Feature integration theory is a theory that explains human object recognition with the help of visual attention and assumes two separate information processing stages. The first stage is an automatic process and occurs so quickly that we do not notice it. Here we automatically process basic visual features of an object such as colour, orientation, shape or whether it is moving or not. Only in a second phase are the features combined so that we perceive the entire object and not just individual features. This second phase requires our attention and is much slower than the first automatic process. Knowledge of such cognitive processes can help us as designers, especially (but not only) in critical areas, to design objects in such a way that they can be found quickly thanks to the so-called pop-out effect.
In our everyday lives, we spend a lot of time searching for certain things or objects. For example, we look for our girlfriend at a concert. We know she has blonde hair and is wearing a red jumper. So we limit our search for her to these characteristics. In psychology, we would describe people with blonde hair and a red jumper as "Target stimulus" or simply "Target" designate.
Visual search is a complex process of perception and attention and deals with the problem of how we find objects that are relevant or of interest to us in a complex environment - in other words, in a world full of objects and things that could also be irrelevant to us. In psychology jargon, the irrelevant objects are known as "distractors".
The process of visual search is necessary and very important for our daily lives. Imagine if we had to process all the information in our field of vision at once. This is not even possible due to our limited cognitive capacity. Visual search is also important for Interface Design very important. For example, we could quickly search for a specific app on our smartphone.
An example from everyday (digital) life
I myself very often accidentally tap on the wrong app icon when I want to open the Face Time app. This happens when we are trying to find a specific app, but several apps have the same colour feature.
The Feature Integration Theory
The Feature Integration Theory by Anne Treisman and Garry Gelade (1980) offers us an explanation for this phenomenon. According to this theory, we perceive objects in two steps.
First of all, basic visual characteristics such as colour, movement or the orientation or shape of an object are automatically and therefore very quickly recognised and processed (so-called pre-attentive stageas no attention is required from us here).
However, the combination and integration of these individual features of an object into the perception of the object as a whole (also known as "conjunction") is a slower process that requires our attention. This phase (attentive stage) needs because of the conscious information processing takes longer than the first automatic process.
In the example above, this means: I have a lot of green apps on my display. The colour perception happens very quickly and unconsciously (pre-attentive stage), which explains the typos. Only in the second stage (attentive stage) do I perceive "finer" details such as the specific icon (camera, arrows, etc.) in combination with the colour and my brain forms a whole from this "Face Time Icon" or "Whatsapp Icon". We - or rather our brain - integrate or "conjugate" all the characteristics of the object into a whole.
The classic experiment
Let's try it out with the classic experiment adapted from Treisman and Gelade (1980): Try to find the blue "X" in the following graphic. The blue "X" is our target stimulus, which is surrounded by so-called "interfering stimuli" that are irrelevant to us.
Ok, that was very easy, wasn't it?
We can also try the same thing again with several disruptive elements:
We can see that our blue "X" "pops out" even with several interfering elements (Pop-out effect) so that we can recognise it very quickly. We look at all objects at the same time and can still recognise the blue "X" among all the other interfering elements very quickly. This is so fast because we use the automatic, parallel processing mentioned above: We simply look at the objects that are within our field of vision and can perceive them all in parallel and our target stimulus "jumps out" at us due to its unique propertywhich it shares with none of the other objects in the vicinity - the blue colour - directly into the eye.
Let's continue with our experiment. We will now try to find the green letter "T" in our graph (integration condition):
That probably took longer, didn't it? Since we are no longer just looking for a unique feature, our target object no longer "stands out". As a result, finding the target stimulus seems much more difficult because it is surrounded by other green letters and other "T's". Our target stimulus (the green T) shares features with all of our interfering objects: the green colour of the letter "X" & the shape with the purple "T".
Therefore, we need to look closely at each object and focus our attention on it to combine the features (shape and colour). So we scan each object, and if it is not our target object, we move on to the next object until we discover our target object. This corresponds to a serial, step-by-step processing or a serial search process.s. We have to scrutinise every object with focussed attention. That takes time.
In the first two conditions ("Find the blue "X" - the so-called feature or characteristic condition), the search time is also not influenced by the number of interfering elements. The target object is recognised automatically, unconsciously and therefore very quickly at a pre-attentive level due to its unique feature. "Colour" has been recognised. We do not need directed - i.e. conscious - attention to recognise our target object, but use rapid parallel information processing - and thus a parallel search.
In the integration condition, however, the search time increases because we have to focus our attention on the interfering objects, which leads to slow serial processing and therefore a serial search. We "scan" each element and check whether it has the characteristics of our target object. The search time therefore also increases with the number of visible interfering elements.
What does this mean for interface design?
If several objects have too many features in common, it can become difficult for us to find what we are looking for or should find. The feature integration theory provides us with a scientific approach to explain this and to take it into account when making design decisions.
Let's remember the first example with Google symbols: The features are all too similar, they have a lot in common. They share the same shape and colour, both of which we perceive quickly and automatically at the so-called pre-attentive stage. This makes it impossible for us to find the right object very quickly at this fast processing stage, as we cannot distinguish between them so quickly. So we need the slower one, attentive level to find our target object - i.e. we first have to consciously scan each individual element and check whether it is our "target object" - and that takes time.
This can pose a risk in situations where rapid action and reaction is required. Think of healthcare, the transport and automotive sectors, aeroplanes, space shuttles or industry in general. But even for products that are not used in safety-critical environments, we can utilise the findings from cognitive psychology to make people's lives a little easier.
Sources
- Treisman, A. M., & Gelade, G. (1980). A feature-integration theory of attention. Cognitive Psychology, 12(1), 97-136. https://doi.org/10.1016/0010-0285(80)90005-5
