Reports

HOPE Report No.41, 18th, May 2005.

Program No.41 (Joint research)

Patrizia Poti Invited talk at the HOPE workshop
 in the 16th annual meeting of 
Japan Society for Developmental Psychology at Kobe

Date: 2005/03/24-2005/04/25

Place: Kobe

Patrizia Poti

SPATIAL CONSTRUCTION BY CHIMPANZEES

Combining objects with each other is a basic way by which human and nonhuman primates acquire and express knowledge about spatial relations. In their spontaneous play with blocks young children, from the age of 2 to 3 years of age, construct miniature architectural forms such as bridges, towers, enclosures, and so on. One particular aspect of children's constructions is repetition, a key feature of any constructional activity and of design. Repeating a spatial relation is a fundamental way to understanding that relation at a higher level than perception or recognition.

However, different types of spatial relations and of constructive procedures imply different levels in understanding inter-object relations and coordinating positions in space. In particular, repeating containment/insertion (I) relations may involve replicating a specific effect and repeating support (V) relations may imply comparing single objects, whatever the procedure used. Repeating next-to (H) relations implies coordinating multiple independent positions in space, if H relations between pairs of objects are replicated in sequence. In fact, H relations are a by-product of the coordination of actions still attached to the body reference if they are repeated with an overlapping procedure such as moving an object against another with each hand.

Six human-enculturated and language-reared chimpanzees, including two bonobos, age 6 and 11 years, and four chimpanzees, ages 6 to 21 years, were presented with sets of 12 objects, that comprised one or two or three different forms. All chimpanzees' spontaneous interactions with objects were recorded, noting which objects were grouped together in what spatial relations to one another through what manipulative actions. Then, the chimpanzees' ability to repeat inter-object relations was examined. Results showed that chimpanzees constructed and repeated different types of inter-object relations, such as containment/insertion (I), support (V) and next-to (H) relations, but they repeated next-to H relations with more primitive procedures than the other relations. In fact, chimpanzees reproduced containment/insertion or support relations between pairs of objects in sequence, whereas they repeated next-to H relations mainly by symmetrical causal actions of the hands. Therefore, during their spontaneous spatial construction with objects chimpanzees seemed to repeat specific effects or compared single objects rather than comparing spatial
relations. Chimpanzees mastered simultaneous spatial relations between separate elements and coordinated independent positions in space only to a very limited extent.

Patrizia Poti
Institute for Cognitive Sciences and Technologies - CNR
p.poti@istc.cnr.it