The field of psychology has been experiencing a “replication crisis” in recent years.
The problem was highlighted in a report that appeared in the journal Science in 2015. For that report, an international team of 270 researchers attempted to replicate the findings from 100 studies published in three leading psychology journals in 2008.
They succeeded with less than half of the studies.
That result doesn’t necessarily mean that the original studies’ findings were wrong, or that psychological research is pointless, but it does underscore why we need to retain skepticism when such studies (or any studies, for that matter) are published — including ones that appear to be well designed.
We need to wait for the studies to be replicated.
As I’ve noted here before, some of psychology’s most famous findings, ones that are widely accepted by the general public, have failed such tests. These include the idea that adopting a superhero-like pose will make you feel more powerful, that smiling will make you happier and that washing your hands can help wash away feelings of guilt.
Passing the test
But some major psychological phenomena have been successfully replicated, including in circumstances in which replication is notoriously tricky — as when the participants have already been tested on the same effect.
Indeed, Dutch researchers recently replicated nine of cognitive psychology’s most important findings — findings that “present good news for the field of psychology,” they write.
In an article for BPS Research Digest (published by the British Psychological Society), psychologist and journalist Christian Jarrett summarizes how these researchers went about their replication task. “[They] tested hundreds of participants on Amazon’s Mechanical Turk survey website,” he writes (with British spellings). “Whichever cognitive effect they were tested on, each participant completed the test twice (either with the exact same stimuli or new versions), to see whether it made any difference to their behaviour or responses if they already had experience of the experiment.”
“In fact, all the effects in question were replicated on all occasions, whether on the first or second testing, and regardless of whether the specific stimuli — such as the words or pictures involved — were familiar or completely new,” he adds.
Here are Jarrett’s descriptions of three of the findings successfully replicated in the study, along with a brief explanation of their importance:
False Memories: Participants were shown sequences of words of related meaning. Tested on their memory of the words later, participants were more likely to mistakenly say that a new word of similar meaning had been present in the earlier sequence than a new word with a meaning unrelated to the earlier list. This is a basic demonstration of the fallibility of memory and how easy it is to feel like we’ve experienced something before when we haven’t.
- The Flanker Task: Participants had to press the correct keyboard key as fast as possible to indicate whether a target stimulus was a vowel or consonant. Participants were faster to respond if the target was surrounded by distracting letters associated with the same response (e.g. a target vowel surrounded by irrelevant, distracting vowels), as opposed to being surrounded by distractors associated with a different response (e.g. a vowel surrounded by consonants). The task shows how we can’t help but process irrelevant information to a certain degree.
Motor Priming: Participants had to press the appropriate keyboard key as fast as possible in response to left- or right-facing arrows flashed on-screen. Preceding arrows (known as a prime) gave advance warning of which way the target arrows would point: sometimes these primes were accurate, which led to faster performance, as you’d expect; if the primes pointed the wrong way, they slowed performance. Crucially, some of the primes were “masked” to make them subliminal (i.e. not consciously visible), in which case the effects were reversed, with primes pointing the wrong way leading to faster responses. The finding shows how information that’s not consciously perceived can affect our behaviour, and that it can have an opposite effect when subliminal than when consciously perceived.
The other successfully replicated phenomenon were the Simon effect, the spacing effect, the serial position effect, associative priming, repetition priming and shape simulation.