1,078 Matching Annotations
  1. May 2016
    1. The right animal has also regenerated on the control left side, but the expression of nAG has rescued the denervated blastema

      This animal had both limbs amputated, but only the right limb was denervated. In addition, the right limb was electroporated with nAG. This causes some number of those cells to express nAG when they normally would not.

      This group of animals acts as the experimental group.

    2. To deliver the protein to the adult newt limb, we electroporated plasmid DNA into the distal stump at day 5 pa

      Using focal point electroporation (previously described), the authors were able to introduce exogenous DNA into the amputated limb.

      The authors chose to use a plasmid (circular DNA) to introduce their gene into the limb.

    3. and then electroporated the nAG plasmid or empty vector on the denervated side

      The authors use an empty vector as the negative control for this experiment. The vector is essentially the exact same as nAG plasmid, but lacks the DNA sequence coding for nAG.

    1. In contrast, we examined learning-induced changes in long-standing social biases

      In contrast to previous work, the authors expand on the existing research by attempting to reduce people's biases. Unlike memories for facts, biases are acquired over a long period of time and are constantly reinforced by people's friends, family, and interpretations of their daily experiences.

    2. electroencephalographic signals

      Data obtained from EEG (electroencephalogram).

      EEG is a non-invasive method that detects electrical activity (from communicating brain cells) in the brain. Participants wear sensors on their head that detect this activity through the scalp.

      Click here for a picture of an EEG cap

      The authors used this device to detect when participants were asleep and to measure different sleep characteristics.

    3. Results were quantified by using a conventional scoring procedure

      This procedure involved calculating the reaction time (how fast participants pressed the button) for trials where the button participants used to classify trials was stereotype consistent (e.g. same button art words and female faces) and subtracting it from the reaction time for trials where the button participants used to classify trials was inconsistent with the stereotype.

      Participants who showed slower reactions when the button was inconsistent with the stereotype demonstrated more implicit bias.

      See the supplemental materials for more information.

    4. recruited as two subsamples that allowed for a direct replication

      The authors divided the 40 participants into two groups to test whether their results were found in both groups. Finding the effect in both groups makes their results more believable.

    1. We hypothesized that caffeine could affect the learning and memory of foraging pollinators.

      Caffeine blocks adenosine receptors, thus enhancing the activity of the neurons involved in learning smells and remembering them.

      Caffeine is also found in the nectar of some plants.

      Therefore, the authors of the study predict that caffeine in the nectar will in some way affect the learning of pollinating insects. They are going to test this hypothesis using behavior tests on bees in the presence of different amounts of caffeine.

    2. nectar concentrations did not exceed 0.3 mM

      See figure 1 for these data.

    3. If bees can detect caffeine, they might learn to avoid flowers offering nectar containing it

      The idea here is actually the opposite of what the authors hypothesized, but is a reasonable concern and thus important to consider.

      The authors hypothesized that caffeine could enhance a honeybee's memory of a plant, causing them to return to that plant. This is because of the memory-enhancing effect of the chemical's interaction with the bee's mushroom body neurons.

      However, the chemical is also very bitter. A bee is as unlikely to want to drink something that is very bitter as a human is. Therefore, if the honeybee can taste the bitter caffeine, it is unlikely to want to return to that plant.

      So how do we figure out which of these two opposite effects caffeine actually has on the bees?

      The authors of the study offered honeybees sugar solutions containing increasing amounts of caffeine, and observed at what concentration the bees found the solution to be repellent.

      If the concentration of caffeine in the nectar of these plants is at that repellent level or higher, it is unlikely that caffeine is attracting bees to those plants.

      However, if the amount of caffeine in the nectar is below that concentration, it is unlikely that the bees would detect its bitterness, and so would not be repelled by it.

    4. fig. S3

      Supplementary figure 3 showed proof that the honeybees have sensilla (sensory organs) that are able to detect caffeine.

      This is what is called a "proof-of-concept" experiment; it shows that the hypothesis is at least possible. Whether or not it is actually the way things are remains to be seen.

      In this case, it needed to be shown that honeybees are capable of detecting caffeine. If not, it doesn't matter that there is caffeine in the nectar of the plants - if the honeybees can't sense it and don't react to it, then caffeine in the nectar won't affect their behavior regardless of its concentration.

