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Proactive and retroactive interference in implicit odor memory
Abstract
To test the hypothesis that longevity of odor memory is due to strong proactive interference (reduction of new learning by prior learning) and to absence of retroactive interference (reduction of prior memory by new learning), subjects, matched in age and gender with those of a previous experiment, were unknowingly exposed in two sessions to the weak concentrations of lavender or orange used before. Implicit odor memory was later tested in a separate experiment. Comparison of the results with those of the previous experiment showed that both proactive and retroactive interference occurred. These results have implications for the general theory about implicit memory for new associations, which may have to be amended when non-verbal material is used. The longevity of odor memory should be explained by the improbability of occurrence of incidences that provoke retroactive interference rather than by the absence of the retroactive interference itself.
... It seems that not focusing on olfaction implies inevitably an increase of odorant concentration necessary to the subject to be detected. Therefore, several authors (84,96,97) chose to use concentrations which are slightly above the detection threshold (Figure 3, D). ...
... Some of them (72,73) used also the term "perithreshold", meaning close to the detection threshold, although it can be either under or just above the threshold (Figure 1, B). (65,68,(93)(94)(95) ; D: weak, low concentration, low intensity, non-attentively perceived, ambient (80,81,84,93,96,97). *non-attentional detection threshold can be shifted depending on environmental factors (task complexity, cognitive state, distractor elements…) ...
... It seems that not focusing on olfaction implies inevitably an increase of odorant concentration necessary to the subject to be detected. Therefore, several authors (84,96,97) chose to use concentrations which are slightly above the detection threshold (Figure 1, D). ...
Certaines études ont montré que des odeurs subliminales – odeurs d'intensité très faible activant le système olfactif mais non perçues consciemment – peuvent impacter le comportement alimentaire. Cependant, les mécanismes sensoriels et cognitifs impliqués dans le traitement des odeurs subliminales demeurent mal connus. Ce travail de thèse avait pour but d'explorer les activations cérébrales induites par des odeurs subliminales au moyen de l'Imagerie par Résonance Magnétique fonctionnelle. Durant les acquisitions IRM, les participants sont exposés à leur insu à deux odeurs présentées à intensité subliminale puis supraliminale. Quatre réseaux cérébraux mis en évidence par Analyse en Composantes Indépendantes s’avèrent spécifiques de la condition subliminale. Ces réseaux ne sont pas propres au traitement des odeurs et semblent liés à des processus attentionnels et de contrôle exécutif. La modulation de leur activité par des odeurs subliminales apporte des éléments nouveaux pour comprendre l’impact de ces odeurs sur le comportement, et suggère des applications possibles d'utilisation de ces odeurs pour réguler le comportement alimentaire.
... This claim has recently been challenged on the basis of new evidence and criticism of the supporting evidence provided by Lawless and Engen (1977). Köster, Degel, and Piper (2002) argued that the intentional paired-associate procedure employed by Lawless and Engen (1977) provides a poor model for the incidental learning about odors that characterizes odor memory in real life. In particular, with intentional procedures, participants are likely to adopt learning strategies that enhance resistance to interference. ...
... In their own experiment on interference in odor memory, Köster et al. (2002) used a procedure that appears to produce both implicit learning-or 'learning without awareness'-and implicit memory-that is, detection of the eVects of previous experience in the absence of conscious recall of that experience. In earlier experiments, this group had found that participants gave a higher rating for the 'Wt' of a particular odor to a room shown in a photograph if they had previously been tested in that room when the odor was present but not noticed; this eVect occurred even though almost no participant realized that they were involved in a memory experiment (Degel & Köster, 1999;Degel, Piper, & Köster, 2001). ...
... In earlier experiments, this group had found that participants gave a higher rating for the 'Wt' of a particular odor to a room shown in a photograph if they had previously been tested in that room when the odor was present but not noticed; this eVect occurred even though almost no participant realized that they were involved in a memory experiment (Degel & Köster, 1999;Degel, Piper, & Köster, 2001). In their most recent experiment they found that this eVect could be eVectively abolished both by a proactive interference procedure-prior exposure to the target odor in another testing room-and by a retroactive procedure-subsequent exposure to the target odor in another testing room (Köster et al., 2002). The two odors used in this experiment were highly familiar to the French participants, namely, orange and lavender, with the consequence that many participants were able to identify the odors. ...
Experiencing two odors as a mixture can later increase their perceived similarity when presented separately. Such an increase in similarity can be used as an implicit measure of how well participants remember the mixture. Three experiments tested the resistance to interference of this effect by first giving participants exposure to two 2-odor mixtures and then presenting each odor from one mixture (interfered pair) separately many times. After the latter interference phase, participants rated the similarity of the two odors in each pair. The experiments varied in terms of the number of initial exposures to the mixtures, the number of odor presentations in the interference phase, and the control conditions employed. No difference in similarity ratings for the interfered and non-interfered pair was found in any experiment. In contrast to the lack of interference with this implicit measure, an explicit measure of memory based on participants’ ratings of odor frequency revealed that they could recall to some degree that the interfered odors had been presented alone in the second phase. These results suggest that implicit memory for odor mixtures is highly resistant to interference and is consistent with a configural encoding account of this effect.
... As suggested by Schab (1991), fewer features per stimulus may be responsible for the relatively flat forgetting curve for odours, since the presence of few features predicts less interference by odourants with the same or similar features. A reduced amount of interference in olfactory memory tasks is indeed often observed in the human literature (Schab & Crowder, 1995;Zucco, 2003), but both proactive and retroactive interference have been demonstrated (Köster, Degel, & Piper, 2002;Lawless & Engen, 1977;Stevenson, Case, & Boakes, 2005). Memory for odours is characterized by limited forgetting due to the effect of subsequent learning experiences on the previous first odour-episode associations (Herz, 2012;Yeshurun, Lapid, Dudai, & Sobel, 2009), which in turn accounts for the endurance of olfactory traces over time. ...
Sensory and consumer research often focuses more on bottom-up than top-down influences on consumers’ perception and acceptance of foods. Yet, cognitive processes create and transform incoming sensory information originating from separate senses, including olfaction, gustation, and somatosensation, into the perception of flavour. The present paper discusses five cognitive processes that affect human chemosensory perception and responses to food flavours: Attention, language, memory, learning, and metacognition. It is argued that each of these processes are important in shaping interactions with food via the chemical senses. Attention moderates perception through its distribution across the environment, fine-tuning it for particular stimuli. Interactions among smells, tastes, and textures are acquired through learning, as are hedonic properties. Language affects food acceptability and preference, as does the memory of prior experiences with a food, even when they are not at a conscious level of processing. Metacognitive knowledge of personal capabilities indirectly influences the results of sensory evaluations. Future sensory and consumer research should take into account the significant role that these cognitive factors play in processing incoming chemosensory information.
... Also, the same component is experienced differently across time, and as a result of experience and context. Finally, memory for odors is shown to be different than visual or sound memory, with smells most often remembered in episodic memory (Koster et al. 2002). Thus, the physical nature of the stimuli combined with the nature of receptors, and our limited memory and cognitive capacities, lead to odor not being organized in a structured whole. ...
... Another option is that the nature of the memory here used to correctly remember the BO is implicit in nature, and therefore explicitly questioning the participants on the recognition of the BO may not be ideal to reveal whether and how the odor information was encoded. This would not be uncommon in the olfactory domain since implicit learning occurs reliably for odors, as repeatedly demonstrated by Ko¨ster, Degel, and Piper (2002). ...
Accurate identification of encoded contextual details depends on recapitulation processes during retrieval. Encoding and retrieval conditions are known to influence the sensory material stored and its recapitulation, however, little is known about such processes in olfaction. Here, we capitalized on the uniqueness of body odors which, similarly to fingerprints, allow for the identification of a specific person, by associating their presentation to a negative or a neutral emotional context. A total of 105 participants (57F, divided into 4 groups) were exposed to male body odors (BO) while watching either criminal or neutral videos (encoding phase) and were subsequently asked to recognize the target BO within either a congruent or an incongruent visual context (retrieval phase). Preliminary results obtained applying signal detection theory suggest that accurate identification (d’) of the BO is more likely to occur when the encoding and retrieval contexts are congruent. Additionally, when the contexts are incongruent, encoding in a neutral context consistently facilitate subsequent identification of BO. The impact of demographic and individual differences as well as BO perceptual features is evaluated. These findings elucidate how memories are processed in emotional situations and implications for nose-witness culprits’ identification are discussed.
... Another option is that the nature of the memory here used to correctly remember the BO is implicit in nature, and therefore explicitly questioning the participants on the recognition of the BO may not be ideal to reveal whether and how the odor information was encoded. This would not be uncommon in the olfactory domain since implicit learning occurs reliably for odors, as repeatedly demonstrated by Ko¨ster, Degel, and Piper (2002). ...
Conditions during information encoding and retrieval are known to influence the sensory material stored and its recapitulation. However, little is known about such processes in olfaction. Here, we capitalized on the uniqueness of body odors (BOs) which, similar to fingerprints, allow for the identification of a specific person, by associating their presentation to a negative or a neutral emotional context. One hundred twenty-five receivers (68 F) were exposed to a male BO while watching either criminal or neutral videos (encoding phase) and were subsequently asked to recognize the target BO within either a congruent or an incongruent visual context (retrieval phase). The results showed that criminal videos were rated as more vivid, unpleasant, and arousing than neutral videos both at encoding and retrieval. Moreover, in terms of BO ratings, we found that odor intensity and arousal allow to distinguish the target from the foils when congruent criminal information is presented at encoding and retrieval. Finally, the accuracy performance was not significantly different from chance level for either condition. These findings provide insights on how olfactory memories are processed in emotional situations.
... Tuttavia queste analisi delle metafore concettuali 3 soggiacenti alle descrizioni olfattive hanno importanti limitazioni. Per prima cosa, evidenze sperimentali (Köster et al., 2002) avevano già mostrato uno stretto legame implicito fra ricordi olfattivi e luoghi. Ma, paradossalmente, proprio da questi studi emerge come il legame odori-luoghi sia soggetto a interferenze che possono provenire proprio dal linguaggio. ...
