Effects of novelty and familiarity on illness-induced aversions to food and place cues in coyotes (Canis latrans)

Two experiments investigated the effects of novelty and familiarity on illness-induced aversions to taste and place cues in coyotes (Canis latrans). Coyotes were made ill on familiar food laced with lithium chloride in a novel place and then received preference tests. In Experiment 1, coyotes avoided the previously poisoned familiar food in the novel treatment place but readily ate the same familiar food in a familiar safe place. In Experiment 2, the results of Experiment 1 were replicated, and it was found that coyotes would eat a different familiar food in the novel treatment place. On the basis of the results of this and other studies, a model for averting animals from places where they are not wanted is presented.     

The CS-Preexposure Effect in Conditioned Taste-Aversion Learning in Golden Hamsters

In Experiment 1, golden hamsters were injected with either 0.9% saline or the nausea-inducing agent, lithium chloride (LiCL), immediately after consuming a flavored diet that was either novel or familiar. The LiCl-induced aversion was strong in hamsters for which the flavored diet was novel, but no significant aversion was observed in hamsters that were familiar with the flavored diet. In Experiment 2, the strength of the LiCl-induced aversion was related inversely to the amount of conditioned-stimulus (CS) preexposure and directly to the duration of the preexposure-conditioning interval. Thus, although some previous researchers have suggested that hamsters may not demonstrate the CS-preexposure effect in a conditioned taste-aversion paradigm, they clearly did so under the conditions of the present experiments, and moreover, the characteristics of the CS-preexposure effect in hamsters were generally similar to those observed in rats.     

The CS-preexposure effect in conditioned taste-aversion learning in golden hamsters

In Experiment 1, golden hamsters were injected with either 0.9% saline or the nausea-inducing agent, lithium chloride (LiCL), immediately after consuming a flavored diet that was either novel or familiar. The LiCl-induced aversion was strong in hamsters for which the flavored diet was novel, but no significant aversion was observed in hamsters that were familiar with the flavored diet. In Experiment 2, the strength of the LiCl-induced aversion was related inversely to the amount of conditioned-stimulus (CS) preexposure and directly to the duration of the preexposure-conditioning interval. Thus, although some previous researchers have suggested that hamsters may not demonstrate the CS-preexposure effect in a conditioned taste-aversion paradigm, they clearly did so under the conditions of the present experiments, and moreover, the characteristics of the CS-preexposure effect in hamsters were generally similar to those observed in rats.     

Social transmission of flavor preferences in two species of hamsters (Mesocricetus auratus and Phodopus campbelli)

Golden hamsters (Mesocricetus auratus) and dwarf hamsters (Phodopus campbelli) interacted with a conspecific demonstrator that had recently consumed a flavored food. When given a choice between their demonstrator's flavor and another flavor, the dwarf hamsters preferred the flavor their demonstrator had eaten. Golden hamsters did not prefer their demonstrators' diets when the demonstrators were unrelated adults or littermates, but they did when the demonstrator was their mother. Videotaping the interactions between demonstrators and observers revealed that adult golden hamsters did not investigate foods hoarded by their demonstrators whereas dwarf hamsters did. These results are interpreted in terms of the stimuli that activate feeding behavior systems in these 2 hamster species.     

Flavour neophobia in gerbils (Meriones unguiculatus) and hamsters (Mesocricetus auratus)

Flavour neophobia in gerbils and hamsters was studied by comparing the ingestive/pouching behaviour of these animals when presented with either a familiar unflavoured peanut or a novel one that imparted basic flavours such as sweet, salty, sour, or bitter. Neophobia was expressed by an aversion towards the novel nut manifested by greater latency either to ingest it (gerbils) or to deposit it in the cheek pouch (hamsters) relative to that of the unflavoured one. This method, involving reactions to the taste of novel solid food, provides a more sensitive measure than the traditional one measuring intake of a novel flavoured fluid. The results indicated that gerbils and hamsters encountering either a sweet, salty, or sour nut for the first time showed a neophobic reaction. However, there was no apparent sign of neophobia when the animals were tested with a nut flavoured with quinine. The theoretical implications of these findings are discussed.     

Characteristics of taste-mediated environmental potentiation in rats

When rats drink a novel flavor in a distinctive environment and are injected with lithium, potentiated aversions are established to the environment as evidenced by the animals' unwillingness to consume a familiar, nonaversive flavor in this environment. Experiment 1 demonstrates that this potentiation is due to the presence of both the distinctive taste and the environmental cues on the conditioning trials, not simply aversive conditioning to each element or to generalization between the two elements. This potentiation phenomenon was shown to be sensitive to the novelty of the potentiating flavor in Experiment 2. Experiment 3 demonstrated that second-order conditioning is difficult to establish using these procedures, although Experiment 4 revealed that postconditioning extinction of the aversive flavor interfered substantially with environmental potentiation. These outcomes are discussed in terms of their implications for adaptive adjustments in feeding behavior as well as for more general conceptions of associative learning.     

