The intersensory redundancy hypothesis: Extending the principle of unimodal facilitation to prenatal development

Abstract

Selective attention to different properties of stimulation provides the foundation for perception, learning, and memory. The Intersensory Redundancy Hypothesis (IRH) proposes that early in development information presented redundantly across two or more modalities (multimodal) selectively recruits attention to and enhances perceptual learning of amodal properties, whereas information presented to a single sense modality (unimodal) enhances perceptual learning of modality-specific properties. The present study is the first to assess this principle of unimodal facilitation in non-human animals in prenatal development. We assessed bobwhite quail embryos’ prenatal detection of pitch, a modality-specific property, under conditions of unimodal and bimodal (synchronous or asynchronous) exposure. Chicks exposed to prenatal unimodal auditory stimulation or asynchronous bimodal (audiovisual) stimulation preferred the familiarized maternal call over a novel pitch-modified maternal call following hatching, whereas chicks exposed to redundant (synchronous) audiovisual stimulation failed to prefer the familiar call over the pitch-modified call. These results provide further evidence that selective attention is recruited to specific stimulus properties of events in early development and that these biases are evident even during the prenatal period.

The role of task difficulty in directing selective attention in bobwhite quail (Colinus virginianus) neonates: A developmental test of the intersensory redundancy hypothesis

“…In contrast, chicks receiving redundant bimodal (audiovisual) exposure did not prefer that familiarized call over the same call with altered pitch. In other words, when the pitch range was narrowed and the detection of the pitch change became more difficult, unimodal facilitation was observed, as was the case in our original prenatal study (Lickliter et al, 2017) with younger, less experienced quail.…”

“…As was the case in our original prenatal study (Lickliter et al., 2017), the data of interest for analyses were measures of duration (in seconds) of proximity to the two auditory stimuli presented during testing. A proportion of total duration time (PTDT) was calculated from the time a chick spent in the approach area containing the familiar version of the maternal call relative to the total duration spent in both familiar and modified approach areas.…”

“…As was the case in our original prenatal study (Lickliter et al, 2017), the data of interest for analyses were measures of duration (in seconds) of proximity to the two auditory stimuli presented during testing.…”

“…In a prior study of bobwhite quail ( Colinus virginianus ) embryos, we showed that quail prenatally exposed to a maternal call were only able to detect a pitch change in that call in subsequent postnatal testing when they had been exposed to unimodal auditory or nonredundant (asynchronous) audiovisual presentations of the call prior to hatching. In contrast, embryos exposed to redundant audiovisual presentations (a light synchronized with the call) did not detect the pitch change in subsequent postnatal tests (Lickliter et al., 2017). Intersensory redundancy between the light and the call interfered with detection of pitch because it directed attention to salient redundantly specified amodal properties at the expense of modality‐specific pitch information.…”

The influence of prenatal experience on behavioral and social development: The benefits and limitations of an animal model

“…Quail embryos receiving exposure to a range of species-atypical auditory stimuli in the week prior to hatching showed reduced species-specific perceptual (auditory) narrowing when compared to control chicks in the week following hatching. In addition, we found that quail embryos exposed to acoustically modified maternal vocalizations prenatally could generalize this familiarization experience and show modified postnatal auditory preferences for maternal vocalizations (Lickliter, Bahrick, & Vaillant-Mekras, 2017). Taken together, these findings underscore the sensitivity of the bird embryo to variations in prenatal experience and point to the range of postnatal consequences of modified prenatal experience.…”