Kid’s Brains on 3D: Overview

Executive Summary

Continuing a piece of research from last year – which found that 3D acts as a kind of ‘brain training’ for adults – a small sample of children took part in our cinematic experiment over two days in May 2016. They completed various cognitive, behavioural, emotional and social measures both before and after watching a 20-minute clip of Disney’s new The Jungle Book, either in 2D or 3D. We found that, indeed, children might benefit from mental stimulation via 3D films to get them engaged with, say, their biology homework right through to their neurosurgery degree!


  • The number of people choosing a surprise emoji to express their mood increased by 32% for 3D and only 5% for 2D
  • 3D increases the strength of reported emotions by 13% more than 2D
  • Watching 3D produces a GSR reading 14% higher – equivalent to driving twice as fast
  • Likewise, 3D produces a maximum heart rate which was 12% higher than that of 2D; in this sense, 3D cinema produces two thirds the excitement of a roller-coaster
  • Compared to 2D, 3D makes children more accurate at spotting emotional faces
  • 3D movies increase cognitive processing speeds (like ‘brain training’), and the increase is 2.67 times the size of that produced by 2D
  • This follows into the ‘real world’, with 3D viewers setting off the Operation game’s buzzer 13% less often while 2D viewers set it off 19% more often


Our experiment produced some fascinating findings.

Following on from our previous research, we found that, just like for adults, 3D films can play the role of ‘brain training’ games and help to make children ‘smarter’ in the short term. The shortening of response times after watching 3D was almost three times as big as that gained from watching 2D; in other words, 3D helps children processing things in their environment more quickly. This is likely to be because 3D is a mentally stimulating experience which ‘gets the brain’s juices flowing’. Indeed, we found that 3D is in fact more stimulating that 2D – it’s the equivalent of driving 60km/h rather than 30km/h.

There’s likely an evolutionary response for this. We are ‘hardwired’, from birth, to think quickly when we need to – say, when a snake falls from a tree. If we put careful thought into everything, we would never get out of bed; yet, if we didn’t pay careful attention to the important things, we would have died out as a species. Indeed, we found that 3D makes people better at recognising potentially threatening faces.

The more realistic, immersive world of 3D ostensibly captures the attention of our limited brains because the experiences ‘feel’ more ‘real’.

Amazingly, we found that this impact on cognitive processing can potentially follow through into the ‘real world’, with 3D causing an enhanced performance on the surgery board-game Operation.


Kids’ Brains on 3D: Detail


The study, which was partly commissioned by Vue Entertainment, saw behavioural scientist Patrick Fagan expand on the 2015 ‘3D Experiments’ study which looked at 3D and cognitive function among adults; specifically, the brief this time was to understand the psychological effects of 3D upon children in the short term.

Last year, the study of adults, found that 3D films, compared to 2D, have a greater ability to immerse and engage the cognitive mind and thus result in enhanced cognitive function, as shown through faster processing speeds.

This year, the remit was broadened to children, and some new metrics examined: in particular, widening the scope beyond cognitive function, emotional and social processes were included as well.


Over Wednesday 4th and Thursday 5th May 2016, a sample of 63 children aged seven to fourteen participated in an experiment hosted at Vue Cinema on Regent Street in Piccadilly, London. About a third (35%) of the sample comprised of boys.

The children were recruited through Into Film, an educational UK-wide programme that includes a network of extra-curricular film clubs. The children arrived in groups from their school, accompanied by school staff, and stayed in their group for the experiment’s duration.

The experiment comprised a pre- and post-test design, with the children completing the same measures before and after viewing the movie clip. This design helps to account for pre-existing individual differences like intelligence which may differ significantly between groups when using a small sample size such as this.

When the children arrived, the study was explained to them and the necessary paperwork was completed. Then, split into groups of ten, the participants completed the two types of pre-test measure (the physical, board-game task and the computer-based tests, as described below), with each taking around 5-10 minutes; while one group was doing the physical task, the other was on the laptops doing the computer-based tests. The computer-based tests looked at social processes and cognitive function, while the physical task sought to ‘bring to life’ the latter with a real-world application. As will be discussed, all of the measures were produced based on previous, peer-reviewed research.

Next, the children moved into a cinema screen to watch a 20-minute clip of Disney’s new blockbuster film The Jungle Book – a film shot natively in 3D and thus perfect for this study. Most of the participants watched the movie in RealD 3D, while a smaller comparison group watched it in 2D.

In each group, Shimmer physiological sensors were worn by a random selection of nine children in order to capture their levels of excitement in response to the film; each time, five participants wore an electrode wrapped around their index finder to measure their galvanic skin response (GSR), while four participants wore a clip on their earlobe to measure their heart rate (as an estimate via photoplethysmography; PPG).

Immediately after viewing ended, the equipment was switched off and a minute was spent removing the physiological equipment, before the children immediately completed the same physical activity and computer-based measures from before.


The following narrative was discovered.


There is a significant body of research indicating that images are processed in a more automatic and emotional way than words, and are therefore a more suitable and predictive tool for measuring emotion metrics.

Therefore, emotional responses to the film were recorded by asking participants to select the Facebook ‘emoji’ which most closely resembled how they currently felt. As can be seen below, both 2D and 3D films resulted in a less ‘ambivalent’ mood: those who watched 3D were 32% less likely to choose the ‘like’ symbol, which was a significant change. 2D viewers were 16% less likely to choose it, although this change was not statistically significant. Furthermore, while these changes were spread fairly evenly over other emotions for 2D, among 3D viewers there was a significant 32% increase in people clicking the surprised face.