Distinctiveness Benefits Novelty (and Not Familiarity), but Only Up to a Limit: The Prior Knowledge Perspective

Novelty is a pivotal player in cognition, and its contribution to superior memory performance is a widely accepted convention. On the other hand, mnemonic advantages for familiar information are also well documented. Here, we examine the role of experimental distinctiveness as a potential explanation for these apparently conflicting findings. Across two experiments, we demonstrate that conceptual novelty, an unfamiliar combination of familiar constituents, is sensitive to its experimental proportions: Improved memory for novelty was observed when novel stimuli were relatively rare. Memory levels for familiar items, in contrast, were completely unaffected by experimental proportions, highlighting their insensitivity to list‐based distinctiveness. Finally, no mnemonic advantage for conceptual novelty over familiarity was observed even when novel stimuli were extremely rare at study. Together, these results imply that novel and familiar items are processed via partially distinct mechanisms, with (at least some facets of) novelty not providing a mnemonic advantage over familiarity.     

The role of response-contingent incentives in lithium chloride-mediated suppression of an operant response

Three experiments investigated what role a novel incentive plays in the development of operant response suppression mediated by lithium chloride. In all experiments animals were trained to press two levers under concurrent schedules of reinforcement. In Experiment 1 responding on one lever delivered a familiar incentive (food pellets), whereas responding on an alternative lever delivered a novel incentive (sucrose solution) prior to lithium chloride injections. If lithium was administered immediately after the instrumental session, the action associated with the novel, but not with the familiar, incentive was suppressed. By comparison, in a control group for which responding on both levers led to the familiar incentive, both actions were suppressed. Experiment 2 examined whether the novelty, rather than the sensory properties, of the incentive is crucial for observing performance suppression. It was found that animals familiarized with the “target” incentive were insensitive to aversion conditioning by lithium, in that there was no difference in response rates between the action that delivered the familiar incentive from that which earned the “target”. In contrast, if animals were unfamiliar with the “target” incentive at the time of aversion conditioning, they suppressed responding on the lever that was associated with the novel incentive but did not suppress responding on the lever associated with the familiar incentive. Experiment 3 investigated the mechanism underlying instrumental performance suppression. After the completion of concurrent lever press training, novel sucrose was introduced in conjunction with the pellets for responding on one lever; responding on the other lever continued to deliver only familiar pellets. Lithium injections were then administered either immediately following the sessions or several hours after the sessions. It was found that the rate of responding on the lever associated with the contingent delivery of sucrose was suppressed below that of the pellet-alone action. By comparison, if lithium injections were administered several hours following the session, an elevation in responding on the sucrose-plus-pellet lever was observed. The outcomes of all three experiments demonstrate not only that the novelty of an incentive is important in obtaining performance suppression, but also that a novel incentive can punish instrumental responding if it has been associated with toxicosis.     

Stimulus generalization as a function of stimulus novelty and familiarity in rats

Three experiments used rats as subjects to investigate the generalization of conditioned responding between stimuli as a function of the subjects' exposure to these cues prior to conditioning. Experiment 1 used a between-subjects design, food as the reinforcer, and measured the tendency of subjects to approach the site of food delivery during the stimuli. Generalization of this response was more marked when the training and test stimuli were equated in terms of their novelty (i.e., when both were novel or both were familiar) than when the stimuli differed in this respect (i.e., when one was novel and the other was familiar). Experiments 2a and 2b used within-subjects designs to confirm the reliability of the results of Experiment 1. Implications of these results for current theories of stimulus representation are discussed.     

Novelty responding and behavioral development in young,developmentally delayed children

This study examined whether or not a measure of information processing ability based on the discrimination of novel and familiar stimuli was related to behavioral development among developmentally-delayed infants. Two samples of handicapped infants were administered multiple measures of visual novelty discrimination and a battery of assessments which were representative of available measures of development in infancy. The results indicated that, as a group, the developmentally delayed infants were capable of discriminating novel and familiar stimuli. Also, correlational analyses indicated that responding to novelty was related to developmental accessment performance in both samples. This finding is consistent with previous data which indicates that novelty response measures are associated with important individual differences in young children.     

