Turns out this illusion is probably universal--not only in humans, but also in other species. Photo: Dr. Dorsa Amir One of the examples in Chapter 14 is about the Mueller-Lyer Illusion (pictured), specifically, as a prominent example of culture's influence on psychological processes. The original study (conducted by Segall, et al., 1966) showed that people …
Continue reading Replication update: Mueller-Lyer Illusion (Ch 14)
A mini meta-analysis found that the average effect size comparing laptop to handwritten notes was negligible. Credit: insta_photos/Shutterstock One of the major empirical examples in Chapter 10 (in the 3rd and 4th editions of the textbook) is a study that tested whether laptop or handwritten notes are better for people's learning from a video lecture. …
Continue reading Replication: “Don’t ditch the laptop just yet”
Here's an update to some effect size content in the textbook. Figure S1.12 First, in Supplemental Chapter S1, there's a comparison of psychological to medical effect sizes (page 477 of the 3rd Edition). Figure S1.12 reproduces a chart by Bushman and Anderson (2001) comparing the correlation between violent media and aggression to effect sizes from …
A blog post in this space (2012) once included a summary of a set of studies on people's cheating behavior. One of those studies found that recalling the Ten Commandments led people to do less cheating. That study has recently been revisited as a registered replication report. The new researchers were not able to replicate …
Her school achievement later in life can be predicted from her ability to wait for a treat (or by her family's SES). Photo: Manley099/Getty Images There's a new replication study about the famous "marshmallow study", and it's all over the popular press. You've probably heard of the original research: Kids are asked to sit alone …
Continue reading Delay of gratification (marshmallow study replication)
The study found an estimated 12% higher rate of fatal accidents after 4:20pm on April 20. Credit: Lars Hagberg/AFP/Getty Images REPLICATION UPDATE (posted Feb 25, 2019) Another set of researchers wondered why the study below compared April 20 to April 13 and April 27, rather than comparing April 20 to every other day in April …
Continue reading Does smoking marijuana cause car fatalities?
Figure 8.1: Data from Mehl et al., (2010) In Chapter 8, one of the examples features a study that found that the more "deep talk" people engage in (as measured by the EAR), the happier they reported being (Mehl et al., 2010) (see Figure 8.1). The same 2010 study also reported that the amount of …
Continue reading “Talk deeply, be happy?” It seems to replicate…
See updates from October 2018 and August 2019 below. My textbook describes several studies from Dr. Brian Wansink's lab. They make excellent teaching examples because students are able to understand the theory and hypotheses almost immediately and therefore focus on the methodological details. For example, in Chapter 10 of the 2nd and 3rd editions, I …
This post isn't a replication update per se. However, this blog post by Daniel Lakens (2017, July 3) challenges an interrupted time series design featured in Chapter 13 (Figure 13.2). The original study, by Danziger et al. (2011), found that judges were more likely to grant parole at the beginning of the day or after …
Continue reading Update: Extraneous factors in judicial decisions (Danzinger et al.)
Science progresses one study at a time. As scientists conduct research and make the results public, we enable others to build upon, replicate, and critique our work, improving the field and building a body of knowledge. Even the studies in the textbook are not certain "truths," but rather steps on a scientific path, selected at …