Human Development

You might be wondering when and how our sensory systems develop in the first place, in order for perception to occur. It turns out that all of our senses are stimulated to some extent when we are still in the womb (prenatal), with the exception of vision.  All sensory systems need to be stimulated early in life in order for them to develop normally.^[16] The timeframe within which they need to be stimulated is called a critical period, and the exact timing of critical periods varies across our senses. Permanent deficits can arise if normal stimulation does not occur during a critical period.

When we are born, our visual system is less developed than our other sensory systems (since it is not stimulated prenatally. If a newborn has problems that prevent them from seeing normally in the first year of their life, they have permanent difficulties with perception of faces for the rest of their lives.^[17]It is important to detect and resolve any sensory issues, e.g., eye and ear problems as early as possible^[18]When you enter this world as an infant, you’re not wired full of memories that your brain will use to predict. Other people cultivate your world and as a consequence, they are wiring your brain full of experiences that your brain will then use to predict. You didn’t have a hand in creating that world, and you are not responsible for it.

Garlic Babies

If you are now wondering how psychologists can study sensation in babies that haven’t even been born yet -you are asking good questions! Indeed, it’s a pretty big claim to say that we start learning even before we are born.

Developmental psychologists have developed methods of working with prenatal and just-born infants to get a peek into how, and even if, babies can learn before they’re born.

In a study by Hepper in 1995, he wanted to know if infants could recognize a smell of a food they were exposed to before they were born – in this case, garlic. Participants were twenty mothers and their infants who were assigned into one of two conditions; a garlic condition and a non-garlic condition. The condition they were in depended on a pre-study survey that asked about garlic preferences.

The ten mothers who were in the garlic condition ate fresh garlic in their meals at least three or four times a week for the last month of their pregnancy. The non-garlic condition was just that, where the mothers didn’t eat any meals containing garlic for the last month of their pregnancy. All twenty of the mothers had normal pregnancies and had healthy babies. Also, it is important to note that the newborns were bottle fed, so were not getting any garlic exposure through breast milk.

In order to make sure the learning was truly prenatal in nature, Hepper and his team tested the infants 15-28 hours after birth. The researchers smeared garlic paste on a piece of wool for the experimental stimuli as well as had a regular piece of wool for the neutral stimuli. They placed the pieces of wool on either side of the newborn, making sure the infant’s head started in a neutral place not looking at either piece of wool. They were looking to see if the babies would turn towards or away from garlic (helpful knowledge – looking time and direction is a valid way to get preference data from infants!). If the babies turned towards the garlic wool, then that would show a preference for the garlic smell. If the babies turned away from the garlic, then that would mean they had an aversion or did not like the smell.

What did they find? They found that the babies in the garlic group would turn their head towards the piece of wool that had the garlic paste on it, and statistically indicated a slight preference for garlic. However, the babies in the non-garlic condition showed a statistically significant aversion to the garlic smell and would turn away. The researchers want to conclude that the aversion to garlic in the non-garlic group and the slight preference for garlic in the garlic group demonstrate the infant’s ability for prenatal learning. It does seem likely that infants get olfactory input prior to birth.

There are many other studies about prenatal learning – and research shows that infants also can learn about stress and be predisposed to language and music if their prenatal environment provides those experiences. There is pretty strong empirical evidence that learning can happen before we are born.

Theory of Mind

Theory of mind (ToM) is a concept in psychology that basically means being able to consider other people’s mental states, such as desires, thoughts, and beliefs. Once you realize that everyone truly has a different perspective, you might want some practice in understanding that. Theory of mind isn’t an innate ability for humans, but rather one that is developed over time and experiences. This means that there are individualistic differences in ability and complexity of being able to ‘read’ other’s theory of mind.

Development

Theory of Mind is often studied through a developmental lens. One common way to access children’s theory of mind is through a task called the False Belief task, also called the false location or Sally-Anne task. This task involved children watching a character – let’s call them Sally-Anne – place an object in one location, then character B – let’s call him Max – comes and moves the object to a different location when character Sally-Anne leaves. When character Sally-Anne comes back, they are asked where they will look for the object – in other words, where does Sally-Anne think the object is?

A child who has developed theory of mind can take the perspective of Sally-Anne, and reasonably assume they would look where Sally-Anne had left the object and not where Max had moved it to, because Sally-Anne didn’t observe the object moving. However, children who have not yet developed ToM will think Sally-Anne would look where the object had been moved to, because the child had seen it move. Children aged 3-4 failed this false belief task, children aged 4-5 passed about 57% of the time and 6-9-year-olds primarily passed.^[2] So, we can clearly see a developmental trajectory for this skill.

Individual Differences 

 One debate in psychology about individual differences in Theory of Mind is whether or not reading fiction has an effect on theory of mind, as fiction is all about engaging in other people’s mental states, even if those mental states are fictional. In 2013, Kidd and Castano found that reading literary fiction improved ToM over reading non-fiction or popular fiction.^[3] This finding prompted other psychologists to try and replicate the original findings, but even when following the same method as the original study, the results didn’t replicate.^[4] There were several papers published creating an academic dialogue of responses and rebuttals to the original Kidd and Castano finding, but the findings on whether or not reading fiction actually improves an individual’s theory of mind is mixed at best.

The False Belief Task

^[5]