Discrimination of color and pattern novelty in one-month human infants

Visual discrimination of novel colors and patterns by one-month infants was studied in two experiments where visual reinforcers were presented contingent upon infants' rate of nonnutritive, high-amplitude sucking. Discrimination was measured by recovery of sucking to the presentation of novel visual reinforcing stimuli following decrements in sucking to familiar visual stimuli. In Expt 1, following decrement to familiar stimuli, independent groups received either a change in color, pattern, both color and pattern, or no stimulus change. Reliable recovery was demonstrated for the three stimulus novelty groups relative to the no-change control. Experiment 2, employing achromatic visual reinforcers also showed reliable recovery to pattern change relative to no-change controls. These findings with one-month infants indicate discrimination between familiar and novel visual reinforcers on the basis of color and pattern differences and an increase due to novelty in the reinforcing effectiveness of visual stimuli. Individual subject differences in response decrement magnitude during familiarization were positively correlated with amount of response recovery to novelty.     

Dimensions of response to novelty are associated with social engagement and aggression in adult male rhesus macaques (Macaca mulatta)

In this study, the authors tested the hypothesis that behavioral response across social and nonsocial, novel and familiar conditions may be guided by the same trait(s) related to impulsivity in adult male rhesus macaques. The authors assessed 23 individuals' behavioral response to a series of nonsocial novel scenarios, as well as aggression and sociality within familiar and novel social contexts. Factor analysis of responses to nonsocial novelty identified two factors: Caution, which reflected latency to engage different novel situations, and Interest in Novelty, which consisted of duration and quality of exploration. Each dimension was associated with different social manifestations. Caution was negatively correlated with social aggression in novel and familiar social circumstances; Interest in Novelty was positively associated with social engagement in familiar, but not novel, social circumstances. The authors conclude that traits influencing impulsive response to novelty contribute to risky and normal social behavior across social contexts.     

A strict response criterion yields a mirror effect in the novelty paradigm

According to the novelty/encoding hypothesis (NEH; Tulving & Kroll, 1995), efficacy of encoding information into long-term memory depends on the movelty of the information. Recognition accuracy is higher for novel than for previously familiarized material. This novelty effect is not a mirror effect: the superiority of novel over familiar items is not found in the hit rates but only in the false-alarm rates. The main result in the present replication study was that novel hit rates were higher than familiar ones when the most confident responses were examined separately, and thus a mirror effect could be demonstrated for these data, for both the low- and the high-frequency words. Similarly, the word-frequency effect on hits was stronger when a stricter response criterion was applied. It was concluded that the novelty effect and the word-frequency effect are more similar to one another than has hitherto been thought.     

Something old,something new: a developmental transition from familiarity to novelty preferences with hidden objects

Novelty seeking is viewed as adaptive, and novelty preferences in infancy predict cognitive performance into adulthood. Yet 7‐month‐olds prefer familiar stimuli to novel ones when searching for hidden objects, in contrast to their strong novelty preferences with visible objects ( Shinskey & Munakata, 2005 ). According to a graded representations perspective on object knowledge, infants gradually develop stronger object representations through experience, such that representations of familiar objects can be better maintained, supporting greater search than with novel objects. Object representations should strengthen with further development to allow older infants to shift from familiarity to novelty preferences with hidden objects. The current study tested this prediction by presenting 24 11‐month‐olds with novel and familiar objects that were sometimes visible and sometimes hidden. Unlike 7‐month‐olds, 11‐month‐olds showed novelty preferences with both visible and hidden objects. This developmental shift from familiarity to novelty preference with hidden objects parallels one that infants show months earlier with perceptible stimuli, but the two transitions may reflect different underlying mechanisms. The current findings suggest both change and continuity in the adaptive development of object representations and associated cognitive processes.     

The influence of novelty and complexity on exploratory behavior in 12-month-old infants

This study investigated the influence of the novelty of the environment and the novelty and complexity of the objects (toys) it contained on the exploratory behavior of 12-month-old infants. Each infant was given a choice between novel and familiar toys located in two adjacent rooms (toy rooms). The novelty of the objects was manipulated by allowing the infants to play with one set of toys during a 5-min familiarization trial prior to the choice trial. The novetly of the environment was manipulated by allowing some infants to see, enter, and remain in the toy rooms during the familiarization trial. Finally, the complexity of the objects was manipulated by varying the number of familiar and novel toys; some Ss had four toys in each set (complex array) and some had only one (simple array). The results indicate that all three factors influenced the infants' exploratory behavior. Ss first approached, and spent more time manipulating, the novel than the familiar toys; they spent more time in the toy rooms if they were novel; and they spent more time manipulating the complex array of toys than the simple array.     

