Knowledge that Transforms

What mechanisms underlie learning in newborn brains? Recently, researchers reported that newborn chicks use unsupervised statistical learning to encode the transitional probabilities (TPs) of shapes in a sequence, suggesting that TP-based statistical learning can be present in newborn brains. Using a preregistered design, we attempted to reproduce this finding with an automated method that eliminated experimenter bias and allowed more than 250 times more data to be collected per chick. With precise measurements of each chick's behavior, we were able to perform individual-level analyses and substantially reduce measurement error for the group-level analyses. We found no evidence that newborn chicks encode the TPs between sequentially presented shapes. None of the chicks showed evidence for this ability. Conversely, we obtained strong evidence that newborn chicks encode the shapes of individual objects, showing that this automated method can produce robust results. These findings challenge the claim that TP-based statistical learning is present in newborn brains.

We sometimes evaluate our environment (e.g., persons, objects, situations) in an automatic fashion. These automatic or implicit evaluations are often considered to be based on qualitatively distinct mental processes compared with more controlled or explicit evaluations. Important evidence for this claim comes from studies showing that implicit evaluations do not change as the result of counterattitudinal information, in contrast to their explicit counterparts. We examined the impact of counterattitudinal information on implicit evaluations in two experiments ( N = 60, N = 72) that included an innovative manipulation: hypnotic suggestions to participants that they would strongly process upcoming counterattitudinal information. Both experiments indicated that hypnotic suggestions facilitated effects of counterattitudinal information on implicit evaluations. These findings extend recent evidence for rapid revision of implicit evaluations on the basis of counterattitudinal information and support the controversial idea that belief-based processes underlie not only explicit but also implicit evaluations.

In “Fictional First Memories,” Akhtar, Justice, Morrison, and Conway (2018) assert that roughly 40% of 6,641 adults’ earliest memories are fictional because these respondents dated their earliest memories from the age of 2 years or younger. “Fictional” memories, in their assessment, may include fragments of actual events. They do not, however, represent lived experience because “children below the age of 2 to 3 years cannot form autobiographical memories” thus making it impossible “for adults to recall such memories” (p. 1613). We agree with the contention that memories may feature some fiction—elements that never actually happened may be a part of memories from any point in life. Moreover, reports of very early experiences may be especially vulnerable to social influences (e.g., family stories). Yet we take issue with Akhtar et al.’s contention that children 2 years old and younger lack the ability to form and retain memories of their experiences and thus with the conclusion that adults’ recollections from this age period must therefore be fictional. In this Commentary, we examine the substantial evidence of autobiographical remembering before the age of 3 years and raise cautions against categorically dismissing recollections of early life events.

Despite advances in the understanding of the reward system and the role of dopamine in recent decades, the heritability of the underlying neural mechanisms is not known. In the present study, we examined the hemodynamic activation of the nucleus accumbens (NAcc), a key hub of the reward system, in 86 healthy monozygotic twins and 88 healthy dizygotic twins during a monetary-incentive-delay task. The participants also completed self-report measures of pleasure. Using voxelwise heritability mapping, we found that activation of the bilateral NAcc during the anticipation of monetary gains had significant heritability ( h 2 = .20–.49). Moreover, significant shared genetic covariance was observed between pleasure and NAcc activation during the anticipation of monetary gain. These findings suggest that both NAcc activation and self-reported pleasure may be heritable and that their phenotypic correlation may be partially explained by shared genetic variation.

When searching for relevant objects in our environment (say, an apple), we create a memory template (a red sphere), which causes our visual system to favor template-matching visual input (applelike objects) at the expense of template-mismatching visual input (e.g., leaves). Although this principle seems straightforward in a lab setting, it poses a problem in naturalistic viewing: Two objects that have the same size on the retina will differ in real-world size if one is nearby and the other is far away. Using the Ponzo illusion to manipulate perceived size while keeping retinal size constant, we demonstrated across 71 participants that visual objects attract attention when their perceived size matches a memory template, compared with mismatching objects that have the same size on the retina. This shows that memory templates affect visual selection after object representations are modulated by scene context, thus providing a working mechanism for template-based search in naturalistic vision.

We studied how children begin to produce spellings that reflect the sounds in words. We asked 75 U.S. preschoolers (mean age = 4 years, 11 months) to participate in two sessions. In one session, the children were asked to spell words (e.g., bead) that begin with a sequence of sounds that matches the name of a letter; in another session, they were asked to spell control words (e.g., bed). The phonological plausibility of children’s spellings, particularly their spellings of the words’ first phonemes, was higher for letter-name words than for control words. When we categorized spelling performance in a session as prephonological if the child used phonologically appropriate letters no more often than would be expected by chance, we found that children were more likely to be prephonological spellers in the session with control words than in the session with letter-name words. Words with letter names can help children move from prephonological spellings to spellings that symbolize at least some of the sounds in words.

Keywords: consequentialism, morality, trolley, utilitarianism

People have been shown to link particular sounds with particular shapes. For instance, the round-sounding nonword bouba tends to be associated with curved shapes, whereas the sharp-sounding nonword kiki is deemed to be related to angular shapes. People’s tendency to associate sounds and shapes has been observed across different languages. In the present study, we reexamined the claim by Hung, Styles, and Hsieh (2017) that such sound–shape mappings can occur before an individual becomes aware of the visual stimuli. More precisely, we replicated their first experiment, in which congruent and incongruent stimuli (e.g., bouba presented in a round shape or an angular shape, respectively) were rendered invisible through continuous flash suppression. The results showed that congruent combinations, on average, broke suppression faster than incongruent combinations, thus providing converging evidence for Hung and colleagues’ assertions. Collectively, these findings now provide a solid basis from which to explore the boundary conditions of the effect.

When lifting an object, it takes time to decide how heavy it is. How does this weight judgment develop? To answer this question, we examined when visual size information has to be present to induce a size-weight illusion. We found that a short glimpse (200 ms) of size information is sufficient to induce a size-weight illusion. The illusion occurred not only when the glimpse was before the onset of lifting but also when the object's weight could already be felt. Only glimpses more than 300 ms after the onset of lifting did not influence the judged weight. This suggests that it takes about 300 ms to reach a perceptual decision about the weight.

When adolescents are asked how likely they think it is that they will go to college, does their answer influence what they will actually do? Typically, it is difficult to determine whether college expectations promote academic achievement or just reflect a reasonable forecast of what is likely to happen to them. We used a sample of siblings from the National Longitudinal Study of Adolescent to Adult Health ( N = 1,766) to test whether associations between college expectations and educational attainment remained after accounting for unobserved family factors that may shape both educational expectations and attainment. Compared with their siblings, adolescents with higher college expectations were also 43% more likely to attend college, even when analyses controlled for grades and IQ. The effect of college expectations on college attendance was strongest among youths living in higher-socioeconomic-status families.