RESUMEN

Foraging confronts animals, including humans, with the need to balance exploration and exploitation: exploiting a resource until it depletes and then deciding when to move to a new location for more resources. Research across various species has identified rules for when to leave a depleting patch, influenced by environmental factors like patch quality. Here we compare human and gerbil patch-leaving behavior through two analogous tasks: a visual search for humans and a physical foraging task for gerbils, both involving patches with randomly varying initial rewards that decreased exponentially. Patch-leaving decisions of humans but not gerbils follow an incremental mechanism based on reward encounters that is considered optimal for maximizing reward yields in variable foraging environments. The two species also differ in their giving-up times, and some human subjects tend to overharvest. However, gerbils and individual humans who do not overharvest are equally sensitive to declining collection rates in accordance with the marginal value theorem. Altogether this study introduces a paradigm for a between-species comparison on how to resolve the exploitation-exploration dilemma.

Asunto(s)

Gerbillinae , Animales , Gerbillinae/fisiología , Humanos , Masculino , Conducta Alimentaria/fisiología , Femenino , Recompensa , Conducta Animal/fisiología

RESUMEN

Should we keep doing what we know works for us, or should we risk trying something new as it could work even better? The exploration-exploitation dilemma is ubiquitous in daily life decision-making, and balancing between the two is crucial for adaptive behavior. Yet, we only have started to unravel the neurocognitive mechanisms that help us to find this balance in practice. Analyzing BOLD signals of healthy young adults during virtual foraging, we could show that a behavioral tendency for prolonged exploitation was associated with weakened signaling during exploration in central node points of the frontoparietal attention network, plus the frontopolar cortex. These results provide an important link between behavioral heuristics that we use to balance between exploitation and exploration and the brain function that supports shifts from one tendency to the other. Importantly, they stress that interindividual differences in behavioral strategies are reflected in differences in brain activity during exploration and should thus be more in the focus of basic research that aims at delineating general laws governing visual attention.

Asunto(s)

Imagen por Resonancia Magnética , Humanos , Masculino , Femenino , Adulto Joven , Adulto , Atención/fisiología , Conducta Exploratoria/fisiología , Mapeo Encefálico , Lóbulo Frontal/fisiología , Oxígeno/sangre , Toma de Decisiones/fisiología

RESUMEN

Adapting to novelty is essential for an organism's survival in an uncertain world. Neuroimaging evidence consistently links the anterior prefrontal, specifically the frontopolar cortex (FPC; BA10), to exploratory reweighting of attentional weights thereby underscoring the role of the FPC in responding to environmental changes that are often complex and may occur very rapidly. Here we report new evidence showing that the FPC serves a role in attentional reallocation even in the absence of conscious awareness. Both mass-univariate and multivariate pattern analyses of fMRI data revealed that the right FPC and other attention-related areas not only are sensitive to unaware changes in the relevant stimulus dimension, but also that unconsciously processed information of the novel stimulus was globally represented across these regions. Our results indicate that unconsciously processed information can reach a global level of representation outside the occipitotemporal cortex, and that the FPC is crucial for the reweighting of selection biases in the absence of visual awareness.

Asunto(s)

Atención , Inconsciencia , Corteza Cerebral , Estado de Conciencia , Humanos , Imagen por Resonancia Magnética

RESUMEN

Visual attention evolved as an adaptive mechanism allowing us to cope with a rapidly changing environment. It enables the facilitated processing of relevant information, often automatically and governed by implicit motives. However, despite recent advances in understanding the relationship between consciousness and visual attention, the functional scope of unconscious attentional control is still under debate. Here, we present a novel masking paradigm in which volunteers were to distinguish between varying orientations of a briefly presented, masked grating stimulus. Combining signal detection theory and subjective measures of awareness, we show that performance on unaware trials was consistent with visual selection being weighted towards repeated orientations of Gabor patches and reallocated in response to a novel unconsciously processed orientation. This was particularly present in trials in which the prior feature was strongly weighted and only if the novel feature was invisible. Thus, our results provide evidence that invisible orientation stimuli can trigger the reallocation of history-guided visual selection weights.