Spatiële nieuwigheid kan woordgeheugen verbeteren. Het is nog onbekend of dit deels komt doordat nieuwigheid onverwacht is. Daarom wordt in deze studie ook gekeken naar het effect van...Show moreSpatiële nieuwigheid kan woordgeheugen verbeteren. Het is nog onbekend of dit deels komt doordat nieuwigheid onverwacht is. Daarom wordt in deze studie ook gekeken naar het effect van onverwachtheid op woordgeheugen. Ook is voorheen in nieuwigheidsonderzoek vooral gekeken naar jongvolwassenen terwijl het effect van nieuwigheid op woordgeheugen voor kinderen en ouderen zwakker is. Daarom wordt in deze studie gekeken naar oudere volwassenen. In de huidige studie hebben oudere volwassenen (n = 14) op drie achtereenvolgende dagen een virtuele omgeving (VO) verkend met ofwel veel onverwachtheid door toevoeging van mist ofwel weinig onverwachtheid door toevoeging van een minimap en verder zicht. De eerste dag was bedoeld voor familiarisatie van de VO. Op dag 2 en 3 was de omgeving voor elke participant wisselend nieuw- of bekend ten opzichte van de eerste dag. Na het verkennen van de VO werd er een ongerelateerde woordleertaak afgenomen. Resultaten lieten zien dat veel onverwachtheid het woordgeheugen verbeterde ten opzichte van weinig onverwachtheid. Verder vergrootte een bekende omgeving de afgelegde afstand vergeleken met een nieuwe omgeving. Ook was er een negatieve correlatie tussen afgelegde afstand en woordgeheugen. Tot slot was er een trainingseffect van de testdag op de afgelegde afstand. Deze resultaten suggereren dat onverwachtheid in een VO invloed heeft op het woordgeheugen. De voorheen aangetoonde effecten van nieuwigheid op het woordgeheugen zijn wellicht dus deels te verklaren door de invloed van onverwachtheid. Dit impliceert dat interventies tegen geheugenverslechtering naast het nieuwigheidseffect dus ook gebruik kunnen maken van een verrassingseffect.Show less
Uit eerder onderzoek is gebleken dat nieuwigheid gunstige effecten heeft op geheugenprestaties bij jongeren. Deze effecten van nieuwigheid op geheugen zijn echter nog niet eerder onderzocht bij...Show moreUit eerder onderzoek is gebleken dat nieuwigheid gunstige effecten heeft op geheugenprestaties bij jongeren. Deze effecten van nieuwigheid op geheugen zijn echter nog niet eerder onderzocht bij oudere volwassenen, waarbij individuele verschillen als motivatie (gemeten door Intrinsic Motivation Inventory) en spontaneous blinkrate (SBR) zijn meegenomen. In ons onderzoek verkenden participanten (n=14) een nieuwe of bekende virtuele omgeving, gevolgd door een onmiddellijke of vertraagde woordherinneringstaak of woordherkenningstaak. Uit de resultaten bleek dat het effect van nieuwigheid geen invloed had op de relatie tussen de geheugentaken, motivatie en SBR, en dat leeftijd mogelijk geen voorspellende factor was in deze relatie. Wanneer gecorrigeerd werd voor de variatie in dagen tussen de vertraagde geheugentaken per participant, vertoonde nieuwigheid wel een effect op verbeterde geheugenprestaties. In de analyses zonder leeftijd bleek dat het effect van geheugentaak en het effect van tijd van elkaar verschilden, wat zou kunnen suggereren dat de prestaties op de geheugentaken afnemen naarmate de tijd verstrijkt. Een belangrijke limitatie in het onderzoek was het beperkte aantal participanten en het minimale leeftijdsverschil. Hierdoor omvatte de variabele leeftijd mogelijk niet voldoende kracht om een werkelijk effect te detecteren over de variabelen geheugen en nieuwigheid tussen jongere en oudere volwassenen. Toekomstig onderzoek zou zich kunnen richten op het meten van motivatie en het manipuleren van nieuwigheid na verloop van tijd. Daarnaast zou het interessant zijn om de relatie tussen dopaminefuncties en nieuwigheid nader in kaart te brengen, om de ontwikkeling van interventies en behandelingen op het gebied van motivatie en mentale gezondheid te bevorderen.Show less
At least one in seven children have experienced child abuse and/or neglect in the past year and more than two thirds of children reported at least one traumatic event by the age of sixteen....Show moreAt least one in seven children have experienced child abuse and/or neglect in the past year and more than two thirds of children reported at least one traumatic event by the age of sixteen. Psychological problems, gender, mood, and socioeconomic status (SES) are all related to the severity of childhood trauma. Childhood trauma has not only been associated with a lower SES, but also with lower scores on IQ-tests. For example, sexual abuse, emotional neglect, and physical neglect are all negatively correlated with IQ. The relationship between SES, IQ and childhood trauma is not well understood. Especially in a population with individuals that report overall higher levels of traumatic experiences and have a lower IQ, such as offspring of people with a mood disorder. In this study, we investigated the relationship between SES, IQ, and trauma in offspring of parents