New behavioral protocols to extend our knowledge of rodent object recognition memory

Animals often show an innate preference for novelty. This preference facilitates spontaneous exploration tasks of novelty discrimination (recognition memory). In response to limitations with standard spontaneous object recognition procedures for rodents, a new task (“bow-tie maze”) was devised. This task combines features of delayed nonmatching-to-sample with spontaneous exploration. The present study explored aspects of object recognition in the bow-tie maze not amenable to standard procedures. Two rat strains (Lister Hooded, Dark Agouti) displayed very reliable object recognition in both the light and dark, with the Lister Hooded strain showing superior performance (Experiment 1). These findings reveal the potential contribution of tactile and odor cues in object recognition. As the bow-tie maze task permits multiple trials within a session, it was possible to derive forgetting curves both within-session and between-sessions (Experiment 1). In Experiment 2, rats with hippocampal or fornix lesions performed at normal levels on the basic version of the recognition task, contrasting with the marked deficits previously seen after perirhinal cortex lesions. Next, the training protocol was adapted (Experiment 3), and this modified version was used successfully with mice (Experiment 4). The overall findings demonstrate the efficacy of this new behavioral task and advance our understanding of object recognition.Understanding the neural basis of recognition memory, the ability to discriminate whether a stimulus is novel or familiar, is heavily reliant on animal research. Here, advances have been closely tied to the introduction of new behavioral tests. The preeminent example concerns one-trial tests of recognition memory for monkeys using delayed nonmatching-to-sample (Mishkin and Delacour 1975). These tasks reward the natural preference that monkeys have for selecting novel items and permit multiple recognition trials within a single session. These features make the task relatively easy to train and then maximize findings from small group sizes. Although rat tasks closely based on delayed nonmatching-to-sample have been devised (Aggleton 1985; Mumby et al. 1990; Steckler et al. 1998; Prusky et al. 2004), they are very rarely employed as they are difficult to train and performance levels are unreliable.Almost all studies of rodent recognition memory now employ the spontaneous object recognition test and its direct variants (Ennaceur and Delacour 1988; Dix and Aggleton 1999; Winters et al. 2008). These tasks again take advantage of an innate preference for novel items, but this preference is displayed by spending more time exploring novel than familiar stimuli. In the standard version of the task, a rodent (rat or mouse) is placed in an arena containing two identical objects and then freely allowed to explore these objects for several minutes (“sample” phase). After a delay, the rodent is placed back in the arena (“test” phase), which now contains one familiar object (a copy of the sample phase objects) and a novel object. Recognition is signified by greater exploration of the novel object. Because the task measures spontaneous behavior, it requires minimal pretraining, but for the same reason it is prone to considerable variance. Unlike delayed nonmatching-to-sample, each trial (sample plus test phase) takes many minutes, and so only one recognition trial is normally given per session. Advantages are that proactive interference between objects is minimized, and the one-trial design lends itself to episodic-like tests of memory (Dere et al. 2005; Good et al. 2007). Disadvantages include the fact that data accumulation, with appropriate counterbalancing, is slow.To address these limitations, a new object recognition test using a “bow-tie maze” (Fig. 1A) has been developed for rats (Albasser et al. 2010). This test combines features of delayed nonmatching-to-sample with spontaneous object preference: It permits multiple trials per session, but the measure of recognition comes from the preferential exploration of novelty. The rat is first placed in one end of a bow-tie–shaped maze that contains a single object (object A; Fig. 1B). After a minute, the rat is allowed to run to the other end of the maze where there are two dissimilar objects (A and B; Fig. 1B). Object A is familiar as it is identical to the object previously explored, while object B is novel. Consequently, a rat will typically prefer to explore object B. On the next trial, a minute later, the rat shuttles back to the initial start point, but this time encounters objects B and C. Object B is now familiar, while object C is novel. The next trial, 1 min later, is between object C (now familiar) and object D (novel), and so on. A food reward placed under every object promotes shuttling back and forth within the maze, and encourages interaction with the objects. Unlike delayed nonmatching-to-sample, the food reward is not contingent on first selecting the novel object.Open in a separate windowFigure 1.(A) Schematic of the bow-tie maze. A sliding door separates the two ends of the maze in which two objects are placed. (B) General procedure showing the presentation order of the objects in the standard object recognition task. All objects are rewarded (+). (Arrow) Rat movements. (Black print) Novel objects, (gray print) familiar objects.The present study used the bow-tie maze to explore recognition memory on four fronts. In Experiment 1, recognition in the light and recognition in the dark were compared to help determine the cues available to detect object familiarity. It is known that rats can perform recognition tasks when solely reliant on visual cues (Aggleton 1985; Bartko et al. 2007; Winters and Reid 2010), but object recognition based on other modalities remains largely unexplored (Winters and Reid 2010). Potential cues for recognition include odor differences and tactile information. It is known that rats can discriminate novel from familiar olfactory cues (Otto and Eichenbaum 1992; Kesner et al. 2002; Fortin et al. 2004; Wolff et al. 2006), while tactile (e.g., vibrissae) cues can be used to distinguish surfaces (e.g., Birrell and Brown 2000). The bow-tie maze is ideal for studying object recognition in the dark as the rats are rewarded for visiting items in set locations (to receive food rewards), and so should readily approach the objects. In contrast, running the standard spontaneous object recognition test (in an arena) in the dark would be problematic as it is not clear how the rats would first appreciate the presence of the to-be-discriminated objects.An additional goal of Experiment 1 was to determine how readily the bow-tie maze could be used to compile within-session and between-session forgetting curves. A limitation with the standard spontaneous object task is that with only one trial per session it can be very time consuming to create forgetting curves, while within-session forgetting curves for individual animals are not feasible. These shortcomings create limitations when examining manipulations thought to affect memory. The possibility of deriving within-session forgetting curves is particularly appealing as: (1) it minimized the impact of those factors that introduce variance when performance is compared across sessions, and (2) the animal need not be removed from the maze, which could additionally disrupt performance, e.g., by increasing stress. A further component of Experiment 1 manipulated object memory strength by presenting objects either once (“single”) or six times (“repeated”). Recognition was tested after a 3-h delay with the twin goals of determining whether repeated presentation would aid performance and whether these performance levels would be sufficiently above chance so that they could be used to examine factors involved in longer term memory.At the same time, Experiment 1 provided the opportunity to compare two rat strains, Dark Agouti (DA) and Lister Hooded (LH). Previous studies suggest that the Dark Agouti strain might be particularly good at visual recognition tasks (Aggleton 1996), though others have argued that this strain has aberrant behavioral properties, including higher anxiety and higher levels of inappropriate nonspatial behaviors in spatial learning tasks (Mechan et al. 2002; Harker and Whishaw 2004; but see Aggleton and Vann 2004).Experiment 2 examined the ability of rats with either hippocampal or fornix lesions to perform object recognition in the bow-tie maze. There is a longstanding debate over the impact of hippocampal damage on recognition memory, with mixed findings coming from spontaneous object recognition tests (Clark et al. 2000; Mumby 2001; Gaskin et al. 2003; Winters et al. 2008). The bow-tie maze should prove informative as numerous trials can be run to assess the impact of selective brain lesions. Although in this initial study only short retention delays were examined, these same delays and conditions are highly sensitive to perirhinal cortex lesions (Aggleton et al. 2010; Horne et al. 2010), a brain region regarded as vital for recognition memory (Brown and Aggleton 2001). In Experiment 3 the training protocol changed so that objects did not cover food rewards. Rather, a single food reward was always placed between the test objects. This modification was examined because: (1) it would preclude any exploration scores that were simply derived from attempts to move the test objects in order to uncover the food reward, and (2) it would introduce a task variant that might be amenable to small rodents not able to move objects. Accordingly, Experiment 4 examined the performance of mice (strain C57Bl/6) on a test of object recognition based on the modified version of the bow-tie maze from Experiment 3.     

