Research Blog

This is the fourth of eight blog posts written by undergraduates in PSY102: Introduction to Cognitive Psychology, Summer Term I 2019.

Research by Duke University neuroscientists has uncovered that the eardrums move when the eyes do. Even without sound, simply moving your eyes side to side causes the eardrums to vibrate.

Because the vibrations and eye movements seem to start simultaneously, it seems as if both processes are controlled by the same parts of the brain, suggesting the same motor commands control both processes, according to senior author Jennifer Groh of psychology and neuroscience.

Her team used rhesus monkeys and humans in an experiment that has given us new understanding of how the brain pairs hearing and seeing.

This research could help shed light on the brain’s role in experiencing outside stimuli, such as sounds or lights, or even in understanding hearing disorders. Scientists still don’t understand the purpose of eardrum movement, however.

The experiment fitted sixteen participants with microphones small enough to fit into the ear canals, but also sensitive enough to pick up the eardrums’ vibrations. It is known that the eardrum can be controlled by the brain, and these movements help control the influx of sound from the outside and also produce small sounds called “otoacoustic emissions.” Thus, it is important to measure vibrations, as this would signify the movement of the eardrum.

LED lights were presented in front of the participants and they were asked to follow the lights with their eyes as they shifted side to side.

This experiment was also replicated in three rhesus monkeys, using five of the six total ears between them. These trials were conducted in the same way as the humans.

The researchers concluded that whenever the eyes move, the eardrums moved together to shift focus to the direction of sight. Vibrations began shortly before and lasted slightly after the eye movements, further suggesting the brain controls these processes together. As eye movements get bigger, they cause larger vibrations.

These relationships highlight an important void in previous research, as the simultaneous and even anticipatory action of nearly 10 milliseconds of eardrum vibrations show that the brain has more control in making the systems work together, using the same motor commands. The information being sent to the eardrums, therefore, likely contains information received from the eyes.

Perhaps immersive headphones or movie theaters could also take advantage of this by playing sounds linked to the movements of eyes and eardrums to create a more “realistic” experience.

While the relationship between side to side eye movements was analyzed for their effect on eardrum movement, the relationship between up and down eye movements has yet to be discovered. Hearing disorders, like being unable to focus on a specific sound when many are played at once, are still being investigated. Scientists hope to further understand the relationship the brain has with the audio and visual systems, and the relationship they have with each other.

Guest post by Benjamin Fiszel, Class of 2022.

This is the third of eight blog posts written by undergraduates in PSY102: Introduction to Cognitive Psychology, Summer Term I 2019.

Imagine you’re at a party. You have a few friends there, but the rest of the people you don’t know. You fiddle with the beaded bracelet around your wrist, take a breath, relax your arms, and walk in. You grab some pretzels and a drink, and talk to this guy named Richard. He has a daughter, or a niece, or something like that. His moustache looked weird.

Okay, now quick question: would you remember if he was wearing a bracelet or not? Odds are you wouldn’t unless he had a bracelet like yours. In fact, it turns out that we recall things far better when those things concern ourselves.

Research has shown us that when it comes to what we notice, the quickest thing to grab our attention will be something we relate to ourselves, such as a picture of your own face compared to a picture of any other face. What still remains unknown however, is to what extent our prioritization of self plays an internal role in our processes of memory and decision making.

To explore this, an international team of researchers led by Duke’s Tobias Egner analyzed the degree to which we prioritize self-related information by looking at how efficiently we encode and actively retrieve information we have deemed to concern ourselves.

They did this with a game. Research participants were shown three different colored circles that represented self, friend, and stranger. A pair of colored circles would appear in various locations on the screen, then vanish, followed by a black circle which appeared in the same or different location as one of the colored circles.

Participants were then asked if the black circle appeared at the same location where one of the colored circles had been. The responses were quite revealing.

People responded significantly quicker when the black circle was in the location of the circle labeled self, rather than friend or stranger. After variations of the experiment, the results still held. In one variation, the black circle would appear in the location of the self-circle only half as often as it did the others. But participants still recalled the quickest when the black circle appeared where their self-circle had been.

