The Thatcher illusion and face processing in infancy

Adults readily detect changes in face patterns brought about by the inversion of eyes and mouth when the faces are viewed upright but not when they are viewed upside down. Research suggests that this illusion (the Thatcher illusion) is caused by the interfering effects of face inversion on the processing of second-order relational information (fine spatial information such as the distance between the eyes). In the current study, 6-month-olds discriminated 'thatcherized' faces when they were viewed upright but not when they were viewed upside down. These results are consistent with the notion that 6-month-olds are sensitive to second-order relational information while processing faces.     

Three-month-olds' sensitivity to orientation cues in the three-dimensional depth plane

Three-month-olds are sensitive to orientation changes of line drawings when they have a three-dimensional (3-D) interpretation and when the changes are defined by both 3-D depth and two-dimensional (2-D) picture plane cues [Bhatt, R. S., & Bertin, E. (2001). Pictorial cues and three-dimensional information processing in early infancy. Journal of Experimental Child Psychology, 80, 315-332]. In the current study, we examined whether 3-month-olds are sensitive to pictorial line junction cues that signal orientation changes solely in the 3-D depth plane. The results revealed that infants discriminated a misoriented elongated cube in an array when the stimuli contained both shading and lines (Experiment 2) but not when only lines depicted the elongated cubes (Experiment 1). Testing with comparable 2-D images revealed that, even in the presence of shading information, detection of orientation changes is specific to images that have a 3-D interpretation. Together, the results suggest that 3-month-olds are sensitive to pictorial line junction cues that signal orientation changes in the 3-D depth plane to adults provided that shading information is available and the images have a 3-D interpretation.     

Pictorial cues and three-dimensional information processing in early infancy.

Adults derive 3-D information from 2-D images by initially processing local line junction cues and then combining information from many junctions. Prior research indicates that 3-month-olds are sensitive to 3-D cues in individual line junctions. In Experiment 1, we examined whether infants are sensitive to holistic combinations of line junctions that adults use to derive overall 3-D structure. Infants detected a misoriented shape in an array depicting 3-D blocks but not in 2-D patterns that contained all of the trilinear junctions of the 3-D shapes but without the connecting lines. Thus, like adults, infants exhibited sensitivity to holistic combinations of line junctions rather than to individual junctions. In Experiment 2, when confronted with two test patterns, one containing an individual novel element among 15 familiar elements and the other containing a single familiar element among 15 novel elements, infants preferred to look at the former pattern in the 3-D condition but at the latter pattern in the 2-D condition. Thus, akin to pop-out in adults, discrepancies in 3-D cues selectively engaged infants' attention. These results suggest that 3-month-olds are not only sensitive to holistic combinations of line junctions that adults use to derive 3-D information but also selectively attend to these 3-D cues in static images.     

The still-face response in newborn, 1.5-, and 3-month-old infants

The present study investigated the still-face response to a female stranger in newborn, 1.5-, and 3-month-old infants. The results revealed that 1.5- and 3-month-olds, but not newborns, reliably decreased their visual attention and positive affect when the interaction partner became unresponsive during the still-face period.     

Adverse childhood experiences and autonomic regulation in response to acute stress: the role of the sympathetic and parasympathetic nervous systems

Background and objectives: After a previous report demonstrated blunted heart rate (HR) reactivity in association with adverse childhood experiences (ACEs) [Voellmin, A., Winzeler, K., Hug, E., Wilhelm, F. H., Schaefer, V., Gaab, J.,?…?Bader, K. (2015). Blunted endocrine and cardiovascular reactivity in young healthy women reporting a history of childhood adversity. Psychoneuroendocrinology, 51, 58–67. doi:10.1016/j.psyneuen.2014.09.008], the present analysis aimed at clarifying the role of the sympathetic and parasympathetic branches of the autonomic nervous system in this relationship.

Design and Methods: One hundred eighteen healthy young women provided data on ACEs and underwent psychosocial stress testing. Systolic blood pressure (SBP) and respiratory sinus arrhythmia (RSA, quantified by high-frequency HR variability) were assessed as measures of sympathetic and parasympathetic cardiovascular activity, respectively. A mediation model was calculated to test the indirect effects of ACEs on HR via SBP and RSA.

Results: The effect of ACEs on HR reactivity was mediated by SBP reactivity but not by RSA reactivity. ACEs were associated with reduced SBP at rest.

