The neural mechanisms of word order processing revisited: electrophysiological evidence from Japanese

We present two ERP studies on the processing of word order variations in Japanese, a language that is suited to shedding further light on the implications of word order freedom for neurocognitive approaches to sentence comprehension. Experiment 1 used auditory presentation and revealed that initial accusative objects elicit increased processing costs in comparison to initial subjects (in the form of a transient negativity) only when followed by a prosodic boundary. A similar effect was observed using visual presentation in Experiment 2, however only for accusative but not for dative objects. These results support a relational account of word order processing, in which the costs of comprehending an object-initial word order are determined by the linearization properties of the initial object in relation to the linearization properties of possible upcoming arguments. In the absence of a prosodic boundary, the possibility for subject omission in Japanese renders it likely that the initial accusative is the only argument in the clause. Hence, no upcoming arguments are expected and no linearization problem can arise. A prosodic boundary or visual segmentation, by contrast, indicate an object-before-subject word order, thereby leading to a mismatch between argument "prominence" (e.g. in terms of thematic roles) and linear order. This mismatch is alleviated when the initial object is highly prominent itself (e.g. in the case of a dative, which can bear the higher-ranking thematic role in a two argument relation). We argue that the processing mechanism at work here can be distinguished from more general aspects of "dependency processing" in object-initial sentences.     

Functional visual field in a rapid serial visual presentation task

Dynamic temporal change in the size of functional visual field was measured using a dual task: a peripheral task in which one square in a background pattern of squares was changed in shape to a dot; and a central task involving the rapid serial visual presentation of a sequence of letters (RSVP task). The temporal lag between the occurrences of the dot and the RSVP target was manipulated. University students were asked to detect the dot and to depress a mouse button as quickly as possible while searching for the RSVP target among a sequence of distracter letters. The abrupt change in the shape of a background square in the peripheral task caused a processing deficit in the RSVP task at relative lags from –3 to –1 (255 ms to 85 ms before presentation of the RSVP target), but the encoding and retaining processes involved in identifying the RSVP target did not impair the detection of the peripheral dot. The functional visual field was found to expand while participants were performing the dual task, suggesting that preattentive detection is affected by general attentional activity.     

Infant's action skill dynamically modulates parental action demonstration in the dyadic interaction

When interacting with infants, human adults modify their behaviours in an exaggerated manner. Previous studies have demonstrated that infant‐directed modification affects the infant's behaviour. However, little is known about how infant‐directed modification is elicited during infant–parent interaction. We investigated whether and how the infant's behaviour affects the mother's action during an interaction. We recorded three‐dimensional information of cup movements while mothers demonstrated a cup‐nesting task during interaction with their infants aged 11 to 13 months. Analyses revealed that spatial characteristics of the mother's task demonstration clearly changed depending on the infant's object manipulation. In particular, the variance in the distance that the cup was moved decreased after the infant's cup nesting and increased after the infant's task‐irrelevant manipulation (e.g. cup banging). This pattern was not observed for mothers with 6‐ to 8‐month‐olds, who do not have the fine motor skill to perform the action. These results indicate that the infant's action skill dynamically affects the infant‐directed action and suggest that the mother is sensitive to the infant's potential to learn a novel action. A video abstract of this article can be viewed at: https://www.youtube.com/watch?v=VNS2IHwLIhg&feature=youtu.be     

Categorical Discrimination of Human Facial Expressions by Pigeons: A Test of the Linear Feature Model

Pigeons were trained to discriminate human facial expressions, happiness and anger, in a go/ no-go discrimination procedure. Five pigeons learned to discriminate photographs of the happy and angry faces of 25 different people and showed high levels of transfer to novel faces expressing the training emotions. The pigeons directed their pecks predominantly to the mouth, eyes, or the area between these features. The pigeons were then tested with familiar stimuli in which the upper and lower parts of the face were manipulated separately by substitution or removal of facial features ('eyes-and-eyebrows' and 'mouth'). It was shown that the salience of particular features differed considerably among the birds, but that a linear feature model adequately accounted for discriminative performance of the birds with these stimuli. Furthermore, the discrimination was maintained when these features were inverted. Thus, the so-called Thatcher illusion did not occur. It is suggested that the discrimination is based not on a feature configuration or perceptual gestalt but on an additive integration of individual features.