- The Role of Literal and Figurative Language Olfaction is still the less investigated of the sensory modalities. This also reflects the fact that olfaction is the most subjective and emotional sensory modality and the one with the fewer relationships with verbal language. Since metaphors are cognitive bridges between perception and language, in principle they might be more effective in giving voice to olfaction, the "speechless sense". However, research in this fascinating field is still in its infancy, and the linguistic and psychological results are still scarce and contradicting. Key Words: Cross modal interactions, Language, Metaphor, Olfaction, Perception, Synaesthetic metaphors.
... The change in methodology between studies highlighted differences between the distinct processes of learning and memory. Within the learning process, proactive interference is defined as a reduction of new learning due to prior learning while retroactive interference is described as a reduction of previously learned material caused by the learning of new material (Koster, Degel, & Piper, 2002). The majority of retroactive interference research is modeled by methods used in Study 1 but fail to differentiate between influences acting on learning versus memory. ...
Three experiments were conducted to assess interference effects acting on procedural task learning and performance using the Tower of Hanoi puzzle. In Experiment 1, participants in the no-interference group completed the Tower of Hanoi faster than the retroactive interference groups, with no differences between the types of tactile interference. These results indicate that retroactive interference may hinder procedural task performance but does not differentiate between consolidation and retrieval. Experiment 2 addressed retroactive interference placement by manipulating the delay prior to the interference task. Interfering with only consolidation or recall did not produce interference effects, but qualitative feedback regarding emotion raised questions about the effects of affect induction. Experiment 3 attempted to address the influence of a proactive and retroactive affect induction technique but did not produce a dichotomous happy versus neutral effect. Overall, the series of experiments conducted provides a conceptual replication of some previous research while contradicting other findings. This research not only extends our current understanding but also highlights the need to continue to explore factors that may influence the practice or acquisition of novel procedural tasks.
... It should be noted that the stimuli need not necessarily be verbal in order to observe PI in the perceptual representation system; for example, Köster et al. (2002) demonstrated PI in implicit memory for odors. ...
Proactive interference (PI) is when something learned earlier impairs the ability to remember something learned more recently. PI can be observed in all subject populations and in all memory systems, including the perceptual representation system, procedural memory, semantic memory, long-term episodic memory, and short-term/working memory. One current theoretical account of PI attributes its cause to cue overload: the more items a cue subsumes, the less effective the cue will be. Other accounts suggest that items learned earlier can reduce the distinctiveness of current items, making successful retrieval less likely.
... In addition, memory for a novel scent is also susceptible to RI (Walk and Johns, 1984;Köster et al., 2002;Olsson et al., 2009;Morrin et al., 2011), despite having previously been thought to be immune (Engen and Ross, 1973;Lawless and Engen, 1977). Walk and Johns (1984) investigated RI in scent memory by exposing participants to two food scents, followed by (or notcontrol condition) further potentially interfering 'unhelpful' stimuli (a third scent; the name of a third scent), or 'helpful' stimuli (the name of one of the original two scents). ...
Retroactive interference (RI) refers to when newly acquired information impairs the retention of previously acquired information. RI is observed in both the declarative and nondeclarative divisions of the long-term memory system. RI is observed across the life span. However, susceptibility to RI is heightened in the elderly and patients with memory impairments. RI is believed to occur via two mechanisms: (1) retrieval interference, where two or more memories sharing the same/highly similar retrieval cue compete for retrieval, and (2) consolidation interference, where new incoming information disrupts the memory strengthening of recently acquired memory traces. Consolidation RI appears to be the main contributor of RI-induced forgetting, the effects of which can be reduced if consolidation RI is delayed and/or minimized. Here we discuss representative behavioral and neuroscience research demonstrating the effects of RI.
... Indeed, scents can alter our perception, cognition, behavior, and physiology (e.g., heart rate, skin conductance) even when there is no conscious scent detection (Li et al., 2007; Pause et al., 2009; Sela and Sobel, 2010; Krusemark and Li, 2012), and even after olfactory adaptation has set in (de Groot et al., 2012; Smeets and Dijksterhuis, 2014). Thus, neither prior associations with olfactory signals, nor conscious processing, are necessary conditions for people to process them as threatening (Köster et al., 2002; Williams et al., 2006; Sela and Sobel, 2010; Pause, 2012; Smeets and Dijksterhuis, 2014). At the most basic level, threat detection increases vigilance and sharpens our reactions to events in the environment (Williams et al., 2006). ...
... First, we tested the hypothesis that non-conscious (unobtrusive) exposure to putrescine 23 could elicit threat management responses. As we highlighted in the Introduction, this possibility 24 is consistent with evidence that scent primes, even when presented at sub-threshold levels, can 25 influence brain activation (Sobel et al., 1999), learning (Koster et al., 2002), and physiological 26 state (Stern & McClintock, 1998). This applies similarly to aversive scent primes, which for 27 example, have the ability to alter skin conductance (Jacquot et al., 2004), social preferences (Li 28 et al., 2007), and cognitive performance (Epple & Herz, 1999) in ways that correspond to 29 supraliminal exposure to aversive stimuli (Sela & Sobel, 2010). ...
The ability to detect and respond to chemosensory threat cues in the environment plays a vital role in survival across species. However, little is known about which chemical compounds can act as olfactory threat signals in humans. We hypothesized that brief exposure to putrescine, a chemical compound produced by the breakdown of fatty acids in the decaying tissue of dead bodies, can function as a chemosensory warning signal, activating threat management responses (e.g., heightened alertness, fight-or-flight responses). This hypothesis was tested by gaging people’s responses to conscious and non-conscious exposure to putrescine. In Experiment 1, putrescine increased vigilance, as measured by a reaction time task. In Experiments 2 and 3, brief exposure to putrescine (vs. ammonia and a scentless control condition) prompted participants to walk away faster from the exposure site. Experiment 3 also showed that putrescine elicited implicit cognitions related to escape and threat. Experiment 4 found that exposure to putrescine, presented here below the threshold of conscious awareness, increased hostility toward an out-group member. Together, the results are the first to indicate that humans can process putrescine as a warning signal that mobilizes protective responses to deal with relevant threats. The implications of these results are briefly discussed.
... Because the brain integrates aroma stimuli with past experiences, an individuals' memory plays an important role in odor perception. Research has shown that an individuals' first encounter with an odor is remembered over a long time (Koster, Degel, & Piper, 2002). Many of these memoryeodor associations are formed as adolescents (Chu & Downes, 2000;Herz, 2004), and are often linked in the brain with a basic emotion (Alaoui-Ismaili, Robin, Rada, Dittmar, & Vernet-Maury, 1997;Croy, Olgun, & Joraschky, 2011). ...
Poor hand hygiene is a leading cause for the spread of foodborne illnesses in the foodservice industry. A series of complex motivational interventions must be employed to permanently change the behavior of workers, to increase their compliance and sustain appropriate levels of proper hand hygiene. Unlike the healthcare industry, which uses large, costly multi-modal behavior modification strategies, the foodservice industry must deploy rapid, cost-efficient strategies that take into account a high employee turnover rate and diverse demographics. This paper reviews the current motivational models used in the foodservice industry and examines the habitual nature of complying with good hand hygiene. It also reviews current techniques to increase hand hygiene compliance using clues from three of the five basic senses (sight, hearing, and smell) and two mechanisms (context-bridging and disgust). Lastly, the current model for habit intervention is evaluated, and its possible applications in the foodservice industry with additional reminders are accessed. We believe that this review will provide foodservice managers the background, theoretical basis and practical applications for making long-term changes in their employees on this and similar critical behaviors in foodservice.
... It has been proposed that the preconditions for declarative olfactory memory may not be optimal. For example, olfactory information often goes unnoticed and barely evokes attention in humans (Köster et al. 2002;Sela and Sobel 2010) and semantic activations that are a prerequisite for optimal episodic memory functioning are typically restricted. A verbal abstraction of incoming information enables a conscious categorization that favors a distinct representation and subsequent successful retrieval. ...
Few attempts have been made to develop an olfactory test that captures episodic retention of olfactory information. Assessment of episodic odor memory is of particular interest in aging and in the cognitively impaired as both episodic memory deficits and olfactory loss have been targeted as reliable hallmarks of cognitive decline and impending dementia. Here, 96 healthy participants (18-92 years) and an additional 19 older people with mild cognitive impairment were tested (73-82 years). Participants were presented with 8 common odors with intentional encoding instructions that were followed by a yes-no recognition test. After recognition completion, participants were asked to identify all odors by means of free or cued identification. A retest of the odor memory test (Sniffin' TOM = test of odor memory) took place 17 days later. The results revealed satisfactory test-retest reliability (0.70) of odor recognition memory. Both recognition and identification performance were negatively affected by age and more pronounced among the cognitively impaired. In conclusion, the present work presents a reliable, valid, and simple test of episodic odor recognition memory that may be used in clinical groups where both episodic memory deficits and olfactory loss are prevalent preclinically such as Alzheimer's disease.
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... The most convincing demonstration that odor identification, being the most outspoken form of explicit awareness, is not a necessary prerequisite in odor memory comes from experiments demonstrating the memory relationship between odors and the places where they were present without being consciously noticed ( Köster, 1998, 1999; Degel et al., 2001; Köster et al., 2002). It was shown that people who had been unknowingly exposed to very slight and consciously unnoticed odors in rooms in which they performed a psychological test, would later, in a seemingly unrelated experiment on room odor selection indicate the exposure odor as fitting the room much better than people who had not been exposed to odor in that room, but only when they could not identify the odor by name. ...
Our senses have developed as an answer to the world we live in (Gibson, 1966) and so have the forms of memory that accompany them. All senses serve different purposes and do so in different ways. In vision, where orientation and object recognition are important, memory is strongly linked to identification. In olfaction, the guardian of vital functions such as breathing and food ingestion, perhaps the most important (and least noticed and researched) role of odor memory is to help us not to notice the well-known odors or flavors in our everyday surroundings, but to react immediately to the unexpected ones. At the same time it provides us with a feeling of safety when our expectancies are met. All this happens without any smelling intention or conscious knowledge of our expectations. Identification by odor naming is not involved in this and people are notoriously bad at it. Odors are usually best identified via the episodic memory of the situation in which they once occurred. Spontaneous conscious odor perception normally only occurs in situations where attention is demanded, either because the inhaled air or the food smell is particularly good or particularly bad and people search for its source or because people want to actively enjoy the healthiness and pleasantness of their surroundings or food. Odor memory is concerned with novelty detection rather than with recollection of odors. In this paper, these points are illustrated with experimental results and their consequences for doing ecologically valid odor memory research are drawn. Furthermore, suggestions for ecologically valid research on everyday odor memory and some illustrative examples are given.
