UBC Home Page  
UBC Home Page
- UBC Home Page UBC Home Page -
News Events Directories Search UBC myUBC Login

Developmental Cognitive Neuroscience

Lab of Adele Diamond

Recently completed

Review of all the different methods use to improve executive functions (cognitive training, physical activity, etc.) and at all ages (not just in children or just in older adults)

Diamond, A., & Ling, D.S., (2015). Conclusions about interventions, programs, and approaches for improving executive functions that appear justified and those that, despite much hype, do not. Developmental Cognitive Neuroscience. [Epub 07 Dec 2015 ahead of print]

Diamond, A., & Ling, D.S. (accepted). Review of the evidence on, and fundamental questions surrounding, efforts to improve executive functions (including working memory.) To appear in M. Bunting, J. Novick, M. Dougherty, & R. W. Engle (Eds.), An integrative approach to cognitive and working memory training: Perspectives from psychology, neuroscience, and human development. NYC: Oxford University Press. 

This is the FIRST review looking at all the different methods employed to improve executive functions (not just cognitive training approaches, or just physical exercise approaches, or only mindfulness or school programs) and at all ages (not just in children or just in the elderly).

Children need some way to prevent them from responding too quickly; itís not that they canít remember what they should do, they are simply too impulsive to be able to do it

Ling, D.S., Wong, C. D., & Diamond, A. (2015). Do children need reminders on the Day-Night task, or simply some way to prevent them from responding too quickly? Cognitive Development. [Epub 04 Nov 2015 ahead of print]

Until children have sufficient self-control to resist impulsively responding too quickly, adults can help them to avoid impulsive errors by giving them something to do, or to listen to, for just a few seconds, just long enough so that the correct response can win out over their first impulse.

We previously reported better performance on the Day-Night task when a ditty was chanted between stimulus presentation and when children could respond (Diamond, Kirkham, & Amso, 2002). Here we investigated competing hypotheses about why the ditty helps. Does it help because it imposes a brief waiting time (the child waits while the ditty is chanted before responding)?  Or, does the ditty help because of its content, providing information helpful to performing the task?

One-third of the 72 children (age 4) were tested with the ditty previously used which reminds them: “Think about the answer; don’t tell me.” Another 24 children were tested with a ditty with no task-relevant content: “I hope you have a nice time; I like you.” One-third received the standard condition. Performance in both ditty conditions was comparable and better than in the standard condition. That indicates that a factor common to both ditties (that chanting them took time, allowing the prepotent response to subside and the more-considered answer to reach response threshold) likely accounts for their benefit. The content of the ditties (whether it reminded children what to do or not) did not affect the results. The challenge of the Day-Night task for preschoolers is not its working memory demands but the need to inhibit a dominant response, making a different response instead.

Integrating Color and Shape aids Conditional Discrimination even though Separating them aids Card Sorting

Ling, D.S., Wong, C., & Diamond, A. (submitted). Double dissociation: Integrating color and shape aids conditional discrimination even though separating them aids card sorting. Developmental Psychology.

We found success in 3-year-olds on conditional discrimination, 12 months younger than previously reported. They succeeded when color was made a property of the stimulus, rather than a property of the background as in all past conditional-discrimination testing. Previously, we and others have shown that children succeed on the dimensional change card sort (DCCS) test 12 months earlier than previously reported (3 years of age) by making color a property of the background, instead of a property of the stimulus as in all past DCCS testing. This double dissociation, with children of the same age performing better on DCCS when color and shape were separated but better on conditional discrimination when color and shape were integrated, was predicted by the same hypothesis: Young children have difficulty mentally separating physical dimensions of the same object (e.g., color and shape) and difficulty mentally integrating physical dimensions that are not part of a single object. This provides the strongest evidence to date against the conceptual change and memory accounts for why children fail the DCCS task and in support of the interpretation that preschoolers rely on perceptual information, specifically physical characteristics of stimuli, for being able to conceive of properties as related or independent.

An Effect of Inhibitory Load in Children while Keeping Working Memory Load Constant

Wright, A., & Diamond, A. (2014). An effect of inhibitory load in children while keeping working memory load constant. Frontiers in Psychology, 5, 1-9. (Special issue on Development of Executive Function during Childhood)

Children are slower and more error-prone when the correct response is counter to their initial inclination (incongruent trials) than when they just need to do what comes naturally (congruent trials). This study explored what the critical difference is between incongruent and congruent blocks that accounts for why children perform so much worse on incongruent blocks. For the first time as far as we know, the order in which congruent and incongruent blocks were presented to children was counterbalanced. Worse performance on the incongruent block when it comes second could be accounted for by greater working memory demands (subjects might still be holding the first rule in mind when performing Block 2), greater inhibitory demands, task-switching demands, or some combination of those.

