Poor indoor air quality indicated by elevated indoor CO2 concentrations has been linked with impaired cognitive function, yet current findings of the cognitive impact of CO2 are inconsistent. This ...review summarizes the results from 37 experimental studies that conducted objective cognitive tests with manipulated CO2 concentrations, either through adding pure CO2 or adjusting ventilation rates (the latter also affects other indoor pollutants). Studies with varied designs suggested that both approaches can affect multiple cognitive functions. In a subset of studies that meet objective criteria for strength and consistency, pure CO2 at a concentration common in indoor environments was only found to affect high‐level decision‐making measured by the Strategic Management Simulation battery in non‐specialized populations, while lower ventilation and accumulation of indoor pollutants, including CO2, could reduce the speed of various functions but leave accuracy unaffected. Major confounding factors include variations in cognitive assessment methods, study designs, individual and populational differences in subjects, and uncertainties in exposure doses. Accordingly, future research is suggested to adopt direct air delivery for precise control of CO2 inhalation, include brain imaging techniques to better understand the underlying mechanisms that link CO2 and cognitive function, and explore the potential interaction between CO2 and other environmental stimuli.
Inferring relationships that go beyond our direct experience is essential for understanding our environment. This capacity requires either building representations that directly reflect structure ...across experiences as we encounter them or deriving the indirect relationships across experiences as the need arises. Building structure directly into overlapping representations allows for powerful learning and generalization in neural network models, but building these so-called distributed representations requires inputs to be encountered in interleaved order. We test whether interleaving similarly facilitates the formation of representations that directly integrate related experiences in humans and what advantages such integration may confer for behavior. In a series of behavioral experiments, we present evidence that interleaved learning indeed promotes the formation of representations that directly link across related experiences. As in neural network models, interleaved learning gives rise to fast and automatic recognition of item relatedness, affords efficient generalization, and is especially critical for inference when learning requires statistical integration of noisy information over time. We use the data to adjudicate between several existing computational models of human memory and inference. The results demonstrate the power of interleaved learning and implicate the formation of integrated, distributed representations that support generalization in humans.
Public Significance StatementThe study provides evidence that presenting information in an intermixed order facilitates the storage of this information in a format that promotes the efficient discovery of hidden relationships.
Children sometimes learn distracting information better than adults do, perhaps because of the development of selective attention. To understand this potential link, we ask how the learning of ...children (aged 7-9 years) and the learning of adults differ when information is the directed focus of attention versus when it is not. Participants viewed drawings of common objects and were told to attend to the drawings (Experiment 1: 42 children, 35 adults) or indicate when shapes (overlaid on the drawings) repeated (Experiment 2: 53 children, 60 adults). Afterward, participants identified fragments of these drawings as quickly as possible. Adults learned better than children when directed to attend to the drawings; however, when drawings were task irrelevant, children showed better learning than adults in the first half of the test. And although directing attention to the drawings improved learning in adults, children learned the drawings similarly across experiments regardless of whether the drawings were the focus of the task or entirely irrelevant.Children sometimes learn distracting information better than adults do, perhaps because of the development of selective attention. To understand this potential link, we ask how the learning of children (aged 7-9 years) and the learning of adults differ when information is the directed focus of attention versus when it is not. Participants viewed drawings of common objects and were told to attend to the drawings (Experiment 1: 42 children, 35 adults) or indicate when shapes (overlaid on the drawings) repeated (Experiment 2: 53 children, 60 adults). Afterward, participants identified fragments of these drawings as quickly as possible. Adults learned better than children when directed to attend to the drawings; however, when drawings were task irrelevant, children showed better learning than adults in the first half of the test. And although directing attention to the drawings improved learning in adults, children learned the drawings similarly across experiments regardless of whether the drawings were the focus of the task or entirely irrelevant.
Extracting shared structure across our experiences allows us to generalize our knowledge to novel contexts. How do different brain states influence this ability to generalize? Using a novel category ...learning paradigm, we assess the effect of both sleep and time of day on generalization that depends on the flexible integration of recent information. Counter to our expectations, we found no evidence that this form of generalization is better after a night of sleep relative to a day awake. Instead, we observed an effect of time of day, with better generalization in the morning than the evening. This effect also manifested as increased false memory for generalized information. In a nap experiment, we found that generalization did not benefit from having slept recently, suggesting a role for time of day apart from sleep. In follow-up experiments, we were unable to replicate the time of day effect for reasons that may relate to changes in category structure and task engagement. Despite this lack of consistency, we found a morning benefit for generalization when analyzing all the data from experiments with matched protocols (n = 136). We suggest that a state of lowered inhibition in the morning may facilitate spreading activation between otherwise separate memories, promoting this form of generalization.
Poor indoor air quality indicated by elevated indoor CO
concentrations has been linked with impaired cognitive function, yet current findings of the cognitive impact of CO
are inconsistent. This ...review summarizes the results from 37 experimental studies that conducted objective cognitive tests with manipulated CO
concentrations, either through adding pure CO
or adjusting ventilation rates (the latter also affects other indoor pollutants). Studies with varied designs suggested that both approaches can affect multiple cognitive functions. In a subset of studies that meet objective criteria for strength and consistency, pure CO
at a concentration common in indoor environments was only found to affect high-level decision-making measured by the Strategic Management Simulation battery in non-specialized populations, while lower ventilation and accumulation of indoor pollutants, including CO
, could reduce the speed of various functions but leave accuracy unaffected. Major confounding factors include variations in cognitive assessment methods, study designs, individual and populational differences in subjects, and uncertainties in exposure doses. Accordingly, future research is suggested to adopt direct air delivery for precise control of CO
inhalation, include brain imaging techniques to better understand the underlying mechanisms that link CO
and cognitive function, and explore the potential interaction between CO
and other environmental stimuli.
Extracting shared structure across our experiences allows us to generalize our knowledge to novel contexts. How do different brain states influence this ability to generalize? Using a novel category ...learning paradigm, we assess the effect of both sleep and time of day on generalization that depends on the flexible integration of recent information. Counter to our expectations, we found no evidence that this form of generalization is better after a night of sleep relative to a day awake. Instead, we observed an effect of time of day, with better generalization in the morning than the evening. This effect also manifested as increased false memory for generalized information. In a nap experiment, we found that generalization did not benefit from having slept recently, suggesting a role for time of day apart from sleep. In follow-up experiments, we were unable to replicate the time of day effect for reasons that may relate to changes in category structure and task engagement. Despite this lack of consistency, we found a morning benefit for generalization when analyzing all the data from experiments with matched protocols (n = 136). We suggest that a state of lowered inhibition in the morning may facilitate spreading activation between otherwise separate memories, promoting this form of generalization.
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