    5. adenosine receptor antagonist DPCPX

      The authors used DPCPX to identify whether or not the increase in nicotinic acetylcholine receptor activation they saw in response to caffeine was the result of caffeine interacting with adenosine receptors.

      DPCPX binds to adenosine receptors, preventing any other molecule, including caffeine, from binding to and interacting with the receptor. This is similar to the antagonistic action of caffeine on adenosine receptors, which blocks its activation by adenosine.

      As DPCPX was applied before caffeine, caffeine was unable to bind to adenosine receptors during this experiment. As a result, the authors could be sure that any effects seen after adding caffeine happened independently of caffeine's ability to bind adenosine receptors.

      This tells the researchers something about about how caffeine behaves in the absence of this antagonist, too - if it's able to act even when the adenosine receptors are inhibited, that means that those receptors are not necessary for this effect to occur. Conversely, if they saw that caffeine-mediated nicotinic acetylcholine receptor activation disappeared when they blocked caffeine from binding to the adenosine receptors, they would know that the adenosine receptors play an important role in inducing this effect.

    6. whole-KC recordings

      The authors took these recordings using a technique called "whole-cell patch-clamp electrophysiology."

      Patch-clamp electrophysiology allows researchers to measure the current flowing through an individual channel in a cell membrane. These currents result from the passage of ions through these channels, and act to send signals from neuron to neuron.

      Researchers isolate a tiny patch of the cell membrane using a glass micropipette. The surface of the cell membrane is suctioned into the tiny opening at the end of the pipette and forms a tight seal. This tight seal allows the current across that portion of the membrane to be measured very precisely, without any distortion of the data by surrounding factors.

      Whole-cell patch-clamp electrophysiology is a specific kind of patch-clamp in which multiple channels are individually measured at the same time. The same seal is made over a patch of the membrane using a glass pipette, but in the case of whole-cell recording, the suction is strong enough that the membrane is ruptured, allowing access to the interior of the cell.

      To see patch-clamp electrophysiology in action, see here, here, here and here.

    7. we trained bees for six trials with 30 s between each pairing of odor with reward

      In order to train the bees to associate the floral odor with receiving sucrose, the authors exposed a honeybee to the odor they wanted it to learn, then immediately fed it sucrose solution. This process was repeated 6 times per bee, with a 30 second interval between each trial.

      In order to test the effect of caffeine on the development of olfactory memory, the bees were split into eight groups. One group was fed either sucrose alone, while the other seven were fed solutions containing seven different concentrations of caffeine.

      The authors tested the bees memory of the smell twice - once 10 minutes after the last conditioning trial and once 24 hours later. The bees were tested with both the floral odor they had been taught to associate with sucrose and with another, unrelated odor to see if their memory to the floral scent was specific.

    8. This intertrial interval approximated the rate of floral visitation exhibited by honeybees foraging from multiple flowers on a single Citrus tree

      In the field, the authors had observed that bees will spend an average of 3.77 seconds at each flower they visit, and then will spend an average of 20.3 seconds traveling from one flower to the next, about 24 seconds total.

      As a result, the authors decided to use a 30 second interval between trials in this study in order to use a time frame between "flowers" (exposure to floral scent) that is similar to that seen in bees feeding in nature.

    1. As expected, measured light attenuation coefficients Kd,λ were strongly related to underwater light absorption by CDOM (aCDOM,λ) (R2 = 0.94, N = 100), and we used our measured aCDOM,λ (N = 2153) to predict Kd,λ when it was not measured directly (fig. S2)

      Kd,λ values in this paper are based on measurements made in the field whereas aCDOM,λ values are based on measurements on water samples taken back to the lab. The authors were able to find a mathematical correlation between the two parameters and use aCDOM,λ to calculate Kd,λ, which they used in their calculations in the information in Table 2.

      The details are provided in supplemental information.

    1. In fig. S1, countries that have lost forests without gain are high on the y axis (Paraguay, Mongolia, and Zambia). Countries with a large fraction of forest area disturbed and/or reforested/afforested are high on the x axis (Swaziland, South Africa, and Uruguay).

      On page 7 of the supplemental material s Figure S2. On the x-axis are the countries with forestry programs, whereas countries on the y-axis have deforestation caused by factors other than forestry.

    2. tree canopy densities

      Tree canopy density is an important concept in this study, because it determines whether an area of land is a "forest" or not a "forest."

