SAGE Journal Articles
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Abstract
Mental imagery typically involves the voluntary retrieval and representation of a sensory memory, but it can also sometimes be involuntary. Despite mental imagery having been a topic of interest for thousands of years, the methodological tools necessary to scientifically probe its underlying mechanisms have only recently been developed. New methods in behavioral psychophysics (the binocular-rivalry technique) and brain imaging (decoding techniques) have been developed and utilized to uncover many new insights into the mechanisms and brain areas involved in mental imagery. These insights are igniting further empirical and theoretical work into imagery itself as well as its role in many high-level cognitive processes and mental disorders.
Discussion questions:
- Explain how fMRI is being used as a “decoding” technique to better understand visual imagery.
- Explain how the binocular-rivalry technique is used to better understand visual imagery.
- What are some limitations to these methods of study?
Abstract
Can people evaluate phenomenal qualities of internally generated experiences, such as whether a mental image is vivid or detailed? This question exemplifies a problem of metacognition: How well do people know their own thoughts? In the study reported here, participants were instructed to imagine a specific visual pattern and rate its vividness, after which they were presented with an ambiguous rivalry display that consisted of the previously imagined pattern plus an orthogonal pattern. On individual trials, higher ratings of vividness predicted a greater likelihood that the imagined pattern would appear dominant when the participant was subsequently presented with the binocular rivalry display. Off-line self-report questionnaires measuring imagery vividness also predicted individual differences in the strength of imagery bias over the entire study. Perceptual bias due to mental imagery could not be attributed to demand characteristics, as no bias was observed on catch-trial presentations of mock rivalry displays. Our findings provide novel evidence that people have a good metacognitive understanding of their own mental imagery and can reliably evaluate the vividness of single episodes of imagination.
Discussion questions:
- Why is the question these researchers wanted to answer difficult to study?
- Explain the task the researchers used in their study to overcome these difficulties.
- From the results of the study, what were the authors able to conclude about how well individuals can evaluate their own visual images?
Abstract
According to several authors in psychology and neurosciences, our ability to perceive affordances is subtended by motor simulation mechanisms. Such mechanisms provide dynamic representations of feasible actions, thus enabling to scale the surrounding structures on the behavioural repertoire and capacities supported by our body. This attractive hypothesis has been taken up in robotics, to build intelligent systems able to determine in advance whether a given action would be successful given the current state of the environment and their own skills. Several arguments, however, suggest that the motor simulation framework is not sufficient to explain affordance perception: (1) it rests on a misunderstanding of what affordances are: not actions that are currently feasible, but actions that are possible; (2) it is computationally unrealistic: motor simulation is too costly in terms of computational resources to explain how one can access prospectively to actions that are potentiated by surrounding structures; (3) it only covers the part of the perceptual field within the scope of our attention, but the affordances we perceive do not reduce to the object or state of affairs our attention is focused on at time t; and (4) it can only work if a first layer of affordances is available: motor simulation cannot explain affordance perception, because its very functioning presupposes such perception. Other mechanisms must consequently be hypothesized.
Discussion questions:
- What, according to Jeannerod, is the function of motor simulation?
- What are “affordances?” What does the author mean by distinguishing between “could” and “can” actions?
- Describe what the author is proposing about the relationship between the three ovals in Figure 1. What does the intersection region represent?