain way at takeoff or landing. They always do it, but if they can’t do that because of some problem and then they continue on the daisy chain, that’s when they forget. They get too far down the daisy chain and they can get themselves back. That’s when these airline accidents have happened, when the flaps haven’t been set because the pilot skipped it.

RG: It seems very analogous. The pilot has probably had 5,000 flights under him or whatever and had done the task many, many times. In this case his mistake is suicidal. There’s certainly no intention to make this mistake.


MARK MCDANIEL: We have a book out on this [topic]. The title is Prospective Memory. It’s by Sage.

RG:  Great. Just a reaction question: when you see this in the news and you read about it, when you hear about this phenomenon every few years, you must have a different perspective than a lot of the lay public does.

MARK MCDANIEL:  I don’t know if I do, but I can tell you this. I always feel it’s a tragedy and I always feel, I don’t quite know how to say it, a little bit sorry about it because I know it could be prevented. It really has to do, in bigger terms, with the fact people’s knowledge about their own cognition, which you would call metacognition, is often inaccurate.

We know this is true about study habits. I just came out with a book called Make It Stick about that very thing, about how insights about our own learning are oftentimes very wrong. I think it’s the same thing with prospective memory. I think for many people their metacognitions about their prospective memory; their understanding of prospective memory, it’s off, and as a consequence, it leads them to behave in ways that they wouldn’t ever think to behave in.

For example, they think that this is so important they’ll never forget it. They also maybe start out driving the car thinking I’ve got to stop a daycare, I’ve got to stop at daycare. They get distracted and they don’t understand how a distraction can completely preempt the maintenance of this intention and awareness.

It’s a tragedy and I’m saddened by it because I feel like with a little bit of education that people would understand this and they would all take appropriate measures then to [avoid the distractions] and make sure the baby gets dropped off.

I remember the case of one woman who forgot her child, she’s a psychologist, she said, “I never thought that a parent could do this and it happened to me. I now understand why, and I understand the failing of the cognitive system. “

That’s why I’m really very happy to talk to you and other reporters, so that may be with enough press and education people will know that they probably have some misconceptions about prospective memory. And if they don’t create external cues and avoid distractions, it can fail them.

RG: I would guess these failures in prospective memory are probably happening to people countless times a year, but most have trivial consequences.

MARK MCDANIEL: That’s right. Also, as far as how rare these cases are, of leaving a child in a car. We don’t really know. They are rare in an absolute sense, but we don’t know how rare they are in a relative sense. For instance, do we know the base rates of how many caretakers one time out of the last two years of their life are asked to take the kid to daycare? We don’t know how many times that happens.

RG: Even when it’s reported …

MARK MCDANIEL: Right, if it happens. Maybe that’s a rare event. It probably is a rare event, right? If you’ve got caretakers always taking the kid to daycare, only in some exceptional instances will they say to their partner, “could you please drop the kid off today?” So it could be a more frequent event. People don’t understand this could be more frequent in a relative sense than it first appears.

RG: Interesting. Some people have come forward in articles or news segments and said, “I left my baby in the car for about 10 minutes one time. I just happened to think of him, and if that thought had not popped in my mind, he would have died.” A fatality didn’t result; that doesn’t go on any kind of record.

MARK MCDANIEL:  Right. A lot of prospective remembering is fortuitous in that your line of thought leads you to think about the [thing you need to remember]. And then you say, “oh my God, what about my baby? “

As one example, we were testing participants in our laboratory and we had one participant who called up the next day and said, “you may have saved my life. I’ve got a heart condition. I have to remember to take my medication and I forgot yesterday. Just by chance, I was doing your experiment and I read the feedback and it was about prospective memory. I realized, whoa, I forgot to take my heart medication.”

It was just a chance encounter in the environment that caused him to think about that. I think if you monitor yourself over the next week, you’ll find that this happens to you more than you would think. You don’t forget, but it’s because somehow the stream of events gave you a cue. Otherwise you would have forgotten.





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