      To explain, Hansen and colleagues could analyze the satellite images of Earth at a resolution of 30 m by 30 m. For each of these 30 m by 30 m sections, they then calculated the proportion of that section that was covered in a tree canopy.

      Using this map, forests can be defined as a user prefers by applying a threshold of tree cover density; for example, tree cover greater than 50% can be labeled as forest.

    3. Landsat data

      Landsat is a a joint program between the U.S. Geological Service (USGS) and the National Aeronautics and Space Administration (NASA).

      In this program, satellites orbit around Earth and take photos of Earth's surface.

      The photos taken from the satellites are not the type of photos you would take with a typical smartphone. Instead, these images can show the energy that is both reflected and emitted from Earth in many different wavelengths, including blue, green, red, near-infrared, midinfrared, and thermal-infrared light.

      For a look at energy wavelengths click here.

      To distinguish forests from other land types (e.g., grasslands, water, etc.), one can look at a combination of different wavelengths in the Landsat data. For instance, looking at a combination of the red, near-infrared, and shortwave infrared wavelengths helps identify forests. Our eyes are similar to a satellite sensor, except we only see in the visible wavelengths, namely red, green, and blue. Forests, to our eyes, appear dark green, meaning low blue and red reflectance and brighter green reflectance. By using remote sensing technology, we can improve our identification of forest extent and change by adding other wavelengths of reflected and emitted energy not visible to the naked eye.

      Find out more about how the different wavelengths can help identify different features, here.

      You can view some Landsat photos here. Be sure to check out the photos of deforestation in Bolivia, which is particularly relevant to this study!

      Also check out this Landsat image video.

      Landsat images are online and available to the public. You can find data here.

    4. preprocessing of geometric and radiometric corrections of satellite imagery

      Before Hansen and colleagues could analyze the Landsat images, they had to preprocess them. This preprocessing included making corrections for clouds and shadows, assessing the quality of the images, and normalizing the images so that they can all be directly compared.

    1. sample sizes

      The total number of samples taken from a sample population.

    2. SEM

      Standard error of the mean = standard deviation/number of samples (Reference)

    3. fig. S5

      Figure 5 in Supplementary Materials shows differences in the cost of treatment in two cases: Average HRT and T=20C, Long HRT and T=25C (As mentioned before HRT describes the time necessary for particles to travel the system from the entrance till the outlet.)

      Figure S5 shows the cost of treatment per m3 of water treated in the y-axis. The x-axis presents the two different scenarios: baseline (average HRT and T=20C) and long HRT and T=25C.

      They looked at the effect of these two scenarios in two samples:

      Source water sulfate with 15 mgS/L and Source water with no sulfate. In both scenarios, source water with sulfate had higher expenses compared with the condition with no sulfate in source water.

      The long HRT condition is investigated to account for the conditions that could favor sulfide formation and corrosion in the sewer, in other words it is a representation of the worst-case scenario.

  2. Apr 2016
    1. Fourth, the estimated duration should be consistent both with the available evidence of increased risk of mortality after MV, compared with uninfected children, and with the time required to build a protective immune repertoire in early life (Fig. 1D, fig. S2, and SM 5 and 6).

      Author's Hypothesis: 4

      The estimated duration of immune suppression in hypothesis 3 must be biologically relevant. We have years of data from other scientists who have measured the amount of mortality following measles infections. Thus, to strengthen the reliability of this paper's findings, then the duration of immune-amnesia that this paper determines should agree with the time frame during which previous studies have found children to be at increased risk of mortality following measles.

      Additionally, a basic hypothesis underlying this paper is that children recover from immune-amnesia by rebuilding their immune response through re-exposure to pathogens. This process is similar to how children first build up their immune response after birth - through exposure to pathogens. Thus, if the hypothesis put forth in this paper is correct, then the time it takes to recover from measles induced immune-amnesia (i.e. the duration of immune-amnesia) should be similar to the amount of time it takes children to build an immune response in the first place.

    2. As a further test of the immunosuppressive impact of measles, we carried out a similar analysis on pertussis.

      This is a control experiment preformed by the authors.

      To test that their analysis doesn't result in falsely positive results another childhood disease, Pertussis, which is preventable by vaccination but does not cause immunomodulation was also analyzed. It was found that data did not demonstrate immunomodulation like measles disease.

