Colour is an inseparable part of our everyday lives and its presence is evident in everything that we perceive. It has been widely recognised that colours have a strong impact on our emotions and moods (Hemphill, 1996; Lang, 1993; Mahnike, 1996). Moreover, some colours may be associated with several different emotions and some emotions are associated with more than one colour (Linton, 1999, Saito, 1996).
Recent studies by Herlitz & Rehnman (2004) on colour affectivity characterise emotional profiles of colour in terms of certain emotional dimensions. Furthermore, the significant influence of chroma (or saturation) of a colour onto human emotions has been researched and found to be consistently evident. (Valdez et al, 1994). Thus approaching the issue of emotional influence of colour attributes and the effects the induced emotion has on memory (Valdez & Mehrabian, 1994). Research into the influence of emotion on memory has been extensive. Data from studies such as Dolcos and cabeza (2002), suggest that stimuli which evoke emotion are remembered better than neutral stimuli. However, it is also suggested that emotion does not only enhance memory, it may also distort the performance of memory recall by inducing a 'recognition bias' (Windmann and Kutas, 2001) meaning that subjects become more likely to respond 'old' to a negative stimulus than a positive or neutral stimulus.
Dolcos and cabeza (2002), study on memory and emotion utilised sixty pleasant, sixty unpleasant and sixty neutral pictures (These images were rated previously by the participants and were not universally standardised). Subjects were instructed to memorise the images for a later memory test. After an analysis of memory performance, the data showed a significant difference between neutral and non-neutral stimuli, however, no significant difference between pleasant and unpleasant. These results suggested that arousal was the key factor in emotional memory. The results also suggested that emotional pictures were encoded faster than non-emotional images. The amygdala, a subcortical structure, has been linked to emotional arousal. Dolcos and Cabeza, 2002 study indicated that activity in the amygdala may modulate hippocampal and medial temporal lobe activity, causing memory effects. Other experiments suggest ventromedial/medial prefrontal region involvement in memory and learning (Windmann and Kutas, 2001). Memory effects are studied in conjunction with electroencephalography (EEG) recording and event related potential (ERP) analysis in an attempt to localize the region related to emotional memory and quantify its effects.
Research demonstrating a relationship between memory recall for list learning tasks and p300 amplitude which is an ERP, recorded via EEG as a positive deflection in voltage at a latency of approximately 300 ms in the EEG. The signal is measured by positioning electrodes in the parietal lobe region. The presence, magnitude and time of this signal are often used as metrics of cognitive function in decision making processes hence its use in list learning tasks, but the variables mediating this p300 - recall relationship are to date little understood. In a study by Wiswede et al 2006 subjects were required to recall items from lists consisting of twelve words, which were presented in front of pictures taken from the International Affective Picture System (IAPS). One word per list was made distinct either by font colour or by a distinctive background IAPS picture. This isolation procedure was first used by Von Restorff.
Their findings indicated that recall performance was enhanced for colour but not for emotional isolates. Event-related brain potentials showed a more positive P300-component for recalled non-isolated words and colour-isolated words, compared to the respective non-remembered words, but not for words isolated by arousing background suggesting that highly arousing environments may force the cognitive system to interrupt rehearsal processes in working memory, which might benefit transfer into other, more stable memory systems. The impact of attention capturing properties of arousing background stimuli may also be an issue in this process, as distinctiveness affects memory performance. It is suggested that objects recall a greater number of items from a list that are distinct in at least one dimension. This phenomenon is called the von- Restorff or VR-effect. Distinctiveness of an item can be created by changing the colour, the size, the meaningfulness, the background colour or many other aspects of a stimulus. As an example, Fabiani & Donchin visually presented lists of twenty words which included physical (different font size) or semantic isolates (different semantic category).
Despite rapidly growing literature on the impact of colour on our emotions and considerable interest in this research area, many studies have failed to use colour samples from a standardised system of colour notation (Boyatzis & Verghese, 1994; Hemphill, 1996; Terwogt & Hoeksma, 1995). Moreover, several studies have used colour - emotion matching tasks (Zentner, 2001); matching colours (e.g., red, yellow, blue) to a certain number of emotions (e.g., happiness, sadness, anger), which results in limited assessments of reactions to colours.
Of the numerous colour systems that exist, one colour system noted internationally for its precise identification process is the Munsell Colour System (Ballast, 2002; Valdez & Mehrabian, 1994). According to this system, each colour has three basic attributes: hue, value (brightness), and chroma (saturation).
