Development of context dependency in human space perception

Abstract

Perception is a complex process, where prior knowledge exerts a fundamental influence over what we see. The use of priors is at the basis of the well-known phenomenon of central tendency: Judgments of almost all quantities (such as length, duration, and number) tend to gravitate toward their mean magnitude. Although such context dependency is universal in adult perceptual judgments, how it develops with age remains unknown. We asked children from 7 to 14 years of age and adults to reproduce lengths of stimuli drawn from different distributions and evaluated whether judgments were influenced by stimulus context. All participants reproduced the presented length differently depending on the context: The same stimulus was reproduced as shorter, when on average stimuli were short, and as longer, when on average stimuli were long. Interestingly, the relative importance given to the current sensory signal and to priors was almost constant during childhood. This strategy, which in adults is optimal in Bayesian terms, is apparently successful in holding the sensory noise at bay even during development. Hence, the influence of previous knowledge on perception is present already in young children, suggesting that context dependency is established early in the developing brain.

Central tendency effects in time interval reproduction in autism

“…The difference between estimates for the common stimuli in the long and the short interval condition was significantly greater than zero only for the younger groups of typical children [6–7 year-olds: t (11) = 2.16, p  = 0.05, d  = 0.63; 8–9 year olds: t (18) = 4.00, p  = 0.001, d  = 0.92] and autistic children [ t (22) = 2.52, p  = 0.02, d  = 0.53], but not for the older groups of typical children [10–11 year-olds: t (17) = −0.19, p  = 0.85, d  = −0.04; 12–14 year olds: t (14) = −0.51, p  = 0.63, d  = −0.13], adults [ t (13) = 2.00, p  = 0.07, d  = 0.53] and the typical comparison children [ t (22) = 0.92, t  = 0.37, d  = 0.19]. Context dependency effects in our data were therefore not as strong as in the developmental study of Sciutti et al 7. in spatial interval reproduction.…”

“…A recent study by Sciutti et al 7. focused on central tendency and context dependency effects in typical development in the spatial domain.…”

“…Computational modelling of the cross-sectional data suggested that children weighted prior knowledge about the mean with sensory signals in a constant manner across development and similarly to adults. Given that children presented marked developmental improvements in their spatial resolution (spatial interval discrimination task), Sciutti et al 7. argued that the Bayesian “use of prior knowledge” strategy is useful for restraining sensory noise across development.…”

“…1). We first established the typical developmental trajectory for central tendency effects in time interval reproduction by administering our paradigm to typically developing children in the age range 6 to 14 years old and adults (similar to the study of Sciutti et al 7. on spatial interval reproduction).…”

“…Next, we examined central tendency effects in a group of autistic children between 6 to 14 years old and compared their performance to a subset of the typically developing children who took part in the study, of similar age and language and reasoning abilities. Finally, we employed computational modelling techniques used in the previous studies78 to assess the relative weighting of prior knowledge and sensory input in developmental groups and children with and without autism and the extent to which the integration of the two sources of information in different groups served optimal computations.…”