Body patterning and cognition in cephalopods - a literature review

Cephalopods are a valuable model for studying the evolution of cognition due to their distinctive brain structure, organisation, and connectivity patterns compared to vertebrates. The development of large brains and behavioural complexities are believed to be triggered by evolutionary pressures stemming from factors like heightened predation, more demanding foraging conditions, and intense mating competition. While the differences between corvid and mammals are less pronounced, the cephalopod brain is closer to the vertebrate brain in terms of encephalisation of ganglionic masses observed by nerve cell clusters. The cerebral ganglion in cephalopods is similar to the vertebrate forebrain and midbrain, while the vertical lobe is similar to the vertebrate cerebral cortex and hippocampus formation, which are involved in learning and memory. These brain regions function in a hierarchical system and are intimately connected with their eyes and optic lobes where visual inputs are processed, motor commands are transmitted to the lower motor centre. Chromatophores are skin elements and the physiological control of body patterning and are visually driven and light sensitive. This sets cephalopods apart from their molluscan families such as gastropods and bivalves. Recent studies have revealed that the opsins present in the skin are like those occurring in the retina. This infers that the connection between visual processing and body patterns is not exclusively innate. Expanding on Macphail's Null Hypothesis which posits no significant qualitative or quantitative differences in intelligence across vertebrates, this study seeks to explore the link between body patterning and cognitive abilities across cephalopod species. By comparing patterns of similarities and differences in cognitive abilities, this study aims to investigate whether body patterning can serve as an indicator of cognitive capacity. In conclusion, the study finds the presence of interindividual variations within species and disparities across different species in both body patterning and cognitive abilities. There are associations between cognitive capacity and body patterns. However, establishing a direct and conclusive connection between high-level cognitive abilities and the expression of body patterns remains elusive, as concrete evidence supporting such a relationship is lacking.Cephalopoda utgör en värdefull modell för att studera den kognitiva evolutionen på grund av deras distinkta hjärnstruktur, organisation och nervernas kontaktmönster jämfört med ryggradsdjur. Utvecklingen av stora hjärnor och komplexa beteenden tros vara resultatet av evolutionär press från faktorer som ökad predation, mer krävande födosökningsförhållanden och intensiv parningskonkurrens. Medan skillnaderna mellan kråkfåglar och däggdjur är mindre uttalade, är bläckfiskhjärnan närmare ryggradsdjurshjärnan när det gäller encefalisering av nervcellkluster. Det cerebrala ganglie hos bläckfiskar liknar ryggradsdjurens främre hjärna och mellanhjärna, medan den vertikala loben liknar ryggradsdjurens hjärnbark och hippocampusformation, som är involverade i inlärning och minne. Dessa hjärnregioner fungerar inom ett hierarkiskt system och är intimt kopplade till deras ögon och optiska lober där visuell information bearbetas och motoriska kommandon överförs till de nedre motoriska centrarna. Kromatoforer är hudstrukturer som fysiologiskt kontrollerar kroppsmönster och är visuellt styrda och ljuskänsliga. Detta skiljer cephalopoder från andra molluskfamiljer som gastropoder och musslor. Studier har nyligenavslöjat att de opsin som finns i huden liknar de som förekommer i näthinnan. Detta antyder att sambandet mellan visuell bearbetning och kroppsmönster inte är uteslutande medfödd. Utöver Macphails nollhypotes, som hävdar att det inte finns några signifikanta kvalitativa eller kvantitativa skillnader i intelligens mellan ryggradsdjur, ämnar denna studie utforska kopplingen mellan kroppsmönster och kognitiva förmågor hos cephalopoda. Genom att jämföra likheter och skillnader i kognitiva förmågor syftar denna studie till att undersöka om kroppsmönster kan fungera som en indikator på kognitiv kapacitet. Resultaten visar på förekomst av variationer mellan individer inom arter och skillnader mellan olika arter både vad gäller kroppsmönster och kognitiva förmågor. Det finns samband mellan kognitiv kapacitet och funktioner samt kroppsmönster. Dock är det fortfarande svårt att fastställa en direkt och definitiv koppling mellan hög kognitiva förmågor och uttrycket av kroppsmönster, eftersom konkret bevis som stöder ett sådant samband saknas

Effects of Nonfiction Guided Interactive Read-Alouds and Think-Alouds on Fourth Grader\u27s Depth of Content Area Science Vocabulary Knowledge and Comprehension