with a mood disorder. Children (N = 198 and N = 40) participating in the MARIO cohort study were assessed for gender, age, SES, and exposure to childhood trauma (emotional abuse, physical abuse, sexual abuse, emotional neglect, and physical neglect) using the Childhood Trauma Questionnaire (CTQ). Child IQ-scores were assessed with either the WISC or the WAIS. A linear regression analysis showed that IQ was only weakly related to childhood trauma. In contrast SES was strongly related to childhood trauma. These findings suggest that IQ is not a determinant of childhood trauma in current research but underscores the importance of SES. The significant association between SES and childhood trauma could be further investigated and implemented in clinical practice. Future interventions could for example focus on preventing and/or reducing childhood trauma in children who grow up with a low SES.Show less
Most studies analyzing decision-making in individuals with impaired impulse control focus on decisions based on unimodal senses e.g., auditory or visual systems. Little is known about the effect of...Show moreMost studies analyzing decision-making in individuals with impaired impulse control focus on decisions based on unimodal senses e.g., auditory or visual systems. Little is known about the effect of impulsivity on overall performance in a decision-making task based on multisensory presentation. Therefore, the current study aimed to investigate the relationship between impulsivity, reaction time and performance accuracy in a multisensory decision-making task. The task consisted of three modalities (visual, auditory, and audiovisual) and two difficulty levels (easy and hard). Data were obtained from 37 participants between the ages of 16 and 18 years old. Participants were either diagnosed with Attention-Deficit/Hyperactivity Disorder (ADHD) or Disruptive Behavioral Disorder (DBD) or were typically developing. Impulsivity was measured using a self-report questionnaire. Due to a small sample of clinical participants, all participants were median split into a low and high impulsivity group. To test the effect of modality, difficulty, and impulsivity on reaction time and performance accuracy two mixed ANOVAs were conducted. The mixed ANOVAs showed no significant effects of impulsivity on reaction time or performance accuracy, thus no significant differences between the low and high impulsivity groups were found. The main effect of modality on reaction time was significant, with a shorter reaction time on the audiovisual trials than on the visual and auditory trials. Moreover, analysis showed a higher performance accuracy on the audiovisual trials compared to the visual and auditory trials. This shows the beneficial effect of multisensory (audiovisual) presentation on reaction time and performance accuracy. The current study confirms that multisensory presentation benefits overall performance but did not find a significant relationship between impulsivity and behavioral performance. Future research could focus on possible differences in multisensory behavioral performance between typically developing individuals and individuals with ADHD or DBD and should include a continuous impulsivity variable.Show less
The effect of stress on the exploration of new environments has shown to be impacted by individual preferences in novelty seeking in rodents, in which high stressed rodents explore novel stimuli...Show moreThe effect of stress on the exploration of new environments has shown to be impacted by individual preferences in novelty seeking in rodents, in which high stressed rodents explore novel stimuli more compared to low stressed rodents. Whereas studies to examine the way this behaviour is expressed in humans have been conducted, the effect of stress and attention on this behaviour has not. In this study, we tested for a relationship between stress, attention, and the combination of these two on the degree of exploration in humans. Participants were divided up among the low and high stress condition in the Sing-a-Song Stress Test (SSST) before roaming a virtual environment after which they were tested on their ability to recollect landmarks from that environment and having to complete a questionnaire to establish attention control. The SSST affected participants in the high stress condition more than in the low stress condition, showing the SSST to be effective as conditioning tool. However, participants’ virtual distance travelled and attention as measured by the Attention Control Scale Test did not reveal any relationship between stress, attention, and exploration behaviour. This suggests that, contrary to rodents, subjective stress and attention do not factor in exploration behaviour in humans. If such a link does however exist, further research on stress, attention, and exploration behaviour could help construct stress coping mechanisms for high-pressure situations and to assist people with stress- and attention deficit disorders.Show less
