Evidence from an emerging sign language reveals that language supports spatial cognition

Abstract

Although spatial language and spatial cognition covary over development and across languages, determining the causal direction of this relationship presents a challenge. Here we show that mature human spatial cognition depends on the acquisition of specific aspects of spatial language. We tested two cohorts of deaf signers who acquired an emerging sign language in Nicaragua at the same age but during different time periods: the first cohort of signers acquired the language in its infancy, and 10 y later the second cohort of signers acquired the language in a more complex form. We found that the second-cohort signers, now in their 20s, used more consistent spatial language than the first-cohort signers, now in their 30s. Correspondingly, they outperformed the first cohort in spatially guided searches, both when they were disoriented and when an array was rotated. Consistent linguistic marking of left-right relations correlated with search performance under disorientation, whereas consistent marking of ground information correlated with search in rotated arrays. Human spatial cognition therefore is modulated by the acquisition of a rich language.

Fig. 1.

Diagram of the apparatus for (A) the disoriented search condition (small gray rectangles indicate the locations of the lights) and (B) the rotated box condition. Both apparatuses had one red wall, shaded gray in the diagram. The first and second cohort's search patterns in (C) the disoriented search condition and (D) the rotated box condition. Mean search responses (out of 8) are in bold, and SDs are in italics (C= correct search, N = near corner error, R = rotational corner error, F = far corner error). The first and second cohort scores overlapped in only one case in the disorientation condition (first cohort: range = 4–6, second cohort: range = 5–8), and in four cases in the rotated box condition (first cohort: range = 3–7, second cohort: range = 5–8). Second-cohort signers significantly outperformed first-cohort signers on both tasks.

Fig. 2.

A second-cohort signer describing the gaming token located (A) to the left of the red wall and (B) to the right of the red wall. In both descriptions, he provides ground information by drawing a rectangle representing the box. Importantly, he linguistically distinguishes left from right, locating the token on the left to his left, and the token on the right to his right.