    1. These y– F1♂ were considered candidates for carrying the y-MCR construct and were crossed to y+ females

      The authors also crossed the yellow F1 males to wildtype females to generate F2 offspring. A diagram of this cross is shown in Figure 2A.

    2. Six such yMCR F1♀ were crossed individually to y+♂

      After they had determined which of the F1 progeny expressed the mutagenic chain reaction allele (yMCR), they crossed the yMCR F1 females back to wildtype males to obtain the F2 progeny.

    3. Wild-type (y+) embryos were injected with the y-MCR element (see supplementary materials), and emerging F0 flies were crossed to a y+ stock

      The authors injected their construct into fly embryos so that the germline cells in the embryo would incorporate the construct into their nuclei. Once these flies (called the F0 generation) were adults, they crossed them back to wildtype flies to obtain the F1 progeny.

    1. This study tests whether summer jobs, which shift focus from remediation to prevention, can reduce crime.

      This paper uses a new approach to look at an old problem--the problem of youth violence. The new approach involves testing whether summer jobs programs result in reduced youth violence.

    1. intravital microscopy (IVM)

      Intravital microscopy is a technique used to image live animals. It is a live video of processes occurring in the animal while it is still alive. It gives information on different cellular interactions and activities in real time.

      In this experiment, the authors inject tumor necrosis factor-α, an inflammatory cytokine within the scrotum of mice, and, via IVM, study local inflammatory response in the cremaster (that covers the testis and speramtic cord) muscles.

    2. we searched for the receptor(s) mediating these contacts

      They next determined the receptor on the cell surface that allows these cells to interact with each other during these collisions.

  3. Mar 2016
    1. However, the theory on summer jobs is not entirely clear-cut

      There are also reasons why summer jobs might not have any effect or have the opposite effect by actually increasing violent activity. This is why this study is important to do.

    1. The left and right y-MCR PCR junction fragments were sequenced from y– F1 progeny from five independent F0 parents.

      In addition to the PCR genotyping, the authors performed DNA sequencing using DNA from F1 flies that were yellow (y-). DNA sequencing is a tool that allows you to determine the exact nucleotide sequence of a region of DNA. The goal of the sequencing was to confirm that the expected MCR construct had been inserted into the y locus.

    1. mean biodegradation rates and mean apparent quantum yields for photoreactions

      This is information from Table 1.

    2. measured and modeled UV radiation in the atmosphere

      In other words, measured or calculated sunlight intensities.

    3. 135 different lakes and 73 rivers

      These are the sites marked on the map in figure S1 (see Figure 1 annotations).

    4. We scaled these measures of DOC processing to the open-water period in three water types—small streams, larger rivers, and lakes

      As briefly discussed earlier in the paper, the authors used their calculated daily areal rated of dissolved organic carbon (DOC) processing to calculate the total amount of each type of DOC processing that occurs in their entire study area.

      They calculated separate rates for three different types of water bodies.

    5. Carbon processing at the scale of the Kuparuk River basin (~8000 km2) was estimated by summing areal rates over time (Fig. 2) for the period 2011–2013 and multiplying by the surface area of each water type (Table 2).

      The authors were able to use their dissolved organic carbon (DOC) degradation rates for the different types of water bodies to calculate the relative importance of sunlight- and microbial-driven DOC degradation in the whole study area (row labeled "sum" in Table 2).

    6. We quantified the importance of photodegradation in DOC processing by directly measuring dark bacterial respiration and each of the DOC photoproducts listed above.

      The authors determined how important sunlight is for breaking down organic carbon by comparing how much microbes can degrade in the dark and how much all the sunlight-driven processes can degrade.

    7. photostimulated bacterial respiration

      Measurement methods are summarized here and provided in detail in Reference 11.

      Photostimulated bacterial respiration was measured by exposing some sterile water samples to sunlight and keeping some in the dark, then adding bacteria and measuring the difference in how much carbon dioxide was produced in the bacteria in the sunlight-exposed samples versus the bacteria in samples that were kept in the dark.

    1. We mapped global tree cover extent, loss, and gain for the period from 2000 to 2012 at a spatial resolution of 30 m, with loss allocated annually.

      Hansen and colleagues looked at satellite images of Earth (see "Landsat data") for every year from 2000 to 2012 and determined how much of Earth is covered in forest, and whether forests increased or decreased in size from year to year.

      This method involves a lot of computer processing, because the raw satellite images need to be screened and assessed before they can be used.

