Summary: A recent study shows that touching everyday objects can create precise and long-lasting memories of those objects, even when people are not trying to memorize them.
Source: APS
Touch alone can form detailed, durable memories that persist over time and transfer across senses, new research published in Psychological Science finds.
“One striking result was that participants could visually identify an object they had only handled a week earlier, despite never having seen it before,” says Fabian Hutmacher of the University of Regensburg. “This is notable because the foils in the recognition test came from the same basic-level category — for example, two different pens — so correct identification depended on subtle tactile details rather than obvious visual cues.”
Hutmacher and coauthor Christof Kuhbandner note that the findings challenge existing cognitive and neural models of memory, which do not fully explain the large amount of detail that seems to be stored after brief haptic exploration.
Most research on long-term memory emphasizes visual experience. Comparatively little is known about how well information acquired through other senses, such as touch, is preserved. To address that gap, the researchers focused on haptic memory — the memory formed by touch.
In the first experiment, blindfolded participants handled 168 common objects (for example, a pen) for 10 seconds each. Participants were told that they would be tested and were asked to attend to each object’s texture, shape, and weight. Immediately after exploration, while still blindfolded, participants completed a haptic recognition test for half of the objects: each trial presented the previously handled object alongside a visually and categorically similar foil that differed only in subtle tactile features, and participants indicated which one they had just explored. The remaining objects were tested the same way one week later.
Performance was almost perfect immediately after exploration — participants correctly identified the previously handled object on 94% of trials. Even after one week, accuracy remained high at 84%.
The researchers then asked two additional questions: would memory remain strong if people did not intentionally try to memorize objects, and could tactile exploration support recognition through a different sensory modality, such as vision?
In a second experiment, a fresh group of participants again handled the same 168 objects while blindfolded, but this time they were not informed about a later memory test. Instead, the task was framed as an investigation of aesthetic impressions: participants rated the pleasantness of each object based on texture, shape, and weight. One week later they returned for a surprise memory assessment.
During the surprise test, participants completed two types of recognition trials. For half of the items they performed a blindfolded haptic recognition task. For the other half they performed a visual recognition task in which two objects — the original and a similar foil — were placed side by side on a table and participants, now sighted, indicated which one they had handled a week earlier. After each decision, participants reported whether they based their choice on a specific recollection of tactile details, on a vague feeling of familiarity, or on a guess.
Even without intentional memorization, participants showed robust memory. In the blindfolded haptic test they were correct on 79% of trials. In the cross-modal visual test, they identified the correct object 73% of the time. Accuracy was highest when participants reported specific tactile recollection, intermediate for vague familiarity, and lowest when they guessed; however, even trials labeled as guesses produced above-chance recognition.
The ability to recognize objects across modalities is especially notable because the visual foils were drawn from the same basic-level category and differed only in fine tactile details. That participants could translate tactile experience into visual recognition suggests that haptic exploration creates rich, multi-sensory representations.
“These findings indicate that the human mind automatically stores detailed and durable representations of many perceptual experiences, including those experienced through touch,” Hutmacher explains. “Storing this wealth of information may serve a practical role by guiding behavior and refining actions even without conscious awareness of those memories.”
Source: Anna Mikulak — APS
Publisher: NeuroscienceNews.com
Image source: NeuroscienceNews.com (public domain)
Original research: Fabian Hutmacher and Christof Kuhbandner, “Long-Term Memory for Haptically Explored Objects: Fidelity, Durability, Incidental Encoding, and Cross-Modal Transfer.” Published in Psychological Science, October 30, 2018. doi: 10.1177/0956797618803644
Suggested citation formats for this article and the original research include common academic styles (MLA, APA, Chicago). When citing the original study, include authors, year, article title, journal name (Psychological Science), and DOI.
Abstract (study summary)
Long-Term Memory for Haptically Explored Objects: Fidelity, Durability, Incidental Encoding, and Cross-Modal Transfer
This study investigated how well tactile experiences of everyday objects are retained in long-term memory. Blindfolded participants explored 168 objects for 10 seconds each and later completed recognition tests that paired previously handled items with similar foils from the same object category. Experiment 1 showed near-perfect memory immediately after exploration (94%) and strong memory after one week (85%). Experiment 2 demonstrated that incidental, non-intentional haptic exploration also produces durable memory: a surprise one-week test revealed 79% correct haptic recognition and 73% correct cross-modal visual recognition. These results indicate that detailed, long-lasting representations are formed naturally through haptic perception.