When a beach bag turns into a memory hole for your sweater

For many people, a trip to the beach is the highlight of the summer. The salty air, lounging on the sand, the sound of waves, swimming, drying off in the sun, the smell of sunscreen, a stack of beach reads.

But first, it’s time to pack those suitcases… Where are the swimming suits again? How about the cooler? The beach umbrella? The sand shovels and pails for the kids? The sunscreen?

Gathering everything you need might require rummaging through every room in your home. The swimming suits might be stashed in a dresser, the cooler in a hall closet, the beach umbrella in the basement, the sand toys in the garage, the sunscreen in the bathroom. And then there are decisions to make. Do you need the foldable outdoor chairs? How about the badminton rackets? Insect repellent? Some sweaters if it gets cold at night?

Let’s jump forward a few hours. Your bags are packed and loaded into the car, and you’re stuck in traffic along with what seems to be the entirety of humanity crawling toward the beach. The perfect time for a little pop quiz. Where in your home did you find those swimming suits? How about those warm sweaters you decided not to bring on the trip?

Findings reported in a recent article in the Psychonomic Society’s journal Attention, Perception, & Psychophysics suggest that after packing that beach bag, you might find it easier to recall where you keep the swimming suits but harder to recall where you keep the sweaters.

Researchers Draschkow and Võ investigated how searching for items influences people’s memory for the identity and location of those items. First, does item relevance matter? In our example, is it easier to remember the items that you packed for your beach trip than the items you decided to put back in the closet? Second, does interaction with the items matter? In our example, does it matter whether you handled and packed the items yourself or whether you just pointed out where the objects were for someone else to pack?

To address these questions, Draschkow and Võ asked people to perform a winter version of the beach packing task—to pack for a ski trip.

Participants were led into an apartment they hadn’t been to before and asked to find a series of items in different rooms. After finding each item, people had to decide whether or not to pack it for the ski trip. The items that were relevant for the trip were clothes and ski equipment, items for entertainment, sandwich-making supplies, and a guest present. Sounds like everything you’d need!

To examine the effect of item interaction, on some trials people were asked to pick up the items and bring them back to a set place to put them in a suitcase (for relevant items) or in a box (for irrelevant items). On non-interaction trials, people simply had to return to the set place after finding the items without touching them.

After participants finished the packing task, they were given a pop quiz: people were asked to write down as many items as they could remember from the apartment. Here, relevance mattered. People recalled more relevant items than irrelevant items, irrespective of whether they interacted with the items or not.

This finding fits with previous work demonstrating that categories can guide memory retrieval. We have known for a long time that in free recall, people tend to cluster together examples that are related to the same category, even when the examples’ presentation was randomized. When someone begins recalling examples from a new category, the time between their responses drops, suggesting that the category primes new examples (e.g., herehere). The same phenomenon can be observed at the neural level: the pattern of brain activation corresponding to a category precedes verbal recall of category members.

In the case of Draschkow and Võ’s study, the task-relevant category “things to pack for a ski trip” could be used to guide retrieval of items seen in the apartment (e.g., ski goggles, hat, book, etc.), leading to better recall of relevant than irrelevant items. This category might be an ad hoc category for people who have never gone skiing, or a well-established category for others who use it frequently.

After recalling as many items from the apartment as they could, people were given another pop quiz to assess their memory of item locations. The items from the packing task had been replaced around the apartment, and had to be found again.

Here, both item relevance and item interaction mattered. As shown in the figure below, people were faster at finding relevant than irrelevant items, but only if they had interacted with the items in the packing task (Handle condition). The pattern did not hold for items that they had not interacted with (Find condition).

The researchers then examined the relationship between identity and location memory. When people did not interact with the items, identity memory predicted location memory: people found items that they had previously recalled faster than items they had failed to recall.

In addition, interaction with items seemed to improve location memory for relevant items but worsen location memory for irrelevant items. People were slower at finding previously-recalled irrelevant items, but faster at non-recalled relevant items.  This overall pattern is shown in the figure below.

Returning to the beach example, Draschkow and Võ’s results imply that packing your bags might have made it easier to recall where you found relevant items (e.g., swimsuits) but harder to recall where you found items you ultimately decided to put back in the closet (e.g., sweaters).

Draschkow and Võ  conclude that “the act of moving/stowing away a task-irrelevant object might facilitate deprioritization or even induce forgetting of the object’s location information.” So now on that long car-ride to the beach, you know how to stump your fellow passengers. “Hey, so where did we put those sweaters?”

Article focused on in this post:

Draschkow, D., & Võ, M. L.-H. (2016). Of “what” and “where” in a natural search task: Active object handling supports object location memory beyond the object’s identity. Attention, Perception, & Psychophysics. DOI:10.3758/s13414-016-1111-x.

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