The effect of color priming on infant brain and behavior

Abstract

Behavioral studies have identified select experiences that can prime infants to attend to color information as the basis for individuating objects prior to the time they do so spontaneously. For example, viewing pretest events in which the color of an object predicts the function in which it will engage leads 9-month-olds (who typically do not attend to color differences) to demonstrate increased sensitivity to color information in a subsequent individuation task (Wilcox & Chapa, 2004). In contrast, viewing pretest events in which the color of an object predicts distinct object motions, but the motions are not functionally relevant, does not produce color priming. The purpose of the present research was to identify the cortical underpinnings of these behavioral effects. Infants aged 8 and 9 months viewed function or motion pretest events and then their capacity to individuate-by-color was assessed in an object individuation task. Behavioral and neuroimaging data were collected. Two main findings emerged. First, as predicted, the infants who viewed the function but not the motion pretest events showed prolonged looking to the test event, a behavioral indicator of object individuation. In addition, they evidenced increased activation in anterior temporal cortex, thought to be a cortical signature of object individuation. A second and unexpected finding was that viewing either type of pretest events led to increased activation in posterior temporal cortex, as compared to infants who did not see pretest events, revealing that prior exposure to the motion pretest events does influence infants’ processing of the test event, even though it is not evident in the behavioral results. The cognitive processes involved, and the cortical structures that mediate these processes, are discussed.

The Lateral Occipital Cortex Is Selective for Object Shape, Not Texture/Color, at Six Months

“…Whereas there have been previous investigations of object processing using fNIRS, these studies have not focused on uncovering shape-selective regions per se and have instead focused on how object identity modulates activity in the inferior temporal cortex (Wilcox et al, 2008(Wilcox et al, , 2014Wilcox and Biondi, 2015) or responds to faces, as a visual category, compared with baseline nonface stimuli (Otsuka et al, 2007;Honda et al, 2010). However, although the current study augments our stimuli with faces to maintain infant attention, facial information is identical across conditions (the eyes and mouth are identical for all stimuli), and whereas we did vary eye gaze across shapes (and thus this varies between variable and repeated blocks), this does not change across conditions.…”

“…Thus, although current findings do not provide evidence about face perception, they do bear on the question of how object perception develops early in life and build from the work of Wilcox and colleagues. Broadly, Wilcox and colleagues have found that the infant inferior temporal cortex selectively tracks object-individuation events (i.e., a greater response when a new object is introduced through a change in shape compared with trials where the types of visual movements where shape and other individuation cues are held constant; Wilcox et al, 2008Wilcox et al, , 2014. In addition to temporal lobe recordings, Wilcox et al (2008) included fNIRS recordings from low-level visual areas and did not target the LOC specifically.…”

“…Broadly, Wilcox and colleagues have found that the infant inferior temporal cortex selectively tracks object-individuation events (i.e., a greater response when a new object is introduced through a change in shape compared with trials where the types of visual movements where shape and other individuation cues are held constant; Wilcox et al, 2008Wilcox et al, , 2014. In addition to temporal lobe recordings, Wilcox et al (2008) included fNIRS recordings from low-level visual areas and did not target the LOC specifically. Correspondingly, they found that, in contrast to the profile of activation in the inferior temporal cortex, these low-level visual cortex areas are activated during visual events regardless of whether there are changes in object identity (e.g., as cued through shape or other cues).…”

“…In the last 15 years, fMRI has been used to reveal the incredible complexity and specialization in the adult human visual system with regions exhibiting preferential activation for low-level, (e.g., color, motion), mid-level (e.g., shape, objects), and high-level (e.g., letters, faces, places) visual features (Grill-Spector and Malach, 2004;Wandell et al, 2005). However, the meaning of these differential patterns of activation is widely debated (e.g., what does the fusiform face area represent?…”

Methodology for high-yield acquisition of functional near-infrared spectroscopy data from alert, upright infants

“…17 Despite the rapid growth in the number of infant fNIRS publications in recent years, this number is relatively low when compared to that of adult studies. 18 Infants are certainly more difficult to study, as they cannot be instructed to remain still, unlike an adult subject.…”