title: Typical visual search performance and atypical gaze behaviors in response to faces in Williams syndrome.
abstract: BACKGROUND
  Evidence indicates that individuals with Williams syndrome (WS) exhibit atypical attentional characteristics when viewing faces. However, the dynamics of visual attention captured by faces remain unclear, especially when explicit attentional forces are present. To clarify this, we introduced a visual search paradigm and assessed how the relative strength of visual attention captured by a face and explicit attentional control changes as search progresses.
  
  
  METHODS
  Participants (WS and controls) searched for a target (butterfly) within an array of distractors, which sometimes contained an upright face. We analyzed reaction time and location of the first fixation-which reflect the attentional profile at the initial stage-and fixation durations. These features represent aspects of attention at later stages of visual search. The strength of visual attention captured by faces and explicit attentional control (toward the butterfly) was characterized by the frequency of first fixations on a face or butterfly and on the duration of face or butterfly fixations.
  
  
  RESULTS
  Although reaction time was longer in all groups when faces were present, and visual attention was not dominated by faces in any group during the initial stages of the search, when faces were present, attention to faces dominated in the WS group during the later search stages. Furthermore, for the WS group, reaction time correlated with eye-movement measures at different stages of searching such that longer reaction times were associated with longer face-fixations, specifically at the initial stage of searching. Moreover, longer reaction times were associated with longer face-fixations at the later stages of searching, while shorter reaction times were associated with longer butterfly fixations.
  
  
  CONCLUSIONS
  The relative strength of attention captured by faces in people with WS is not observed at the initial stage of searching but becomes dominant as the search progresses. Furthermore, although behavioral responses are associated with some aspects of eye movements, they are not as sensitive as eye-movement measurements themselves at detecting atypical attentional characteristics in people with WS.
authors: Institute for Developmental Research, Aichi Human Service Center, 713-8 Kagiya-cho, Kasugai, Aichi 480-0392 Japan ; Present address: Center for Development of Advanced Medical Technology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 392-0498 Japan.
authors: Masahiro
authors: M
authors: Hirai
authors: Institute for Developmental Research, Aichi Human Service Center, 713-8 Kagiya-cho, Kasugai, Aichi 480-0392 Japan.
authors: Yukako
authors: Y
authors: Muramatsu
authors: Department of Pediatrics, Central Hospital, Aichi Human Service Center, 713-8 Kagiya-cho, Kasugai, Aichi 480-0392 Japan.
authors: Seiji
authors: S
authors: Mizuno
authors: Department of Pediatrics, Central Hospital, Aichi Human Service Center, 713-8 Kagiya-cho, Kasugai, Aichi 480-0392 Japan.
authors: Naoko
authors: N
authors: Kurahashi
authors: Department of Pediatrics, Central Hospital, Aichi Human Service Center, 713-8 Kagiya-cho, Kasugai, Aichi 480-0392 Japan.
authors: Hirokazu
authors: H
authors: Kurahashi
authors: Institute for Developmental Research, Aichi Human Service Center, 713-8 Kagiya-cho, Kasugai, Aichi 480-0392 Japan.
authors: Miho
authors: M
authors: Nakamura
keywords: Attention; Eye tracking; Face perception; Williams syndrome