Oculomotor responses of stereo‐anomalous observers to pulse and ramp disparities

We examined oculomotor responses to binocular disparities of one stereo‐normal and three stereo‐anomalous observers, who were identified through a stereoscopic depth‐discrimination task, in two experimental conditions. In the pulse disparity condition, crossed and uncrossed disparities (1–6°) were briefly presented (for .25–2.0 s). In the ramp disparity condition, disparities were varied continuously with constant velocities (.7–2.0°/s) and with an amplitude of 10°. The stereo‐normal observer showed vergence responses to both pulse and ramp disparities. The three stereo‐anomalous observers showed a marked reduction or absence of vergence responses to pulse disparities but showed vergence responses to ramp disparities. The results suggest the existence of separate sub‐systems mediating disparity vergence eye movements.     

汉语成语谜语问题解决中思路竞争的眼动研究

在谜语问题解决过程中, 可能存在着通过简单联想和新异联想寻找答案这两种思路。两个实验中设置了包括寻常答案与新颖答案在内的若干备择答案(实验1为4个, 实验2为6个)供被试选择, 利用眼动技术记录被试在解题过程中的不同时间段内对新颖答案与寻常答案的平均注视时间, 考察汉语成语谜语问题解决中两种思路之间冲突的过程。实验1操纵了任务要求, 实验2操纵了规则线索的有效性。实验结果表明：(1)在成语谜语问题解决中的一段时间内新异联想和简单联想能够同时发生且形成竞争; (2)选择“新颖且合适答案”的任务要求, 提高了成功形成新颖语义联结的概率, 但是并没有加快新异联想发生、发展的进程, 也没有改变两种思路相互竞争的局面; (3)有效的规则线索可以抑制简单联想, 阻止其发生, 同时可以加快新异联想发生、发展的进程。     

男性化与女性化对面孔偏好的影响—— 基于图像处理技术和眼动的检验

采用图像处理技术和眼动探讨了性别二态线索对面孔偏好的影响。实验1发现非面孔线索未掩蔽和掩蔽时, 感知男性化技术与原始照片条件下女性化的男性面孔更有吸引力和信任度; 性别二态技术条件下, 非面孔线索未掩蔽时男性化的男性面孔更有吸引力和信任度。实验2表明被试对男性面孔的平均瞳孔大小和注视次数均大于和多于女性面孔, 首次注视时间短于女性面孔; 被试对男性化面孔的首次注视时间和首次注视持续时间均长于女性化面孔。     

合理性对汉语阅读中双字词语义预视效益的优势作用：眼动研究

语义预视效益(SPB)对于揭示阅读中读者能否从副中央凹提取高水平信息具有重要意义。关于SPB的产生机制仍然存在争议。本研究通过同时操控预视词的合理性和语义相关性考察了二者对汉语阅读中双字词SPB的影响。结果发现,合理性主效应显著,合理预视下目标词的注视时间显著短于不合理预视;语义相关性主效应不显著,未发现二者的交互作用。研究结果支持了语境匹配假说,进一步说明了汉语阅读中预视词的合理性对SPB的优势作用。     

Investigating how children produce rotation and pointing movements when they learn to write letters

How do children learn to write letters? During writing acquisition, some letters may be more difficult to produce than others because certain movement sequences require more precise motor control (e.g., the rotation that produces curved lines like in letter O or the pointing movement to trace the horizontal bar of a T). Children of ages 6–10 (N = 108) wrote sequences of upper-case letters on a digitizer. They varied in the number of pointing and rotation movements. The data revealed that these movements required compensatory strategies in specific kinematic variables. For pointing movements there was a duration decrease that was compensated by an increase in in-air movement time. Rotation movements were produced with low maximal velocity but high minimal velocity. At all ages there was a global tendency to keep stability in the tempo of writing: pointing movements exhibited a duration trade-off whereas rotation movements required a trade-off on maximal and minimal velocity. The acquisition of letter writing took place between ages 6 and 7. At age 8 the children shifted focus to improving movement control. Writing automation was achieved around age 10 when the children controlled movement duration and fluency. This led to a significant increase in writing speed.     