... Most studies discuss "external context'', which refers to any extrinsic influence on perception or behavior. Thus, many studies on context have focused on environmental and task-based influences, such as repeated exposure, location/occasion, scaling anchor type, instructions or information given to participants, such as brand names and nutritional information (Edwards et al., 2003;Hersletch et al., 2003;King et al., 2004;Köster et al., 2002;Popper et al., 2004). In this article we focus on another kind of context effect: the "internal context," here called "mental context." ...
The experiments conducted in this research aimed to increase our understanding of olfactory properties and classify them hierarchically through entailment. The research objective was to build an odor classification based on internal knowledge (i.e. mental context). Twelve floral scents were described freely by 60 participants. First, three sensory judges undertook a semantic analysis of the 1145 olfactory terms gathered. Secondly, a study of the entailment between olfactory properties was conducted using 42 subjects working on four lists of terms describing the characteristics of floral perfumes. The results confirmed the hypothesis that olfactory properties show tree-like structure. This allowed us to propose a classification system composed of two superordinate categories: First, objects, being olfactory sources, constitute the first category and are considered as olfactory properties themselves (i.e. civilization, food and natural sources). Second non-objects properties are those applicable to a diversity of objects: (i.e. properties, such as objects' physical state: sensory, intensity, space, time) and those related to the subject (as personal feelings and value judgments). Based on these results, it appears that olfactory properties can be organized as a semantic network in line with the general theory of categorization.
... This procedure, also known as counter-conditioning (Bouton, 2004), is associated with slower development of a conditioned response (Nasser and McNally, 2012). Finally, the sense of smell primarily acts beyond consciousness (Koster et al., 2002), presumably due to its unique anatomical (i.e. no thalamic intermediary; Carmichael et al., 1994;Gottfried, 2006) and physiological (i.e. ...
Pavlovian fear conditioning has been thoroughly studied in the visual, auditory and somatosensory domain, but evidence is scarce with regard to the chemosensory modality. Under the assumption that Pavlovian conditioning relies on the supra-modal mechanism of salience attribution, the present study was set out to attest the existence of chemosensory aversive conditioning in humans as a specific instance of salience attribution. fMRI was performed in 29 healthy subjects during a differential aversive conditioning paradigm. Two odors (rose, vanillin) served as conditioned stimuli (CS), one of which (CS+) was intermittently coupled with intranasally administered CO2. On the neural level, a robust differential response to the CS+emerged in frontal, temporal, occipito-parietal and subcortical brain regions, including the amygdala. These changes were paralleled by the development of a CS+-specific connectivity profile of the anterior midcingulate cortex (aMCC), which is a key structure for processing salience information in order to guide adaptive response selection. Increased coupling could be found between key nodes of the salience network (anterior insula, neo-cerebellum) and sensorimotor areas, representing putative input and output structures of the aMCC for exerting adaptive motor control. In contrast, behavioral and skin conductance responses did not show significant effects of conditioning, which has been attributed to contingency unawareness. These findings imply substantial similarities of conditioning involving chemosensory and other sensory modalities, and suggest that salience attribution and adaptive control represent a general, modality-independent principle underlying Pavlovian conditioning.
... M = .49). The authors concluded that odor recognition memory can indeed be interfered with (see also Koster, Degel, & Piper, 2002;Olsson, Lundgren, Soares, & Johansson, 2009). ...
Research shows that scent enhances memory for associated information. Current debate centers around scent's immunity to “retroactive interference,” i.e., reduced memory for earlier-learned information after exposure to additional, subsequently-learned information. This paper demonstrates that scent-enhanced memory is indeed prone to retroactive interference, but that some of the information lost is restored using a
scent-based retrieval cue. Two process explanations for interference effects are proposed, with the evidence providing more support for an inhibition rather than a response competition explanation. The results enhance our understanding of the encoding and retrieval of olfactory information from long-term memory, and reasons why interference occurs.
... As such, the current data argue for implicit testing as a suitable means, which is justified by two reasons. First, the sense of smell is often regarded as ''hidden sense'' as it primarily acts beyond consciousness [46], presumably due to its unique anatomical (i.e. no thalamic intermediary; [8,47]) and physiological (i.e. ...
Navigation based on chemosensory information is one of the most important skills in the animal kingdom. Studies on odor localization suggest that humans have lost this ability. However, the experimental approaches used so far were limited to explicit judgements, which might ignore a residual ability for directional smelling on an implicit level without conscious appraisal.
A novel cueing paradigm was developed in order to determine whether an implicit ability for directional smelling exists. Participants performed a visual two-alternative forced choice task in which the target was preceded either by a side-congruent or a side-incongruent olfactory spatial cue. An explicit odor localization task was implemented in a second experiment.
No effect of cue congruency on mean reaction times could be found. However, a time by condition interaction emerged, with significantly slower responses to congruently compared to incongruently cued targets at the beginning of the experiment. This cueing effect gradually disappeared throughout the course of the experiment. In addition, participants performed at chance level in the explicit odor localization task, thus confirming the results of previous research.
The implicit cueing task suggests the existence of spatial information processing in the olfactory system. Response slowing after a side-congruent olfactory cue is interpreted as a cross-modal attentional interference effect. In addition, habituation might have led to a gradual disappearance of the cueing effect. It is concluded that under immobile conditions with passive monorhinal stimulation, humans are unable to explicitly determine the location of a pure odorant. Implicitly, however, odor localization seems to exert an influence on human behaviour. To our knowledge, these data are the first to show implicit effects of odor localization on overt human behaviour and thus support the hypothesis of residual directional smelling in humans.
... Holland et al (2005) checked the participants' awareness of scent after the experiment, and indicated that only a few of them were aware of the odour, confirming that the implicit exposure to an odour can automatically enhance the accessibility of related concept. Our data provide a strong argument in favour of odours implicitly interacting with vision Ko« ster 1998, 1999;Ko« ster et al 2002) and that the retrieval of odour^visual associations can occur automatically (see also Castiello et al 2006;Gottfried and Dolan 2003, for a converging proposal). Yet these findings are not sufficient to claim that such a process takes place in an unconscious manner as they rely solely on explicit reports. ...
Crossmodal linkage between the olfactory and visual senses is still largely underexplored. In this study, we investigated crossmodal olfactory-visual associations by testing whether and how visual processing of objects is affected by the presence of olfactory cues. To this end, we explored the influence of prior learned associations between an odour (eg odour of orange) and a visual stimulus naturally associated with that odour (picture of orange) on the movements of the eyes over a complex scene. Participants were asked to freely explore a photograph containing an odour-related visual cue embedded among other objects while being exposed to the corresponding odour (subjects were unaware of the presence of the odour). Eye movements were recorded to analyse the order and distribution of fixations on each object of the scene. Our data show that the odour-related visual cue was explored faster and for a shorter time in the presence of the congruent odour. These findings suggest that odours can affect visual processing by attracting attention to the possible odour source and by facilitating its identification.
... The subsequent presentation of a relevant odor can spontaneously retrieve the related memory (Cann & Ross, 1989;Pointer & Bond, 1998;Smith, Standing, & DeMann, 1982). These associations are resistant to extinction (Engen & Ross, 1973;Herz & Cupchik, 1992Herz & Engen, 1996), and so it is hard to establish new ones when an odor brings back earlier memories (Engen, 1991;Köster, Degel, & Piper, 2002;Lawless & Engen, 1977). ...
Thirty-two undergraduates inhaled odors while outlining episodes, set in 8 living rooms, involving either themselves or the actual inhabitants. They rated odors, rooms, and episodes on 7-point scales and were tested for odor recognition. Episodes were content analyzed, and the frequency of categories was assessed. Separate factor analyses determined relationships between rating scales and content analysis categories. Regression analysis showed greater odor recognition when participants judged the odor to fit the imagined episode but less recognition when an unpleasant odor was incongruously paired with a warm episode. Odor recognition also was greater when the narrative outlines described familiar characters figuring out the scenes. Results supported the congruity hypothesis, whereby odors become markers for meaningful scenes with which they fit.
... Not all findings, however, agree with this conclusion. Koster, Degel, and Piper (2002) reported that retroactive interference affected an implicit odor memory task, in which participants were asked to judge the 'goodness of fit' between pictures of a room and particular odors. Participants who had experienced an odor in one room, and then later received the same odor within a different room, experienced retroactive interference, but only if they could not identify the odorant. ...
Olfactory memory is especially persistent. The current study explored whether this applies to a form of perceptual learning, in which experience of an odor mixture results in greater judged similarity between its elements. Experiment 1 A contrasted 2 forms of interference procedure, 'compound' (mixture AW, followed by presentation of new mixtures each containing 1 of its elements, AX and OW) and 'elemental' (mixture CY, followed by presentation of its elements C and Y) against a non exposed control. Learning was evident in both interference conditions to the same degree, relative to the control. Experiment 1 B established that the interference conditions did not significantly differ from uninterfered paired controls. Experiment 2 compared the 'compound' procedure with 2 exposed control conditions and assessed whether participants had acquired the interfering mixtures too (AX and OY). Learning was evident in the 'compound' treated pair (AW) and also for the mixtures AX and OW that made up the interfering compounds. These results are problematic for configural Elxplanations and a new formulation is suggested.
... Implicit associations were assessed independently of, and did not match, explicit associations between the concepts. Although the distinction between implicit versus explicit information processing has received attention previously in the odor literature (e.g., Nordin et al. 1995; Degel and Kö ster 1999; Kö ster et al. 2002; Dematte et al. 2006), it has not been applied in the context of odors as signals of illness or health (but see: Witthö ft et al. 2006). The finding that people intrinsically associate the concept odor with illness, regardless of self-reported attitudes, raises the question as to the purpose served by such fast and automatic associations between odors and illness, rather than between odors and health. ...
