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In this project, we assess changes in orientation perception across the lifespan. Participants will perform an orientation reproduction task for cardinal and oblique orientations and we will assess whether the reproduction error and bias per tested orientation changes with age. We have previously shown that older adults perform worse for oblique orientations than younger adults but perform as well as younger adults, if not better, for cardinal ones. In this project, we are investigating whether orientation perception gradually changes across the lifespan by testing adults ranging from 18 to 99 years.

Attention can be focused on specific locations in our visual field (space-based attention), but also spreads along objects (object-based attention). However, object-based effects are prone to large individual differences and seem not as prevalent as previously assumed. In a previous study, we investigated individual differences in the temporal dynamics of attentional selection. Our results showed that individual differences in the temporal aspects of attentional selection are not the underlying cause for the low-prevalence of object-based effects. We further assessed the rhythmic sampling of visual space underlying object- and space-based effects. Our data suggest that the rhythmic sampling depends on the target frequency and is particularly enhanced for targets with a low frequency (invalid targets: 10% validity for invalid same and different targets) and robust for those with a high frequency (valid trials: 80% cue validity). In three experiments, we further assess the effects of target frequency on attentional selection and the rhythmic sampling of visual space. Experiment 1 is a direct replication of our previous study. However, we will collect data for all three experiments online. In Experiment 2, we change the target frequency to be 50% (50% valid, 25% invalid same- and different-object target locations). In Experiment 3, target frequency was balanced across valid, invalid same- and different-object target locations.

Familiar faces are recognized with ease despite tremendous changes in appearance. Unfamiliar faces, however, are very hard to recognize. Even small changes in appearance make it difficult to decide whether photographs of unfamiliar faces belong to the same person not. What is the mechanism underlying the encoding and later recognition of faces? One mechanism that has been suggested to underlie face learning is ensemble coding. Ensemble coding describes the phenomenon that we extract the average identity when viewing images of a number of different people. It is a general perceptual mechanism that allows for the automatic extraction of summary statistics from large amounts of visual information. It is possible that ensemble coding is refined by experience. On the other hand, it could simply reflect a common human learning mechanism. Here, we will investigate whether ensemble coding improves with age, in particular for older faces (own-age bias). We will test younger (20-30) and older adults (60-70) on sets of younger, and older face stimuli. On a given trial, participants will be shown four faces. After that, they will be presented with the average face, a different average faces, one of the four images shown in the sequence, or an image of a different person.

Supplemental material, sj-pdf-1-ipe-10.1177_20416695211004616 for A Search Advantage for Horizontal Targets in Dynamic Displays by Ian M. Thornton, Quoc C. Vuong and Karin S. Pilz in i-Perception

Attention can be focused on specific locations in our visual field (space-based attention), but also spreads along objects (object-based attention). However, object-based effects are prone to large individual differences and seem not as prevalent as previously assumed. Here we investigated whether the low prevalence of object-based effects is related to individual differences in temporal dynamics of attentional selection. We measured space- and object-based effects on reaction times for individual participants in a two-rectangle discrimination task. Cue-to-target intervals were varied between 50 and 600 ms. We used bootstrapping to investigate in which cue-to-target intervals object-based effects were maximal, and fast Fourier transform (FFT) to investigate rhythmic samplings of visual space within and between objects. Whereas overall, space-based effects were robust and stable across all cue-to-target intervals for most participants, object-based effects were small and were only found for a small subset of participants. In the frequency domain, our results confirm rhythmic patterns of visual-target detection within (8 Hz) and between objects (4 and 8 Hz). However, we found large inter-individual variability for the phase of the sampling rhythms and no consistent phase relationship. Our results show that the low-prevalence of object-based effects cannot be explained by inter-individual variability in the temporal dynamics of attentional selection, and provide further evidence for considering individual variations in developing theories of visual attention.

Research on functional changes across the adult lifespan has been dominated by studies related to cognitive processes. However, it has become evident that a more comprehensive approach to behavioral aging is needed. In particular, our understanding of age-related perceptual changes is limited. Visual motion perception is one of the most studied areas in perceptual aging and therefore, provides an excellent domain on the basis of which we can investigate the complexity of the aging process. We review the existing literature on how aging affects motion perception, including different processing stages, and consider links to cognitive and motor changes. We address the heterogeneity of results and emphasize the role of individual differences. Findings on age-related changes in motion perception ultimately illustrate the complexity of functional dynamics that can contribute to decline as well as stability during healthy aging. We thus propose that motion perception offers a conceptual framework for perceptual aging, encouraging a deliberate consideration of functional limits and resources emerging across the lifespan.