Entrepreneurial personality: The role of narcissism

Research has established a number of personality features and behaviours associated with business creation and success. The similarities between these traits and narcissism, a concept with roots in clinical psychology and psychiatry, led the authors to conduct this study, which proposes to measure whether entrepreneurs score higher on a narcissism scale than other vocational groups. The second goal of this study is to measure the role of narcissism on intention to start a business. Student entrepreneurs have been compared with non-entrepreneur students, city workers, and employees and managers from a branch of a large financial institution. Then, students filled out measures of general self-efficacy, locus of control and risk propensity as well as a narcissism scale. Results indicate that student entrepreneurs score significantly higher than all other vocational groups on a measure of narcissism. Results also indicate that narcissism is positively correlated with general self-efficacy, locus of control and risk propensity. Moreover, narcissism plays a significant role in explaining entrepreneurial intentions, even after controlling for self-efficacy, locus of control and risk propensity. Overall, these findings shed new light on the underlying personality traits of entrepreneurs and entrepreneurial intentions and suggest new directions in the study of entrepreneurs’ personality profile.     

Specificity and Abstraction of Examples: Opposite Effects on Fixation for Creative Ideation

Fixation is one of the major obstacles that individuals face in creative idea generation contexts. Several studies have shown that individuals unintentionally tend to fixate to the examples they are shown in a creative ideation task, even when instructed to avoid them. Most of these studies used examples formulated with high level of specificity. However, no study has examined individuals’ creative performance under an instruction to diverge from given examples, when these examples are formulated with a high level of abstraction. In the present study, we show that (a) instructing participants to avoid using common examples when formulated with a high level of specificity increases fixation; whereas (b) instructing participants to avoid such examples while using a more abstract level for stating these common examples—such as a categorization of these examples—mitigates fixation and doubles the number of creative ideas generated. These findings give new insights on the key role of categorization in creative ideation contexts.     

