Why do people use multiple maps when one would do? And why do people use one combination much more than the opposite combination? Tantalizing answers to these and other questions await in the open-access paper! @psychscience.bsky.social doi.org/10.1177/0956...

This shows people are not limited to using one reference frame at a time, even in the very same action. Instead, people across cultures may habitually use compound cognitive maps composed of multiple reference frames to represent the multidimensional spatial relations of their environment.

A group of US undergrads were more egocentric overall (more blue), but often made the same kind of hybrid responses: Egocentric on the front-back axis and allocentric on the left-right axis at the same time. One action, two reference frames.

Here’s a canoncal response. She finds an object in her far right cup, turns around, and places it in her far LEFT cup. This preserves the object’s EGOcentric position in front-back space (i.e. far, far) but preserves its ALLOcentric position in left-right space (e.g. window-side, window-side).

Here’s what they did. Some of their responses were fully egocentric (blue), and some were fully allocentric (pink), but most were mixed (purple), corresponding to an egocentric frame on one axis and an allocentric frame on the other axis in the very same action (i.e. placing an object in a cup).

The trick is that the cup you choose reveals which reference frame you were using to remember the object’s position. And because of the layout of the cups, choosing a cup actually means choosing a position on both the left-right axis and the front-back axis.

In each trial, participants picked up an object from one of 16 cups laid out on the "study" table (in four groups of four), turned around 180 degrees to face an identical "test" table, and were asked to put the object in the corresponding cup.

The question here is whether they would not only switch quickly between reference frames, but actually mix them together, using one frame on one axis and a different frame on the other axis *at the same time*. To find out, we designed a new, 2-dimensional test of spatial memory, the 4Quads task.

We know from a past study that Tsimane’ switch reference frames depending on which spatial axis is relevant, lateral (left-right) or sagittal (front-back):
tinyurl.com/347h9b2y.

We addressed this question with the Tsimane’, an indigenous group of farmer-foragers living in the Bolivian Amazon.

But neuroscience says otherwise. All sorts of animals – including humans – integrate egocentric and allocentric spatial information all the time, to be able to navigate a complex 3D spatial world. So which is it? One-at-a-time or habitually integrated?

We know people can flexibly switch between egocentric and allocentric reference frames. But on some psycholinguistic accounts, they are limited to using one at a time like in language – you can say “The spoon is on the right” or “The spoon is North” but not both at once.

*Egocentric* coordinates are centered on the body (e.g. my left) and so turn with the observer. *Allocentric* coordinates are based on the environment (e.g. East-West, uphill-downhill), and so stay put even if you don’t.

Like other animals, humans depend on spatial memory to navigate, coordinate the movement of our bodies, and keep track of the hundreds of objects that compose our environment. But there are two fundamentally different ways to remember where things are: body-centered and environment-centered

Another great PhD opportunity: An ERC-funded project on “Children as agents of cultural evolution,” lead by @sheinalew.bsky.social at Durham University. Come do fieldwork with Mayan groups in Belize with her, @dorsaamir.bsky.social, and I! One of three, 3-year PhD positions starting Fall 2026.

I’ll be considering graduate school applications for Fall 2026 – positions are fully funded, typically for 5 years. Deadline to apply to the Cognition program is December 1. Come do science with me in beautiful Amherst, Massachusetts! www.umass.edu/natural-scie...

The Cognitive Construction Lab will study children and adults across cultures to understand how the diversity of human experience produces a diversity of human minds. Check out the brand new lab website! cognitiveconstructionlab.com