Some individuals ascribe health symptoms to odor exposures, even when none would be expected based on toxicological dose-effect
relationships. In these situations, symptoms are believed to have been mediated by beliefs regarding the potential health
effects from odorants, which implies a controlled type of information processing. From an evolutionary perspective, such a
form of processing may hardly be the only route. The aim of the present study was to explore the viability of a fast and implicit
route, by investigating automatic odor-related associations in the context of health. An Implicit Association Test assessing
association strengths between the concept odor and the concepts healthy and sick was conducted. Three experiments (N = 66, N = 64, and N = 64) showed a significantly stronger association between the concepts odor and sick than between odor and healthy. These
results did not match explicit associations and provide evidence for a fast and automatic route of processing that may complement
consciously controlled processes. A dual-processing theory of olfactory information is proposed leading to new hypotheses
regarding the development and maintenance of odor-induced health symptoms.
... We can note that the well-known Proustian effect, whereby an odor can recreate the distant past, complete with sights, sounds, and emotions, would seem on its surface to involve implicit processes. Others have explored phenomena of relevance to that experience, with reasonable success (see Köster, Degel, & Piper, 2002). Smell may, as usual, bring up the rear, but in the case of implicit memory it may have some unique dimensions to add to the corpus of results. ...
In two experiments, implicit and explicit tests were used to investigate the lateralization of odor memory. Odors were at all times presented monorhinically. At test, odors were presented to either the ipsi- or the contralateral side of the nostril used for inspection. In Experiment 1, participants were first primed to a set of odors. At test, response latencies for odor identification were measured. The results were that priming odors tested via the left but not the right nostril were identified faster than control odors. In Experiment 2, a similar design probed episodic recognition memory. Memory performance did not differ between the left and right nostrils, but the measures of response latency favored the right side. The study demonstrates that it is possible to tap differences in memory performance between the cerebral hemispheres through monorhinic presentation of odors in healthy persons, and that these differences depend on the test nostril rather than the inspection nostril.
... Or are odours indeed encoded as perceptual entities [8][9][10][11], that are automatically remembered in association with the situation in which they are encountered [12]? This latter possibility seems most likely, since it has been shown, that even monomolecular odours may be perceived as complex composites of sensory impressions [13,14]. Thus, remembering sensory features would be a more demanding task, than rejecting odours that are not connected with a previous encounter. ...
Studies of human odour memory have in most cases been obscured by the experimental designs utilised, in which verbal memory played a crucial role in the subjects' performance. Previously, attempts have been made to minimise verbal mediation in the assessment of odour memory by the use of incidental or implicit learning, which is how odours are learned in everyday life; it is still under debate whether this form of learning is age-dependent or not. In this experiment we make use of very uncommon odours and show that incidental learning of odours is as good in elderly people as in the young, whereas intentional learning is better in young people.
... The opposite can also occur, inducing a case of proactive interference. Research has been reported in the literature indicating the existence of both types of interference in the sensory olfactory modality (Köster, Degel, & Piper, 2002;Lawless & Engen, 1977;Walk & Johns, 1984). ...
In order to provide insights into why discrimination protocols with three stimuli sometimes tend to be less sensitive than protocols with two stimuli, two experiments were conducted. In these experiments, the relative effects of memory decay and memory interference were investigated. Both experiments involved purified water and/or solutions of low NaCl concentration. In Experiment 1, three protocols were compared: the traditional same-different test (Protocol 1), the same protocol with a rinse between the two samples (Protocol 2), and Protocol 2 with an added time delay between the first sample and the intermediate rinse (Protocol 3.) The decrease in measured d' values as time delay increased indicated that memory decay might be a factor for tests with three stimuli, such as the triangle method, rendering it less sensitive than tests with two stimuli, such as the same-different method. In Experiment 2, four protocols were compared: the traditional same-different test, the two-rinse same-different test, the triangle test, and what will be called duo same-different test. The experimental design allowed the individual consideration of memory decay and interference effects. From this last experiment, the substantial effect of memory interference was uncovered. Further experimentation will be necessary to estimate the exact relative effects of memory interference and memory decay.
... Incidental odor learning and implicit memory were studied by Degel et al. (2001) and Köster et al. (2002). While performing psychological tests, subjects were exposed to weak odors that remained unnoticed, as checked by debriefing and four independent behavioral criteria) see Degel et al., 2001). ...
... Although the distinction between implicit versus explicit information processing has received attention previously in the odor literature (e.g. Nordin et al., 1995; Degel & Köster, 1999; Köster et al., 2002; Dematte et al., 2006), it has not been applied in the context of odors as signals of illness or health (but see: Witthöft et al., 2006). The finding that people intrinsically associate the concept odor with illness, regardless of selfreported attitudes, raises the question as to the purpose served by such fast and automatic associations between odors and illness, rather than between odors and health. ...
Health symptoms attributed to environmental odor exposure are not well understood. Cognitive factors seem to play a significant role in odor-related illness. In the present study, we investigated whether such influences are predominantly interpretational (i.e. best understood as interpretations of perceived odors), or also perceptual (i.e. affect perceptions of the characteristics of the odor). To investigate the neuronal activation behind such processes olfactory ERPs were recorded. The experiment consisted of two conditions: one where participants expected just several administrations of one odor (labelled as the "non-painful" condition), and one where they also expected, in between the odor administrations, to feel irritation in the nose (labelled as the "painful" condition). Participants received painless H(2)S stimuli during both conditions. To reinforce pain-expectancy, a CO(2) pulse was given occasionally during the "painful" condition. Crucial comparisons were made between reactions to H(2)S, under the two expectancy conditions. Detection sensitivity (reflected by amplitudes and latencies of the early N1 peak) and stimulus salience (reflected by amplitudes and latencies of the late "cognitive" positivity) were examined. Peak amplitudes were unaffected by expectancy condition. However, a significant main effect of expectancy on the N1 latency was found, which suggests that expecting a painful stimulus reduces the time to detect a harmless odor. In conclusion, expectancies seem to alter early aspects of odor perception.
To detect and organize trillions of possible volatile molecules, the human olfactory system deploys approximately 3% of the genes in the human genome as olfactory receptors. Our understanding of how the olfactory system organizes the resulting information has many gaps, and relative to other sensory systems, our current ability to measure and reproduce smells is poor. Here we cover the anatomy, circuitry, and psychophysics of olfaction, with an emphasis on the gaps that prevent us from measuring an odor, representing it digitally, and reproducing a perceptual target from a set of sensory primaries.
Even though rarely thought of, all environmental spaces contain odor information. It has been proposed that the preconditions for episodic olfactory memory
may not be optimal. For example, environmental olfactory information often goes unnoticed and barely evokes attention in humans and semantic activations that are a prerequisite for optimal episodic memory functioning are typically restricted. Still, it is highly likely that olfactory information will become part of a memory representation that is linked to a specific event. This implies that an event-congruent exposure of an odor carries the potential to trigger all, or parts of, a previous episode. Indeed, available evidence shows that odors may serve as powerful reminders of past experiences. This is demonstrated by studies exploring the nature of odor-evoked autobiographical memories
and by controlled experimental paradigms where odors have been embedded in a learning context and later reinstated at retrieval where an increased memory recollection for the target information is often observed. These observations converge on the notion that odor memories are retained over long periods oftime.
In this chapter, we will highlight olfactory cueing of memory and how odors may act as reminders of the recent and distant past.
Sensory memory plays an important role in perception. This chapter discusses the spontaneous and implicit sensory learning and memory processes as they function in the ordinary person in everyday life. Implicit sensory memory differs in a number of aspects in face recognition and odour recognition; both depend strongly on incidental learning. Although discrimination is equally good in both cases, identification of faces is much easier than identification of odours. Odour-odour learning and the changes in the odour perception it provokes are indeed a unique aspect of olfactory sensory memory and perception. In the memory-testing session, the implicit sensory memory effect of the target stimuli, should be shown by measures that are free from verbal or semantic memory. The importance of sensory memory, as the basis for the expectations with which consumers approach new products, is still underestimated.
The present study reports normative ratings for 200 food and non-food odors. One hundred participants rated odors across measures of verbalisability, perceived descriptive ability, context availability, pleasantness, irritability, intensity, familiarity, frequency, age of acquisition, and complexity. Analysis of the agreement between raters revealed that four dimensions, those of familiarity, intensity, pleasantness, and irritability, have the strongest utility as normative data. The ratings for the remaining dimensions exhibited reduced discriminability across the odor set and should therefore be used with caution. Indeed, these dimensions showed a larger difference between individuals in the ratings of the odors. Familiarity was shown to be related to pleasantness, and a non-linear relationship between pleasantness and intensity was observed which reflects greater intensity for odors that elicit a strong hedonic response. The suitability of these data for use in future olfactory study is considered, and effective implementation of the data for controlling stimuli is discussed.
This chapter discusses how sensory evaluation is used in various non-food sectors. The relative importance of each sense to perception in different circumstances is examined, and general guidelines regarding the set-up of tests, including environment and method, are described. Examples based on industrial case studies or international standards for different product categories are included, focusing on the critical senses involved.
Olfaction is an unavoidable and ubiquitous source of perceptual experience from the earliest stages of mammalian development. This chapter summarizes current understanding of how olfaction functions in concert with the other senses during human development, and the various ways early multisensory effects involving the chemical senses operate. This chapter first summarises aspects of current biological and psychological knowledge concerning olfaction in humans in order to provide some functional principles useful to understand the development of chemosensation in the context of multisensory processes. Finally, the available results concerning odour-based intersensory effects are reviewed.
RESUMO (PT): Uma das formas mais antigas de os organismos se relacionarem entre si e com o meio envolvente é através da estimulação química olfativa, que desempenha um papel determinante em comportamentos de sobrevivência. Os odores corporais modelam a nossa interação com os outros, funcionando como um alerta para potenciais ameaças e despoletando respostas de luta/fuga. Devido à sua relevância ecológica, este tipo de odores é processado de modo singular, relativamente aos odores comuns, constituindo uma área de investigação recente.
