A software technique which reduces jaggies which are steps where there should be curves or straight lines. They result from the screen having a low resolution.

Applied research

Research which aims to solve practical real-world problems.

Cloze procedure

A participant is asked to identify words that have been removed from a text which tests their ability to understand the text.

Cognitive load

The mental effort being used in working memory

Confounding variable

Something which varies along with the specific variable selected for study. As a consequence, the results cannot be reliably interpreted. Either one or the other variable, or both, might be responsible for the results. This affects the internal validity of the study.


A way of viewing the world; a person construes or gives meaning to their own experience.

Continuous text

Sometimes referred to as ‘running text’, this refers to sentences arranged in paragraphs which are designed to be read in a linear manner and can be distinguished from lists, etc.

Critical print size

The smallest character size for which reading is possible at maximum speed.


In the context of reading, this is the effect of surrounding letters in words on the ease of identifying letters.

Desirable difficulty

This typically describes a learning task that requires a lot of effort to do, but this amount of effort is an advantage as it improves performance over the longer term (e.g. retention of information). The term was first used by Robert Bjork in 1994.

Developmental dyslexia

People diagnosed with developmental dyslexia have difficulty in reading accurately and fluently which cannot be explained by their intellectual ability or educational opportunities.


The subjective (metacognitive) experience of ease or difficulty when completing a mental task.

Ecological hypothesis

In this context, a theory which proposes that we have evolved to be good at processing certain visual signs that are found in our physical environment.

Ecological validity

The extent to which a study can be generalised to real life settings. This is sometimes called face validity.

External validity

The extent to which the results of a study can be generalized to other situations and to other people. External refers to outside the study.

Internal validity

This is determined by how well the study has been designed to avoid confounding variables, and describes the relationship between the outcomes of the study and the object of study.

Letter frequency

The number of times a letter appears, on average, in the language.

Lexical decision task

Participant indicates whether the item is a word or not a word.


Logarithm of the Minimum Angle of Resolution


An author’s text that has not yet been published. This was originally handwritten but is now always a digital version.


In the context of an experiment, mediating refers to something that is causing the result.

Metacognitive experience

This describes our awareness of what we are experiencing, such as whether something is easy (fluent) or difficult (disfluent) to read.

Nominal point size

The number given to the size of the font, even though it may not match any dimension of the letters and varies from font to font.


Standardised symbols for testing vision.

Perceptual salience

Drawing attention, standing out, easily perceived.

Perceptual span

The area around the current eye fixation position which contains useful information: about 4 letters to the left and 15 letters to the right. We can fully discriminate about 10 letters.

Practice effect

This is a recognised effect of repeating a similar test and is usually improvement in performance due to familiarity with the test. In research studies, this effect is controlled by varying the order of different conditions of the experiment across participants.


A technique used in psychological studies where presenting one stimulus (e.g. part of a letter) before presenting another stimulus (e.g. whole letter) can speed up a response.


A non-word that appears to be a word in the language, but isn’t, e.g. cirtion, sibrin


Refers to measurements using experiments which determine how reading performance (often reading speed) is affected by physical properties of text (e.g. type size, typeface). It is therefore measuring the relationship between the physical and the psychological.

Pure research

Also called ‘basic’ or ‘theoretical’ research, the aim is to further develop scientific theory and understanding, as opposed to solving a particular problem (which is the province of applied research).


If an experiment can be reproduced by different researchers, using the same or very similar methods and materials, and the results are the same, we can say that the study has been replicated. This is an important means of ensuring that the research is robust.

Robust research

Research which can be relied upon and can withstand changes so we can assume that the results will apply to more than one situation.

Short exposure method

Presenting a letter or word for a very brief time which increases the sensitivity of the method.

Standardised test

A standardised reading test is a device to measure reading which has been checked for reliability and validity (see Chapter 4: Key criteria) and is typically sold by a publisher.

Threshold legibility

The smallest size that we can recognise letters and words.

Typographic cueing

Use of bold, italic, underline, capitals, etc. to differentiate a word or phrase from surrounding text.

Visual or vision science

Studies of vision and how visual information is processed by people and by computers.

Working memory

A cognitive system with limited capacity where we temporarily hold information for processing.