We tested 96 children (49 girls) 6-10 years of age. The congruent block and incongruent blocks each had only one rule (e.g., “press on the same side as the stimulus” for congruent trials and “press on the side opposite the stimulus” for incongruent trials), Regardless of the order in which the congruent and incongruent blocks were presented, children at every age were slower and made more errors on the incongruent block than the congruent one. We expected task-switching demands to account for some of the variance, but performance was fully comparable on the incongruent block whether it came first or second.

Our results show success on conditional discrimination in children younger 3 years old than that has ever been demonstrated before. We were able to do that by having color be a property of the stimuli rather than a property of the background against which the stimuli were displayed as in all past conditional discrimination studies.

These results strongly support that the source of the difficulty for children is not switching from the rule in Block 1 to the rule in Block 2, nor that they might still be holding in mind the rule for Block 1 when they perform Block 2 (i.e., not having efficiently deleted it from working memory). The source of their difficulty seems to be in the need to inhibit a prepotent response on incongruent trials.

A Powerful Example of how Biological and Environmental Factors Interact to produce a behavior

Weikum, W. M. T, Grunau, R. E., Brain, U., Chau, C. M. Y., Boyce, W. T., Diamond, A., & Oberlander, T. F. (2013). Prenatal serotonin reuptake inhibitor (SRI) antidepressant exposure and serotonin transporter promoter genotype (SLC6A4) influence executive functions at 6 years of age. Frontiers in Cellular Neuroscience, 7, 1-12.         

We found that it is not possible to say which genotype of the serotonin-regulatory gene(SLC6A4) is associated with better executive functions (EFs) without taking into account an environmental factor (mother’s mood).

We have been following a cohort of children since before birth whose mothers were moderately depressed during pregnancy (some took an SSRI [a selective serotonin re-uptake inhibitor] antidepressant during pregnancy while others did not). We found that if the mother was depressed when the child was 6 years old, that child’s EFs at age 6 varied depending on the child’s SLC6A4 genotype. The EFs of children with at least 1 short allele of the gene stayed fine even if their mom reported many depressive symptoms (i.e., they showed resilience and relative insensitivity to the environmental risk of a sad mom). But the EFs of children with 2 long forms of the SLC6A4 gene were very affected by their mom’s mood. If their mom was sadder, these children displayed worse EFs than any other group; but if their mom was happier, these children’s EFs were better than any other group.  Thus, given a sadder mother, children with > 1 short allele of the SLC6A4 gene showed the best EFs, but given a mom who wasn’t sad, children with 2 long alleles of the gene showed the best EFs.

Double Dissociation: Integrating Color and Shape Aids Conditional Discrimination but Separating them Aids Card Sorting in Preschoolers

Daphne Ling, Cole Wong, & Adele Diamond. (manuscript in prep.), Double dissociation: Integrating color/ shape aids conditional discrimination but separating them aids card sorting in 3-year-olds. Poster presented at the Cognitive Development Society meeting, Memphis, TN.

Previously, we were able to show success on the Dimensional Change Card Sort (DCCS) task in children younger than had ever been reported before (3 years) by having color be a property of the background against which the stimuli were displayed rather than being a property of the stimuli as in all past DCCS testing (Diamond, Carlson, & Beck, 2005).

We predicted this double dissociation because card sorting requires dissociating color and shape (focusing on only one at a time) whereas conditional discrimination requires integrating color with shape because the color tells you which shape is correct.

A Dramatically Larger, more Robust, and Developmentally More-Sensitive Flanker Effect

Sarah Munro, Cecil Chau, Karine Gazarian, Nancy Wang, & Adele Diamond. (manuscript in prep.) Dramatically larger Flanker effects (6-fold elevation). Poster presented at the Cognitive Neuroscience Society annual meeting, San Francisco, CA.

On our Flanker Task there are 3 blocks. Block 1 is the standard Flanker paradigm (where the stimuli are blue and subjects are to attend to the center stimulus and ignore the flanking stimuli).  Block 2 is Reverse Flanker (attend to the flankers, ignore the center stimulus; the stimuli are pink). In Block 3, Flanker (blue stimuli trials) and Reverse Flanker (pink stimuli trials) trials are randomly intermixed. 
Results with our Flanker paradigm reveal:

     The Flanker effect is 6-10 larger in the context of switching (Block 3) than we or others find on the standard Flanker paradigm. (In Block 3, only trials comparable to standard Flanker trials were used for this comparison, i.e., only Flanker, non-switch trials.)

      Unlike on the standard Flanker task, in the context of switching (Block 3), the Flanker effect is robust in the face of variations in stimulus characteristics (e.g., whether the stimuli are larger or smaller or closer together or farther apart).

The developmental progression extends for far longer in the context of switching (Block 3) than on the standard Flanker task.