A inexistência de estudos que explorem as aplicações dos odores corporais em situações de crime, utilizando alinhamentos em que o reconhecimento seja feito por humanos, levou-nos a conduzir esta investigação. Aliado ao facto de que somos bons na deteção e discriminação de odores e que cada indivíduo possui um odor corporal único que pode ser transferido entre pessoas e objetos, colocámos como principal questão de investigação se serão essas capacidades potenciadas em circunstâncias que envolvam maior vulnerabilidade física e emocional (e.g., crimes).
Foram apresentados filmes de crime (grupo experimental) e filmes de controlo (grupo de controlo) ao mesmo tempo que os participantes cheiravam um odor corporal, que instruímos ser do perpetrador no caso dos filmes de crime, ou do homem presente no caso dos filmes de controlo. Os participantes teriam de, por aprendizagem acidental, reconhecer em alinhamento o odor a que estiveram expostos durante o filme.
Os principais resultados mostraram que o grupo experimental teve maior número de acertos (68%) comparativamente com o grupo de controlo (45%), sendo esta diferença estatisticamente significativa. Os resultados apontam assim para as potenciais implicações dos odores corporais no âmbito forense ao nível da redução da probabilidade de erro no reconhecimento de pessoas inocentes e na formação de órgãos de polícia criminal que podem desenvolver estratégias para as suas investigações. A compreensão do olfato em situações onde a sobrevivência é colocada em risco pode ser crucial na intervenção com vítimas e/ou testemunhas de crime.
ABSTRACT: One of the oldest forms of how organisms relate to each other and the environment is through the olfactory chemical stimulation, which plays a key role in survival-related behaviors. Body odors shape our interaction with others, working as an alert to potential threats and therefore triggering fight and/or flight responses. Due to its ecological relevance, such odors are processed in a unique way, different from common odors, and their study represents a recent area of research.
The lack of studies exploring the applications of body odors in crime situations using line-ups in which the recognition is done by humans, led us to conduct this research. Coupled with the fact that we are good at detection and discrimination of odors and that each individual has a unique body odor that can be transferred between people and objects, our main question is whether these capabilities will increase in circumstances that involve physical and emotional vulnerability (e.g., crimes).
Participants viewed crime films (experimental group) and control films (control group) which were presented while they smelled a body odor that we instructed to be from the perpetrator in the case of the crime scenes (and from the male presented in the control scenes). The participants’ task was to recognize the target-odor in a line-up of body odors by incidental learning. The main results showed that the experimental group had a higher number of correct answers (68%) compared to the control group (45%), with this difference being statistically significant. Thus, the results point to the potential implications of body odors in forensics in reducing the probability of error in the recognition of innocent people and in the training of criminal police forces who can develop strategies for their investigations. The understanding of smell in situations where survival is at risk can be crucial in the intervention with victims and / or witnesses of crimes.
Consumer feedback and complaints provide utilities with useful data about consumer perceptions of aesthetic water quality in the distribution system. This research provides a systematic approach to interpret consumer complaint water quality data provided by four water utilities that recorded consumer complaints, but did not routinely process the data. The utilities tended to write down a myriad of descriptors that were too numerous or contained a variety of spellings so that electronic “harvesting” was not possible and much manual labor was required to categorize the complaints into majors areas, such as suggested by the Drinking Water Taste and Odor Wheel or existing check-sheets. When the consumer complaint data were categorized and visualized using spider (or radar) and run-time plots, major taste, odor, and appearance patterns emerged that clarified the issue and could provide guidance to the utility on the nature and extent of the problem. A caveat is that while humans readily identify visual issues with the water, such as color, cloudiness, or rust, describing specific tastes and odors in drinking water is acknowledged to be much more difficult for humans to achieve without training. This was demonstrated with two utility groups and a group of consumers identifying the odors of orange, 2-methylisoborneol, and dimethyl trisulfide. All three groups readily and succinctly identified the familiar orange odor. The two utility groups were much more able to identify the musty odor of 2-methylisoborneol, which was likely familiar to them from their work with raw and finished water. Dimethyl trisulfide, a garlic-onion odor associated with sulfur compounds in drinking water, was the least familiar to all three groups, although the laboratory staff did best. These results indicate that utility personnel should be tolerant of consumers who can assuredly say the water is different, but cannot describe the problem. Also, it indicates that a T&O program at a utility would benefit from identification of aesthetic issues in water.
This study examined differences in implicit and explicit memory performance between people with Down syndrome (DS), their siblings, children matched on mental age, and university undergraduates, using olfactory stimuli. The DS and mental-age matched participants were also compared on two tasks of executive function. The data revealed implicit memory for olfactory stimuli. Further, people with DS performed similarly to each control group on the implicit memory task, but performed significantly poorer than all control groups on the explicit memory task. Impairment to executive functioning was identified as a possible cause of this deficit in explicit memory as people with DS performed more poorly than the mental-age matched controls on both tasks of executive function.
Odor perception does not simply consist in hierarchical processing from transduction to a single "true" cerebral representation. Odor sensation may be modulated by available sensory information during encoding. The present study set out to examine whether the presence of a pure trigeminal stimulus during odor encoding may modulate odor perception at both behavioral and cortical levels.
Participants were tested in a 2-session within-subject design: first, an odor encoding session included a delay conditioning procedure in which relatively selective olfactory stimulants (phenyl ethyl alcohol or vanillin, Conditioned Stimulus+, CS+) were presented either with a pulse of CO(2) (Unconditioned Stimulus, US), or alone (Conditioned Stimulus-, CS-); then, in the second session, both pure odorants (CS+ and CS-) were presented alone. During this second session, olfactory event-related potentials were simultaneously recorded and analyzed at different electrode sites including Cz and Pz (sites known to have maximal amplitudes for trigeminal and olfactory stimuli, respectively). After each trial, subjects were asked to rate odor intensity and hedonics.
The results showed that CS+ intensity ratings increased in 8 subjects and decreased in 6. Cortically, a group effect was observed for P2 amplitude, which increased in the "CS+ intensity increase" group vs. the "CS+ intensity decrease" group at Cz (p<0.05) but not at Pz (p>0.05).
This result suggests that the presence of a pure trigeminal stimulus (CO(2)) during odor encoding alters the neural representation of a pure odor.
The neural representation of odors comprises not only the odor itself but also contextual information (trigeminal in the present case) presented during encoding.
It is widely accepted that unconscious processes can modulate judgments and behavior, but do such influences affect one's daily interactions with other people? Given that olfactory information has relatively direct access to cortical and subcortical emotional circuits, we tested whether the affective content of subliminal odors alters social preferences. Participants rated the likeability of neutral faces after smelling pleasant, neutral, or unpleasant odors delivered below detection thresholds. Odor affect significantly shifted likeability ratings only for those participants lacking conscious awareness of the smells, as verified by chance-level trial-by-trial performance on an odor-detection task. Across participants, the magnitude of this priming effect decreased as sensitivity for odor detection increased. In contrast, heart rate responses tracked odor valence independently of odor awareness. These results indicate that social preferences are subject to influences from odors that escape awareness, whereas the availability of conscious odor information may disrupt such effects.
Synopsis
In the present study, we familiarized menopausal women with a pleasant smell in the skin care products, they used for 1 week and assessed whether their mood and emotions improved using behavioural and physiological tools. Eventually, we studied the effects of inhaling the familiar fragrance on physiological response of the subjects. An anhedonia questionnaire was used to distinguish the effects of the test products according to low vs. high score of anhedonia. Familiarization with the fragrance induced a modification of some physiological parameters, reflecting a relaxing effect, and these unconscious effects paralleled the conscious positive effects on mood recorded during the familiarization phase; it appeared that the effects were more prominent in subjects with higher scores of anhedonia.
These results suggest that the pleasant smell of a skin care product contributes to the quality of life in a population of menopausal women with low easiness to experience pleasure.
We critically review the cognitive literature on olfactory memory and identify the similarities and differences between odor memory and visual-verbal memory. We then analyze this literature using criteria from a multiple memory systems approach to determine whether olfactory memory can be considered to be a separate memory system. We conclude that olfactory memory has a variety of important distinguishing characteristics, but that more data are needed to confer this distinction. We suggest methods for the study of olfactory memory that should make a resolution on the separate memory system hypothesis possible while simultaneously advancing a synthetic understanding of olfaction and cognition.
Abstract Research examining the relation between explicit and implicit forms of memory has generated a great deal of evidence concerning the issue of multiple memory systems. This article focuses on an extensively studied implicit memory phenomenon, known as direct or repetition priming, and examines the hypothesis that priming effects on various tasks reflect the operation of a perceptual representation system (PRS)-a class of cortically based subsystems that operate at a presemantic level and support non conscious expressions of memory. Three PRS subsystems are examined: visual word form, structural description, and auditory word form. Pertinent cognitive, neuropsychological, and neurobiological evidence is reviewed, alternative classificatory schemes are discussed, and important conceptual and terminological issues are considered.
The human organs of perception are constantly bombarded with chemicals from the environment. Our bodies have in turn developed complex processing systems, which manifest themselves in our emotions, memory, and language. Yet the available data on the high order cognitive implications of taste and smell are scattered among journals in many fields, with no single source synthesizing the large body of knowledge, much of which has appeared in the last decade. This book presents the first multidisciplinary synthesis of the literature in olfactory and gustatory cognition. Leading experts have written chapters on many facets of taste and smell, including odor memory, cortical representations, psychophysics and functional imaging studies, genetic variation in taste, and the hedonistic dimensions of odors. The approach is integrative, combining perspectives from neuroscience, psychology, anthropology, philosophy, and linguistics, and is appropriate for students and researchers in all of these areas who seek an authoritative reference on olfaction, taste, and cognition.
