In simple terms

In this experiment designed by Vanessa Loaiza and colleagues (2024), people were asked to remember several shapes for a short time. Some of the shapes were concrete, like familiar everyday objects, while others were abstract, meaning meaningless scrambled versions of objects. People usually do better with concrete shapes, because they can connect them to long-term memory (for example, you can label a “chair” in your mind, but you can’t easily label a random squiggle).

The key twist in this task is the retro-cue. After the shapes disappeared, a brief cue appeared telling participants which shape would be tested. This cue doesn’t show new information; instead, it directs attention to one item already in memory. By focusing mental resources on the cued item, people can “refresh” it and remember it more accurately later.

The results showed two things.

  1. People could hold more concrete shapes in mind than abstract ones, confirming that long-term memory helps working memory overall.

  2. More importantly for this study than finding one, the retro-cue improved memory for both concrete and abstract shapes equally. That means the act of focusing attention in working memory works just as well whether the item is something you already know or something completely unfamiliar.

Research history

Psychologists have long debated how working memory (WM) and long-term memory (LTM) are related. We know that LTM generally improves WM performance—for example, people remember familiar objects or words more easily than unfamiliar ones. But it has been unclear whether LTM specifically helps with refreshing information in WM, that is, bringing items back into focus when they are no longer visible. Some studies suggested that familiar information gets a bigger boost from attention (retro-cues), while others found retro-cue benefits regardless of familiarity.

In this study, they found that retro-cues help regardless of familiarity.

This debate matters because it touches on the basic architecture of memory. If WM is simply an “activated part” of LTM, then attention-based refreshing should depend on prior knowledge. If WM and LTM are separate systems, then retro-cues should work the same way no matter what the items are. This study builds on that debate by carefully testing both familiar (concrete) and unfamiliar (abstract) shapes, controlling performance at baseline, and asking whether LTM changes the size of the retro-cue effect.

Critical discussion

The authors interpret their results as support for the idea that working memory (WM) and long-term memory (LTM) are distinct systems. Because retro-cues improved memory equally for both familiar and unfamiliar shapes, they argue that LTM does not directly influence the mechanism of refreshing in WM.

One can argue, however, that this conclusion depends on a specific interpretation of what retro-cues are doing. Retro-cues are usually thought to “refresh” items by reactivating them, but they may instead work by strengthening items that are already active, by protecting them from interference, or simply by guiding attention to the right place at test. If so, the finding of no difference between concrete and abstract shapes does not necessarily prove that WM and LTM are separate. It may just show that retro-cues are a powerful attentional tool that helps regardless of prior knowledge.

This means the study adds strong evidence that retro-cues consistently help memory, but whether that settles the larger theoretical debate about WM and LTM remains open.

Task design

Trial timeline (Experiment 1 of the study):

  • Fixation (0.5 s): A cross appears.

  • Memory array (1.0 s): Several shapes are shown—either concrete (familiar, nameable) or abstract (scrambled, meaningless) depending on the block.

  • Retention interval (2.25 s): Screen is blank.

  • Test prompt: One of the shapes appears at screen center; participants report its color using a continuous color wheel with the mouse. Responses are untimed, but participants are encouraged to answer quickly and accurately; recall error (distance between target color and response) is recorded (degrees)

  • Intertrial interval (1.0 s): Next trial begins.

Conditions:

Factor 1 is shape type (concrete or abstract) Factor 2 is the type of cue (no cue or a cue)

These two factors form a 2x2 design with four conditions: Condition 1: Concrete shapes with cue Condition 2: Concrete shapes without cue Condition 3: Abstract shapes with cue Condition 4: Abstract shapes without cue

Abstract shapes here means simply objects that look like nothing you know, they are sort of random line drawings.

About our implementation

We followed the paper carefully, but we added a few features.

  1. We added a practise block with unique shapes, just so people understand the basics of the task. If you do not want this, you can remove this from the task by removing the trainingblock.

  2. After people responded, we gave detailed feedback, that is, we showed the original location and shape and color, and also where people clicked and how far away it was from the required response. We also show a running score on the screen to encourage participants.

Run the demo

Click here to run a demo

Data output file

You do not need this information, unless you want to understand the output data file. You can ignore this if you just want to find out your own score. This is only necessary if you want to carry out the experiment with multiple participants.
In PsyToolkit, the data output file is simply a textfile. The save line of the PsyToolkit experiment script determines what is being saved in the data output file. Typically, for each experimental trial, you would have exactly one line in your text file, and each number/word on that line gives you the information you need for your data analysis, such as the condition, response speed, and whether an error was made.

Meaning of the columns in the output datafile. You need this information for your data analysis.

Colum

Meaning

save BLOCKNUMBER &setSize &conditionAC &rotationWheel &targetAngle &chosenAngle &diffScore RT &targetR &targetG &targetB MOUSE_R MOUSE_G MOUSE_B

1

Block number

2

The number of objects in the memory array

3

Type of shapes: 0) training shapes, 1) concrete shapes, 2) abstract shapes

4

Retro-cue present: 1) Yes, 2) No cue

5

Rotation of colorwheel (reported, but not really useful for analysis)

6

Angle of the target

7

Angle chosen by participant

8

The score (difference between the two angles)

9

Reaction time

10

The red channel value of the target stimulus (0-255)

11

The green channel value of the target stimulus (0-255)

12

The blue channel value of the target stimulus (0-255)

13

The red channel value the participant picked (0-255)

14

The green channel value the participant picked (0-255)

15

The blue channel value the participant picked (0-255)

How to analyze data from experiments

When you embed the retrocue experiment in your survey, you need (as always), make sure you set the "analyze" parameters of your experiment. In this case, it is very simple, for the dependent variable you just use value 8 (the score, lower values are better). For groups you use the conditions (3 and 4)

This way, you get the response time for all the conditions. For more sophisticated analyses, we recommened to use R and the PsyToolkit R pacakge.

Check out the source code

The PsyToolkit code

Download

The PsyToolkit code zip file, including stimulus file

If you have a PsyToolkit account, you can upload the zipfile directly to your PsyToolkit account.

If you want to upload the zipfile into your PsyToolkit account, make sure the file is not automatically uncompressed (some browsers, especially Mac Safari, by default uncompress zip files). Read here how to easily deal with this.

Further reading

  • Loaiza, V. M., Cheung, H. W., & Goldenhaus-Manning, D. T. (2024). What you don’t know can’t hurt you: Retro-cues benefit working memory regardless of prior knowledge in long-term memory. Psychonomic Bulletin & Review, 31(3), 1-12. Open access