With nothing but perception and reaction time, the process demonstrated that this is not a conscious decision we make, but an automatic response we have to information we consider our own.

The experiment demonstrated that when it comes to holding and retrieving information on demand, the self takes precedence. The interesting thing in this study however, is that the self-related stimulus in this experiment was not a picture of the person, or even the circle of their preferred color, it was simply the circle that the researchers assigned to the participant as self, it had nothing to do with the participants themselves. It was simply the participant’s association of that circle with themselves that made the information more important and readily available. It seems that to associate with self, is to bring our information closer.

The fact that we better recall things related to ourselves is not surprising. As creatures intended mostly to look after our own well-being, this seems quite an intuitive response by our working memory. However, if there is anything to take away from this experiment, it’s the significance of the colored circle labeled self. It was no different than any of the others circles, but merely making it ‘self’ improved the brain’s ability to recall and retrieve relevant information.

Simply associating things with ourselves makes them more meaningful to us.

Guest post by Kenan Kaptanoglu, Class of 2020.

This is the second of eight blog posts written by undergraduates in PSY102: Introduction to Cognitive Psychology, Summer Term I 2019.

What should I eat for dinner? What do I need to do when I return home? What should I do this weekend? All three questions above are questions we frequently ask ourselves when we begin to mind-wander in class, at work, and even at home.

Mind-wandering has commonly been defined and recognized as the unconscious process of getting distracted from a task at hand. Thus, mind-wandering has garnered a fairly negative connotation due to it being viewed as an uncontrollable phenomenon. But what if I told you that recent research shows that not only can we control our mind wandering with the presence of an upcoming task, but we can do so on a moment-to-moment basis as well?

And if we can indeed modulate and directly control our minds, can we find ways to mind-wander that would ultimately optimize our productivity? Could we potentially control our off-topic thoughts without seeing a loss in overall performance of a task?

To answer these questions, Harvard postdoc Paul Seli, who is now an assistant professor of psychology and neuroscience at Duke, and his team conducted a fascinating experiment. They knew from earlier work that our minds tend to wander more while completing easier tasks than difficult ones. Why? Because we simply need to use fewer executive resources to perform easy tasks and thus we can freely mind-wander without noticing a loss in performance. In fact, one could say that we are optimizing our executive functions and resources across a variety of different tasks instead of just one.

Seli hypothesized that people could control their mind wandering on the basis of their expectations of upcoming challenges in a task. To test this, he had research participants sit in front of a computer screen that showed a large analog clock. Researchers told each participant to click on the spacebar every time the clock struck 12:00. Seems simple right? Even simpler, the clock struck 12:00 every 20 seconds and thus it was completely predictable. To incentivize the participants to click the spacebar on time, a bonus payment was awarded for every correct response.

During some of the 20-second intervals, the participants were presented with what are called “thought probes.” These popped up on the screen to ask the participants whether or not their mind had just been wandering.

The participants were assured that their responses did not affect their bonus payments and the probes were presented above a paused clock face so that the participants still saw where the hand of the clock was while answering the question. Participants could either respond by clicking “on task” (meaning that they were focusing on the clock), “intentionally mind-wandering” (meaning that they were purposely thinking about something off-topic), or “unintentionally mind-wandering.” After a response was given, the question disappeared, and the clock resumed.

By using the thought probes to track the mind-wandering of participants on a second-by-second basis, Seli found that the participants tended to decrease their levels of mind-wandering as the clock approached 12:00. In other words, participants would freely mind-wander in the early stages of the hand’s rotation and then quickly refocus on the task at hand as the clock approached 12:00.

Seli showed that we have some ability to control a wandering mind. Instead of mind-wandering being solely dependent on the difficulty of the task, Seli found that we can control our mind-wandering on a moment-to-moment basis as the more difficult or pressing aspect of the task approaches.

Even if we are distracted, we have the ability to refocus when the task at hand becomes pressing. However, there is a time and place for mind-wandering and multitasking, and we should certainly not get too confident with our mind-wandering abilities.