Previous research has demonstrated performance dissociations between explicit and implicit memory for newly acquired associations between unrelated words. The present article accounts for this finding in terms of two factors: unitization and grouping. Unitization involves representing previously separate items as a single unit, and grouping involves forming associations among separate representations. We propose that grouping facilitates primarily explicit remembering by providing the routes for accessing encoded word pairs via the cues available during testing; in contrast, unitization affects primarily implicit remembering by enabling the reintegration of studied items in response to partial cues. Consistent with this view, the results from two experiments show that by focusing processing on the relation between target word pairs, explicit remembering can be manipulated independently of implicit remembering. Two further experiments reveal that a material manipulation (concreteness of words) affects both implicit and explicit remembering. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Explored the relation between elaborative processing and implicit memory for new associations (i.e., the phenomenon that priming effects on word-completion tests are influenced by newly acquired associations between normatively unrelated words) in 4 experiments, using a total of 240 undergraduates. Results indicate that implicit memory for new associations, like explicit memory, depended on encoding of meaningful relations between paired words in the study list. However, variations in degree and type of associative elaboration had a large effect on explicit memory, as revealed by performance on letter-cued recall and paired-associate tests, but had little effect on implicit memory, as revealed by performance on a word-completion test. Discussion focuses on the theoretical implications of the observed similarities and differences between implicit and explicit memory for new associations. (49 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Examined the effects of interference manipulation on explicit and implicit memory for pairs of normatively unrelated words in 2 experiments, involving 128 undergraduates. Findings show that interference affected explicit memory, as indexed by performance on cued recall, pair matching, and modified free-recall tests, but it did not affect implicit memory, as indexed by performance on a word-completion test. This pattern of results complements several previous findings, including those of the present authors (see PA, Vol 73:12203 and 29150), on performance dissociations between explicit and implicit memory for new associations. (44 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Memory for a recent event can be expressed explicitly, as conscious recollection, or implicitly, as a facilitation of test performance without conscious recollection. A growing number of recent studies have been concerned with implicit memory and its relation to explicit memory. This article presents an historical survey of observations concerning implicit memory, reviews the findings of contemporary experimental research, and delineates the strengths and weaknesses of alternative theoretical accounts of implicit memory. It is argued that dissociations between implicit and explicit memory have been documented across numerous tasks and subject populations, represent an important challenge for research and theory, and should be viewed in the context of other dissociations between implicit and explicit expressions of knowledge that have been documented in recent cognitive and neuropsychological research. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
In two experimental field studies, the hypothesis was tested that Pavlovian conditioning may modify adults’ liking or disliking
of an odor. In Experiment 1, an odor (CS) was first paired unobtrusively with toilet stimuli (US). Next, Ss rated the experimental
and a control odor on Semantic Differential items. For Ss evaluating going-to-the-toilet negatively, an acquired dislike for
the toilet-paired odor relative to a nonexposed control odor was observed, whereas in Ss evaluating going-to-the-toilet positively,
the reverse was observed. In Experiment 2, a neutral odor (CS) was mixed into the massage oil with which a physiotherapist
treated his patients. Half of the Ss were treated with Positive-relaxing massage, half of the Ss with Negative-painful massage.
At the medical follow-up, Semantic Differential ratings were obtained both for the treatment-odor and for a control odor.
In the Positive massage group, the treatment odor was rated as more positive and as less dynamic than the control odor. No
similar effects were observed in the Negative massage group, a failure which was probably due to the intended Negative massage
not really being experienced as a disliked event. In both experiments, an almost identical pattern of results was observed
in the subgroup of Ss who didnot consciously recognize the experimental odor as the treatment odor, eliminating the possibility that the results should be
due to demand. As mere exposure cannot account for the results, they most probably represent genuine instances of evaluative
odor conditioning. The results are discussed in terms of the understanding of the origins of the affective meaning of odorants,
and are related to human evaluative conditioning and implicit memory issues.
Certain odors are routinely described as smelling sweet, This phenomenon may result from the co-occurrence of such odors and tastes outside the laboratory. Experiment 1 tested this possibility by pairing a selected odor with sucrose and another with citric acid in a masked design, using 24-h spaced sessions, preceded and followed by ratings of the odors' taste attributes when sniffed and when rated with tastes in solution. Following conditioning, the odor paired with sucrose smelled sweeter and with citric acid, sourer. In Experiment 2, contingency awareness was examined using a recognition measure, in an otherwise similar design. Again, odors smelled sweeter and sourer postconditioning. Contingency aware and unaware subjects did not differ in performance. Experiment 3 examined an exposure account of these changes, using a similar paradigm to Experiment 1, but with no exposures to sucrose or citric acid. No changes in odor taste attributes were observed. Overall, these findings demonstrate that associative learning, irrespective of awareness, has an important role in tile acquisition of odor-taste qualities.
Studied the effect of the duration of the retention interval between presentation of an odorant and a later test with the same or different odorant on the proportion of hits and false alarms. 26 high school and college students were assigned to 3 conditions varying in the number of odorants inspected and the duration of the retention interval (3-30 sec). Results show that the number of alternative odorants did not influence S's response criterion, but only his recognition accuracy. Ability to recognize odors is only slightly affected by the length of the interval between smelling and recognition. Characteristics that may distinguish perception of odors from perception in other modalities (rehearsal, verbal coding, and adaptation) are discussed.
In previous research we demonstrated that newly acquired associations between unrelated word pairs influence the magnitude of priming effects on word-completion tests. This phenomenon of implicit memory for new associations is observed only following semantic study elaboration. The present experiments reveal that implicit memory for new associations, though elaboration dependent, is also modality specific: Associative effects on a visual word-completion test were consistently reduced by study-test modality shifts. In contrast, explicit memory for new associations, as indexed by cued-recall performance, was uninfluenced by modality shifts. The modality effect on completion performance was eliminated when subjects were given brief visual preexposures to, or were required to construct visual images of, word pairs presented in auditory study conditions. The results pose a theoretical puzzle insofar as they indicate that within the domain of implicit memory, access to the products of elaborative processing depends on modality-specific, sensory-perceptual processing.
Perceptual learning in olfactory quality discrimination was investigated in two experiments. In Experiment 1, it was asked
whether training participants to label target odorants would improve subsequent discrimination performance. Four groups participated.
Prior to discrimination testing, one group was asked to provide a name for each of seven target odors and received training
to ensure that reliable naming occurred (label training). A second group profiled the quality of the target odorants, using
an odor-adjective attribute list (profile group). A third group was trained to label seven control odorants, and a fourth
received no prior experience. Discrimination performance by each group ranked as follows: [label training on targets] > [profile
experience on targets] > [label training on controls = no prediscrimination experience]. Experiment 2 was designed to relate
the odor knowledge a participant brought into the experiment to performance on a discrimination task wherein an odorant (the
target) was paired either with itself or with a mixture consisting of target odorant plus a familiar or an unfamiliar contaminant
(target transform). Six different targets were selected for each participant, to represent three familiar and three unfamiliar
odors. Familiar targets and familiar contaminants facilitated discrimination. Taken together, these two experiments demonstrate
that olfactory quality discrimination can be improved through training, or via experience naturally accumulated over time.
Conducted 3 experiments with 179 undergraduates and faculty members. In Exp I, Ss indicated which of 21 pairs of odors had been in the original group of 48 odors at presentation-test intervals of up to 1 mo. Exp II (n = 68) Ss were presented with 20 odors and asked to write labels for each; recognition was tested after 3 mo. In Exp III (n = 74), Ss assigned labels to each of 20 odors and were tested for recognition 3 mo later. Immediate recognition tests produced numerous errors, but there was little further retention loss for periods up to 3 mo. Neither verbal labeling nor odor familiarity aided memory, while long-term retention held up even when there were no instructions to memorize. Use of similar odors as test distractors impaired recognition significantly, but it remained well above chance after 3 mo. It is suggested that odors are coded as unitary perceptual events with little attribute redundancy; this leads to poor immediate retention but great subsequent resistance to distortion of immediately retained odors.
The distinctiveness of an ambient odor was examined in relation to its success as a cue in context-dependent memory. Distinctiveness was examined in terms of both cue novelty and contextual appropriateness. Two experiments were conducted in which three different ambient odors that varied in familiarity and contextual appropriateness were manipulated at an incidental word learning encoding session and at a free recall retrieval session 48 h later. Experiment 1 revealed that when a novel ambient odor (osmanthus) was the available context cue, word recall was better than in any other condition. Further, among familiar odor cues, recall was better with a contextually inappropriate odor (peppermint) than with a contextually appropriate odor (clean fresh pine). Experiment 2 confirmed that superior word recall with osmanthus and peppermint depended on the odor cue's being available at both encoding and retrieval, and that the relation of an odor to the situational context is a key factor for predicting its effectiveness as a retrieval cue.
Emotional potentiation may be a key variable in the formation of odor-associated memory. Two experiments were conducted in which a distinctive ambient odor was present or absent during encoding and retrieval sessions and subjects were in an anxious or neutral mood during encoding. Subjects' mood at retrieval was not manipulated. The laboratory mood induction used in Experiment 1 suggested that anxiety might increase the effectiveness of an odor retrieval cue. This trend was confirmed in Experiment 2 by capturing a naturally stressful situation. Subjects who had an ambient odor cue available and were in a preexam state during encoding recalled more words than subjects in any other group. These data are evidence that heightened emotion experienced during encoding with an ambient odor can enhance the effectiveness of an odor as a cue to memory.
It has been proposed that memory for odors does not have a short-term (or working) memory system. The distinction between short- and long-term memory in other sensory modalities has been generally supported by three main lines of evidence: capacity differences between the proposed systems, evidence of differential coding, and differential memory losses in neuropsychological patients. The present paper examines these issues in an effort to establish a similar distinction for the memory of olfactory stimuli. Each of these lines of evidence is examined in relation to the literature on olfactory memory. Based on this examination, it seems that there is at least preliminary support from each of these lines of evidence to advocate a distinction between a long- and short-term memory for olfactory stimuli. Emphasis is placed upon the qualitative similarity of olfactory memory to other memory systems. This similarity is further highlighted through an examination of the literature pertinent to serial position effects in memory for olfactory stimuli.
This study investigated the relationship between perception of an odour when smelled and the taste of a solution to which the odour is added as a flavorant. In Experiment 1 (E1) sweetness, sourness, liking and intensity ratings were obtained for 20 odours. Taste ratings were then obtained for sucrose solutions to which the odours had been added as flavorants. Certain odours were found to enhance tasted sweetness while others suppressed it. The degree to which an odour smelled sweet was the best predictor of the taste ratings. These findings were extended in Experiment 2 (E2), which included a second tastant, citric acid, and employed four odours from E1. The most sweet smelling odour, caramel, was found to suppress the sourness of citric acid and, as in E1, to enhance the sweetness of sucrose. Again, odours with low sweetness suppressed the sweetness of tasted sucrose. The study demonstrated that the effects of odours on taste perception are not limited to sweetness enhancement and apply to sour as well as sweet tastes. The overall pattern of results is consistent with an explanation of the taste properties of odours in terms of prior flavour-taste associations.
