Cognitive Psychology Practicals Online Resource

Designed by George Lovell and Ken Scott-Brown of Abertay University

 

Equipment Required

Most of these experiments will now work with a laptop, smart-phone or tablet. It's likely that the screen of a smartphone may be a bit too small for some of the studies to run correctly, but will enable you to experience the studies at least.

Those studies that need a keyboard are indicated, you'll find they 'hang' at certain points on smart-phones and tablets

Early Vision

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A sinewave grating

Blind Spot Finder

No Data Saved Each eye has a 'blind-spot' where no information is gathered. This occurs because the neural connections from the retina to the brain have to exit the eye. The optic nerve gathers these connections together and they exit the eye. Your retina is essentially 'blind' at this location, despite the fact that you do not experience this in day to day life. In this brief experiment we try to find the blind spot for your left eye, then we manipulate the stimulation at just this location.(Further reading)

Hermann Grid Illusion (needs keyboard)

Results so far Open Science Framework

In the Hermann grid illusion we "hallucinate" grey circles at the crosses of the white grid. This study is based upon suggestions by Schiller  and  Carvey (2005). Spillman (1994) argues that the illusion occurs due to the centre-surround nature of receptive fields and the strength of the illusion varies from foveal (looking directly at) to peripheral (looking to the side of) viewing because of the variation in the size of receptive fields.

ebbinghaus image, two orange circles, one surrounded by smaller circles. The surrouned circle seems larger.

Simplified Ebbinghaus Illusion

Results so far Open Science Framework.

A context-based size illusion which has it's origins with the work of Hermann Ebbinghaus (1850-1909). This is a widely studied illusion that illustrates how context can influence our perception of size. The illusion has been examined in the context of schizophrenia (Silverstein et. al 2013), in developmental psychology (Doherty et. al, 2009), in baboons (Parron and Fagot, 2007) and even in baby chicks (Salva et al. 2013).

In this experiment we simply count the number of times the central disc within the illusion is "larger" or "smaller" than a control-disc on it's own. With this design we can see whether the illusion works, but we cannot identify how much it shifts the percieved sized of the disc.

ebbinghaus image, two orange circles, one surrounded by smaller circles. The surrouned circle seems larger.

The Ebbinghaus Illusion

Results so far Open Science Framework.

Here we use visual psychophysics to estimate the percieved size of the disc as the illusion is varied. This is done by testing choices with different disc sizes, seeking to find the "point of subjective equality" [PSE] between the disc within the illusion and the disc on its own.

illustration of the cafe wall illusion. offset black tiles with grey grout. The grout appears to be sloping, i.e. not horizontal.

Cafe Wall Illusion

Results so far Open Science Framework

The Cafe Wall Illusion was reported by Richard Gregory in 1973 (see Gregory and Heard, 1979). But had also been previously reported as early as 1898 by Pierce.

illustration of the Ponzo illusion. A field with two cows one is higher up than the other.

Ponzo Illusion - with cows!

Results so far Open Science Framework

The Ponzo illusion was reported by Mario Ponzo in 1911 (see Byosier, 2020). In the classic illustration a pair of horizontal bars of the same size are positoned over a drawing of a railway track. The bar that is higher up the image is asumed by our perceptual system to be further away and must therefore be much larger. In honour of the contribution to Vision Science made by the sitcom Father Ted (link) we test the Ponzo illusion using cows.

Objects

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two computer generated images of objects made up of grey blocks. One object is rotated

Mental Rotation

Averaged data for participants Open Science Framework. Can we make judgements of the similarity of two objects regardless of rotation? If we could make judgements just as quickly, regardless of rotation, then this might suggest that object recognition is viewpoint-invariant, i.e. we have to form an object-centred internal representation of the object before we can make a comparison. This task is based upon Sheppard and Metzler (1971) using stimuli created by Ganis and Kievit (2015).

two bw photos of natural environments, the left has a cougar.

Fast detection of objects

Averaged data for participants Open Science Framework. Here we use the stimuli from Crouzet et. al (2012) to measure how quickly objects, animals and vehicles, can be detected against man-made and natural backgrounds. See also Fabre-Thorpe (2011). We do not use the RSVP (rapid serial visual presentation) method, rather it's just a simple reaction time task with two alternative images and responses.

