Celeste Kidd

The Goldilocks effect: human infants allocate attention to visual sequences that are neither too simple nor too complex.

Human infants, like immature members of any species, must be highly selective in sampling information from their environment to learn efficiently. Failure to be selective would waste precious computational resources on material that is already known (too simple) or unknowable (too complex). In two experiments with 7- and 8-month-olds, we measure infants’ visual attention to sequences of events varying in complexity, as determined by an ideal learner model. Infants’ probability of looking away was greatest on stimulus items whose complexity (negative log probability) according to the model was either very low or very high. These results suggest a principle of infant attention that may have broad applicability: infants implicitly seek to maintain intermediate rates of information absorption and avoid wasting cognitive resources on overly simple or overly complex events.

Rational snacking: Young children's decision-making on the marshmallow task is moderated by beliefs about environmental reliability

Children are notoriously bad at delaying gratification to achieve later, greater rewards (e.g., Piaget, 1970)-and some are worse at waiting than others. Individual differences in the ability-to-wait have been attributed to self-control, in part because of evidence that long-delayers are more successful in later life (e.g., Shoda, Mischel, & Peake, 1990). Here we provide evidence that, in addition to self-control, childrens wait-times are modulated by an implicit, rational decision-making process that considers environmental reliability. We tested children (M=4;6, N=28) using a classic paradigm-the marshmallow task (Mischel, 1974)-in an environment demonstrated to be either unreliable or reliable. Children in the reliable condition waited significantly longer than those in the unreliable condition (p<0.0005), suggesting that childrens wait-times reflected reasoned beliefs about whether waiting would ultimately pay off. Thus, wait-times on sustained delay-of-gratification tasks (e.g., the marshmallow task) may not only reflect differences in self-control abilities, but also beliefs about the stability of the world.

The Psychology and Neuroscience of Curiosity.

Curiosity is a basic element of our cognition, but its biological function, mechanisms, and neural underpinning remain poorly understood. It is nonetheless a motivator for learning, influential in decision-making, and crucial for healthy development. One factor limiting our understanding of it is the lack of a widely agreed upon delineation of what is and is not curiosity. Another factor is the dearth of standardized laboratory tasks that manipulate curiosity in the lab. Despite these barriers, recent years have seen a major growth of interest in both the neuroscience and psychology of curiosity. In this Perspective, we advocate for the importance of the field, provide a selective overview of its current state, and describe tasks that are used to study curiosity and information-seeking. We propose that, rather than worry about defining curiosity, it is more helpful to consider the motivations for information-seeking behavior and to study it in its ethological context.

The Goldilocks Effect in Infant Auditory Attention

Infants must learn about many cognitive domains (e.g., language, music) from auditory statistics, yet capacity limits on their cognitive resources restrict the quantity that they can encode. Previous research has established that infants can attend to only a subset of available acoustic input. Yet few previous studies have directly examined infant auditory attention, and none have directly tested theorized mechanisms of attentional selection based on stimulus complexity. This work utilizes model-based behavioral methods that were recently developed to examine visual attention in infants (e.g., Kidd, Piantadosi, & Aslin, 2012). The present results demonstrate that 7- to 8-month-old infants selectively attend to nonsocial auditory stimuli that are intermediately predictable/complex with respect to their current implicit beliefs and expectations. These findings provide evidence of a broad principle of infant attention across modalities and suggest that sound-to-sound transitional statistics heavily influence the allocation of auditory attention in human infants.

Extraordinary intelligence and the care of infants

Significance One mystery of human evolution is why our cognition differs qualitatively from our closest evolutionary relatives. Here we show how natural selection for large brains may lead to premature newborns, which themselves require more intelligence to raise, and thus may select for even larger brains. As we show, these dynamics can be self-reinforcing and lead to runaway selection for extremely high intelligence and helpless newborns. We test a prediction of this account: the helplessness of a primate’s newborns should strongly predict their intelligence. We show that this is so and relate our account to theories of human uniqueness and the question of why human-level intelligence took so long to evolve in the history of life. We present evidence that pressures for early childcare may have been one of the driving factors of human evolution. We show through an evolutionary model that runaway selection for high intelligence may occur when (i) altricial neonates require intelligent parents, (ii) intelligent parents must have large brains, and (iii) large brains necessitate having even more altricial offspring. We test a prediction of this account by showing across primate genera that the helplessness of infants is a particularly strong predictor of the adults’ intelligence. We discuss related implications, including this account’s ability to explain why human-level intelligence evolved specifically in mammals. This theory complements prior hypotheses that link human intelligence to social reasoning and reproductive pressures and explains how human intelligence may have become so distinctive compared with our closest evolutionary relatives.

Endogenous or exogenous? The data don't say.

In an exciting in-depth study of Korean language learners, Han, Musolino, and Lidz (1) show that children often arrive at grammars that do not match their parents. Learners appear to choose between multiple linguistic systems that are consistent with their most direct observed evidence. The authors frame these results as informing the nature vs. nurture debate: because learners acquire a grammar that is not determined by their input, they must be bringing information to the problem “on the basis of an internally driven learning mechanism” (1).

The dynamics of idealized attention in complex learning environments

Effective allocation of attention is crucial for many cognitive functions, and attentional disorders (e.g., ADHD) negatively impact learning. Despite the importance of the attentional system, the origins of inattentional behavior remain hazy. Here we present a model of an ideal learner that maximizes information gain in an environment containing multiple objects, each containing a set amount of information to be learned. When constraints on the speed of information decay and ease of shifting attention between objects are added to the system, patterns of attentional switching behavior emerge. These predictions can account for results reported from multiple object tracking tasks. Further, they highlight multiple possible causes underlying the atypical behaviors associated with attentional disorders.

Seeing Colors: Cultural and Environmental Influences on Episodic Memory

Expectations learned from our perceptual experiences, culture, and language can shape how we perceive, interact with, and remember features of the past. Here, we questioned whether environment also plays a role. We tested recognition memory for color in Bolivia’s indigenous Tsimanè people, who experience a different color environment than standard U.S. populations. We found that memory regressed differently between the groups, lending credence to the idea that environmental variations engender differences in expectations, and in turn perceptual memory for color.