Event-related potentials reveal limited readiness to access phonetic details during word processing in dogs.

L Magyari,A Andics,A Turzó,Zs Huszár

doi:10.1098/rsos.200851

Abstract

While dogs have remarkable abilities for social cognition and communication, the number of words they learn to recognize typically remains very low. The reason for this limited capacity is still unclear. We hypothesized that despite their human-like auditory abilities for analysing speech sounds, their word processing capacities might be less ready to access phonetic details. To test this, we developed procedures for non-invasive measurement of event-related potentials (ERPs) for language stimuli in awake dogs (n = 17). Dogs listened to familiar instruction words and phonetically similar and dissimilar nonsense words. We compared two different artefact cleaning procedures on the same data; they led to similar results. An early (200–300 ms; only after one of the cleaning procedures) and a late (650–800 ms; after both cleaning procedures) difference was present in the ERPs for known versus phonetically dissimilar nonsense words. There were no differences between the ERPs for known versus phonetically similar nonsense words. ERPs of dogs who heard the instructions more often also showed larger differences between instructions and dissimilar nonsense words. The study revealed not only dogs' sensitivity to known words, but also their limited capacity to access phonetic details. Future work should confirm the reported ERP correlates of word processing abilities in dogs.

Highlights

Certain capacities for auditory processing of language, such as analysing speech sounds and mapping signals into meaning, are royalsocietypublishing.org/journal/rsos R
Dogs were presented with three different word-types: (i) with familiar instruction words (WORDS condition), (ii) with phonetically similar nonsense words (SIMILAR), and (iii) with dissimilar nonsense words (NONSENSE)
There is no standard way of data cleaning of awake, non-invasive dog EEG; many movement artefacts are present in the raw signal

Summary

Introduction

Certain capacities for auditory processing of language, such as analysing speech sounds and mapping signals into meaning, are royalsocietypublishing.org/journal/rsos R. A behavioural study using a head-orientation paradigm has shown similar functional hemispheric asymmetries for dogs compared with humans in processing vocalizations [12]. A study from our laboratory has recently shown similarities in the neural correlates of human and dog word processing [13]. Differences in learning words and in vocabulary size between dogs and humans are apparent. While there are differences in lexical capacity between dogs and human adults, humans do not process words in the same way from birth, but word processing capacities go through on developmental changes. We hypothesized that dogs’ word processing abilities may be different from capacities of human adults and are more similar to that of young infants who are in an early stage of the development of word processing skills. We aim to investigate this by measuring electrophysiological brain activity in dogs

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Results