Category: Anniversary

Unusual experiences in everyday life

By Vaughan Bell, of Mind Hacks.

To generalise, most psychiatrists see themselves as applied neuroscientists, while most clinical psychologists explain psychopathology in terms of mental processes and social relationships, and make little reference to the brain. This rift is partly fuelled by a lack of research that examines how biological and psychological factors interact to cause mental ill health. One 2005 study was a notable and refreshing exception, and has provided a compelling glimpse into how stress and the dopamine system interact to predict the presence of unusual experiences in everyday life.

Dr Inez Myin-Germeys and her team recruited 50 people who had close relatives with psychosis, as well as 50 control participants who had no family history of psychosis. Relatives of people with psychosis are more likely to have slight or fleeting psychosis-like experiences, even if they never become mentally ill themselves. This makes them an interesting and important group to study, because these experiences seem to react in a similar way to full blown psychosis, but the participants are otherwise healthy and do not take medication, both of which can muddy research findings.

The research team first gave the participants a harmless infusion of 2-deoxyglucose, a substance known to cause a temporary but measurable response in the dopamine system, to see which participants would demonstrate the most dopamine reactivity. Although the neurobiology of psychosis is complex, research has shown that dopamine function (particularly in the mesolimbic pathway of the brain) plays an important role.

Many studies that examine brain function and psychosis take place in the lab, which can make it difficult to generalise the results to everyday life. Crucially, Myin-Germeys and her colleagues used a technique called ‘experience sampling’ where participants are given a watch that beeps randomly throughout the day. When the alarm sounded, the participants were asked to note their current situation, rate their levels of stress and rate the intensity of any psychosis-like experiences.

The results showed that for the relatives, those with the most reactive dopamine systems had unusual experiences (such as hearing voices or feeling unreal) in response to everyday stresses. In contrast, stress wasn’t linked to unusual experiences in any of the other participants. In other words, the presence of psychotic experiences could only be accounted for by examining a combination of genetic risk, dopamine reactivity and stress in everyday life.

This is an important finding in itself but the study has deeper implications. One of the most heated debates in science concerns whether psychiatric conditions are mainly caused by lifelong brain dysfunction or are largely the result of stress and trauma. This study is one of a growing number that are important because they suggest that a narrow view of human distress is counter-productive, and that we need to understand both the lived experience and the biology of the brain to fully comprehend it.

Myin-Germeys, I., Marcelis, M., Krabbendam, L., Delespaul, P. & van Os, J. (2005) Subtle fluctuations in psychotic phenomena as functional states of abnormal dopamine reactivity in individuals at risk. Biological Psychiatry, 58, 105-110.

Dr. Vaughan Bell is a clinical psychologist in training, working and studying between the Institute of Psychiatry and the South London and Maudsley (SLaM) NHS Trust. He is also a researcher, interested in understanding brain injury, mental distress and psychological impairment.

Fusing psychology and neuroscience

By Chris Chatham, of Developing Intelligence.

Psychology is appealing to me partly because it requires so much stealthiness. We can’t directly observe mental events, but must instead use indirect methods to test our hypotheses. We must cleverly misdirect the suspicions of our subjects, to ensure they don’t guess the hypotheses being tested and thus affect our results. And, as if by magic, psychologically-informed visual illusions can reveal the mind’s inner mechanisms right before our eyes.

For those who particularly admire psychology’s furtive manner, neuroscience’s focus on direct measurement of our mental hardware might seem crude and ordinary, at least in comparison to the artful techniques of experimental psychology. What can neuroscience add, beyond telling us that cognition happens in the brain? One answer to that question comes from a study by Vogel and Machizawa on a topic of perennial debate: the question of how much information people can hold in their short-term ‘working’ memory.

In just three pages, the authors describe how they were able to use electroencephalography (EEG) to identify waves of electrical activity on the surface of the brain that predicted how much visual information someone could hold in their working memory. Subjects first donned an elastic electrode cap, and were then asked to remember just one side (either the left or right) of a display of coloured squares. After a one second delay, subjects were asked to judge whether a second display was the same as or different from the first display.

