Pitfall or pratfall? Behavioral differences in infant learning from falling.

Researchers routinely infer learning and other unobservable psychological functions based on observable behavior. But what behavioral changes constitute evidence of learning? The standard approach is to infer learning based on a single behavior across individuals, including assumptions about the direction and magnitude of change (e.g., everyone should avoid falling repeatedly on a treacherous obstacle). Here we illustrate the benefits of an alternative "multiexpression, relativist, agnostic, individualized" approach. We assessed infant learning from falling based on multiple behaviors relative to each individual's baseline, agnostic about the direction and magnitude of behavioral change. We tested infants longitudinally (10.5-15 months of age) over the transition from crawling to walking. At each session, infants were repeatedly encouraged to crawl or walk over a fall-inducing foam pit interspersed with no-fall baseline trials on a rigid platform. Our approach revealed two learning profiles. Like adults in previous work, "pit-avoid" infants consistently avoided falling. In contrast, "pit-go" infants fell repeatedly across trials and sessions. However, individualized comparisons to baseline across multiple locomotor, exploratory, and social-emotional behaviors showed that pit-go infants also learned at every session. But they treated falling as an unimpactful "pratfall" rather than an aversive "pitfall." Pit-avoid infants displayed enhanced learning across sessions and partial transfer of learning from crawling to walking, whereas pit-go infants displayed neither. Thus, reliance on a predetermined, "one-size-fits-all" behavioral expression of a psychological function can obscure different behavioral profiles and lead to erroneous inferences. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Training effects and sex difference in preschoolers' spatial reasoning ability.

This study examined sex difference in spatial reasoning, a type of spatial cognition necessary for everyday activities. An aggregated data set was composed of data from 273 3- to 4-year olds who participated in 12 different studies using variants of the same spatial reasoning task. This data set was used to investigate whether and how sex difference is related to learning opportunities through training. The results showed that boys outperform girls in general, but this sex difference was influenced by training. When children received additional training, boys showed improved spatial reasoning ability compared to girls. But when children did not receive additional training, there was no sex difference. The type and amount of training did not influence the sex difference in this data set. These findings add to our understanding of how sex difference in spatial cognition emerges in early development.

Motor training at 3 months affects object exploration 12 months later.

The development of new motor skills alters how infants interact with objects and people. Consequently, it has been suggested that motor skills may initiate a cascade of events influencing subsequent development. However, only correlational evidence for this assumption has been obtained thus far. The current study addressed this question experimentally by systematically varying reaching experiences in 40 three-month-old infants who were not reaching on their own yet and examining their object engagement in a longitudinal follow-up assessment 12 months later. Results revealed increased object exploration and attention focusing skills in 15-month-old infants who experienced active reaching at 3 months of age compared to untrained infants or infants who only passively experienced reaching. Further, grasping activity after - but not before - reaching training predicted infants' object exploration 12 months later. These findings provide evidence for the long-term effects of reaching experiences and illustrate the cascading effects initiated by early motor skills.

Colorful success: preschoolers' use of perceptual color cues to solve a spatial reasoning problem.

Spatial reasoning, a crucial skill for everyday actions, develops gradually during the first several years of childhood. Previous studies have shown that perceptual information and problem solving strategies are critical for successful spatial reasoning in young children. Here, we sought to link these two factors by examining children's use of perceptual color cues and whether their use of such cues would lead to the acquisition of a general problem solving strategy. Forty-eight 3-year-olds were asked to predict the trajectory of a ball dropped into one of three intertwined tubes. Children who received additional perceptual cues in the form of distinctly colored tubes succeeded twice as often as those who did not receive the cues. A third group of children who received the additional cues on only the first half of the test trials succeeded while the cues were present but reverted to making errors once they were removed. These findings demonstrate that perceptual color cues provide preschoolers with answers to spatial reasoning problems but might not teach children a general strategy for solving the problem.

Imagining a way out of the gravity bias: preschoolers can visualize the solution to a spatial problem.

Can young children visualize the solution to a difficult spatial problem? Forty-eight 3-year-olds were tested in a spatial reasoning paradigm in which they were asked to predict the path of a ball moving through 1 of 3 intertwined tubes. One group of children was asked to visualize the ball rolling down the tube before they made their predictions, a second group was given identical instructions without being asked to use visual imagery, and a third group was given no instructions. Children in the visualization condition performed significantly better than those in the other conditions, suggesting that encouraging young children to use visual imagery may help them to reason through difficult problems.

Infants' perception of affordances of slopes under high- and low-friction conditions.