      Hansen and colleagues performed the computational processing in Google's Earth Engine.

    2. being derived through an internally consistent approach that is exempt from the vagaries of different definitions, methods, and data inputs

      This sentence is referring to how Hansen and colleagues used Landsat data (e.g., the satellite images of Earth), which is all collected in exactly the same way each time. Thus, there are no inconsistencies between one sampling event (e.g., photo) and another sampling event.

    3. The proportion of total aggregate forest change emphasizes countries with likely forestry practices by including both loss and gain in its calculation, whereas the proportion of loss to gain measure differentiates countries experiencing deforestation or another loss dynamic without a corresponding forest recovery signal.

      By looking at the forest loss with or without subsequent forest gain, Hansen and colleagues can determine whether a country may have forestry programs or some other type of deforestation.

      To explain, forestry programs treat forests as a crop in that the trees are harvested and subsequently replanted/regrown until the next harvest, and so on. Thus, countries that experience forest loss and subsequent gain likely have forestry programs.

      Countries that have forest loss without much forest gain probably do not have forestry programs, and thus the deforestation is caused by some other factor. What could be some other causes of deforestation?

    4. efficiently process and characterize global-scale time-series data sets in quantifying land change

      Hansen and colleagues are illustrating how the work they conducted in this study can be applied and used by governments around the globe to monitor changes in land cover over time.

      Also, to clarify, "time-series data sets" refers to how their data (forest cover measurements) were collected, i.e., in this case in a series of collections through time (one collection of satellite images of Earth for each year from 2000 to 2012).

    1. Logistic regressions predicting the presence or absence of emotion words/emoticons at the tweet level were conducted, with political party followed as the independent variable

      The researchers examined whether or not an individual's usage of positive/negative words and emoticons in tweets could be statistically predicted based on that individual's assumed political party affiliation (either Democrat or Republican).

    2. In study 4, we analyzed 457 publicly available photographs of individuals from LinkedIn, a business-oriented social networking Web site.

      This study is essentially the same as the one that examined photographs of members of Congress (Study 2), but this one uses photographs from a business setting, rather than a political one.

    3. whether conservatives’ reports of greater subjective well-being, relative to liberals, could be attributed to self-enhancing tendencies

      This is the main hypothesis for Study 1. The authors predict that the reason why conservatives report higher levels of well-being is that, compared with liberals, conservatives are more likely to self-enhance.

  4. Nov 2015
    1. Stimulation was discontinued at any sign of arousal from sleep

      This procedure is necessary in order to ensure that any effect the authors find is specific to sleep (as opposed to hearing the sound consciously while awake).

    2. we administered another task wherein the same two sounds prompted participants to form a corresponding face-word pairing

      The purpose of this task is to make the association between the sound and the training stronger.

      On each trial participants were presented with a female face, a Black face, a science word and a good word.

      If they they heard the gender-associated sound they had to match the female face with the science word. If they heard the race-associated sound they had to match the Black face with the good word.

    3. Two unusual frequency-modulated sounds were presented during training

      The sounds were played immediately after a correct response. One sound was played for counter-gender bias responses, the other for counter-race bias responses.

      For some participants Sound A was played with the gender items and Sound B with the race items, and for other participants Sound B was played with the gender items and Sound A with the race items.

      Click to hear Sound A

      Click to hear Sound B

    4. Participants viewed several types of face-word pairing but were required to attend and respond only to pairings that countered the typical bias

      Participants were asked to press the spacebar as quickly as possible after seeing a face-word pair that countered the typical bias (e.g. a female face with the word 'science').

      Half the pairs countered the typical bias and half were filler trials that participants were not supposed to respond to (female + art, male + science, male + art).

  5. Oct 2015
    1. could be expanded through the use of homologs with different PAM requirements (9) or by directed evolution

      This is another area for potential future research

    2. directed evolution of these nucleases toward higher specificity

      This is another area for potential future research.

    3. off-target nuclease activity

      This is a problem that will definitely need to be resolved before these technologies can be deployed in human beings

    4. it is likely that the target locus's underlying chromatin structure and epigenetic state will also affect the efficiency of genome editing in eukaryotic cells (13), although we suspect that Cas9's helicase activity may render it more robust to these factors, but this remains to be evaluated

      This is another area for possible future research.