The Social Simon Effect is seen as Early as the Simon Effect

Yvette Wu, Sarah Munro, & Adele Diamond (manuscript in prep.) Development of the social ĎSimoní effect. Poster presented at the Jean Piaget Society annual meeting, Amsterdam, Netherlands

Perception of a stimulus on one side of space tends to activate the hand on that same side. To respond with the other hand requires inhibition of that prepotent response. Hence people are slower to act on the rule, “Press the right hand button whenever you see astar,” if the star appears on the left than if it appears on the right. This “Simon Effect” is copiously documented in adults. Recently it has been demonstrated in adults that if the task is shared with another person, so that the person sitting beside you is responsible for the right hand button and so should always press when the star appears and you are responsible for the left hand button and so should always press when the frog appears, adults still show the Simon Effect. However if the interpersonal dimension is removed and the task is presented as a Go/No-go (press for the frog, do nothing when a star appears), the Simon Effect is NOT found, even though what you do here is exactly the same as in the interpersonal situation.

We wanted to see if this was true in children, and if so, how early it would be seen.

We tested 4 age groups: mean age in years= 3.6 (range= 3.4-3.8), 4.1 (range= 3.9-4.3), 4.7 (range= 4.5-4.9), and 20.7 (range= 18.5-22.7), 16 subjects per group (50% female).

We replicated the findings previously reported in adults: longer RTs when a stimulus appeared on the side opposite its associated response than when it appeared on the same side (the Simon effect) in the basic and team conditions, but not in go/no-go. We also replicated that the earliest age for the Simon effect is 4 years. Our 4.1-year-old group showed the Simon effect, but our 3.6-year-old group did not. The task was too difficult for them and they responded randomly.

Would children show the Social Simon effect and how early? From the earliest age that children can perform the task (4 years) they showed the Social Simon effect (a Simon effect in the Team but not the Go/No-go condition -- and comparable Simon effect in the Team and Basic conditions) and it was completely as robust as that for adults. This was true (a) if the Simon effect was determined by the usual formula: RT on incongruent trials minus RT on congruent trials. It was also true when we corrected for children’s slower RTs: (b) (RT incongruent trials minus RT congruent trials) divided by the child’s average RT in that condition.

These results imply that children as young as 4.1 years are treating the other person in Team Simon as an extension of themselves. It’s as if they themselves were pressing the other button.

EF Advantages in Bilingual Children include Working Memory, as well
as Inhibition and Cognitive Flexibility

Xiaojia Feng, Ellen Bialystok, & Adele Diamond (manuscript in prep.) Manipulating information in working memory - an advantage for bilinguals. Poster presented at the biennial meeting of the Society for Research in Child Development,Boston, MA

Bialystok and colleagues have previously shown that if children continually exercise inhibition and cognitive flexibility by inhibiting one language when using another and flexibly switching between languages, their performance on non-linguistic inhibition and switching tasks at 4-5 years of age is dramatically ahead (1-2 years ahead!) of monolingual peers.

We have extended evidence of that bilingual advantage here to working member.

Daily EF "exercise" appearsto enhance and accelerate EF development much as physical exercise builds the body.

What's Best for Men is Not Always what's Best for Women: Sex Differences
in the Effects of COMT Genotypes in Older Adults

Adele Diamond, Paige Scaile, Arthur Kramer, John Fossella, David Abbott, & Jennie Kim. (manuscript in prep.) Whatís best for men is not always whatís best for women: Gender differences in the effects of COMT genotypes.

Sex Difference in which polymorphism of the COMT Gene is more Beneficial
for Executive Functions varies with the Menstrual Cycle

Jeanette Evans, John Fossella, Elizabeth Hampson, Clemens Kirschbaum, & Adele Diamond. (manuscript in prep.) Gender differences in the cognitive functions sensitive to the level of dopamine in prefrontal cortex. Poster presented at the Association for Psychological Science annual meeting, San Francisco, CA.

Estrogen down-regulates catechol-o-methyltransferase (COMT) gene transcription. The COMT enzyme is 30% less active in women than men (a less active COMT enzyme clears dopamine more slowly, leaving more dopamine around longer in PFC). With estrogen resulting in a slower COMT enzyme, further slowing of the enzyme by the COMT gene polymorphism with methionine at codon 158 could result in too much dopamine in PFC (too much or too little dopamine in PFC impairs EFs). Hence the COMT gene variant usually associated with better EFs for men (COMT-Met158) is not the variant associated with better EFs for women, at least when their estrogen levels are high (instead COMT-Val158 is).

Since the sex difference is estrogen-mediated, which variant of the COMT gene is most beneficial for women varies with the menstrual cycle.

Normative Study of the Development of Executive Functions from 4 Ė 18 years of age

Daphne Ling, David Abbott, Sarah Munro, Holly MacPherson, Yvette Wu, Kay Robinson, & Adele Diamond (manuscript in prep.)

Our lab has recently completed data collection for a 5-year NIDA-funded study of the normal development of EFs, using diverse tasks tapping various aspects of EFs all given to each child, over a wide age range (4 - 18 years). We tested 1,080 children, >60 children at each age, roughly 50% male and 50% female, 50% higher and 50% lower SES per age; 15 ages and 14 tasks per age (2 sessions / child). This complements the Diamond labís past work studying EF development yearly from 4-13 years with a small battery of tasks and smaller number of subjects (Davidson et al. 2006).