Folk wisdom dictates that odours are especially powerful reminders of autobiographical experience, an effect which has become known as the Proust phenomenon. This paper reviews the relevant literature to determine whether there is any substantive evidence to support this view. Different methodologies have been adopted in addressing this issue, but the most revealing and ecologically valid have been the few studies which have examined naturally formed autobiographical memories. From these data, there is at least preliminary evidence that olfactory stimuli can cue autobiographical memories more effectively than cues from other sensory modalities. Explanations for these effects can be invoked from accepted principles in contemporary cognitive psychology.
* INRA URD BP 86510 21065 Dijon cedex (FRA) Diffusion du document : INRA URD BP 86510 21065 Dijon cedex (FRA) Diplôme : Dr. d'Université
Recognition tests demonstrated unique features of odor memory. The forgetting curve over a span of one month showed a very slow decay from an initial performance of 85% correct recognition, a finding that contrasts with the rapid decay for stimuli presented to other sense modalities. The variables of labelling, codability, serial position, and retention interval had little or no effect on performance. Even the variables of familiarity and pleasantness, salient aspects of odor experience, had no effect on recognition. Hence, the connection between linguistic processing and odor recognition is weak.
Surveys recent research on the problem of naming odors and on the arrangement of odors in memory. It considers not how many odors can be named, but how accurately an untrained person can do it and the nature of the words he/she uses for the task. The associative power of odor, contrasts between odors and colors, the effect of names of odors, and the function of smell are discussed. Research indicates that the association between odors and their verbal descriptions is generally weak. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
This study determined the extent to which re-exposure to the unique combination of odours present in a museum (the Jorvik Viking Centre in York) aids the recall of a previous visit to the museum, which had typically taken place several years earlier. To test this, three groups of participants completed questionnaires about the contents of the museum, but in different conditions. One group completed the questionnaire in the presence of exactly the same distinctive odours as those present in the museum at the time of their original visit. Those in two other groups were given either a different (control) set of odours or no odours at all. After a brief delay, the same questionnaire was presented again to participants in all three groups. Those who had initially been given a novel (control) set of odours were now tested in the presence of the genuine Jorvik museum odours, while the group that had received the Jorvik odours were now tested with the control odours. The third group received no odours on either test. Only the novel odour-Jorvik odours condition led to a highly significant improvement in performance. This interaction showed that the museum odours could act as effective retrieval cues for this incidentally acquired, real-world episode.
In this study, human Ss (N = 48) were first exposed to a differential evaluative flavor-flavor conditioning schedule, consisting of either 6 or 12 colored CS+ flavor/US compounds and 6 or 12 colored CS− flavor presentations. Two fruit flavors were used as CS+ and CS−, and Tween 20 (Polysorbate 20) was used as a disliked flavor US. The CS− flavor was either presented in plain water or in a moderately positive sugar compound solution. At the moment of testing, visual-analog CS+ and CS− flavor evaluations were obtained in compounds containing the acquisition color, a new color, or no color. The test series was split up in two equivalent logical blocks, allowing to assess the extinction sensitivity of the conditioned flavor valence. A clear acquired evaluative CS+/CS− flavor differentiation was observed when the CS− flavor had been presented in compound with sugar, but only a nonsignificant tendency was obtained when the CS− flavor was presented in plane water. The latter finding was most probably related to the CS−/ water solution not representing a neutral but a mildly negative stimulus. The number of acquisition trials did not influence the size of the conditioning effect, and the test color context did not systematically weaken or strengthen the expression of the acquired evaluative flavor differentiation. Finally, the conditioning effect did not weaken as testing proceeded: An equally strong CS+/CS− differentiation was observed in the second as in the first block of test trials.
Pavlovian flavor-flavor associative learning has been suggested as one of the determinants of humans' food likes and dislikes (e.g., Rozin & Zellner, 1985). However, few experimental studies exist which directly examined this proposal. In the present study, the hypothesis was tested that the contingent presentation of a neutral flavor (CS) with an already (dis)liked flavor (US) should result in an increase (or decrease) in liking for the originally neutral flavor. Second, the question was addressed whether or not a perceptual characteristic of food other than its flavor (c.q. its color) may also acquire evaluative value when paired with an appetitive or an aversive flavor US. Finally, the relationship was studied between evaluative conditioning and subjects' explicit knowledge of the stimulus relationships presented during the conditioning phase. In a differential conditioning paradigm, subjects drank 12 compound fluids and 12 CS− fluids. Sugar was used as a positive US, and Tween20 as a negative US, while either the flavor or the color of the drink was scheduled as the CS. As indexed by postconditioning visual analog scale ratings, a strong differential evaluative conditioning effect was observed in the flavor-flavor, negative condition. The evidence for positive flavor-flavor conditioning was weak at best, and no evidence was obtained for color-flavor conditioning. On the other hand, none of the subjects in flavor-flavor groups evidenced any explicit knowledge of the CS-US relation, whereas about half of the color-flavor subjects did so. These results are related to the theoretical issues of positive/negative asymmetry, selective associations, and implicit/explicit knowledge dissociations.
Behavioral studies of memory and learning in both humans and animals support a role for sleep in the consolidation and integration of memories. Physiological studies of hippocampal and cortical activity as well as of brainstem neuromodulatory systems demonstrate the state-dependence of communication both between and within the neocortex and hippocampus. These findings are consonant with observed cognition during sleep and immediately following awakening.
Tasting an odor in citric acid can result in that odor becoming less liked and sourer smelling. Both these changes appear to be resistant to extinction. As acquired hedonic responses to faces are also resistant to extinction, but amenable to counter-conditioning, the current experiment tested whether conditioned changes in odors could also be counter-conditioned. Presenting an odor in citric acid and then in sucrose did not change the perceptual and hedonic consequences of the initial pairing in citric acid. However, pairing a color with citric acid and then with sucrose produced a color–sweetness association. These findings are suggestive of a difference in counter-conditioning sensitivity between odors and other types of stimuli, which may result from encoding odor–taste mixtures in a relatively unanalyzed configural form.
Nearly all stimuli encountered in the natural environment are multidimensional, possessing a variety of attributes that can be assessed by a human observer. In a typical psychophysical scaling experiment, observers are asked to rate one or more of these attributes which are of special interest to the experimenter. It is typically assumed that the number of attributes that are rated, and which attributes are attended to has little effect on the outcome of the experiment. However, a recent series of experiments with chemosensory stimuli calls this assumption into question. These studies suggest that similar stimulus attributes are combined when response alternatives are restricted, and are separated when appropriate response alternatives are available. A model of psychophysical judgment is proposed to account for the effects of changing response alternatives on estimates of attribute intensity.
In two experiments the smelled sweetness of odors was increased by using them as flavorants of sucrose solution. Experiment 1 used blind experimenters to compare a target odor mixed with sucrose with a control odor mixed with water during masked training trials. The increased sweetness of the target odor was unaffected by whether or not subjects revealed some explicit knowledge of the contingencies in a post-conditioning recognition test. Experiment 2 found that such a conditioned increase in odor sweetness occurred whether training solutions were sipped from a cup or sucked through a straw. Using a frequency test designed to provide a sensitive assay of contingency awareness, there was still no indication that this affected conditioning. It was concluded that such modification of the taste-properties of odors results from implicit simultaneous associative learning and provides an example of learned synesthesia, (C) 1998 Academic Press.
While flavours comprised of simple taste/odour combinations can be easily decomposed, there is evidence that the individual components are seldom perceived independently. Manifestations of interactions include smell/taste confusions, attribution of taste properties such as sweetness or sourness to odours, and the enhancement and suppression of tastes by such odours. These phenomena are probably the result of blurring of the perceptual boundaries of odour and taste properties during repeated pairings as flavours. Following such pairings in the laboratory, odours can be shown to increase in perceived taste properties. It is proposed that during flavour formation, the components are encoded in memory in such a way that a later odour stimulus also elicits taste properties. Sensory properties such as sweetness can thus be seen as cognitive phenomena associated with both tastes and odours, in the latter case residing in memory. However, unlike some odour combinations, flavours, although usually perceived as a functional whole, are not indivisible synthetic entities. Perceptual interactions between odours and tastes are dependent on the extent to which an analytical approach is taken to the measurement of flavour qualities. Thus, odour enhancement of sucrose sweetness is not observed when the intensities of all the components in a flavour are rated. This has been interpreted as a consequence of rating strategies. However, the data are more consistent with a perceptual/cognitive interpretation. Recent research from our lab has shown that the cognitive strategy employed during the pairing of odours and tastes will also determine whether taste/odour interactions occur. The question of how to measure flavour properties is raised by these findings. Whether panellists focus on the sensory source of, for example, sweetness will depend upon the perceptual strategy they adopt. Asking panellists to focus only on the taste sweetness, while possible, may be assuming that odour and taste properties are independent within foods. (C) 1999 Elsevier Science Ltd. All rights reserved.
Panellists tasted sucrose solutions mixed with the enhancer maltol at concentrations of 50, 100 and 200 p.p.m. Nose-clips were worn to prevent the identification of the maltol by its smell. At these levels maltol is reported to enhance sweetness. In the present study these concentractions of maltol did not significantly enhance the intensity or persistence of the sweetness of sucrose. In another experiment, panellists tasted solutions of 5% sucrose mixed with 312 p.p.m. maltol. Tastings were performed with and without the panellists wearing nose-clips. The smell of the maltol did not confuse trained panellists into believing that the mixture of sucrose and maltol tasted sweeter than sucrose alone. However, in another experiment when both smell and taste were assessed, untrained panellists found that a sucrose-maltol solution possessed an overall greater sweetness than an equivalent concentration of sucrose. That is, if panellists concentrate only on taste then maltol does not appear to enhance sweetness whereas if od our and smell are assessed then maltol was found to elevate total sweetness intensity.