Neuroticism is a personality trait that has been associated with higher stress intensity and a poor ability to cope with stress. Research has also linked neuroticism with daily spatial behavior and...Show moreNeuroticism is a personality trait that has been associated with higher stress intensity and a poor ability to cope with stress. Research has also linked neuroticism with daily spatial behavior and roaming entropy, affirming that higher neuroticism negatively influences these factors. In the current research we examined whether highly neurotic individuals showed lower distance traveled, and whether this effect was different after stress induction. The sing-a-song stress test (SSST) was used to induce stress in half of the participants, their distance traveled was then measured based on their exploration behavior in a virtual environment. The participants filled out the big five personality questionnaire and their neuroticism score was calculated. The results showed no effects of neuroticism on distance traveled, regardless of stress induction or lack thereof. We also found no link between neuroticism and stress, or between stress and distance traveled. The results did show that the SSST increased stress level, in line with the expectations. In conclusion, the outcomes of this research did not find a link between neuroticism, stress and roaming entropy, this is not in line with earlier done research and further testing is necessary.Show less
Mensen hebben interesse in het exploreren van nieuwe omgevingen. We zien in het dagelijks leven echter ook dat de mate waarin mensen exploreren verschilt en dat het exploreren van nieuwe omgevingen...Show moreMensen hebben interesse in het exploreren van nieuwe omgevingen. We zien in het dagelijks leven echter ook dat de mate waarin mensen exploreren verschilt en dat het exploreren van nieuwe omgevingen stress kan oproepen. Wat we niet weten is of het ontdekkingsgedrag in een nieuwe omgeving wordt beïnvloed door een staat van hoge stress, of dit stresseffect gedurende een langere tijd aanwezig blijft en of daarbij man-vrouw verschillen een rol spelen. Uit dit onderzoek blijkt dat de sing-a-song stresstest een significant effect heeft op de subjectieve stress. Daarnaast laten we zien dat sekse wel invloed heeft op het ontdekken van nieuwe omgevingen. We hebben gevonden dat mannen gemiddeld meer afstand afleggen tijdens het ontdekken van nieuwe omgevingen dan de gemiddelde afstand die vrouwen afleggen tijdens het ontdekken. Er is geen bewijs gevonden dat stress hier invloed op heeft. Onze resultaten laten zien dat mannen en vrouwen op verschillende manieren omgaan met nieuwe omgevingen. Verwacht wordt dat dit onderzoek van invloed kan zijn op het diagnosticeren van depressie en het behandelen van de manische symptomen van de bipolaire stoornis. In toekomstig onderzoek kan gekeken worden naar hoe de ontdekking van nieuwe omgevingen onder continue stress plaatsvindt. Daarnaast kan ook gekeken worden naar wat de invloed van de eigenschap harm avoidance hierop is. Aangezien uit de literatuur blijkt dat hier een verband verwacht kan worden.Show less
Exploration behaviour is essential in becoming familiar with one’s environment and is necessary to survive in life-threatening situations. Previous studies found that stress negatively affects...Show moreExploration behaviour is essential in becoming familiar with one’s environment and is necessary to survive in life-threatening situations. Previous studies found that stress negatively affects exploration behaviour and introverts are more stress-prone than extroverts. Moreover, high levels of extroversion are positively related to explorative behaviour. However, no study focused on whether the effects of stress on explorative behaviour differ between introverts and extroverts. The current study hypothesised that extroversion and stress correlate since previous studies found this correlation. It is also hypothesised that introverts will explore less than extroverts in low- and high-stress conditions. To test this, 51 participants were recruited and assigned to the high- or low-stress condition through the counterbalance method. Participants in the high-stress condition were asked to sing a song (known as the Sing-a-Song Stress Test (SSST)), and participants in the low-stress condition were asked to listen to a song. During the SSST, an eye tracker was used to measure arousal. Hereafter, participants explored a VR environment, carried out the Landmark test and filled in questionnaires. Results indicated that the SSST caused stress among our participants in both conditions. No correlation was found between the stress groups and personality type extroversion and introversion, nor exist significant effects of personality and stress on exploration behaviour. It is advised that future research includes a larger number of subgroups and considers all the individual variables underlying exploration behaviour to get insights into the relationship between stress and personality type on exploration behaviour.Show less