Furthermore, however, 3D also resulted in a somewhat bigger strength of emotional feeling.In sum, the movie appears to enhance emotional states, but especially so when viewed in 3D; as one might expect, of the ‘emojis’ available, 3D viewing resulted in a significant increase in surprise.

After participants had selected their appropriate emoji, they indicated how strongly they felt it by selecting one of four sizes of the emoji from small to large. For 2D viewers, the strength of feeling increased by just 2%, a non-significant increase; however, for 3D viewers, it increased by 15%, which was significant. Likewise, the post-viewing increase in strength of feeling was higher for 3D than for 2D, as shown in the chart below.



As discussed, some participants also wore electrodes on their skin via pads on their fingers in order to measure GSR, which is a well-established, sensitive measure of ‘physiological arousal’, i.e., excitement. A slightly smaller sample meanwhile was monitored in terms of heart rate, another well-established measure of physiological response to stimuli.

In line with the above self-report image-based findings, a 3D movie was found to be more exciting than a 2D movie. Firstly, 3D movies were found to produce a GSR reading around 14% higher than that of 2D movies; according to one study, this is akin to driving about twice as fast on the motorway (from 30km/h to 60km/h).


Furthermore – and as one would expect since the physiological processes behind the two measures are so interconnected – heart rate was also higher for the 3D movie compared to the 2D movie. The maximum recorded heart rate, on average across all participants, was, similarly, 17% higher for the 3D film. According to one heart-rate study, this makes a 2D film equivalent to 67% of a rollercoaster, while 3D is closer to the ride at 79% of its average maximum heart rate.


Emotional and Social Perception

Participants completed a task to assess their social and emotional state of mind. In line with previous research which has used a similar paradigm[8], participants were presented with a picture of a face at almost a subliminal level (75ms), after which participants were given one second to decide whether what they had seen was a real face or not by pressing the ‘space’ bar or simply waiting for the next picture; participants viewed twenty ‘non’-faces, twenty emotional faces and ten neutral faces.

Participants who viewed the 2D film correctly spotted an average of 0.32 more neutral faces [t(18)=0.72, p=.482], and the same again for emotional faces [t(18)=0.45, p=0.656]; this likely reflects a training effect due to enhanced skills the second time round.

While those who viewed the 2D film did correctly spot a significantly higher number of neutral faces after viewing, this change was not significantly different from that of the 2D viewers. This may therefore also be a training effect, although it may also reflect the enhanced processing speeds discussed below.

Interestingly, those watching 3D, compared to 2D, showed a significantly greater increase in the number of emotional faces they recognised, suggesting that 3D primes emotional thoughts more than does 2D. This may be because 3D is more immersive.


Reaction Times

As tested with adults previously, and similar to the above, the children were asked to press the ‘space’ bar on their keyboard as quickly as possible whenever an ‘O’ appeared on-screen; when a ‘Q’ appeared, they were not to press anything and instead allow the ‘Q’ to pass by itself after two seconds. Each letter was preceded by a blank screen for 500ms, a masking ‘X’ for 125ms, and a blank screen for 125ms. Performance was defined as the average reaction time for correct presses of the ‘space’ key.

This test is a measure of reaction time – that is, how quickly a participant can cognitively process and behaviourally respond to a stimulus.

Previously, among adults, a significant result was found wherein participants were significantly quicker after watching 3D compared to 2D.

Strikingly, as can be seen below, an almost identical result to the adults’ study was found: while 2D viewers were faster the second time (16.1ms faster), this was likely a training effect; meanwhile, the decrease in response times for 3D viewers was two and two thirds times as large (43ms).

While it should be noted that this finding is not statistically significant, this may well be due to the relatively small sample sizes in use in this study.


It would therefore appear likely that watching a 3D film, compared to a 2D one, increases cognitive processing speeds among children just as it does among adults. Pondering the adult findings previously, it was considered whether this might have any real-world applications – for example, could it help surgeons to watch a 3D film before surgery?

This question was explored with the next methodology.

‘Playing Doctor’

The board game Operation has been used in previous peer-reviewed research as a measure of concentration or attentiveness. Having been validated this way, it appeared to be the perfect tool to address the previous question.

Before the procedure began in earnest, participants were given some time to play with (i.e. practice on) the board game, which requires players to use metal tweezers to carefully remove small plastic ‘organs’ from a patient without touching the sides of the holes, lest the buzzer go off.

In this study, participants were given two minutes to remove as many of the thirteen plastic pieces as possible, as carefully as possible.

As can be seen below, there was a (near-) significant difference between the two groups, with 2D viewers setting the buzzer off more often after viewing (a 19% increase in buzzes on average) and 3D viewers setting it off 13% less often. This suggests that 3D films can induce a type of mental engagement and cognitive enhancement that 2D cannot.

Furthermore, there was also a significant difference between conditions in the change in the amount of time spent removing all thirteen pieces, up to the maximum of two minutes . On average, 2D viewers spent 19.1s less time on the game, while this time reduction was approximately halved, at 8.6s, for 3D viewers. It is natural that players would become more skilled at the game and thus take less time to complete it; however, in line with the aforementioned past research, taking into account the increasing number of buzzes, the higher decrease in time spent on the game for 2D viewers here would suggest a deficit in attentiveness.



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