The current study has been conducted to further delineate the relationship between item distinctiveness and recall performance by introducing emotional or physical attributes for the words to be recalled. The hypotheses tested reflects some of the findings previously mentioned, however the researcher has found no evidence of past studies utilising universally standardised measures in regards to colour as well as the images presented when emotional characteristics of colour corresponding to the emotional content of an image and the effect of this distinctiveness has on word recall for related/non-related words.
The universally standardised Munsell Colour system was utilised to present words with a colour backdrop appertaining to the emotion/valence of the IAPS images for one of two variables, colour relating to emotional distinctiveness of the image/no colour. It is predicted that recall for words relating to the IAPS images which included a colour backdrop appertaining to the emotion of the IAPS images would be significantly higher than those without a colour backdrop. However, studies by Ainsworth, Simpson and Cassell 1993 as well as kwalleck, Lewis, Lin-Hsiao and woodson 1996 have contradicted these findings as they found no significant relationship between human emotions and colour. (GO INTO MORE DETAIL)
Furthermore, it is predicted that recall for words relating to the IAPS images would be significantly higher than for words not relating to the IAPS images. Moreover, it is also predicted that recall for words between gender, across all variables would have no significant effect.
This study employed a 3 (words relating to (congruent) IAPS; words not relating to (non-congruent) IAPS images and congruent words with colour backdrop appertaining to valence (pleasant, neutral and unpleasant) of the IAPS images - between) x 2 (gender - between) x 3 (valence - within) mixed subjects ANOVA.
The IAPS were identical as well as in array for each of the three between subject variables (Congruent words to IAPS images, Non-congruent words to IAPS images and congruent words presented with colour backdrop) within each test was three within subject variables in valence (IAPS images provoking a pleasant emotion, IAPS images provoking a neutral emotion and IAPS provoking an unpleasant emotion).Participants
63 participants were employed to carry out the study (31 males, 32 females) 36 were randomly assigned members of the public, 27 were randomly assigned students from the University of Central Lancashire. The mean age was 30 years of age (range = 18 - 64 years). None of the participants had known defective colour vision or dyslexia. No other personal information was collected.Materials
The study employed 36 International Affective Picture System images (IAPS) presented via a 19" lcd PC monitor, the IAPS images were categorised by valence scores (see page X of the Appendix section) 12 IAPS images per within subjects valence level. Within subjects valence variables consisted of positive neutral and negative IAPS images. All IAPS images were controlled within a range of XX (see page XX of the Appendix section for image lists and valence scores).
The three between subjects' variables consisted of 3 sets of 12 IAPS images which differed in valence with congruent words, identical IAPS image sets were used for the second between subjects variable with non-congruent words and again repeated with congruent words that included a colour backdrop appertaining to valence.
Three colours taken from the Munsell colour system were utilised; pleasant = yellow (7.5y (hue), 9 (value/ 10 (chroma), unpleasant = yellow/green (2.5g (hue),5(value)/10 (chroma) and neutral = grey (n/s). The colour samples were compared to the Munsell colour system via Microsoft colour programme, a full page view of each colour was presented with the words presented centrally. These colours were chosen from the findings of Helen H Epps PH.D. in her study 'Relationship between colour and emotion' as they were supported by studies carried out by Ballast, 2002, Linton 1999, Davey, 1998, Saito, 1996, Mahnke, 1996, Wexner, 1982.
The word stimuli were extracted from 'common five letter words' based on TWI-2006&CSW-2007 (Author XX). (Word list for the 3 between subject variables are presented on page XXX of the Appendix section). The incongruent words were randomly chosen only being omitted if the word appertained to the IAPS image in any way. Congruent words were chosen with best fit to the emotional content of the IAPS image (i.e. image of a car accident was presented with the word 'crash'.
The 3 between subject variables were pre-recorded and comprised of standardised verbal instructions, identical IAPS slides (one variable with colour backdrop), followed by a word screen all research stimuli were presented for 2 seconds (measured using PowerPoint slide timings). A verbal debrief was presented at the end of each between subjects variable. Also a typed debrief was available for the subjects to take with them. All subjects undertaking the relevant variable were presented with an identical presentation. (The study presentation disc is on page XX of the appendix section).
Samples of the unpleasant IAPS images were shown to the subjects prior to the study taking place (These sample images can be seen on page XX of the Appendix section), it was explained that they may leave the study at any time.