Triangle tests were performed to determine whether lemonade drinks containing 15 p.p.m. maltol were perceptually different from the original lemonade drink containing no maltol. No significant difference was found between the two lemonades and it was concluded that the addition of a sub-threshold concentration of maltol did not significantly affect the taste of lemonade drinks.
In a paired-associate paradigm using odors as stimuli and pictures for multiple-choice responses, the first of two associations to an odor was retained far better than the second over a 2-week period. The persistence of first-learned associations may be responsible for the long lasting nature of odor memories. Subjects reported constructing mediational schemes for mnemonic devices to link the odors and pictures. Latencies for a task of naming odors indicated that although naming odors is difficult, labels could be generated sufficiently fast that they could be employed as mediators in the paired-associate task. A third task investigated the phenomenon of knowing that an odor was familiar but being unable to name it. Subjects in this tip-of-the-nose state were questioned about the odor quality and the name of the odor and were given hints about the name. These subjects were found to have information available about the odor quality but none for the name as found in the tip-of-the-tongue state. However, as in the tip-of-the-tongue phenomenon, hints given to the subjects in the tip-of-the-nose state often led to the correct name.
In four experiments, young (18-26 years, M = 21) and elderly (over 65 years, M = 72) people were compared for recognition memory of (a) graphic stimuli (faces of presidents and vice presidents, engineering symbols, and free forms) and (b) everyday odors. On graphic stimuli, the elderly consistently matched the young, but on odors the performance of the elderly was worse. Their poorer olfactory performance was observed after only 26 s, but became truly marked after 1 hr or more. Somewhere between 1 hr and 2 weeks, their odor performance fell to chance, but their graphic performance remained well above chance. Although the young did forget both graphic and odor materials progressively, their performance always stayed above chance over a 6-month period. Experiments 1 and 2 revealed that the elderly are less sensitive to odors than the young (with thresholds about 10-fold higher), which may explain, in part, their poorer olfactory memory performance. Knowledge that the subjects brought to the tasks by way of familiarity with and ability to name odors and faces played a positive role in recognition memory. Because of this positive role, together with the negative role played by verbal distraction, we conclude that odor recognition memory depends, perhaps heavily, on semantic processing. Impaired semantic processing may result even when odors are simply rendered desaturated, or pastel because of the weakening of olfactory sensitivity with aging.
Two experiments examined whether repetition priming effects on a word completion task are influenced by new associations between unrelated word pairs that were established during a single study trial. On the word completion task, subjects were presented with the initial three letters of the response words from the study list pairs and they completed these fragments with the first words that came to mind. The fragments were shown either with the paired words from the study list (same context) or with other words (different context). Both experiments showed a larger priming effect in the same-context condition than in the different-context condition, but only with a study task that required elaborative processing of the word pairs. This effect was observed with college students and amnesic patients, suggesting that word completion performance is mediated by implicit memory for new associations that is independent of explicit recollection.
This study investigated short-term memory for odors using a four-alternative, forced-choiced recognition paradigm. Stimuli
were the odors of 36 common food substances. Twelve subjects were tested in each of four conditions, which differed in the
activity performed during the retention interval. Recognition performance was poorest when subjects free associated to an
additional odorant presented during the retention interval. Thus, interference from interpolated events does occur in odor
memory. Recognition performance was best when the subjects free associated to the name of the target odorant during the retention
interval. Thus, the memory code for odors may incorporate semantic information. Remembering odors appears, therefore, to be
governed by the same principles as remembering stimuli in other modalities.
In the first session, two groups of male and female subjects were given a stressful task involving the completion of eleven WAIS block patterns under time limitations. A low intensity of a neutral odour (TUA) was present for half of the subjects. During a second session several days later, subjects completed a mood rating scale and then entered a room, where the odour of TUA was present, to judge a series of photographs of people and complete a second mood rating scale. During the first session female subjects completed significantly fewer block patterns, and completed fewer correct designs. In the second session, female subjects who had experienced TUA odour in the stress condition showed an increase in anxiety ratings. They also had higher ratings scores when judging the photographs. In contrast, subjects who did not experience odour during the stress session became calmer during the second session. None of the female subjects reported perceiving the odour irn either session. As both pairing and elicitation occurred at low levels of awareness, the study demonstrates how odours might acquire values through pairing with emotionally significant events.
Time-related measurements pose some challenges to psychophysics and to applied sensory testing methods including control of psychological biases which have been found in single-point scaling. This research examined enhancement of ratings when response alternatives were limited in time-intensity scaling tasks using repeated category ratings. Panelists rated a pseudo-beverage containing sweetener and flavor and one with sweetener only over a 90-s period. The aromatic flavor caused an increase in sweetness intensity and especially so when the panelists were limited to sweetness responses only. The odor-induced enhancement of sweetness was smaller when panelists were given both flavor and sweetness response options than when the panelists were given only a sweetness scale. Prior use of both scales in a previous experimental session did not lessen the halo-dumping enhancement effect. In one study, sweetness ratings of sucrose alone were depressed when the additional scale for flavoring was provided, perhaps due to inappropriate partitioning of responses.
Observers are often asked to make intensity judgments for a sensory attribute of a stimulus that is embedded in a background of "irrelevant" stimulus dimensions. Under some circumstances, these background dimensions of the stimulus can influence intensity judgments for the target attribute. For example, judgments of sweetness can be influenced by the other taste or odor qualities of a solution (Frank & Byram, 1988; Kamen et al., 1961). Experiments 1 and 2 assessed the influence of stimulus context, instructional set, and reference stimuli on cross-quality interactions in mixtures of chemosensory stimuli. Experiment 1 demonstrated that odor-induced changes in sweetness judgments were dramatically influenced when subjects rated multiple attributes of the stimulus as compared with when they judged sweetness alone. Several odorants enhanced sweetness when sweetness alone was judged, while sweetness was suppressed for these same stimuli when total-intensity ratings were broken down into ratings for the sweetness, saltiness, sourness, bitterness, and fruitiness of each solution. Experiment 2 demonstrated a similar pattern of results when bitterness was the target taste. In addition, Experiment 2 showed that the instructional effects applied to both taste-odor and taste-taste mixtures. It was concluded that the taste enhancement and suppression observed for taste-odor and taste-taste mixtures are influenced by (1) instructional sets which influence subjects' concepts of attribute categories, and (2) the perceptual similarities among the quality dimensions of the stimulus.
In 4 experiments the authors used 2-stage designs to study susceptibility to interference in human discrimination learning. The experiments used a food allergy task. In Experiment 1, participants were presented with a discrimination in Stage 1 in which Food A predicted an allergy outcome (A-->O). In Stage 2, when combined with Food B, Food A predicted the absence of the allergy (B-->O, AB-->no O). In the test phase, Food A was found to have retained its Stage 1 association with the allergy despite the potentially interfering Stage 2 trials. In Experiment 2, a discrimination between 2 compounds (AB-->O, CD-->no O) remained intact despite subsequent complete reevaluation of the elements, (A-->no O, B-->no O, C-->O, D-->O); in Experiments 3 and 4, a discrimination between 2 pairs of elements (A-->O, B-->O, C-->no O, D-->no O) remained intact despite subsequent complete reevaluation of the AB and CD compounds, (AB-->no O, CD-->O). These experiments yielded evidence of remarkable resistance to interference in human discrimination learning. The results are at variance with the predictions of J. M. Pearce's (1987, 1994a) configural theory of associative learning.
In an experiment 143 subjects were instructed to assign odors to contexts which were displayed in a slide session. The slides depicted contexts from three areas of everyday life which partly contained visual cues related to a presented odor. After rating the fit of each odor to a context, the subjects rated the odors for pleasantness. Analysis showed a strong influence of the visual cue on the rating of fit for the contexts containing an odor-related visual element. In contexts without a visual cue, rating of fit showed an influence of implicitly learned memories of odor. The rating was not affected by the pleasantness of the odors. The 1995 work of Schab and Crowder is critically reviewed, and results are discussed within the framework of new, more ecologically oriented research on memory for odor.
In order to assess the influence of odors on human performance and implicit memory for odors, 108 subjects completed a variety of tests in weakly scented (jasmine, lavender or odorless) rooms without having been made aware of the odor. After a 30 min interval the subjects were shown slides of different surroundings, including the room they had been in, and were requested to rate how well a set of 12 odors, including a blank, would fit to these surroundings. Half of these contexts contained visual cues related to two of the presented odors (leather and coffee). After the rating of fit the subjects had to rate the odors for pleasantness, were asked to identify the odors with their correct names and to tell where and when they had last smelled these odors. One subject remembered smelling the odor (jasmine) in the room and was discarded from the analysis of the results for the rating of fit. None of the others reported recollection of the experimental odors. The results showed that in general jasmine had a negative and lavender a positive effect on test performance. If an odor-related visual cue was present in the context, the related odor was always rated highest in fit to that context. Furthermore, the subjects working in rooms with an odor subsequently assigned this odor to the visual context of that room to a significantly higher degree than subjects working in rooms with different odors. Since none of the subjects reported that they had smelled the odor in the rooms where performance testing took place, it was concluded that the memory for these odors was implicit. Further analysis showed that such memory was only found in subjects who were unable to supply the right name for the odor. The possible consequences of this latter finding for understanding the relationship between sensory (episodic) and semantic odor memory are discussed.
A study with 133 adults, who had been breast-fed or bottle-fed after birth, shows that neonatal experience with vanilla influences preferences for other foods in later life.
The inability to detect odours, anosmia, can cause profound psychological effects resulting in feelings of physical and social vulnerability and victimization. In addition, there may be unhappiness related to the loss of the ability to detect pleasurable food smells and, as a consequence, anosmics may develop problems relating to eating. These profound effects arise from a condition which can have a rapid onset and a very poor prognosis for recovery, and are largely treated with a lack of sympathy and indifference by people with normal olfactory ability. In an attempt to educate, inform and help sufferers, a questionnaire was developed in the early 1980s and sent to those who contacted the Warwick Olfaction Research Group. The responses from this questionnaire form the basis of this review. Feelings of personal isolation, lack of interest in eating and emotional blunting were common responses from these sufferers and it seems that we still have some way to go before an adequate recognition of problems associated with anosmia is gained by the general population and, more importantly, within the medical profession.