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• Engagement in social pretense predicted preschoolers' inhibitory control growth. • Gains associated with social pretense held controlling for other forms of social play. • Solitary pretense did not predict gains in inhibitory control. Recent experimental evidence suggests that engaging in pretend play can improve children's executive functions (EFs). Yet, evidence regarding how play relates to the development of EF remains sparse. The current study investigated whether preschoolers' social and solitary pretend play over the course of one preschool year predicted growth in inhibitory control, a key component of EF. Participants were 132 Spanish-speaking preschoolers (M age = 53 months) from 10 Head Start classrooms in the southwest United States. Multiple 15-s naturalistic observations of children's interactions (e.g., social, solitary) and activities (e.g., pretense, non-pretense) were gathered across free-play classroom contexts. Among observed play behaviors, social pretense was the only predictor of inhibitory control growth in preschool contexts. The current study speaks to the importance of continued research on play-based interventions, especially in diverse populations, and corroborates a growing body of theoretical and empirical evidence for the importance of pretend play in the development of EF. [ABSTRACT FROM AUTHOR]

Humans are the only species that engages in sustained, complex pretend play. As pretend play is practically ubiquitous across cultures, it might support or afford a context for developmental advances during the juvenile period that have implications for functioning in adulthood. Early in development, learning to separate our thoughts from reality is practiced in pretend play and is associated with changes not just in cognition, but in emotional and social domains as well. Specifically, pretend play affords opportunities to engage in abstractions that could support abilities such as perspective-taking, emotion recognition and regulation, and cooperation and negotiation in childhood. In turn, the abstraction skills promoted by early pretend play might underlie creativity, innovation, and our capacity to feel empathy and moral obligation to others in later childhood and adulthood. In fact, because pretend play affords sharing our abstractions with others, it might be an early context for behaviors that ultimately promote the shared abstractions of human culture itself. [ABSTRACT FROM AUTHOR]

Highlights: [•] A developmental relation between executive function (EF) and pretense is investigated in the preschool period. [•] A large battery of EF measures fit both a 1-factor and a 2-factor (Conflict and Delay) model in a confirmatory factor analysis. [•] Individual differences in pretense representation and EF were significantly related, over and above several controls. [•] Understanding the pretend–reality distinction was related to Conflict EF, whereas performing pretend actions was related to Delay EF. [•] A bidirectional between EF and pretense is proposed, with implications for pretend play interventions designed to foster EF development. [Copyright &y& Elsevier]

The process of flocculation in dredge plumes was investigated by field measurements using Laser In-Situ Scattering and Transmissometry (LISST), Optical Back Scatter (OBS) sensors and an Acoustic Current Doppler Profiler (ADCP) during dredging campaigns in Port Curtis, Queensland (Australia). Suspended sediment characteristics differed significantly between natural ambient suspended sediment and sediment suspended by dredging as well as between sediment suspended by mechanical and hydraulic dredgers. LISST measurements enabled distinction of the suspended sediment by origin and showed that the majority of sediment particles naturally in suspension were aggregated flocs made up of multiple smaller particles. Primary particles in natural suspended sediment had a median particle size (d 50) of 8 to 14 μm, while in-situ flocs had a d 50 of 52 to 99 μm. There were both microflocs and macroflocs present in the natural suspended sediment, with the microflocs being dominant (representing 67%–80% of the flocs). Mechanical dredging resulted in the release of individual particles, microflocs and macroflocs, with the potential for a comparable percentage of macroflocs as in natural suspended sediment (11%–27% compared to 20%–33% in natural suspended sediment). Macroflocs released by mechanical dredging were likely to have originated from the seabed. During overflow from the hopper, the suspended sediment released from the hydraulic dredger had smaller flocs compared to the natural suspended sediment, with a reduction in the d 50 of in-situ flocs from 91 to 67 μm and a reduction in the proportion of macroflocs from 32% to 24%. These results indicate that larger macroflocs present on the seabed had been broken up by the hydraulic dredging, with most of the suspended sediment remaining in the form of smaller microflocs, suggesting that the flocs were not completely disaggregated by the shear-stress generated during hydraulic dredging. Ongoing aggregation of suspended sediment was shown to occur in the sediment suspended by both dredging methods within 20–25 min of the plumes being generated. This study demonstrates the importance of considering flocculation in predictive dredge plume modelling studies to prevent significantly underestimating the settling velocity and substantially over-estimating the extent and intensity of dredge plumes if flocculation is not accounted for. • Flocculation occurs in plumes generated by both mechanical and hydraulic dredging • Flocs released by mechanical dredging were comparable to natural flocs • Flocs from hydraulic dredging were smaller than natural flocs • Ongoing aggregation of flocs occurred in the plume for both dredge types [ABSTRACT FROM AUTHOR]