The ability to perceive novelty in the surrounding environment and memorize the changes has been crucial for all species throughout evolution. Exploring novel environments induces memory...Show moreThe ability to perceive novelty in the surrounding environment and memorize the changes has been crucial for all species throughout evolution. Exploring novel environments induces memory consolidation mechanisms and may facilitate consolidating even weakly encoded, unrelated events into long-term memory. Based on animal studies, exposure to novelty activates dopaminergic neuronal networks and, thus, the memory consolidation mechanisms. These networks mature and deteriorate throughout human development, but the consequences to environmental novelty-related responses in memory are still unknown. This study examined the effects of environmental novelty on verbal and landmark memory in different ages throughout human development. In the present study, participants (n = 439) in different age groups explored novel or familiar VR environments in two exploration rounds, with landmarks presented on the second round. Simultaneously, their paths in the VR environment were constantly tracked. Afterwards, words were introduced during a deep or shallow encoding task, and the level of the memory performance for recalling words and recognizing words and landmarks was measured. As expected, adolescents and young adults benefited more from environmental novelty on word recall and recognition than children or older adults. The words were recalled better after an exposure to a novel rather than to a familiar environment and in deep rather than in shallow learning conditions. In general, novelty did not interact with age or learning condition, except slightly in recognition task. In deep learning, younger adults benefited significantly more from novelty than children. In shallow learning, adolescents benefited significantly more from novelty than older adults or children. Landmarks were recognized better in a familiar rather than novel environment, and adolescents and younger adults recognized more landmarks than other age groups. The tendency to explore novel paths instead of familiar ones predicted the level of word and landmark recognition, but not for word recall. Older age was not associated with a reduced tendency to explore novel paths. As a conclusion, younger individuals benefit more from environmental novelty than older adults, who generally show novelty detriment – this is in line with the developmental changes in the dopaminergic system.Show less
Wanneer dieren stress ervaren, kunnen zij een aantrekking of vermijding richting een nieuw object laten zien. Ondanks verschillende dierenstudies naar de invloed van stress op exploratiegedrag...Show moreWanneer dieren stress ervaren, kunnen zij een aantrekking of vermijding richting een nieuw object laten zien. Ondanks verschillende dierenstudies naar de invloed van stress op exploratiegedrag richting nieuwe objecten keken, is dit bij mensen niet eerder onderzocht. Eerder onderzoek bij mensen onderzocht de rol van stress op navigatietaken en ruimtelijke taken in een virtuele omgeving. De hippocampus zou ook een mogelijk rol kunnen spelen bij de relatie tussen stress en exploratiegedrag. Verder laat onderzoek zien dat slaapduur een rol kan spelen in zowel stress als exploratiegedrag. Er is nog niet eerder gekeken naar de invloed van stress en slaapduur op exploratiegedrag, gemeten door roaming entropy, in een virtuele omgeving bij mensen. Dit wordt in de huidige studie onderzocht door stress te verhogen door middel van de Sing-a-Song Stress Test en de participanten vervolgens een virtuele omgeving, gedurende 150 seconden, te laten verkennen. Daarna dienden de participanten in te vullen wat hun gewoonlijke slaapduur was. De resultaten van de huidige studie lieten geen effect van stress en slaapduur op exploratiegedrag zien. Dit kan mogelijk verklaard worden doordat de stressmanipulatie afwijkt van de stressmanipulatie in dierenstudies, er geen nieuwigheid werd getest, individuele verschillen (e.g. persoonlijke factoren) een rol kunnen spelen, slaapduur niet werd gemanipuleerd en geen andere slaapfactoren werden geïncludeerd (e.g. slaapefficiëntie en slaapkwaliteit). Dit moet verder worden onderzocht. Aangezien dit een begin studie is naar het effect van stress en slaapduur op exploratiegedrag, is er vervolgonderzoek nodig om de vraag; ‘wat is de invloed van stress en slaapduur op exploratiegedrag?’, te beantwoorden.Show less