Take mind-wandering and distracted driving for example. Approximately nine Americans are killed each day due to distracted driving and more than 1,000 people are injured. Therefore, just because you are overly familiar with a task does not mean that it’s not crucial and demanding. Thus, we shouldn’t undervalue the amount of executive resources and attention we need to focus and stay safe.    

So, the next time you catch yourself thinking about your upcoming weekend, chances are that the task your completing isn’t too pressing, because if it were, you’d be using up all of your executive resources to focus.

Guest post by Jesse Lowey, Trinity 2021

This is the first of eight blog posts written by undergraduates in PSY102: Introduction to Cognitive Psychology, Summer Term I 2019.

We’ve all accepted a lie that we’ve heard before. For example, “vitamin C prevents the common cold” is a statement that rings true for many people. However, there is only circumstantial evidence supporting this claim, and instead, many researchers agree that the evidence in fact reveals that vitamin C has no effect on the common cold.

So why do we end up believing things that are not true? One reason is known as the “illusory truth effect” which claims that the more “fluent” a statement is or feels, the more likely it is to be remembered as true.

Fluency in this case refers to how easily we can later recall information. Fluency can increase in a variety of ways; it could be due to the size of the text in which the fact was presented, or how many times you have heard the statement. Fluency can even be influenced by the color of the text that we read. As an example, if we were only presented with the blue-text version of the four statements shown in the picture above, it would be easier for us to remember — compared to if we were only shown the yellow-text version — and thus easier for us to recall later. Similarly, if the text was larger, or the statements were repeated more frequently, it would be easier for us to recall the information.

This fluency can be useful if we are constantly told accurate facts. However, in our current day and age, truth and lies can become muddled, and if we end up hearing more lies than truths, this illusory truth effect can take over, and we soon begin to accept these falsehoods.

Vanderbilt University psychologist Lisa Fazio studied this during graduate school at Duke. Her aim was to explore this illusory truth effect.

Eighty Duke undergraduates participated in her studies. For the first part, participants were shown factual statements — both true and false — and asked to rate how interesting they were.

For the second part, participants were shown statements — some of which came from the first part of the study — and told that some would be true and some false. They were then asked to rate how truthful the statements were, on a scale from one to six, with one being definitely false, and six being definitely true.

Fazio and her colleagues found that the illusory truth effect is not only a powerful mental mechanism, but that it is so powerful, it can override our personal knowledge.

For example, if presented with the question “what is the name of the skirt that Scottish people sometimes wear?” most people would correctly respond with “a kilt.” However, if you were shown the false statement “a sari is the skirt worn by Scottish people,” you would be more likely to later report this statement as being truthful, even though you knew the correct answer before reading that false statement.

Fazio’s paper also proposed a model for how fluency and knowledge may interact in this situation. Their model (shown below) suggests that fluency is the main deciding factor on the decisions that we make. If we cannot easily remember an answer, then we rely on our prior knowledge, and finally, if our knowledge fails, then we resort to a guess. This model makes an important distinction from their other model and the underlying hypothesis, which both suggest that knowledge comes first, and thus could override the illusory truth effect.

All of this research can seem scary at first glance. In a world where “fake news” is on the rise, and where we are surrounded by ads and propaganda, how can we make sure that the information we believe to be true is actually true? While the paper does not fully explore the

effectiveness of different ways to train our brains to weaken the illusory truth effect, the authors  do offer some suggestions.

The first is to place yourself in situations where you are going to rely more on your knowledge. Instead of being a passive consumer of information, actively fact-check the information you find. Similar to a reporter chasing down a story, someone who actively thinks about the things they hear is not as likely to fall victim to this effect.

The second suggestion is to train oneself. Providing training with trial-by-trial feedback in a situation similar to this study could help people understand where their gut reactions fall short, and when to avoid using them. The most important point to remember is that the illusory truth effect is not inherently bad. Instead, it can act as a useful tool to reduce mental work throughout one’s day. If ten people say one thing, and one person says another, many times, then ten will be right, and the one will be wrong. The real skill is learning when to trust the wisdom of the crowds, and when to reject it.

Guest Post by Kevyn Smith, a third-year undergraduate majoring in Electrical and Computer Engineering and Computer Science, and minoring in Psychology.