Labelling and Family Resemblance in the discrimination of polymorphous categories by pigeons

publication-status: Acceptedtypes: Article© 2011 Springer Verlag. This is a post print version of the article published in Animal Cognition, 2011, 14 (1), pp 21-34. The final publication is available at link.springer.comTwo experiments examined whether pigeons discriminate polymorphous categories on the basis of a single highly predictive feature or overall similarity. In the first experiment, pigeons were trained to discriminate between categories of photographs of complex real objects. Within these pictures, single features had been manipulated to produce a highly salient texture cue. Either the picture or the texture provided a reliable cue for discrimination during training, but in probe tests, the picture and texture cues were put into conflict. Some pigeons showed a significant tendency to discriminate on the basis of the picture cue (overall similarity or family resemblance), whereas others appeared to rely on the manipulated texture cue. The second experiment used artificial polymorphous categories in which one dimension of the stimulus provided a completely reliable cue to category membership, whereas three other dimensions provided cues that were individually unreliable but collectively provided a completely reliable basis for discrimination. Most pigeons came under the control of the reliable cue rather than the unreliable cues. A minority, however, came under the control of single dimensions from the unreliable set. We conclude that cue salience can be more important than cue reliability in determining what features will control behavior when multiple cues are available

Are Children with Autism Spectrum Disorder Initially Attuned to Object Function Rather Than Shape for Word Learning?

We investigate the function bias-generalising words to objects with the same function-in typically developing (TD) children, children with autism spectrum disorder (ASD) and children with other developmental disorders. Across four trials, a novel object was named and its function was described and demonstrated. Children then selected the other referent from a shape match (same shape, different function) and function match (same function, different shape) object. TD children and children with ASD were 'function biased', although further investigation established that having a higher VMA facilitated function bias understanding in TD children, but having a lower VMA facilitated function bias understanding in children with ASD. This suggests that children with ASD are initially attuned to object function, not shape

Can We Dissociate Contingency Learning from Social Learning in Word Acquisition by 24-Month-Olds?

Colin Bannard is with UT Austin; Michael Tomasello is with Max Planck Institute for Evolutionary Anthropology.We compared 24-month-old children’s learning when their exposure to words came either in an interactive (coupled) context or in a nonsocial (decoupled) context. We measured the children’s learning with two different methods: one in which they were asked to point to the referent for the experimenter, and the other a preferential looking task in which they were encouraged to look to the referent. In the pointing test, children chose the correct referents for words encountered in the coupled condition but not in the decoupled condition. In the looking time test, however, they looked to the targets regardless of condition. We explore the explanations for this and propose that the different response measures are reflecting two different kinds of learning.Linguistic