A Behaviourally Sensitive Brain — Shaping Value Assessment in Novel Visual Stimuli.
The human brain can, apparently, be trained to judge a book by its cover.
In order to ensure optimal performance in a socially complex world, the brain must encode representations of new stimuli across a number of dimensions; this involves the perception, categorization, and storage of countless grouped memories. Where new objects are observed, they are assessed against known objects to determine similarity, a process that increases neural activity in several key areas. In the case of visual stimuli, neural activity suggests that we examine new items comparing their orientation, spatial frequency (Mazer, et. al, 2002), colour, and shape (Roe et al., 2012).
Persichetti et. al (2015) sought to determine whether the brain encodes more abstract and subjective object features, such as value. They found that value similarity can indeed trigger consistent neurological responses during visual assessment tasks (even when distracted by features along other dimensions), but this does not occur automatically (Persichetti et. al, 2015).
To test subjective feature recognition, they trained participants to assign value to novel objects and monitored the assessment of their similarity through the performance of visual decision tasks. Thirteen right-handed participants (mean age=24.3 years, nine women) were exposed to shapes resembling an incomplete moon that varied across shape (specifically width), colour, and monetary value. Participants were then required to perform tasks that required the assessment of objective (shape, colour, etc) and subjective (monetary value) dimensions. To measure abstract value assessment, participants were assigned a personal bank account, and directed to accumulate as much wealth as possible. They would be shown two objects simultaneously on a computer screen and asked to select the object that would maximise their total personal bank balance. Objects would be displayed, initially, with no monetary value indicators. Once an object was selected, the value of both objects would be displayed, and the participant’s new personal bank balance would be displayed (see Figure 1 for example stimuli). Because monetary value was randomly assigned to each object, subjects performed a number of practice trials with impunity (Persichetti et. al, 2015).
To gauge the neural response to objective traits, at the beginning of each trial, participants would see one object (from the same object set as the value tasks) bisected by a vertical line leaving up to 65% of the object either on the left or right side of the line. The participant indicated by button press on each trial whether more of the shape was to the left or to the right of the line. Participant brain activity was measured using fMRI (Functional Magnetic Resonance Imaging) before and after training (Persichetti et. al, 2015).
Persichetti et. al (2015) tracked activity across five regions of interest (ROI), including two in the visual cortex (EVC and LOC), their primary focus, and three from other more traditional value-related areas, namely the ventromedial pFC (VMPFC), the dorsomedial pFC (DMPFC), and the Striatum. They predicted that they could compare spikes in visual cortex activity with similar changes in the other value-related areas to support any indication that both areas were actively interpreting monetary value. Before training, they found no significant neural effect suggesting the accurate interpretation of the monetary value of objects. After training, they observed that the EVC showed adaptation to shape before and after training, and adaptation to value after training. In contrast, LOC, DMPFC, and VMPFC showed adaption to shape (at both time points) but no adaptation to monetary value.
Whereas value-related neurological differences have been examined across different cultures (Kim et. al, 2012), and task-types (Delotterie et. al, 2015), the fact that the EVC can be trained to respond to visual characteristics not immediately apparent is a tremendous enabler; an agile EVC means that human beings can adapt their immediate perception of the value of an object just by looking at it (provided they have some prior exposure to it).
As this experiment established that neural perception of value can be altered through behavioural training, one might consider exploring whether the manual stimulation of neural activity can shape a person’s perception of the monetary value of novel stimuli. The concept of cognitive misattribution has been explored in the case of mistakenly interpreting physiological responses to acute fear for sexual arousal (White and Knight, 1984), anger and aggression (Younger & Doob, 1974), and other emotions; if it were possible to influence the assignment of monetary (or other abstract characteristic) value to novel objects by manually stimulating activity in any of the reward areas, or at least the EVC, this could have significant implications for retail-driven organizations.
Imagine walking into a store where someone shows you a video that is deliberately designed to stimulate particular areas of your brain, which in turn was designed to influence how much you would pay for something.
Take a look around you; how far are we from that reality right now?
References
Delotterie, D. F., Mathis, C., Cassel, J. C., Rosenbrock, H., Dorner-Ciossek, C., & Marti, A. (2015). Touchscreen tasks in mice to demonstrate differences between hippocampal and striatal functions. Neurobiology of Learning and Memory, 120, 16–27.
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