Date Published: February 28, 2019
Publisher: Public Library of Science
Author(s): Lisa Finkel, Simone Engler, Jennifer Randerath, Katsumi Watanabe.
Will I fit into the overcrowded subway? Advanced aging can change our abilities associated with accurately judging the fit between perceived environmental properties and our own actual physical capabilities (affordance judgments). Two experimental studies examined the effects of aging and trainability in affordance judgments. Participants were asked to decide whether their hand fits into a given opening (Aperture Task). We used a detection theory approach to evaluate different judgment characteristics. Study 1 demonstrated that older (N = 39) compared to younger adults (N = 39) produced rather conservative judgments, but did not differ in perceptual sensitivity. Distributions of Hit and False-Alarm rates, as well as risk-perception statements (DOSPERT questionnaire), indicated a heightened concern about potential consequences of misjudgments in older adults. In Study 2, 20 younger and 22 older adults were trained by actually trying to fit their hand into each presented opening. Training included acoustic, haptic and visual feedback. Compared to pre-training, both groups demonstrated significant increases in accuracy when assessed post-training and after a one-week follow-up. While younger adults improved in perceptual sensitivity in post-training as well as in follow-up, the older group adjusted their tendency towards less conservative judgments in both following sessions. Our results are consistent with affordance models that propose a complex and dynamic interplay of different neural processes involved in this skill. Future studies are needed to further elucidate that interplay and the trainability of affordance judgments.
When navigating through our environment, we recurrently make judgments upon whether a certain action is possible or not. The ecological theory of affordances by Gibson states that an important aspect of this ability is that “the information to specify the utilities of the environment is accompanied by information to specify the observer himself, his body, legs, hand, and mouth” . The central idea is that propertied substances and surfaces afford actions, meaning that they offer the potential for certain actions or constraints. At the same time, affordances need to be considered relative to the individual’s action capabilities and therefore are unique to the individual. Thus, affordance judgments are based on the fit between perceived environmental properties and one’s own physical capabilities
This project was approved by the ethical committee of the University of Konstanz and conducted in accordance with the Declaration of Helsinki. All participants provided informed written consent and received financial or study credit compensation. One participant was tested shortly before turning 18 years old (legal adult age according to German law), for this person written consent was additionally obtained from the parents.
In Study 1, we aimed at examining potential advanced aging effects in performing affordance judgments. This portion of the investigation comprised one session lasting approximately one and a half hours.
In Study 2, we aimed at examining whether participants would benefit from training and whether training effects would last over a one-week period. Each training session lasted approximately one and a half hours.
Actor-related affordance judgments are decisions concerning the outcome of an effective and efficient fit between our bodily actions and the environment, for example, when judging whether that tea-cup on the shelf is within reach, or whether one may be able to squeeze the hand into the locked mailbox to retrieve a letter. These judgments are thought to be substantially influenced by the comparison of on-line perceived environmental properties with an experience-based judgment criterion. Because the actor’s bodily and cognitive capabilities typically alter due to aging, these changes need to be taken into account by the actor when judging affordances.
The current study investigated effects of aging in affordance judgments by use of an Aperture Task. When judging whether or not a hand fits into a slot, older compared to younger adults did not differ in perceptual sensitivity. Yet, older adults produced rather conservative judgments, and they appeared to have a heightened concern about potential consequences of misjudgments.