For analysis, the authors subtracted EEG activity in the cerebral hemisphere on the same side of space (ipsilateral) as the part of the display the participants had tried to remember, from activity in the hemisphere on the opposite side (contralateral). Using this subtraction method, Vogel and Machizawa were able to isolate activity related to effortful memory processes from activity related to passive visual processing. Their results showed a wave of electrical activity over contralateral posterior parietal and lateral occipital electrodes, whose amplitude increased both with the accuracy of the subjects’ response, and with the number of items that had been presented.

At first glance, this methodology might seem overly simplistic – what if the amplitude increased merely because of increases in difficulty, and/or changes in executive processing? To those who favour the more nuanced methods of psychology, these shortcomings might reflect a lack of theoretical sophistication in much of cognitive neuroscience.

And yet, a closer look reveals that some alternative explanations could potentially be ruled out: as the number of items to be remembered increases beyond an individual’s capacity, one would expect a measure of executive- or difficulty-related activity to continue increasing. However, if this measure truly isolates capacity from difficulty and executive demands, it should level out at an individual’s memory capacity limit.

Accordingly, Vogel and Machizawa determined that the observed wave of electrical activity did not increase as display set size increased beyond an individual’s capacity, despite the fact that accuracy continued to decrease, suggesting that the EEG wave in question does indeed index the number of items maintained in visual working memory. Going even farther, the authors showed that the magnitude of amplitude increase between set-sizes could be used as an alternate measure of visual working memory capacity, because low-capacity individuals tend to “max out” their capacity sooner, and thus show less increase between supra-capacity set-sizes than higher-capacity individuals.

Some might interpret these results to mean that visual working memory capacity limits can be independent of executive functions, and given the location of the wave, that these limits arise from modality-specific processes. Others might disagree. Perhaps most inspiring, however, is the way these authors integrated the methods of neuroscience with traditional psychology: consider the use of bilateral displays and subtractive logic to equate for visual processing across both hemispheres, or the elimination of alternative explanations with careful quantitative analysis. This study exemplifies how an intelligent fusion of methods from both psychology and neuroscience can help to address questions of central importance – even those that have been hotly debated for nearly a century, such as this one.

Vogel, E.K. & Machizawa, M.G. (2004). Neural activity predicts individual differences in visual working memory capacity. Nature, 15, 428, 748-51.

Christopher H. Chatham is pursuing a PhD in cognitive neuroscience at the University of Colorado.

The route to happiness

By Will Meek, of Vancouver Psychologist.

One of the biggest questions being tackled in the subjective well-being/happiness literature is whether we can achieve sustainable change to our happiness level, or whether we can only achieve momentary departures from our baseline disposition. The answer to this question has been different (yes, no, maybe) depending on the angles and variables employed by each researcher in attempting to answer it.

In 2005, a team of U.S. researchers developed a comprehensive model of sustainable happiness change that integrated the major lines of the subjective well-being literature. The result was a theory which proposed that up to 50 per cent of one’s happiness was rooted in a genetically determined set-point, 10 per cent was related to circumstantial factors (nation of residence, demographics, culture, income, etc), and the remaining 40 per cent was determined by intentional activities such as pursuing goals, looking at things optimistically, and being physically active. The keys to sustainable happiness change rest in these activities, and the first direct empirical validation for the theory is my favourite article from the past 3 years.

Kennon Sheldon (Cal-San Diego) and Sonja Lyubomirsky (Cal-Riverside) creatively examined differences in well-being for university students over the course of several months, capturing real life changes in life circumstances and happiness related intentional activities. The main conclusions drawn from the three studies were that changing circumstances and engaging in happiness related activities both offer a boost to one’s happiness, but that people habituate to circumstantial changes whereas continuing the activities sustained increases in happiness, subjective well-being, and psychological well-being.

“In other words, our data suggest that effort and hard work offer the most promising route to happiness. In contrast, simply altering one’s superficial circumstances (assuming they are already reasonably good) may have little lasting effect on well-being. (p.82-83).”

As a clinician who works with people trying to become happier in one way or another, this theory and research created a level of excitement and optimism about the ability of individuals to create meaningful change that few other studies have. For me, that implication combined with the creative methodology and the comprehensiveness of the theoretical model made this a standout piece of work.

Sheldon, K.M. & Lyubomirsky, S. (2006). Achieving sustainable gains in happiness: change your actions not your circumstances. Journal of Happiness Studies, 7, 55-86.