Three experiments investigated whether 14- and 15-month-old infants use information for both friction and slant for prospective control of locomotion down slopes. In Experiment 1, high- and low-friction conditions were interleaved on a range of shallow and steep slopes. In Experiment 2, friction conditions were blocked. In Experiment 3, the low-friction surface was visually distinct from the surrounding high-friction surface. In all three experiments, infants could walk down steeper slopes in the high-friction condition than they could in the low-friction condition. Infants detected affordances for walking down slopes in the high-friction condition, but in the low-friction condition, they attempted impossibly slippery slopes and fell repeatedly. In both friction conditions, when infants paused to explore slopes, they were less likely to attempt slopes beyond their ability. Exploration was elicited by visual information for slant (Experiments 1 and 2) or by a visually distinct surface that marked the change in friction (Experiment 3).

One sound or two? Object-related negativity indexes echo perception.

The ability to isolate a single sound source among concurrent sources and reverberant energy is necessary for understanding the auditory world. The precedence effect describes a related experimental finding, that when presented with identical sounds from two locations with a short onset asynchrony (on the order of milliseconds), listeners report a single source with a location dominated by the lead sound. Single-cell recordings in multiple animal models have indicated that there are low-level mechanisms that may contribute to the precedence effect, yet psychophysical studies in humans have provided evidence that top-down cognitive processes have a great deal of influence on the perception of simulated echoes. In the present study, event-related potentials evoked by click pairs at and around listeners' echo thresholds indicate that perception of the lead and lag sound as individual sources elicits a negativity between 100 and 250 msec, previously termed the object-related negativity (ORN). Even for physically identical stimuli, the ORN is evident when listeners report hearing, as compared with not hearing, a second sound source. These results define a neural mechanism related to the conscious perception of multiple auditory objects.

Gauging possibilities for action based on friction underfoot.

Standing and walking generate information about friction underfoot. Five experiments examined whether walkers use such perceptual information for prospective control of locomotion. In particular, do walkers integrate information about friction underfoot with visual cues for sloping ground ahead to make adaptive locomotor decisions? Participants stood on low-, medium-, and high-friction surfaces on a flat platform and made perceptual judgments for possibilities for locomotion over upcoming slopes. Perceptual judgments did not match locomotor abilities: Participants tended to overestimate their abilities on low-friction slopes and underestimate on high-friction slopes (Experiments 1-4). Accuracy improved only for judgments made while participants were in direct contact with the slope (Experiment 5), highlighting the difficulty of incorporating information about friction underfoot into a plan for future actions.

Why walkers slip: shine is not a reliable cue for slippery ground.

In a series of four studies, we investigated the visual cues that walkers use to predict slippery ground surfaces and tested whether visual information is reliable for specifying low-friction conditions. In Study 1, 91% of participants surveyed responded that they would use shine to identify upcoming slippery ground. Studies 2-4 confirmed participants' reliance on shine to predict slip. Participants viewed ground surfaces varying in gloss, paint color, and viewing distance under indoor and outdoor lighting conditions. Shine and slip ratings and functional walking judgments were related to surface gloss level and to surface coefficient of friction (COF). However, judgments were strongly affected by surface color, viewing distance, and lighting conditions--extraneous factors that do not change the surface COF. Results suggest that, although walkers rely on shine to predict slippery ground, shine is not a reliable visual cue for friction. Poor visual information for friction may underlie the high prevalence of friction-related slips and falls.

Learning from falling.

Walkers fall frequently, especially during infancy. Children (15-, 21-, 27-, 33-, and 39-month-olds) and adults were tested in a novel foam pit paradigm to examine age-related changes in the relationship between falling and prospective control of locomotion. In trial 1, participants walked and fell into a deformable foam pit marked with distinct visual cues. Although children in all 5 age groups required multiple trials to learn to avoid falling, the number of children who showed adult-like, 1-trial learning increased with age. Exploration and alternative locomotor strategies increased dramatically on learning criterion trials and displays of negative affect were limited. Learning from falling is discussed in terms of the immediate and long-term effects of falling on prospective control of locomotion.

Effects of priming duration on retention over the first 1 1/2 years of life.

Exposing individuals to an isolated component (a prime) of a prior event alleviates its forgetting. Two experiments with 120 human infants between 3 and 18 months of age determined the minimum duration of a prime that can reactivate a forgotten memory and how long the reactivated memory persists. Infants learned an operant task, forgot it, were exposed to the prime, and later were tested for renewed retention. In Experiment 1, the minimum duration of an effective prime decreased logarithmically with age, but was always longer than the duration of a mere glance. In Experiment 2, the reactivated memory was forgotten twice as fast after a minimum-duration prime as after a full-length one, irrespective of priming delay and infant age. These data reveal that the minimum effective prime duration psychophysically equates the accessibility of forgotten memories. We conclude that priming is perceptually based with effects that are organized on a ratio (log) scale.