Anxiety disorders are highly prevalent mental disorders. Treatment of these disorders, such as exposure-based treatment, is commonly derived from the principle of fear conditioning and fear...Show moreAnxiety disorders are highly prevalent mental disorders. Treatment of these disorders, such as exposure-based treatment, is commonly derived from the principle of fear conditioning and fear extinction. In the current study the element of novelty was introduced into the process of extinction to explore how to promote fear extinction, as with standard extinction fear frequently returns over time. Extinction by means of novelty was studied in 32 human subjects using a within-subjects design. First, the participants underwent fear conditioning, in which conditioned stimuli (sounds) were paired with fearful images. This phase was directly followed by an extinction phase with a novelty-facilitated, familiar and standard extinction condition. After a time gap of a minimum of 12 to a maximum of 36 hours responses to the conditioned stimuli were tested again. Pupil size measurements and subjective arousal ratings during this post-extinction phase did not indicate an effect for novelty-facilitated extinction on the extent of fear, this may be the result of potential weak conditioning in the current study. The results of this study express the need for more research to understand the effect of novelty on fear extinction. This could contribute to future implementation of novelty in treatment of anxiety disorders.Show less
The objective of the present study was to gain a better understanding on the relationship between intolerance of uncertainty (IU) and novelty-facilitated fear extinction (NFE). Previous research...Show moreThe objective of the present study was to gain a better understanding on the relationship between intolerance of uncertainty (IU) and novelty-facilitated fear extinction (NFE). Previous research found that IU is associated with impaired extinction learning and a higher relapse rate, but not within the context of NFE. Even so, it remains unclear under which conditions and to what extent IU may influence NFE. To investigate this further, the data of 31 participants was collected in a within-subjects design. During the conditioning phase, participants were shown images of negative and neutral valence paired with neutral sounds, followed by the extinction phase where the previously conditioned sounds were paired with novel or familiar images. Both phases included control conditions where no images were presented. All participants returned to the experiment room within 18 to 36 hours for the post-extinction phase, where they heard the sounds again but without any visual stimuli. Pupil dilation was measured as an indication of arousal and IU was measured with the IU scale. The results indicate that the novelty did assist individuals with high IU in the extinction phase. The post-extinction phase showed that individuals with high IU had smaller pupil sizes when they heard sounds paired to a familiar image. Pupil sizes were, however, largest in the control conditions. The implications of NFE may have far-reaching consequences for the development of clinical treatment methods. Future research should study the effects of NFE outside laboratory settings, and explore the various ways individual characteristics might be of influence.Show less
Animal studies have shown that the exploration of novel environments has a positive effect on memory. As shown in virtual reality studies, this positive effect of novelty on memory also seems to...Show moreAnimal studies have shown that the exploration of novel environments has a positive effect on memory. As shown in virtual reality studies, this positive effect of novelty on memory also seems to hold for humans. However, one study failed to find such a positive effect. It is possible that this is due to individual differences in the novelty seeking personality trait. Therefore, in this master thesis the effect of novelty on recall and recognition memory is identified and the role of novelty seeking in these relationships is addressed. Since novelty processing is associated with dopaminergic neuromodulation in the hippocampus and novelty seeking is related to dopamine sensitivity, it was hypothesized that novelty affects hippocampus-dependent memory (recall) and that this effect is moderated by novelty seeking. No effect was expected on hippocampus-independent memory (recognition memory). Participants in the study were familiarized with a virtual environment and later explored the same (familiar) environment again or a novel one. After this exposure, the participants performed a word-learning task, a visuomotor adaptation task and a landmark test. They also filled out questionnaires regarding their mood and the novelty seeking personality trait. Hierarchical regression analyses suggested that novelty exposure has no effect on memory performance. No moderating effect of novelty seeking was found. Bayesian statistics support this null finding. Future studies need to investigate the influence of individual differences further with a wider range of novelty seekers and the inclusion of the variables age and depth of processing.Show less