A data recall sheet, containing three boxes appertaining to each of the three within subject variables (valence) was employed to collect the raw data. (A copy of this is illustrated on page XX of the Appendix section).
Although the brief and the debrief were presented on the lcd monitor as well as verbally recorded a hard copy of each was also presented. (This is on page XX of the Appendix section).Procedure
All participants gave informed consent when taking part in this study, which was approved by the University of Central Lancashire ethics committee. Stimuli were presented visually in three between subjects variables: One for recall for words incongruent to IAPS images in three within subject variables/valence (pleasant, neutral and unpleasant), the second, recall for words congruent to IAPS images (with colour backdrop appertaining to valence) of the three within subject variables (valence) and the third; words congruent to the IAPS images in the three within subject variables (valence). The order in which the within subject variables was presented was not counterbalanced. (See discussion for details).
A preliminary test was compiled based on SAM (EXPLAIN) ratings of ten subjects; a satisfactory level of internal consistency was gained. Thus, the emotional profiles of pleasant, unpleasant and neutral colours were deemed as consistent throughout the study.
The main study was carried out in a quiet lab room at the University of Central Lancashire; room size was approximately 3m x 2m, all participants executed the study under daylight with lights on, window closed and all presented on an identical lcd screen to control the natural pigment variation between monitors.
Participants were tested in paired groups, all participants were shown three examples of unpleasant IAPS images due to the nature of the images used, it was explained to all participants that they were not under any obligation to undertake the study and could leave at any time. The instructions, and debrief were displayed via PowerPoint slides alone. Participants were provided with a raw data sheet for memory recall. The order of presentation of valence for each between subject variable was standardised across all participants. Each experimental session lasted approximately ten minutes.
The participants were instructed to view twenty four slides (twelve IAPS image slides each followed by a word slide) in each of the within subject variables (pleasant, neutral and unpleasant)). After the welcome slide, brief and task instructions, participants viewed each IAPS slide for two seconds followed by a word slide for two seconds at the start of each variable an introduction slide was presented. This was carried out across the between subject variables.
Following each of the three within subject variables, the participants were given sixty seconds recall period during which they were instructed to recall as many of the five letter words as they could recall by filling in the relevant box provided on their recall sheet. Once the test was complete the participants were thanked for their time and debriefed via a pre-recorded verbal presentation and via a hard copy to take away when exiting the laboratory.Results
The raw data consists of total word recall and was analysed by gender, word congruence, valence levels and colour/no-colour presentation. (This can be viewed on page 1 of the Appendix section). The data was analysed using Statistical Package for Social Sciences (SPSS) software programme version 17. Descriptive statistics were used to summarise data, based on the results obtained from the participants' responses.Discussion
The primary goal of this study was to examine the effect that colour induced emotion has on recall for words, this was carried out by presenting words with IAPS images with a colour backdrop appertaining to the valence (ie unpleasant image with an unpleasant colour backdrop). Overall the number of words recalled was greater when a colour backdrop was presented that appertained to the valence (colour =8.00, no-colour =6.19) throughout each valence, greater word recall was achieved when presented with a colour backdrop. This interaction was highly significant, thus supporting the hypotheses that colour appertaining to the emotional content would produce greater levels of recall for words. However, when congruency was introduced no significant interaction was found between recall for congruent words with colour backdrop and congruent words with no-colour backdrop. Suggesting that colour does not have a significant effect on word recall when accompanied with congruent words. This may be due to an existing distinct dimension (congruency) causing a VR-effect. Thus, weakening the significance that colour has on word recall when accompanied with another distinct dimension, resulting in a non significant interaction.
As this study takes president in this area of research, there is a lack of empirical evidence that directly supports these current findings. However, as Valdez supports the suggestion that certain colours influence human emotion along with research appertaining to emotion and memory we may boldly draw a conclusion in supporting research. Valdez (1994) suggested that colour induced human emotions, this evidence was consistent throughout continuing research. Hence, the colours/chroma and hue used within the current study for proven accuracy in provoking an array of emotions. The current findings suggest that colour appertaining to the emotional content has a significant effect on recall for words, this was apparent throughout the array of valence. Participants recalled on average 1.81 more words when accompanied with a colour backdrop.
