Peak shift in honey bee olfactory learning

If animals are trained with two similar stimuli such that one is rewarding (S+) and one punishing (S?), then following training animals show a greatest preference not for the S+, but for a novel stimulus that is slightly more different from the S? than the S+ is. This peak shift phenomenon has been widely reported for vertebrates and has recently been demonstrated for bumblebees and honey bees. To explore the nature of peak shift in invertebrates further, here we examined the properties of peak shift in honey bees trained in a free-flight olfactory learning assay. Hexanal and heptanol were mixed in different ratios to create a continuum of odour stimuli. Bees were trained to artificial flowers such that one odour mixture was rewarded with 2 molar sucrose (S+), and one punished with distasteful quinine (S?). After training, bees were given a non-rewarded preference test with five different mixtures of hexanal and heptanol. Following training bees’ maximal preference was for an odour mixture slightly more distinct from the S? than the trained S+. This effect was not seen if bees were initially trained with two distinct odours, replicating the classic features of peak shift reported for vertebrates. We propose a conceptual model of how peak shift might occur in honey bees. We argue that peak shift does not require any higher level of processing than the known olfactory learning circuitry of the bee brain and suggest that peak shift is a very general feature of discrimination learning.     

A little bit transparent with one another: Constructing vulnerability in the evangelical discourse of women preachers

Using four categories of Brown’s shame resilience theory (SRT), this paper analyses two similar online videos by prominent American evangelical female preachers: Joyce Meyer and Beth Moore. As each unpacks her survivor’s story of childhood sexual abuse, SRT (and its components of vulnerability, critical awareness, reaching out and speaking shame) can provide a matrix for interpreting the narrative in which each preacher frames her self-disclosure.     

Leg Asymmetries and Coordination Dynamics in Walking

Models of interlimb coordination (H. Haken, J. A. S. Kelso, &; H. Bunz, 1985 Haken, H., Kelso, J. A. S. and Bunz, H. 1985. A theoretical model of phase transitions in human hand movements. Biological Cybernetics, 51: 347–356. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; P. N. Kugler &; M. T. Turvey, 1987 Kugler, P. N. and Turvey, M. T. 1987. Information, natural law, and the self-assembly of rhythmic movement, Hillsdale, NJ: Erlbaum.  [Google Scholar]) were tested in walking by examining the role of asymmetries between limbs. Participants walked on a treadmill with and without a metronome. Five asymmetry conditions were created via ankle loads of 0, 3, or 6 kg on either leg. With the metronome, participants matched the target period. Without the metronome, stride rate slowed as the mass was increased on either leg. The loads led to an increase in stride period that was predicted by Huygens’ law and the hybrid pendulum-spring model. In agreement with extended Haken–Kelso–Bunz model predictions, leg asymmetries led to deviations from antiphase coordination. Also, perception–action coordination was influenced by the asymmetry between the legs and metronome. In contrast, no predicted stability effects were observed. These findings reveal that some properties of interlimb coordination, apparent in laboratory-based tasks, can also be observed in human walking.     

Hemispheric Differences in the Processing of Words Learned Early Versus Later in Childhood

The research investigated whether there are hemispheric differences in processing for words acquired early in childhood (early AoA) and words acquired later in childhood (late AoA). We hypothesized that because of recent evidence suggesting that there is a right hemisphere dominance in early childhood, early AoA words would be represented in the right hemisphere, and late AoA words would be represented in the left hemisphere. This hypothesis differs from an early view that late AoA words would be represented in the left hemisphere, and early AoA words would be represented in both hemispheres (Gazzaniga, 1974). We report two experiments using the divided visual field (DVF) technique. The results showed that there was a right visual field (RVF)/left hemisphere (LH) advantage only for late AoA words. For early AoA words, there was a left visual field (LVF)/right hemisphere advantage (RH). Implications for theories of hemispheric differences in word processing are discussed.     

Assessing the role of orthography in speech perception and production: Evidence from picture–word interference tasks

The effects of orthographic and phonological relatedness between distractor word and object name in a picture–word interference task were investigated. In Experiment 1 distractors were presented visually, and consistent with previous findings, priming effects arising from phonological overlap were modulated by the presence or absence of orthographic similarity between distractor and picture name. This pattern is interpreted as providing evidence for cascaded processing in visual word recognition. In Experiment 2 distractors were presented auditorily, and here priming was not affected by orthographic match or mismatch. These findings provide no evidence for orthographic effects in speech perception and production, contrary to a number of previous reports.     

Book reviews

Over the last 30 years or so, various findings have been reported which suggest that the perception of spoken words may involve the automatic coactivation of orthographic properties. Here we assessed this possibility in auditory rhyme judgement tasks and replicated a classic finding reported by Seidenberg and Tanenhaus (1979), showing that orthographic similarity between stimuli facilitated responses on rhyming pairs, but had the opposite effect on nonrhyming pairs. However, Experiments 2 and 3 showed that manipulating the nature of the nonrhymes, or adding a large proportion of filler items, eliminated the effects of orthographic match or mismatch. These findings suggest the involvement of strategic factors in the emergence of orthographic effects in rhyme judgement tasks.     

Boundary Conditions of the High‐Investment Human Resource Systems‐Small‐Firm Labor Productivity Relationship

Although a few published, multiindustry, firm‐level, empirical studies have linked systems of high‐investment or high‐performance human resource management practices to enhanced small‐firm performance, this stream of strategic human resource management research is underdeveloped and equivocal. Accordingly, in this study, we use a sample of for‐profit, private‐sector, small Canadian firms with fewer than 100 employees from a variety of industry sectors to examine boundary conditions of the relationship between firm‐level high‐investment human resource systems and objective small‐firm labor productivity. Congruent with contingency theory, this study's results indicate that the extent and nature of the influence of high‐investment human resource systems on objective small‐firm labor productivity is contingent on internal (differentiation strategy and firm capital intensity) and external boundary conditions (industry dynamism and industry growth). Implications and limitations of this research study as well as avenues for future research are discussed.