Target distinctiveness modulates resource allocation in visual working memory for faces: implications for eyewitness face identification

Visual working memory (VWM) is a limited-capacity resource for the temporary storage of visual information (Cowan, 2001). Selective visual attention can protect VWM capacity by filtering relevant from irrelevant information during encoding or maintenance (Griffin & Nobre, 2003).The aim of the current study was to investigate whether target distinctiveness bias the allocation of visual working memory (VWM) resources during the encoding of unfamiliar faces. The results indicate that VWM capacity for unfamiliar faces is poor and declines as a function of the number of faces in the display (load). When one of the faces in the display was made distinct (i.e. by adding a tattoo to it), recall accuracy was independent of load, suggesting bottom-up attentional mechanisms protect against competition for limited VWM resources. These findings have a number of implications in real-world eyewitness scenarios. For example, the accuracy of eyewitness identification is likely to depend upon the number of individuals at the crime scene and differences in their salient visual characteristics.</p

Independent effects of resolution and set size on recognition memory for unfamiliar faces

Visual working memory (VWM) is a limited-capacity resource for the temporary storage of visual information (Cowan, 2001). Selective visual attention can protect VWM capacity by filtering relevant from irrelevant information during encoding or maintenance (Griffin & Nobre, 2003). The current study was designed to investigate the consequences of attentional selection on the accuracy of recognition for unfamiliar faces. We used a Change Detection task to measure d’ for cued and uncued faces in displays of 1, 2 and 4 faces, in a free-view (Experiment 1) and single-fixation Experiment 2) displays. In both experiments, recall accuracy was greater for cued than uncued faces. Recognition accuracy was also higher in free-view compared to single fixation displays and declined as a function of set size.This suggests the acquisition of high spatial frequency information during saccadic sampling improves recognition memory. Importantly, this advantage appears to be independent of the decrease in accuracy associated with set size, indicating that increasing the resolution of memoranda in VWM does not dilute resources in the same way as increasing the number of objects to remember.</p

Spatial attention can bias the accuracy of eyewitness identification

Visual working memory (VWM) is a limited-capacity resource for the temporary storage of visual information (Cowan, 2001). Selective visual attention can protect VWM capacity by filtering relevant from irrelevant information during encoding or maintenance (Griffin & Nobre, 2003).The aim of the current study was to investigate changes in the accuracy of face recognition memory when attention was reflexively oriented to the location of a face before (pre-cue) or after (retro-cue) it was disappeared. The results indicate that VWM capacity for unfamiliar faces is poor and declines as a function of the number of faces in the display (load). When attention was oriented by a pre-cue, recall accuracy was independent of load, suggesting attention captures VWM resource in a reflexive manner. This advantage was not observed for retro-cued faces, suggesting reflexive attention operates by biasing VWM resources during encoding rather than the maintenance of remembered faces. These findings have a number of implications in real-world eyewitness scenarios. For example, the accuracy of eyewitness identification is likely to depend upon the number of individuals at the crime scene and differences in their salient visual characteristics.</p

How the characteristics of words in child-directed speech differ from adult-directed speech to influence children’s productive vocabularies

Child-directed speech has long been known to influence children’s vocabulary learning. However, while we know that caregiver utterances differ from those directed at adults in various ways, little is known about any differences in the lexical properties of child-directed and adult-directed utterances. We compare over half a million word tokens from adult speech directed at children (from caregiver–child transcriptions) to the same quantity directed at adults. We show that child-directed speech contains greater numbers of words that are lower in phonemic length, higher in frequency, lower in phonotactic probability, and higher in neighborhood density than adult-directed speech; furthermore, child-directed speech explains over twice the variability of children’s productive noun vocabularies than adult-directed speech. These findings indicate that children’s word production is clearly influenced by the characteristics of the words spoken directly to them and that researchers need to be wary of using adult-directed language corpora when calculating lexical measures.</p

How the characteristics of words in child-directed speech differ from adult-directed speech to influence children’s productive vocabularies

Child-directed speech has long been known to influence children’s vocabulary learning. However, while we know that caregiver utterances differ from those directed at adults in various ways, little is known about any differences in the lexical properties of child-directed and adult-directed utterances. We compare over half a million word tokens from adult speech directed at children (from caregiver–child transcriptions) to the same quantity directed at adults. We show that child-directed speech contains greater numbers of words that are lower in phonemic length, higher in frequency, lower in phonotactic probability, and higher in neighborhood density than adult-directed speech; furthermore, child-directed speech explains over twice the variability of children’s productive noun vocabularies than adult-directed speech. These findings indicate that children’s word production is clearly influenced by the characteristics of the words spoken directly to them and that researchers need to be wary of using adult-directed language corpora when calculating lexical measures.</p