Faces

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an inverted face, split horizontally at the nose

Face Familiarity

Results Open Science Framework How do we recognise a face? Do we have an internal list of features that we check against what we are seeing? Or do we have some kind of holistic representation that also encodes the relationship between each part of the face? In this study you're asked whether you recognise a face, in fact the top-half of the face, while the bottom half and the overall orientation are manipulated. Does the presence of someone else's chin interfere with recognition? This study is based upon Young, Hellawell and Hay (1987) but with updated celebrities and a control condition featuring non-familiar faces.

sad face with rating gizmo below

Judging facial emotions

Results Open Science Framework. How do different facial expressions influence our perception of a personality? Based upon a combination of Knutson (1996), Hess, Blairy and Kleck (2000) and Bradley and Lang (1994). The face photographs used were drawn from the Radboud faces database.

 

Attention

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Stroop Task

Results Open Science Framework

The stroop test demonstrates how selectively attending to one aspect of a stimulus and ignoring another can be very difficult. In the current experiment you are asked to respond to the ink-colour of a series of words, but the words themselves spell out the names of colours too. Sometimes these words are congrous - same word and ink, sometimes they are incongrous - different word and ink.
The classic Stroop test is named after John Ridley Stroop, who published an article on the effect in 1935. But the effect is reported earlier in German by Erich Rudolf Jeansch (1929).

two images, one with a chimney removed

Change Blindness

Results Open Science Framework Based upon Rensink O'Regan and Clark (1997). Can you spot the changes made in these pairs of images? You'll be amazed how hard it is to spot even really big changes.

person looking and pointing to left of screen

Posner Gaze Cueing

Results Open Science Framework. The Posner task demonstrates that our attentional resources aren't simply directed by where we look. In fact we can covertly attend to one location, while apparently viewing another. The Posner task illustrates that this focus of attention can be cued in an experiment. Based upon Posner (1980) and Friesen and Kingstone (1998). The images used come from Ken Scott-Brown, Santiago Martinez and Rob Madden (2013).

multiple object tracking

Multiple Object Tracking

No data yet Originally devised by Pylyshyn and Storm (1988). This study takes the approach of Ryokai et al. (2013) offering a motion tracking task that uses a staircase method to enable a gradual increase in difficulty. Multiple object tracking tasks suggest that attention isn't a simple circular spotlight, rather we can simultaneously attend to multiple areas and objects - up to a limit.

an image with letters, one of the letters is a blue N

Visual Search Task

Results Open Science Framework. Triesman and Gelade's visual search task based upon Triesman and Gelade (1980). Search for items in a display based upon colour, shape or both colour and shape.

 

Memory

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three rows of letters

Iconic Memory (needs keyboard)

Results Open Science Framework.. George Sperling's Iconic Memory Experiment (Needs headphones) based upon Sperling (1960, 1963) and follow on papers.

illustration of the forgetting curve with higher recall for first and last items in the list

Forgetting Curve

Results
Open Science Framework

Murdoch (1962) demonstrated that when participants are asked to memorise a list of words, that not all words are recalled as well as others. There is an effect of position within the word list. Earlier and later items are recalled more reliably than those in the centre of the list. This is termed the Serial Position Effect. Here we partially replicate this study - the difference being that we use a recognition task at the end rather than speaking or writing-down the words. This makes it easer to score the results automatically.

image of the working memory model

Working Memory: Articulatory Suppresion

Results

Open Science Framework

Baddeley, Thomson and Buchanan (1975) presented a series of experiments designed to explore and illustrate the structure of working memory. This study is a partial replication of the experiment reported in Figure 5 of that paper. The stimuli consist of short and long words that are presented sequentially. In half of the trials you are also asked to undertake an articulatory suppression task (counting from 1-8 repeatedly).

 

Thinking and Biases

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confused general standing in front of a tower

Problem Solving (needs keyboard)

Results Open Science Framework. A study of problem solving based upon Gick and Holyoak (1980).

spinning coin

Gambling

Open Science Framework A study that measures your ability to predict coin tosses, very loosely based upon Gilovich, Vallone and Tversky (1985) and Roney and Trick (2009)

Now that most of the studies run on phones and tablets it's possible to embed QR codes in lectures so that students can run the studies during your presentation for each link <click here to download the images>.