John Protzko

How to Make a Young Child Smarter: Evidence From the Database of Raising Intelligence

Can interventions meaningfully increase intelligence? If so, how? The Database of Raising Intelligence is a continuously updated compendium of randomized controlled trials that were designed to increase intelligence. In this article, the authors examine nearly every available intervention involving children from birth to kindergarten, using meta-analytic procedures when more than 3 studies tested similar methods and reviewing interventions when too few were available for meta-analysis. This yielded 4 meta-analyses on the effects of dietary supplementation to pregnant mothers and neonates, early educational interventions, interactive reading, and sending a child to preschool. All 4 meta-analyses yielded significant results: Supplementing infants with long-chain polyunsaturated fatty acids, enrolling children in early educational interventions, reading to children in an interactive manner, and sending children to preschool all raise the intelligence of young children.

Believing There Is No Free Will Corrupts Intuitive Cooperation

Regardless of whether free will exists, believing that it does affects ones behavior. When an individuals belief in free will is challenged, one can become more likely to act in an uncooperative manner. The mechanism behind the relationship between ones belief in free will and behavior is still debated. The current study uses an economic contribution game under varying time constraints to elucidate whether reducing belief in free will allows one to justify negative behavior or if the effects occur at a more intuitive level of processing. Here we show that although people are intuitively cooperative, challenging their belief in free will corrupts this behavior, leading to impulsive selfishness. If given time to think, however, people are able to override the initial inclination toward self-interest induced by discouraging a belief in free will.

Context Moderates Affirmation Effects on the Ethnic Achievement Gap

We attempted to replicate a self-affirmation intervention that produced a 40% reduction in the academic achievement gap among at-risk students. The intervention was designed as a protection against stereotype threat—, which creates stress and suppresses the performance, engagement, and learning of students stereotyped as intellectually inferior. In previous research, Black and Hispanic students who engaged in a values-affirmation exercise significantly improved their academic performance over the course of a school semester. We attempted to replicate these salutary effects in both an inner-city school and a more wealthy suburban school—contexts not tested in the original research. Despite employing the same materials, we found no effect of the affirmation on academic performance. We discuss these results in terms of the possibility that negatively stereotyped students benefit most from self-affirmations in environments where their numbers portray them neither as clearly “majority” nor minority.

Does the raising IQ-raising g distinction explain the fadeout effect?

Previous investigations into raising IQ show that after an intervention ends, the effects fade away. This paper is an attempt to understand one possible reason for this fadeout. A large (N = 985) randomized controlled trial is re-analyzed to investigate whether the intervention, which began at birth and lasted for the first three years of their life, raised the underlying cognitive factor of IQ tests. The intervention indeed raised the g factor at age three. No such relationship is seen at follow-up assessments at ages five and eight after the intervention ends. Therefore, the raising IQ/raising g distinction is not appropriate to explain the fadeout effect, as changes to the environment can improve the g factor and still fade.

Effects of cognitive training on the structure of intelligence

Targeted cognitive training, such as n-back or speed of processing training, in the hopes of raising intelligence is of great theoretical and practical importance. The most important theoretical contribution, however, is not about the malleability of intelligence. Instead, I argue the most important and novel theoretical contribution is understanding the causal structure of intelligence. The structure of intelligence, most often taken as a hierarchical factor structure, necessarily prohibits transfer from subfactors back up to intelligence. If this is the true structure, targeted cognitive training interventions will fail to increase intelligence not because intelligence is immutable, but simply because there is no causal connection between, say, working memory and intelligence. Seeing the structure of intelligence for what it is, a causal measurement model, allows us to focus testing on the presence and absence of causal links. If we can increase subfactors without transfer to other facets, we may be confirming the correct causal structure more than testing malleability. Such a blending into experimental psychometrics is a strong theoretical pursuit.

Girls’ internalization of their female teacher’s anxiety: A “real-world” stereotype threat effect?

The deleterious effects that stereotypes can have on girls’ school performance in mathematics are best exemplified by the stereotype threat paradigm (1) showing that when women are reminded of stereotypes alleging male superiority in math, their math performance suffers (2). However, evidence is mixed on how much these threat effects apply to girls’ math performance in “real-world” settings (3), and how girls develop their vulnerability in the first place.