    5. 8 to 12 bases is less well understood and may depend on the binding strength of the matching gRNAs or on the inherent tolerance of Cas9 itself

      This could be an area of future research

    6. puromycin selection

      Puromycin is an antibiotic that can be used to select cells which have developed resistance to it by killing off all the cells which have not. It is used here to purify a cell strain by eliminating all the cells which did not develop resistance. http://agscientific.com/blog/index.php/2012/10/10/puromycin-faqs/

    7. endogenous locus

      That is, the AAVS1 locus in the PPP1R12C gene of chromosome 19 as mentioned above.

    8. next-generation sequencing of the targeted locus

      The authors checked the DNA sequence of daughter cells after they did the editing

    9. which demonstrates that CRISPR-mediated genome editing is sequence-specific

      This supports the authors' interpretation of what is happening.

    10. HR but lower nonhomologous end joining (NHEJ) rates

      By increasing the proportion of homologous recombination the researchers have better control over the process. Nonhomologous end joining is a less exact process and leads to more spontaneous errors.

    11. GFP+ cells appearing ~20 hours post transfection compared with ~40 hours for the AAVS1 TALENs.

      The results of the editing process appeared sooner in the case of the authors' engineered guide RNAs as compared with the earlier method using TALENs

    12. gene correction rates using the T1 and T2 gRNAs approaching 3% and 8%

      In other words, 3-8% of the cells returned to being fluorescent.

    13. two gRNAs

      The authors constructed two different guide RNAs

    14. the intervening AAVS1 fragment

      This is the 68-bp fragment mentioned toward the end of the last paragraph. When it is expressed, it makes the protein non-fluorescent.

    15. flow-activated cell sorting (FACS)

      This method uses a laser to identify which cells are of interest and thus sort them out. http://www.bio.davidson.edu/courses/genomics/method/facs.html

    16. renders the expressed protein fragment nonfluorescent

      By introducing the green fluorescent protein sequence and then disrupting it the authors were able to measure how well their genetic editing worked. They could measure this by determining how many of the daughter cells were fluorescent.

    17. guide RNAs

      In the natural CRISPR system guide RNAs take fragments of the viral or plasmid DNA and guide them to specific locations in the CRISPR locus. The idea here is that these artificial guide RNAs can similarly guide a short strand of nucleic acids into a specific place in the target genome.

    18. crRNA-tracrRNA fusion transcripts

      The authors combined two proteins which are needed for correct functioning of the CRISPR type II system.

    19. a mammalian expression system

      Genes code for proteins, but characteristics of the cells that the genes are in may either help or hinder the genes from actually producing the desired protein.

      For example, there are differences between insect protein and the protein of mammals. Cells can be engineered to produce the desired type of protein. For more about expression systems, see this link: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3848218/

    20. C-terminal SV40 nuclear localization signal

      Nuclear localization signals are amino acid sequences that mark a protein to be transported to a specific place in the nucleus.

    21. human codon–optimized version

      A codon is a sequence of DNA "letters" that corresponds to a specific amino acid. By using a sequence of codons, specific proteins can be constructed.

    1. Taking into consideration the role of sleep in memory consolidation, we adapted procedures for (i) reducing implicit social biases and (ii) reactivating this training during sleep.

      To design their study, the authors combined counterbias training (discussed in the previous paragraph) with memory reactivation during sleep (discussed in this paragraph) in order to reduce racial and gender biases.

    2. We reactivated counterbias information during sleep using subtle auditory cues that had been associated with counterbias training

      While participants were asleep, the experimenters played one of two sounds - either the sound associated with the gender counterbias training or the sound associated with the racial counterbias training. The sounds were played softly so that the participants did not wake up.

    3. implicit association test (IAT)

      The IAT is a test that measures your implicit (unconscious) biases. You initially practice classifying items based on one set of two categories (e.g. good words respond with the left hand and bad words respond with your right hand). After a number of trials you then classify another set of two categories (e.g. White faces with the left hand and Black faces with the right hand). Then the categories are paired together (e.g. if you see a good word or a White face respond with the left hand and if you see a bad word or a Black face respond with your right hand). Finally the pairings are switched (e.g. if you see a good word or a Black face respond with the left hand and if you see a bad word or a White face respond with your right hand).

      Your score is calculated based on your reaction times for responding to White faces when the same key is used to classify good words than your reaction time for responding to Black faces when the same key is used to classify good words.

      Try the IAT for yourself here!