Conclusions: ACEs were associated with down-regulation in a measure of sympathetic but no alteration in a measure of parasympathetic cardiovascular stress reactivity in adulthood. Future research will need to clarify whether this indicates risk or resilience.     

Contribution of facial and vocal cues in the still-face response of 4-month-old infants

The contribution of contingent facial and vocal information in the still-face effect was investigated. Four-month-old infants either saw and heard their mother, only saw their mother, or only heard their mother interacting with them. These interaction periods were followed by the cessation of the mother's interactive face and/or voice. Only infants who observed their mother's face become still and neutral, showed a still-face effect by decreasing their visual attention and positive affect. The findings provide further support that the mother's interactive voice does not contribute to the still-face effect. The developing sensitivity to vocal information in dyadic and triadic contexts is discussed.     

Optic-flow-based perception of two-dimensional trajectories and the effects of a single landmark

Human observers can detect their heading direction on a short time scale on the basis of optic flow. We investigated the visual perception and reconstruction of visually travelled two-dimensional (2-D) trajectories from optic flow, with and without a landmark. As in our previous study, seated, stationary subjects wore a head-mounted display in which optic-flow stimuli were shown that simulated various manoeuvres: linear or curvilinear 2-D trajectories over a horizontal plane, with observer orientation either fixed in space, fixed relative to the path, or changing relative to both. Afterwards, they reproduced the perceived manoeuvre with a model vehicle, whose position and orientation were recorded. Previous results had suggested that our stimuli can induce illusory percepts when translation and yaw are unyoked. We tested that hypothesis and investigated how perception of the travelled trajectory depends on the amount of yaw and the average path-relative orientation. Using a structured visual environment instead of only dots, or making available additional extra-retinal information, can improve perception of ambiguous optic-flow stimuli. We investigated the amount of necessary structuring, specifically the effect of additional visual and/or extra-retinal information provided by a single landmark in conditions where illusory percepts occur. While yaw was perceived correctly, the travelled path was less accurately perceived, but still adequately when the simulated orientation was fixed in space or relative to the trajectory. When the amount of yaw was not equal to the rotation of the path, or in the opposite direction, subjects still perceived orientation as fixed relative to the trajectory. This caused trajectory misperception because yaw was wrongly attributed to a rotation of the path: path perception is governed by the amount of yaw in the manoeuvre. Trajectory misperception also occurs when orientation is fixed relative to a curvilinear path, but not tangential to it. A single landmark could improve perception. Our results confirm and extend previous findings that, for unambiguous perception of ego-motion from optic flow, additional information is required in many cases, which can take the form of fairly minimal, visual information.     

On the origin of the understanding of time, speed, and distance interrelations

We examined 18- and 24-month-old infants' sensitivity to the functional relationships between time, speed, and distance. The task included a train moving first visibly and then into a tunnel. The movement of the train was always accompanied by a train-characteristic sound signalling the travel duration. After the train concluded its travel, infants were requested to search for it in two possible locations inside the tunnel. Infants' reaching and head turn behavior indicated that 24-month-olds were sensitive to time-speed-distance interrelations, while 18-month-olds showed no such understanding. Reducing occlusion duration (by shortening the tunnel's length) revealed an increase in 18-month-olds' reaching and anticipatory head turns. Results are discussed in terms of the developmental course of the understanding of time-speed-distance interrelations and the strength of infants' representations.     

A controlled trial of an internet-based intervention program for cannabis users

In the last decade, several programs for the treatment of cannabis-related disorders were developed. Until now, no information is available on the efficacy of Internet-based counseling approaches for this target group. This article describes the evaluation of "quit the shit," a web-based intervention developed to help young people to quit or reduce their cannabis use significantly. Cannabis users seeking web-based treatment were included in a two-arm controlled trial conducted on a website for drug-related information and prevention. After the baseline assessment, members of the treatment condition were randomized to a 50-day intervention program. Other trial participants were put on a waiting list. A post-test was conducted 3 months after randomization. Of all 1,292 subjects included in the trial, a total of 206 participants took part at the post-test. Per-protocol- and intention-to-treat analyses were conducted. Members of the treatment condition showed a significantly stronger reduction in cannabis use (primary outcome) than the control group. In the per-protocol analyses, moderate-to-strong effects were found for the reduction of the frequency and the reduction of the quantity of consumed cannabis. Small-to-moderate effects were observed on the secondary outcomes (use-related self-efficacy, anxiety, depression, and life satisfaction). Despite limitations concerning the interpretation of the results, the intervention seems to offer an effective treatment option for persons with cannabis-related problems.