Naturalistic face adaptation: How we adapt to freckles fast and sustainably.

While sunbathing, our skin becomes susceptible to quite remarkable changes in visual appearance, that is, freckles appear or increase in intensity-most obviously on the face. Research on face adaptation repeatedly showed that the inspection of manipulated versions of faces (so-called adaptor faces) leads to robust and sustainable changes in the perception of subsequently presented faces. Therefore, during the adaptation phase of the present study, participants saw faces with either strongly increased or decreased intensities of freckles. After a 5-minute break, during the test phase, participants had to identify the veridical (non-manipulated) face out of two faces (a slightly manipulated face combined with a non-manipulated face). Results showed strong adaptation effects to increased and decreased levels of freckles. We conclude that updating facial representations in memory is relatively fast, and these representation updates seem to sustain over a certain time span (at least 5 minutes). Face-specificity of our effects will be discussed. The results align with our everyday experience that the appearance of freckles in spring is a salient change in a familiar face; however, we seem to not register these changes after a few exposures due to a loss of information quality.

Under the sun: adaptation effects to changes in facial complexion.

BACKGROUND: Many Western people enjoy sunshine, and through the sun's stimulated increase in melanin, the skin tone or skin complexion will darken (and lighten again during winter). Although the initial salience of such a new look is remarkable - especially in the face - we seem to adapt to this new look relatively quickly. Research on face adaptation in general repeatedly showed that the inspection of manipulated versions of faces (so-called adaptor faces) leads to a change of the perception of subsequently presented faces. The present study investigates face adaptation to very natural changes in faces such as changes in complexion. METHODS: During the adaptation phase in the present study, participants saw faces with either strongly increased or decreased complexion. After a pause of 5 min, participants had to identify the veridical (non-manipulated) face out of two faces (a face slightly manipulated in complexion combined with the non-manipulated face) during a test phase. RESULTS: Results show strong adaptation effects to decreased complexion intensities. DISCUSSION: It seems that we are updating our facial representations in memory quite quickly (i.e., optimizing our processing through adaptation) and seem to sustain those new representations over a certain timespan (at least 5 min). Our results demonstrate that changes in complexion draw our attention for deeper analysis (at least with decreased complexion). However, it loses its informative quality quickly via fast and relatively sustainable adaptation.

Face Adaptation-Investigating Nonconfigural Saturation Alterations.

Recognizing familiar faces requires a comparison of the incoming perceptual information with mental face representations stored in memory. Mounting evidence indicates that these representations adapt quickly to recently perceived facial changes. This becomes apparent in face adaptation studies where exposure to a strongly manipulated face alters the perception of subsequent face stimuli: original, non-manipulated face images then appear to be manipulated, while images similar to the adaptor are perceived as "normal." The face adaptation paradigm serves as a good tool for investigating the information stored in facial memory. So far, most of the face adaptation studies focused on configural (second-order relationship) face information, mainly neglecting non-configural face information (i.e., that does not affect spatial face relations), such as color, although several (non-adaptation) studies were able to demonstrate the importance of color information in face perception and identification. The present study therefore focuses on adaptation effects on saturation color information and compares the results with previous findings on brightness. The study reveals differences in the effect pattern and robustness, indicating that adaptation effects vary considerably even within the same class of non-configural face information.

Face Adaptation Effects on Non-Configural Face Information.

Inspecting new visual information in a face can affect the perception of subsequently seen faces. In experimental settings for example, previously seen manipulated versions of a face can lead to a clear bias of the participant's perception of subsequent images: Original images are then perceived as manipulated in the opposite direction of the adaptor while images that are more similar to the adaptor are perceived as normal or natural. These so-called face adaptation effects can be a useful tool to provide information about which facial information is processed and stored in facial memory. Most experiments so far used variants of the second-order relationship configural information (e.g., spatial relations between facial features) when investigating these effects. However, non-configural face information (e.g., color) was mainly neglected when focusing on face adaptation, although this type of information plays an important role in face processing. Therefore, we investigated adaptation effects of non-configural face information by employing brightness alterations. Our results provide clear evidence for brightness adaptation effects (Experiment 1). These effects are face-specific to some extent (Experiments 2 and 3) and robust over time (Experiments 4 and 5). They support the assumption that non-configural face information is not only relevant in face perception but also in face retention. Brightness information seems to be stored in memory and thus is even involved in face recognition.

Face Adaptation and Face Priming as Tools for Getting Insights Into the Quality of Face Space.

During the recognition of faces, the incoming perceptual information is matched against mental representations of familiar faces stored in memory. Face space models describe an abstract concept of face representations and their mental organization, in which facial representations are located on various characteristic dimensions, depending on their specific facial characteristics. However, these models are defined just as incompletely as the general understanding of face recognition. We took two phenomena from face processing to better understand face recognition, and so the nature of face space: face adaptation and face priming. The face literature has mainly focused on face adaptation, largely neglecting face priming when trying to integrate outcomes regarding face recognition into the face space framework. Consequently, the present paper aims to review both phenomena and their contributions to face recognition, representation, and face space.

Improvement and simplification of fed-batch bioprocesses with a highly soluble phosphotyrosine sodium salt.

Fed-batch culture bioprocesses are currently used predominantly for the production of recombinant proteins, especially monoclonal antibodies. In these cultures, concentrated feeds are added during cultivation to prevent nutrient depletion, thus extending the cellular growth phase and increasing product concentrations. One limitation in these bioprocesses arises from the low solubility or stability of some compounds at high concentrations, in particular amino acids. This study describes the synthesis and evaluation of a phosphotyrosine disodium salt as a tyrosine source in fed-batch processes. This molecule is highly soluble in concentrated feeds at neutral pH. Mechanistic studies demonstrated that the molecule is cleaved in the cell culture supernatant after processing by released phosphatases, leading to phosphate and free L-tyrosine which can be taken up by the cells. No intact phosphotyrosine was detected intracellularly or incorporated into the sequence of the monoclonal antibody. The use of this new molecule allows the simplification of fed-batch processes in large scale manufacturing via the implementation of neutral pH, highly concentrated feeds.