# Tunable processing

> A perceptual mechanism involved in the pop-out effect, the phenomenon in which a particular visual pattern readily catches the eye. For example, the backward slash mixed among the forward slashes below is easy to spot.

A perceptual mechanism involved in the pop-out effect, the phenomenon in which a particular visual pattern readily catches the eye. For example, the backward slash mixed among the forward slashes below is easy to spot.

```
/ / / / / / / / / /
/ / / / / / / / / /
/ / / \ / / / / / /
/ / / / / / / / / /
```

## Terminology

Psychologist <Anne Treisman>, who published the first systematic study of the pop-out effect, called it "preattentive processing."[^1]

But the study explicitly told participants in advance which pattern to look for. Considering that a pattern may not stand out on its own without such advance notice (see: <inattentional blindness>), "preattentive" is not an appropriate term. For this reason, <Colin Ware> proposed "tunable processing" as an alternative. We can, to some extent, tune which patterns stand out by adjusting where we direct our [attention](https://wiki.g15e.com/en/pages/Attention.txt):

> A better term would be tunable, to indicate those visual properties that can be used in the planning of the next eye movement. --p29, [Visual thinking for design](https://wiki.g15e.com/en/pages/Visual%20thinking%20for%20design.txt)

## Visual features

The following are examples of visual features that produce the pop-out effect.

![Visual features with pop-out effect.png](https://wiki.g15e.com/data/Visual%20features%20with%20pop-out%20effect.webp)

Pop-out can be produced using visual features primarily recognized in the <primary visual cortex>, such as a striking color, a different orientation or size, shadows, and focus. I say "primarily" because some features known not to be processed entirely in V1, such as motion, can also produce pop-out effects.

## See also

- [Feedback from V1 to LGN](https://wiki.g15e.com/pages/Feedback%20from%20V1%20to%20LGN.txt): There are far more reverse signals from V1 → LGN than signals from the <LGN> → <V1>. This may be related to why attention can tune the pop-out effect.

## Footnotes

[^1]: [Feature analysis in early vision: evidence from search asymmetries](https://pubmed.ncbi.nlm.nih.gov/3353475/)