Effects of nonfiction guided interactive read-alouds and think-alouds as a supplement to basal science textbooks on three vocabulary measures, definitions, examples, and characteristics, and one multiple-choice comprehension measure were assessed for 127 fourth graders over three time periods: pretest, posttest, and a 2-week delayed posttest. Two of three fourth grade elementary science teachers implemented a series of 12 content enhanced guided interactive scripted lessons. Two of these teachers implemented two treatments each. The first condition employed basal science textbooks as the text for guided interactive read-alouds and think-alouds while the second treatment employed basal science textbooks in conjunction with nonfiction text sets as the texts for guided interactive read-alouds and think-alouds. The third teacher, guided by traditional lesson plans, provided students with silent independent reading instruction using basal science textbooks. Multivariate analyses of variance and analyses of variance tests showed that mean scores for both treatment groups significantly improved on definitions and characteristics measures at posttest and either stabilized or slightly declined at delayed posttest. The treatment-plus group lost considerably on the examples posttest measure. The treatment group improved mean scores on the examples posttest measure, outperforming the treatment-plus group and the control group. Alternately, the control group significantly improved on the delayed posttest examples measure. Additionally, the two groups implementing guided interactive read-alouds and think-alouds performed better than the independent reading group on multiple-choice comprehension measures at posttest and sustained those gains 2 weeks later on delayed posttests. Findings maintain the incremental nature of vocabulary acquisition and development research and emphasize the roles of listening and speaking as critical features for integrating vocabulary into long-term memory

Improvement of individual camouflage through background choice in ground-nesting birds.

Animal camouflage is a longstanding example of adaptation. Much research has tested how camouflage prevents detection and recognition, largely focusing on changes to an animal's own appearance over evolution. However, animals could also substantially alter their camouflage by behaviourally choosing appropriate substrates. Recent studies suggest that individuals from several animal taxa could select backgrounds or positions to improve concealment. Here, we test whether individual wild animals choose backgrounds in complex environments, and whether this improves camouflage against predator vision. We studied nest site selection by nine species of ground-nesting birds (nightjars, plovers and coursers) in Zambia, and used image analysis and vision modeling to quantify egg and plumage camouflage to predator vision. Individual birds chose backgrounds that enhanced their camouflage, being better matched to their chosen backgrounds than to other potential backgrounds with respect to multiple aspects of camouflage. This occurred at all three spatial scales tested (a few cm and five meters from the nest, and compared to other sites chosen by conspecifics), and was the case for the eggs of all bird groups studied, and for adult nightjar plumage. Thus, individual wild animals improve their camouflage through active background choice, with choices highly refined across multiple spatial scales

Animal vision and colour change for camouflage

Camouflage is a well-studied form of antipredator defence. A key issue is how animals ensure camouflage effectiveness when the visual environments many camouflage strategies rely on vary. Phenotypic plasticity allows animals to adjust coloration to best match such environmental variation. It is assumed that vision is used in identifying this variation and guides changes in colour. However, questions still exist regarding the opportunities and limitations afforded from vision-guided changes for camouflage. Carcinus maenas, the green shore crab, already a widely used species to investigate a variety of questions regarding camouflage, was used to test the assumption that vision is directly responsible for guiding (and limiting) colour change for camouflage. In the first chapter, tests of spectral sensitivity and colour discrimination were performed, which were then compared to colour change responses. Following this, crabs’ spatial resolution was tested and compared to pattern change responses on uniform and patterned backgrounds. Finally, crabs’ brightness change responses to varying illumination and substrate brightness conditions were recorded to examine directional light’s role in substrate perception for plasticity. My results indicate that C. maenas colour change for camouflage is determined and limited by their vision. First, spectral and colour discrimination results indicate C. maenas cannot perceive differences in colour. This aligns with colour change results, with crabs only showing significant achromatic change despite apparently possessing the chromatophores needed for chromatic change. Following this, crab’s changed patterning by increasing pattern contrast proportionate to background pattern size, without changing pattern shape or size. This change in patterning is indicative of a shift from uniform background matching to disruptive markings. Finally, C. maenas colour change corresponds to the relative reflectance of substrates, accounting for illumination. This indicates some level of assessment of directional light, likely dependent on the differential stimulation of an eye perceiving light from multiple directions at once. These results indicate that while species’ vision can limit colour change for camouflage, effective improvements in camouflage are still capable within these limits

What is in an octopus\u27s mind?

It is difficult to imagine what an animal as different from us as the octopus ‘thinks’, but we can make some progress. In the Umwelt or perceptual world of an octopus, what the lateralized monocular eyes perceive is not color but the plane of polarization of light. Information is processed by a bilateral brain but manipulation is done by a radially symmetrical set of eight arms. Octopuses do not self-monitor by vision. Their skin pattern system, used for excellent camouflage, is open loop. The output of the motor system of the eight arms is organized at several levels — brain, intrabrachial commissure and local brachial ganglia. Octopuses may be motivated by a combination of fear and exploration. Several actions — a head bob for motion parallax, a ‘Passing Cloud’ skin display to startle prey, and particularly exploration by their arms — demonstrate the presence of a controlling mind, motivated to gather information. Yet most octopuses are solitary and many are cannibalistic, so they must always be on guard, even against conspecifics. The actions of octopuses can be domain general, with flexible problem-solving strategies, enabling them to survive “by their wits” in a challenging and variable environment