Heterogeneous inhibition processes involved in different facets of self-reported impulsivity: evidence from a community sample

Whiteside and Lynam (Whiteside, S. P., & Lynam, D. R. (2001). The Five Factor Model and impulsivity: Using a structural model of personality to understand impulsivity. Personality and Individual Differences, 30, 669-689) clarified the multifaceted nature of impulsivity by identifying four distinct facets of self-reported impulsive behaviors: urgency, (lack of) premeditation, (lack of) perseverance, and sensation seeking. Building on work by Bechara and Van der Linden (Bechara, A., & Van der Linden, M. (2005). Decision-making and impulse control after frontal lobe injuries. Current Opinion in Neurology, 18, 734-739), the main objective of this study was to investigate the hypothesis that perseverance and urgency map onto the two distinct inhibitory functions distinguished by Friedman and Miyake (Friedman, N. P., & Miyake, A. (2004). The relations among inhibition and interference control functions: A latent-variable analysis. Journal of Experimental Psychology: General, 133, 101-135): prepotent response inhibition and resistance to proactive interference. Participants (N = 126) completed the UPPS Impulsive Behavior Scale and three tasks: a recent-negatives task to assess proactive interference in working memory, and two Go/No-Go tasks at different paces, the slower of which also assessed task-unrelated thoughts (TUTs). Consistent with the hypothesis, TUTs were positively correlated with lack of perseverance, and multiple regressions revealed that urgency was specifically related to errors in prepotent response inhibition, and lack of perseverance to errors due to difficulties overcoming proactive interference.     

Goal orientation dispositions and performance trajectories: The roles of supplementary and complementary situational inducements

Integrating goal orientation theory with interactionist approaches, this experimental study (N = 104) tested the unique and interactive effects of individual differences in goal orientations and situational goal orientation inducements on performance trajectories during skill acquisition. Results indicated that learning goal orientation predicted performance trajectories more positively when coupled with one situational inducement that captures a complementary feature (a performance, as opposed to a learning, goal frame), and when jointed with a situational inducement that captures a supplementary feature (self-referenced vs. normative-based performance feedback). There was also a complementary-like interaction between the two situational inducements, such that a learning goal frame led to more positive performance trajectories when coupled with normative, as opposed to self-referent, feedback. Implications for the motivation and skill acquisition literatures are discussed.     

Patterns of semantic memory impairment in Mild Cognitive Impairment

Although the semantic memory impairment has been largely documented in Alzheimer's disease, little is known about semantic memory in the preclinical phase of the disease (Mild Cognitive Impairment). The purpose of this study was to document the nature of semantic breakdown using a battery of tests assessing different aspects of conceptual knowledge: knowledge about common objects, famous people and famous public events. Results indicate that all domains of semantic memory were impaired in MCI individuals but knowledge about famous people and famous events was affected to a greater extent than knowledge about objects. This pattern of results suggests that conceptual entities with distinctive and unique properties may be more prone to semantic breakdown in MCI. In summary, results of this study support the view that genuine semantic deficits are present in MCI. It could be useful to investigate the etiological outcome of patients failing or succeeding at such tests.     

Antecedents and Outcomes of Informal Learning Behaviors: a Meta-Analysis

Purpose

Over the past two decades, research has shown a growing consensus that 70% to 90% of organizational learning occurs not through formal training but informally, on-the-job, and in an ongoing manner. Despite this emerging consensus, primary data on the nature and correlates of informal learning remains sparse. The purpose of this study was to provide an integrative definition of informal learning behaviors (ILBs) and to synthesize existing primary data through meta-analysis to explore ILB correlates.

Design/Methodology/Approach

Given that there has been little systematic treatment of ILBs, we defined their construct domain and tested relationships suggested by our research questions with antecedents (personal factors, situational factors) and outcomes (attitudes, knowledge/skill acquisition, performance) using random effects meta-analyses (k = 49, N = 55,514).

Findings

Our results showed both personal and situational antecedent factors to be predictive of ILBs, as well as ILB–outcome relationships.

Implications

Findings indicate that engagement in ILBs for working adults is linked to valued criteria such as attitudes (ρ = .29), knowledge/skill acquisition (ρ = .41), and performance (ρ = .42). We provide suggestions for future research and actionable advice for organizations to support the development of ILBs.

Originality/Value

Although hundreds of studies and over a dozen meta-analyses have explored the nature and effectiveness of formal learning in the workplace, our work is the first attempt to conceptualize a unified definition of ILBs and to aggregate primary data on ILB correlates using meta-analysis.

     

The impact of national integration policies on prejudice and psychological well-being: The fundamental role of the clarity and coherence of integration policies

Recent advances in social psychological research have shown that national integration policies influence how immigrants are perceived and treated by the mainstream population. However, the processes by which these policies come to have an impact on prejudice and well-being of the general population are largely unknown. Moreover, past research has often relied on unrepresentative samples limiting generalizability. The present research proposes that when the national integration policies of a given society are perceived as clearly defined and coherent, they have a direct impact on the perceived cultural norm related to those national integration policies. In turn, the perceived cultural norm affects personal attitudes toward cultural norms (i.e., the degree to which individuals support a given policy), which influence the level of anti-immigrant prejudice as well as psychological well-being. Findings from two correlational studies with representative samples of the mainstream population conducted in France on the policy of secularism (N = 940) and in Québec on the policy of interculturalism (N = 912) supported the proposed theoretical model.