Windmann and Kutas (2001) suggested that emotion does not only enhance memory, it may also distort the performance of memory recall by inducing a 'recognition bias.' The current research supported these findings as word recall for neutral valence IAPS accompanied with colour backdrop was highly significant (See table 1 for mean scores) over that of pleasant and unpleasant (Neutral valence/colour = 8.62, pleasant valence/colour = 7.38 and un-pleasant valence = 8.00). Therefore neutral arousal generated higher levels of recall when accompanied with a non-arousing colour backdrop. Interestingly when a neutral colour backdrop was presented with neutral stimuli, participants recalled on average 2.22 more words than when no colour was present.
Moreover, significant results were found to further support these findings. There was a significant interaction between neutral and unpleasant valence, results indicated that a greater number of words were recalled when presented with a neutral IAPS image (Neutral = 7.14, pleasant = 6.38, unpleasant = 6.86). There was no significant interaction between pleasant and neutral (However a greater number of words were recall for neutral) or pleasant and unpleasant valences (pleasant = 6.38, pleasant = 6.38, unpleasant = 6.86). This supports Dolcos and Cabeza's (2002) study on memory and emotion. They found that a significant difference between neutral and non-neutral stimuli, however no significant difference between pleasant and unpleasant thus resulting in the suggestion that emotion was a key factor in emotional memory. Interestingly however, Dolcos and Cabeza found that emotional stimuli were recalled on a significantly greater level than non-emotional stimuli, the total opposite to these current findings.
To further delianate on the suggestion that colour has a enhanced effect on recall we may draw from empirical evidence from Wiswede (2006) who studied the relationship between memory recall for list learning tasks with distinctive IAPS images and utilising p300 amplitude recorded via an EEG. Results indicated that recall performance was enhanced for colour but not for emotional isolates. This supports the theory that emotionally arousing stimuli distorts memory recall, with a significant interaction between neutral and unpleasant stimuli. Refuting the theory of highly arousing backgrounds forcing the cognitive system to interrupt rehearsal processes in working memory, benefitting transfer into other, more stable memory systems. It may be concluded that unpleasant valence/emotional stimuli within an image is processed differently than that of colour, therefore as word recall accompanied by an unpleasant image is significantly less than when a colour backdrop is introduced, on average, 1.91 more words.
There was also a highly significant interaction with word congruence and valence. Results show that words congruent to the valance of the IAPS images had greater levels of recall over non congruent words (congruent = 7.41, non-congruent = 5.54). This supports the hypotheses that there would be greater recall for congruent words as it would add an extra dimension to the stimuli. However there was no other significant interaction with any other variable.
Overall conclusion to the findings are that by introducing just one extra dimension to the stimuli effects recall for words highly significantly, however when one dimension is in-place there is no significant effect of introducing a second dimension. It is suggested therefore that distinctiveness on one dimension affects memory performance hence supporting the theory of the VR-effect. (By introducing colour rather than congruent words, participants recalled on average 1.59 more words).
Secondary findings reveal that there was a significant interaction within gender and word recall (N=31 Male 6.08, N=32 female 7.48), with females remembering significantly more words throughout each valence. This does not support the initial hypotheses as it was predicted that there would be no difference between gender. However it does concur with recent findings. Research looking into memory performance for men and women revealed that women did better at verbal episodic memory tasks, such as remembering words, objects, pictures or everyday events, and men outperformed women in remembering symbolic, non-linguistic information, known as visuospatial processing (Herlitz, 2008).
The current approach to the organisation of the visual cortex still holds that certain brain regions are solely dedicated to particular aspects of perception. The current status of investigations of colour cognition from the standpoint of modern neuro-psychology provides clear evidence, based on a large body of empirical studies on colour perception and naming, that colour appears to be one of the basic modules from which perception is constructed and our memories organised. Davidoff (xxx) systematically relates this evidence to an explicit model of colour cognition from sensation through functional role to naming.
limitations of the study include as the hues used in reproducing the exact shades could have had a dramatic impact on this study. Each hue could possibly create its own mood association.
Since there appears to be a consistent agreement amongst participants in this study could point to a cultural or biological factor. Exposure to the same experiences culturally could lead to these associations. Cimbalo, Beck, and Sendziak (1978) states that the fact that young children respond as older subjects can be used to argue for the innate association of colours and emotions. A possible challenge for future research would be to examine the role of biology and culture in colour and mood associations. Also, different hues could be used as it seems likely that different results might be obtained if differing shades of the same colour were to be used. (WHY).