Stigma,staring, and discomfort: A novel-stimulus hypothesis

Three experiments were conducted in order to assess the validity of the novel-stimulus hypothesis as an explanation for why people who are physically different (i.e., novel) are avoided. The hypothesis states that avoidance is mediated by conflict over a desire to stare at novel stimuli and a desire to adhere to a norm against staring when the novel stimulus is another person. In the first two field experiments, subjects viewed photographs of novel (handicapped or pregnant) and familiar (physically normal) people under conditions where staring was sanctioned or not. It was found that staring increased with novelty when staring was unobserved (sanctioned); however, the reverse obtained when an observer was present. In the third experiment, subjects interacted with a crippled, pregnant, or physically normal partner. Half of the subjects were first given the opportunity to observe their partner through a one-way mirror. The reduction in stimulus novelty for this group resulted in reduced avoidance. The question of whether such avoidance of the disabled results from feelings of dislike or disgust as previously suggested, or from discomfort created by novelty, is discussed.     

Linear Position Preference Habits of Monkeys

While novelty is well established as a motivational factor in children's preferences, the methodology with which the effect is demonstrated seems poorly equipped to deal with the issue of the strength of novelty, since choices alternatives have frequently been limited to items of comparable base attractiveness. Data, drawn from 216 first graders, are reported for a procedure in which stimulus unattractiveness was pitted against novelty to test the capacity of this variable to sway Ss' choices in the presence of resistance. Consistent with previous findings, it is shown that roughly 80% of preschoolers chose a novel item rather than a familiar one when the alternatives were comparably desirable except for the element of novelty. However, when a difference in base attractiveness favored the familiar item, novelty choice dropped sharply. Problems of specification of the strength of novelty and interpretation of observed levels of novelty preference are discussed in terms of the methodology of choice research with children. The motivational strength of novelty for children is questioned.     

Novelty assessment in the brain and long-term memory encoding

Recent positron emission tomography (PET) studies have identified neuronal components of widespread novelty-assessment networks in the brain. We propose that the efficacy of encoding on-line information into long-term memory depends on the novelty of the information as determined by these networks, and report a test of this “novelty/encoding” hypothesis. Subjects studied a list of words. Half of the words were “familiar” by virtue of their repeated presentation to the subjects before the study of the critical list; the other half were novel, in that they had not previously been encountered in the experiment. The results conformed to the prediction of the novelty/encoding hypothesis: accuracy of explicit (episodic) recognition was higher for novel than for familiar words.     

The novelty effect: support for the Novelty-Encoding Hypothesis

In two experiments, we examined the "Novelty-Encoding Hypothesis" proposed by Tulving and Kroll (1995), suggesting that the encoding of online information into long-term memory is influenced by its novelty and that novelty increases recognition performance. In Phase 1 (familiarization phase), subjects participated in a standard memory experiment in which different types of materials (verbs and nouns) were studied under different encoding conditions (enactment and non-enactment) and were tested by an expected recognition test. In Phase 2 (critical phase), subjects evaluated the materials (both familiar materials which were encoded earlier in Phase 1, and novel materials which were not presented earlier in Phase 1) in a frequency judgment task and were given an unexpected recognition test. The results of both experiments showed that novel items were recognized better than familiar items. This result held true for both hit rates - false alarms and hit rates. The novelty effect was observed for different subjects (Swedish and Japanese), different materials (verbs and nouns; high frequency and low frequency), and different types of encoding in Phase 1 (enactment and non-enactment). These findings provide support for the "Novelty-Encoding Hypothesis" stating that the effect is based on the encoding of target items at the time of the critical study (Phase 2). A comparison between the present experiments and the Tulving and Kroll (1995), Dobbins, Kroll, Yonelinas & Liu (1998) and Greene (1999) studies suggests that the novelty effect is more pronounced under incidental encoding than under intentional encoding.     

Enhancing visual working memory encoding: The role of target novelty

Perceptual salience improves the encoding of information into visual working memory (WM). However, the factors that contribute to this facilitation effect are not well understood. This study tested the influence of target familiarity on WM encoding. In each trial, participants were presented with either one or three targets and asked to encode their locations into WM. In Experiment 1, target familiarity was manipulated by presenting either an upright (familiar target) or upside-down (unfamiliar/novel target) A. Increasing the novelty of the targets led to improved performance in the spatial WM task. Experiment 2 showed that participants were faster in responding to novel versus familiar targets in a spatial detection task. Experiment 3 demonstrated that the beneficial effect of target novelty on WM encoding was not driven by differences in low-level features. Our results suggest that target novelty enhances the processes required for WM encoding, just as it facilitates perceptual processing.