William D. Meek is a doctoral candidate in counselling psychology at the University of Missouri – Kansas City, and current pre-doctoral intern at the University of Delaware Centre for Counselling and Student Development.

Expanding representations

By Dave and Greta Munger of Cognitive Daily.

Greta and I always have a tough time deciding on a “best” or “favorite” study. For both of us, generally, it’s typically more of a yes / no distinction: either we like a study enough to write about it on Cognitive Daily, or we don’t. We’re both surprised when one of our posts gets noticed by a high-traffic blog or web site, and suddenly thousands of readers stop by to read it. Other studies that we like just as much rate hardly a blip in our site statistics.

That said, the work of Helene Intraub has been extremely important both in how it influences my writing in Cognitive Daily and other venues, and how it affects Greta’s research and teaching. Intraub and Michael Richardson were the first researchers to identify the phenomenon of boundary extension. In boundary extension, when you see a scene such as a photograph or even a three-dimensional representation with a clear border, then your memory of that scene tends to extend beyond the original boundary: you remember the scene as larger than it actually was, sometimes even just a few seconds after seeing it. As we discussed in our March 2005 post, Intraub explains the phenomenon in this way:

Boundary extension may be due to the active creation of a mental representation of a scene. Since our mind constructs a “scene” based on scant available information (the area visible by the fovea as the eye looks at different parts of the scene), it makes sense that it might also construct a representation of parts beyond the boundary of what is actually viewable. If we “fill in the blanks” between places we’ve actively looked at, why not extend our representation beyond the boundaries of what we’ve seen as well?

Intraub’s 2004 Cognition paper (ref. below) is the one we’d like to nominate as our favourite of the past three years. In a remarkable set of experiments, Intraub extends the phenomenon of boundary extension to a new modality: touch. Here’s the description we wrote of the study last year:

She showed participants six different “scenes” composed of real, physical objects (groups of ordinary things like toys, books, and toiletries), each demarcated by a “boundary” of black cloth. She then had an assistant remove the boundaries and asked the participants to mark where the boundaries had been. As expected, they placed the borders well beyond where they had been in the original scenes.

Next, she blindfolded another set of participants and showed them the same scenes, with an easily detectable three-inch-tall wooden “boundary” replacing the original cloth border. When they returned later to the same scenes with the border removed (and still blindfolded), they were asked to place wooden blocks where the borders had been.

Finally, she repeated the “blindfolded” condition with a volunteer who had been deaf and blind from early childhood. Intraub calls this participant (named only by her initials, KC) a “haptic expert” because she has spent her entire life negotiating the world by the sense of touch. At the age of 25, KC was a successful college student who could easily identify the objects in the experiment by touch (the only difficulty was reminding her to use the entire 30 seconds allotted for each scene, so as to match the blindfolded group).

As you might guess now, the results for KC were the same as those from the blindfolded group: She extends boundaries in the same way sighted people do. There was one difference between the blindfolded and the vision group: the vision group showed more boundary extension than the blindfolded group, suggesting that the modalities of sight and touch are not precisely analogous.

Nonetheless, the study does raise some provocative questions about the relation between the senses and the perceptual systems that we use to understand them. Do we represent tactile regions and visual areas using the same neurological systems? Do blind people “see” the world the same way others do? Or are visual representations analogous, but separate from tactile ones? It’s the type of study that makes you want to roll up your sleeves and try to understand even more. That’s what the best science is all about.

The study also inspired Greta to see if other phenomena are related to boundary extension. The result was a paper coauthored with Ryan Owens and John Conway in Visual Cognition, “Are boundary extension and representational momentum related?” The experiment supported the notion that boundary extension and representational momentum are actually separate cognitive processes, even though they are both distortions of memory for a scene.

Intraub, H. (2004). Anticipatory spatial representation of 3D regions explored by sighted observers and a deaf-and-blind observer. Cognition, 94, 19-37.

Munger, M.P., Owens, T.R. & Conway, J. (2005). Are boundary extension and representational momentum related? Visual Cognition, 12, 1041-1056.

Dave Munger is a writer whose works include Researching Online and The Pocket Reader. Greta Munger is Associate Professor of psychology at Davidson College.