Divergent effects of absolute evidence magnitude on decision accuracy and confidence in perceptual judgements.

Whether people change their mind after making a perceptual judgement may depend on how confident they are in their decision. Recently, it was shown that, when making perceptual judgements about stimuli containing high levels of 'absolute evidence' (i.e., the overall magnitude of sensory evidence across choice options), people make less accurate decisions and are also slower to change their mind and correct their mistakes. Here we report two studies that investigated whether high levels of absolute evidence also lead to increased decision confidence. We used a luminance judgment task in which participants decided which of two dynamic, flickering stimuli was brighter. After making a decision, participants rated their confidence. We manipulated relative evidence (i.e., the mean luminance difference between the two stimuli) and absolute evidence (i.e., the summed luminance of the two stimuli). In the first experiment, we found that higher absolute evidence was associated with decreased decision accuracy but increased decision confidence. In the second experiment, we additionally manipulated the degree of luminance variability to assess whether the observed effects were due to differences in perceived evidence variability. We replicated the results of the first experiment but did not find substantial effects of luminance variability on confidence ratings. Our findings support the view that decisions and confidence judgements are based on partly dissociable sources of information, and suggest that decisions initially made with higher confidence may be more resistant to subsequent changes of mind.

The relationship between response dynamics and the formation of confidence varies across the lifespan.

Accurate metacognitive judgments, such as forming a confidence judgment, are crucial for goal-directed behavior but decline with older age. Besides changes in the sensory processing of stimulus features, there might also be changes in the motoric aspects of giving responses that account for age-related changes in confidence. In order to assess the association between confidence and response parameters across the adult lifespan, we measured response times and peak forces in a four-choice flanker task with subsequent confidence judgments. In 65 healthy adults from 20 to 76 years of age, we showed divergent associations of each measure with confidence, depending on decision accuracy. Participants indicated higher confidence after faster responses in correct but not incorrect trials. They also indicated higher confidence after less forceful responses in errors but not in correct trials. Notably, these associations were age-dependent as the relationship between confidence and response time was more pronounced in older participants, while the relationship between confidence and response force decayed with age. Our results add to the notion that confidence is related to response parameters and demonstrate noteworthy changes in the observed associations across the adult lifespan. These changes potentially constitute an expression of general age-related deficits in performance monitoring or, alternatively, index a failing mechanism in the computation of confidence in older adults.

Neural correlates of metacognition across the adult lifespan.

Metacognitive accuracy describes the degree of overlap between the subjective perception of one's decision accuracy (i.e. confidence) and objectively observed performance. With older age, the need for accurate metacognitive evaluation increases; however, error detection rates typically decrease. We investigated the effect of ageing on metacognitive accuracy using event-related potentials (ERPs) reflecting error detection and confidence: the error/correct negativity (Ne/c) and the error/correct positivity (Pe/c). Sixty-five healthy adults (20 to 76 years) completed a complex Flanker task and provided confidence ratings. We found that metacognitive accuracy declined with age beyond the expected decline in task performance, while the adaptive adjustment of behaviour was well preserved. Pe amplitudes following errors varied by confidence rating, but they did not mirror the reduction in metacognitive accuracy. Ne amplitudes decreased with age for low confidence errors. The results suggest that age-related difficulties in metacognitive evaluation could be related to an impaired integration of decision accuracy and confidence information processing. Ultimately, training the metacognitive evaluation of fundamental decisions in older adults might constitute a promising endeavour.

Development of the Vision Impairment in Low Luminance Questionnaire.

Purpose: The purpose of this study was to design and evaluate an instrument for assessing vision-related quality of life appropriate for the specific visual impairment characteristic for all stages of age-related macular degeneration (AMD), with a focus on the low luminance deficit in early/intermediate stages. Methods: A standardized questionnaire was developed in three steps with participants with early, intermediate, and late AMD: (1) based on in-depth interviews (n = 19) and two focus group discussions (n = 5 each), content was developed followed by 2. (2) The questionnaire development using cognitive debriefing interviews (n = 3) and leading to a preliminary version of the questionnaire. (3) This version was then administered to 127 participants with early, intermediate, and late AMD. Psychometric properties, such as response category functioning (floor and ceiling effects) and targeting of item difficulty to patient ability of the pilot Vision Impairment in Low Luminance (VILL) questionnaire were evaluated using Rasch analysis. Results: The preliminary VILL questionnaire consisted of 68 items with a 5-step response scale. Several items were removed based on floor/ceiling effects or misfit and a final pool of 37 items remained. The response scale was collapsed to four categories as one category was underutilized. The targeting of the instrument was good with minimal difference in person and item means (0.52 logits). Precision was also good with a person separation index of 3.55 and reliability of 0.93. There was evidence of multidimensionality (eigenvalue of the first contrast = 5.95) in the scale, which could be resolved by splitting the items into subscales including a reading, mobility, and emotional well-being subscale. Conclusions: Individuals with AMD report difficulties with vision-related activities and functioning under visually challenging conditions at all stages of the disease. These aspects were considered when developing the 37-item VILL, which demonstrates promising psychometric characteristics. Further assessments of reliability and validity are warranted. Translational Relevance: The VILL questionnaire is a new patient-reported outcome (PRO) measure developed for future use in AMD studies.