A novel two-body sensor system to study spontaneous movements in infants during caregiver physical contact

Spontaneous movements, which refer to repetitive limb movements in the absence of any external stimulus, have been found to be reflective of neurodevelopmental status during infancy. These movements are modulated by both individual and environmental factors, including physical contact (holding) with the caregiver. However, it is a challenge to measure spontaneous movements during physical contact because infant-generated movements become coupled with caregiver-generated movements in such contexts. Here, we propose the use of a novel two-body sensor system to distinguish infant-generated movements in the presence of physical contact with the caregiver. Data from seven typically developing infants and their caregivers were recorded during different simulated home activities, which involved different combinations of physical interaction, caregiver’s movement and infant positions. The two-body sensor system consisted of two wearable accelerometers – one placed on the infant’s arm and one on the caregiver’s arm, and we developed a Kalman-filter based algorithm to isolate the infant-generated movements. In addition, video was recorded for qualitative analysis. Results indicated that spontaneous movement activity was higher when there was no physical contact with caregiver. When there was physical contact, spontaneous movements were increased when the caregiver was still and when the infant was held horizontally. These results show that the novel two-body sensor system and the associated algorithms were able to isolate infant-generated movements during physical contact with the caregiver. This approach holds promise for the automated long-term tracking of spontaneous movements in infants, which may provide critical insight into developmental disorders.     

Forward inference in risky choice: Mapping gaze and decision processes

The study of cognitive processes is built on a close mapping between three components: overt gaze behavior, overt choice, and covert processes. To validate this overt–covert mapping in the domain of decision‐making, we collected eye‐movement data during decisions between risky gamble problems. Applying a forward inference paradigm, participants were instructed to use specific decision strategies to solve those gamble problems (maximizing expected values or applying different choice heuristics) during which gaze behavior was recorded. We revealed differences between overt behavior, as indicated by eye movements, and covert decision processes, instructed by the experimenter. However, our results show that the overt–covert mapping is for some eye‐movement measures not as close as expected by current decision theory, and hence question reverse inference as being prone to fallacies due to a violation of its prerequisite, that is, a close overt–covert mapping. We propose a framework to rehabilitate reverse inference.     

Eyewitness testimony

The study of eyewitness testimony is thriving. Over the last three decades, psychologists have made important discoveries, and applied those discoveries to the legal system in myriad ways. Along the way, there were disagreements, which were typically healthy in nature. I discuss a few, for example, centering around the impact of misinformation on witnesses, the role of witness confidence and lineup procedures, and expert testimony. The “Memory Wars” were not so friendly, but hopefully the collective effort has helped to make the world a fairer place.     

Infant gaze following depends on communicative signals: An eye‐tracking study of 5‐ to 7‐month‐olds in Vanuatu

Gaze is considered a crucial component of early communication between an infant and her caregiver. When communicatively addressed, infants respond aptly to others’ gaze by following its direction. However, experience with face‐to‐face contact varies across cultures, begging the question whether infants’ competencies in receiving others’ communicative gaze signals are universal or culturally specific . We used eye‐tracking to assess gaze‐following responses of 5‐ to 7‐month olds in Vanuatu, where face‐to‐face parent–infant interactions are less prevalent than in Western populations. We found that—just like Western 6‐month‐olds studied previously—5‐ to ‐7‐month‐olds living in Vanuatu followed gaze only, when communicatively addressed. That is, if presented gaze shifts were preceded by infant‐directed speech, but not if they were preceded by adult‐directed speech. These results are consistent with the notion that early infant gaze following is tied to infants’ early emerging communicative competencies and rooted in universal mechanisms rather than being dependent on cultural specificities of early socialization.     

Demystifying infant vocal imitation: The roles of mouth looking and speaker’s gaze

Vocal imitation plays a fundamental role in human language acquisition from infancy. Little is known, however, about how infants imitate other's sounds. We focused on three factors: (a) whether infants receive information from upright faces, (b) the infant's observation of the speaker's mouth and (c) the speaker directing their gaze towards the infant. We recorded the eye movements of 6‐month‐olds who participated in experiments watching videos of a speaker producing vowel sounds. We found that an infants’ tendency to vocally imitate such videos increased as a function of (a) seeing upright rather than inverted faces, (b) their increased looking towards the speaker's mouth and (c) whether the speaker directed their gaze towards, rather than away from infants. These latter findings are consistent with theories of motor resonance and natural pedagogy respectively. New light has been shed on the cues and underlying mechanisms linking infant speech perception and production.